Exemplo n.º 1
0
def test_queue_stop():
    myqueue = Queue()
    player1 = mock.MagicMock(spec=Player)

    myqueue.add(player1)
    myqueue.stop()
    player1.stop.assert_called_once()
Exemplo n.º 2
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def test_queue_stop(display):
    myqueue = Queue(display)
    player1 = mock.MagicMock(spec=Player)

    myqueue.add(player1)
    myqueue.stop()
    assert player1.stop.call_count == 1
Exemplo n.º 3
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def test_queue_seek():
    myqueue = Queue(config)
    myqueue.add(player1)
    myqueue.play()
    myqueue.seek(1)
    assert player1.time == int(config["seek_distance"]) * 1000
    myqueue.stop()
Exemplo n.º 4
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def test_queue_pause():
    myqueue = Queue(config)
    myqueue.add(player1)
    myqueue.play()
    myqueue.pause()
    assert player1.state == 2
    myqueue.stop()
Exemplo n.º 5
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def test_queue_stop():
    myqueue = Queue(config)
    myqueue.add(player1)
    myqueue.play()
    while player1._player.get_state() != vlc.State.Playing:
        pass
    myqueue.stop()
    assert player1.state == 0
Exemplo n.º 6
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def test_queue_next():
    myqueue = Queue(config)
    myqueue.add(player1)
    myqueue.add(player2)
    assert myqueue.length == 2
    myqueue.next()
    assert myqueue.length == 1
    assert myqueue.first.state == 1
    myqueue.stop()
Exemplo n.º 7
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def test_queue_seek():
    myqueue = Queue(config)
    myqueue.add(player1)
    myqueue.play()
    while player1._player.get_state() != vlc.State.Playing:
        pass
    myqueue.seek(1)
    assert player1.time == int(config["seek_distance"]) * 1000
    myqueue.stop()
Exemplo n.º 8
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def test_queue_toggle():
    myqueue = Queue(config)
    myqueue.add(player1)
    assert player1.state == 0
    myqueue.toggle()
    assert player1.state == 1
    myqueue.toggle()
    assert player1.state == 2
    myqueue.stop()
Exemplo n.º 9
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def test_queue_toggle():
    myqueue = Queue(config)
    myqueue.add(player1)
    assert player1.state == 0
    myqueue.toggle()
    while player1._player.get_state() != vlc.State.Playing:
        pass
    assert player1.state == 1
    myqueue.toggle()
    assert player1.state == 2
    myqueue.stop()
Exemplo n.º 10
0
class Display:
    """The user-facing display.

    This class is used to handle all user-interaction. It creates and handles
    all aspects of the application's interface, including windows and menus. It
    retrieves input from the user and performs corresponding actions.
    """
    MIN_WIDTH = 20
    MIN_HEIGHT = 8
    INPUT_TIMEOUT = 1  # 1ms
    STATUS_TIMEOUT = 4000  # multiple of INPUT_TIMEOUT
    COLOR_NAMES = {
        'black': curses.COLOR_BLACK,
        'blue': curses.COLOR_BLUE,
        'cyan': curses.COLOR_CYAN,
        'green': curses.COLOR_GREEN,
        'magenta': curses.COLOR_MAGENTA,
        'red': curses.COLOR_RED,
        'white': curses.COLOR_WHITE,
        'yellow': curses.COLOR_YELLOW,
        'transparent': -1
    }
    KEY_MAPPING = {chr(i): i for i in range(256)}
    KEY_MAPPING.update(
        (name[4:], value) for name, value in vars(curses).items()
        if name.startswith('KEY_')
    )
    KEY_MAPPING.update(
        {
            'ENTER': 10,
            'SPACE': 32
        }
    )
    AVAILABLE_PLAYERS = {}

    def __init__(self, stdscr, database) -> None:
        """
        Args:
            stdscr: a stdscr from curses.initscr()
            database: a connected castero.Database
        """
        self._stdscr = stdscr
        self._database = database
        self._parent_x = -1
        self._parent_y = -1
        self._perspectives = {}
        self._active_perspective = 1
        self._header_window = None
        self._footer_window = None
        self._queue = Queue(self)
        self._download_queue = DownloadQueue(self)
        self._status = ""
        self._status_timer = self.STATUS_TIMEOUT
        self._menus_valid = True
        self._modified_episodes = []

        # basic preliminary operations
        self._stdscr.timeout(self.INPUT_TIMEOUT)
        curses.start_color()
        curses.use_default_colors()
        curses.noecho()
        curses.curs_set(0)
        curses.cbreak()
        self._stdscr.keypad(True)

        self.update_parent_dimensions()
        self.create_color_pairs()
        self._load_perspectives()
        self._load_players()
        self._restore_queue()
        self._create_windows()
        self.create_menus()

    def color_number(self, color: str) -> int:
        """Convert color string to valid color number"""
        if color in self.COLOR_NAMES:
            return self.COLOR_NAMES[color]
        if color.isnumeric() and int(color) < curses.COLORS:
            return int(color)
        return -1

    def create_color_pairs(self) -> None:
        """Initializes color pairs used for the display.

        Creates the following color pairs (foreground, background):
            - 1: foreground, background
            - 2: background, foreground
            - 3: background_alt, foreground_alt
            - 4: foreground_alt, background_alt
            - 5: foreground_dim, background
        """

        curses.init_pair(
            1,
            self.color_number(Config["color_foreground"]),
            self.color_number(Config["color_background"]),
        )
        curses.init_pair(
            2,
            self.color_number(Config["color_background"]),
            self.color_number(Config["color_foreground"]),
        )
        curses.init_pair(
            3,
            self.color_number(Config["color_background_alt"]),
            self.color_number(Config["color_foreground_alt"]),
        )
        curses.init_pair(
            4,
            self.color_number(Config["color_foreground_alt"]),
            self.color_number(Config["color_background_alt"]),
        )
        curses.init_pair(
            5,
            self.color_number(Config["color_foreground_dim"]),
            self.color_number(Config["color_background"]),
        )
        curses.init_pair(
            6,
            self.color_number(Config["color_foreground_status"]),
            self.color_number(Config["color_background"]),
        )
        curses.init_pair(
            7,
            self.color_number(Config["color_foreground_heading"]),
            self.color_number(Config["color_background"]),
        )
        curses.init_pair(
            8,
            self.color_number(Config["color_foreground_dividers"]),
            self.color_number(Config["color_background"]),
        )

    def _load_perspectives(self) -> None:
        """Load instances of perspectives from the `perspectives` package.
        """
        # load a list of modules names by manually detecting .py files
        module_files = glob.glob(dirname(__file__) + "/perspectives/*.py")
        module_names = [basename(f)[:-3] for f in module_files if isfile(f)]

        for name in module_names:
            p_mod = importlib.import_module("castero.perspectives.%s" % name)
            p_cls = getattr(
                p_mod,
                dir(p_mod)[[cls.lower() == name
                            for cls in dir(p_mod)].index(True)])
            inst = p_cls(self)
            self._perspectives[inst.ID] = inst

    def _load_players(self) -> None:
        """Load player classes from the `players` package.
        """
        # load a list of modules names by manually detecting .py files
        module_files = glob.glob(dirname(__file__) + "/players/*.py")
        module_names = [basename(f)[:-3] for f in module_files if isfile(f)]

        for name in module_names:
            p_mod = importlib.import_module("castero.players.%s" % name)
            p_cls = getattr(
                p_mod,
                dir(p_mod)[[cls.lower() == name
                            for cls in dir(p_mod)].index(True)])
            self.AVAILABLE_PLAYERS[p_cls.NAME] = p_cls

    def _restore_queue(self) -> None:
        """Recreate players in queue from the database.
        """
        for episode in self.database.queue():
            player = Player.create_instance(
                self.AVAILABLE_PLAYERS, str(episode),
                episode.get_playable(), episode)
            self.queue.add(player)

    def _create_windows(self) -> None:
        """Creates and sets basic parameters for the windows.

        If the windows already exist when this method is run, this method will
        delete them and create new ones.
        """
        # delete old windows if they exist
        if self._header_window is not None:
            del self._header_window
            self._header_window = None
        if self._footer_window is not None:
            del self._footer_window
            self._footer_window = None

        # create windows
        self._header_window = curses.newwin(2, self._parent_x,
                                            0, 0)
        self._footer_window = curses.newwin(2, self._parent_x,
                                            self._parent_y - 2, 0)

        # create windows for all perspectives
        for perspective_id in self._perspectives:
            self._perspectives[perspective_id].create_windows()

    def create_menus(self) -> None:
        """Creates the menus used in each window.

        Windows which have menus should be created prior to running this method
        (using _create_windows).
        """
        for perspective_id in self._perspectives:
            self._perspectives[perspective_id].create_menus()

    def show_help(self) -> None:
        """Show the help screen.

        This method takes over the main loop, displaying the screen until a key
        is pressed. This means that typical loop actions, including checking
        the state of the current player, will not run while this screen is up.
        """
        self.clear()
        self._stdscr.refresh()

        padding_yx = (1, 4)

        help_window = curses.newwin(self._parent_y, self._parent_x, 0, 0)

        # display lines from __help__
        help_lines = \
            castero.__help__.split('\n')[:self._parent_y - padding_yx[0] - 1]
        help_lines.append("Press any key to exit this screen.")
        for i in range(len(help_lines)):
            help_window.addstr(i + padding_yx[0], padding_yx[1],
                               help_lines[i][:self._parent_x - padding_yx[1]],
                               curses.A_BOLD)
        help_window.refresh()

        # simply wait until any key is pressed (temporarily disable timeout)
        self._stdscr.timeout(-1)
        self._stdscr.getch()
        self._stdscr.timeout(self.INPUT_TIMEOUT)

        self.clear()

    def display(self) -> None:
        """Draws all windows and sub-features, including titles and borders.
        """
        # check if the screen size has changed
        self.update_parent_dimensions()

        # check to see if menu contents have been invalidated
        if not self.menus_valid:
            for perspective_id in self._perspectives:
                self._perspectives[perspective_id].update_menus()
            self.menus_valid = True

        # add header
        playing_str = castero.__title__
        if self._queue.first is not None:
            state = self._queue.first.state
            playing_str = ["Stopped", "Playing", "Paused"][state] + \
                ": %s" % self._queue.first.title
            if self._queue.length > 1:
                playing_str += " (+%d in queue)" % (self._queue.length - 1)

            if helpers.is_true(Config["right_align_time"]):
                playing_str += ("[%s]" % self._queue.first.time_str).rjust(
                    self._header_window.getmaxyx()[1] - len(playing_str))
            else:
                playing_str += " [%s]" % self._queue.first.time_str

        self._header_window.addstr(0, 0,
                                   " " * self._header_window.getmaxyx()[1])
        self._header_window.addstr(0, 0, playing_str,
                                   curses.color_pair(6) | curses.A_BOLD)

        # add footer
        footer_str = "%sPress %s for help" % (
            self._status + " -- " if len(self._status) > 0 else "",
            Config["key_help"])
        footer_str = footer_str[:self._footer_window.getmaxyx()[1] - 1]
        max_width = self._footer_window.getmaxyx()[1] - 1
        self._footer_window.addstr(1, 0,
                                   footer_str.ljust(max_width)[:max_width],
                                   curses.color_pair(6) | curses.A_BOLD)

        # add window borders
        self._header_window.hline(1, 0,
                                  0, self._header_window.getmaxyx()[1],
                                  curses.ACS_HLINE | curses.color_pair(8))
        self._footer_window.hline(0, 0,
                                  0, self._footer_window.getmaxyx()[1],
                                  curses.ACS_HLINE | curses.color_pair(8))

        # update display for current perspective
        self._perspectives[self._active_perspective].display()

    def _get_active_perspective(self) -> Perspective:
        """Retrieve the active/visible Perspective.
        """
        return self._perspectives[self._active_perspective]

    def _change_active_perspective(self, perspective_id) -> None:
        """Changes _active_perspective to the given perspective.

        Args:
            perspective_id: the ID of the perspective to change to
        """
        assert perspective_id in self._perspectives

        self._active_perspective = perspective_id
        self._perspectives[perspective_id].made_active()
        self.clear()

    def _get_input_str(self, prompt) -> str:
        """Prompts the user for input and returns the resulting string.

        This method assumes that all input strings will be obtained in the
        footer window.

        Args:
            prompt: a string to inform the user of what they need to enter

        Returns:
            str: the user's input
        """
        assert self._footer_window is not None
        assert isinstance(prompt, str)

        curses.curs_set(1)
        self._stdscr.timeout(-1)  # disable timeouts while waiting for entry

        # display input prompt
        self._footer_window.addstr(
            1, 0, " " * (self._footer_window.getmaxyx()[1] - 1)
        )
        self._footer_window.addstr(1, 0, prompt)

        entry_pad = curses.newpad(1, 999)
        current_x = 0
        scroll_x = 0
        input_char = None
        while input_char not in [curses.KEY_ENTER, 10]:
            if input_char is not None:
                # manually handle backspace
                if input_char in [curses.KEY_BACKSPACE, 127]:
                    if current_x > 0:
                        entry_pad.delch(0, current_x - 1)
                        current_x -= 1
                        if scroll_x > 0:
                            scroll_x -= 1
                else:
                    # scroll the input pad if necessary
                    if current_x + len(prompt) > \
                            self._footer_window.getmaxyx()[1] - 1:
                        scroll_x += 1

                    # add the entered character to the pad
                    entry_pad.addch(0, current_x, input_char)
                    current_x += 1

                # display current portion of pad
                entry_pad.refresh(0, scroll_x,
                                  self._parent_y - 1, len(prompt),
                                  self._parent_y - 1,
                                  self._footer_window.getmaxyx()[1] - 1)

            # get the next input character
            input_char = self._footer_window.getch()

        self._stdscr.timeout(self.INPUT_TIMEOUT)
        self._footer_window.clear()
        curses.curs_set(0)

        return entry_pad.instr(0, 0, entry_pad.getmaxyx()[1]) \
            .decode('utf-8').strip()

    def _get_y_n(self, prompt) -> bool:
        """Prompts the user for a yes or no (y/n) input.

        Args:
            prompt: a string to inform the user of what they need to enter

        Returns:
            bool: true if the user presses y, false otherwise
        """
        assert self._footer_window is not None
        assert isinstance(prompt, str)

        curses.echo()
        curses.curs_set(1)

        self._footer_window.addstr(
            1, 0, " " * (self._footer_window.getmaxyx()[1] - 1)
        )
        self._footer_window.addstr(1, 0, prompt)
        char = self._footer_window.getch()

        self._footer_window.clear()
        curses.curs_set(0)
        curses.noecho()

        return char == ord('y')

    def handle_input(self, c) -> bool:
        """Performs action corresponding to the user's input.

        Args:
            c: the input character

        Returns:
            bool: whether or not the application should continue running
        """
        for perspective_id in self._perspectives:
            if c == self.KEY_MAPPING[str(perspective_id)]:
                self._change_active_perspective(perspective_id)

        return self._get_active_perspective().handle_input(c)

    def add_feed(self) -> None:
        """Prompt the user for a feed and add it, if possible.
        """
        path = self._get_input_str("Enter the URL or path of the feed: ")
        try:
            # assume urls have http in them
            if "http" in path:
                feed = Feed(url=path)
            else:
                feed = Feed(file=path)
            if feed.validated:
                self.database.replace_feed(feed)
                self.database.replace_episodes(feed, feed.parse_episodes())
            self.menus_valid = False
            self.change_status("Feed '%s\' successfully added" % str(feed))
        except FeedError as e:
            if isinstance(e, FeedLoadError):
                self.change_status(
                    "FeedLoadError: %s" % str(e)
                )
            elif isinstance(e, FeedDownloadError):
                self.change_status(
                    "FeedDownloadError: %s" % str(e)
                )
            elif isinstance(e, FeedParseError):
                self.change_status(
                    "FeedParseError: %s" % str(e)
                )
            elif isinstance(e, FeedStructureError):
                self.change_status(
                    "FeedStructureError: %s" % str(e)
                )
            else:
                self.change_status(
                    "FeedError [ambiguous]: %s" % str(e)
                )

    def delete_feed(self, feed: Feed) -> None:
        """Deletes the given feed from the database.

        If the delete_feed_confirmation config option is true, this method will
        first ask for y/n confirmation before deleting the feed.

        Deleting a feed also deletes all downloaded/saved episodes.

        Args:
            feed: the Feed to delete, which can be None
        """
        if feed is not None:
            should_delete = True
            if helpers.is_true(Config["delete_feed_confirmation"]):
                should_delete = self._get_y_n(
                    "Are you sure you want to delete this feed? (y/n): "
                )
            if should_delete:
                self.database.delete_feed(feed)
                self.menus_valid = False
                self.change_status("Feed successfully deleted")

    def reload_feeds(self) -> None:
        """Reloads the users' feeds.

        If the total number of feeds is >= the reload_feeds_threshold config
        option, this method will first ask for y/n confirmation.

        This method starts the reloading in a new un-managed thread.
        """
        should_reload = True
        if len(self.database.feeds()) >= int(Config["reload_feeds_threshold"]):
            should_reload = self._get_y_n(
                "Are you sure you want to reload all of your feeds?"
                " (y/n): "
            )
        if should_reload:
            t = threading.Thread(target=self.database.reload, args=[self])
            t.start()

    def save_episodes(self, feed=None, episode=None) -> None:
        """Save a feed or episode.

        If the user is saving an episode and the episode is already saved, this
        method will instead ask the user if they would like to delete the
        downloaded episode. However, if the user is saving a feed, there is no
        prompt to delete episodes, even if some are downloaded. In this case,
        downloaded episodes are simply skipped.

        Exactly one of either feed or episode must be given.

        Args:
            feed: (optional) a feed to download all episodes of
            episode: (optional) an episode to download or delete
        """
        assert (feed is None or episode is None) and (feed is not episode)

        if feed is not None:
            for episode in self.database.episodes(feed):
                if not episode.downloaded:
                    self._download_queue.add(episode)
        else:
            if episode.downloaded:
                should_delete = self._get_y_n(
                    "Are you sure you want to delete the downloaded"
                    " episode? (y/n): ")
                if should_delete:
                    episode.delete(self)
            else:
                self._download_queue.add(episode)

    def filter_menu(self, menu: Menu) -> None:
        menu.filter_text = self._get_input_str("Filter: ")
        self.menus_valid = False

    def clear(self) -> None:
        """Clear the screen.
        """
        self._stdscr.clear()

    def refresh(self) -> None:
        """Refresh the screen and all windows in all perspectives.
        """
        self._stdscr.refresh()

        for perspective_id in self._perspectives:
            self._perspectives[perspective_id].refresh()

        self._header_window.refresh()
        self._footer_window.refresh()

    def terminate(self) -> None:
        """Set console settings to their normal state.

        This method does not, by itself, cause the application to exit. Nor
        does it even cause the input loop to end. It should simply be seen as
        a "wrapping up" method for any actions which need to be performed
        before the object is destroyed.
        """
        self._queue.stop()

        self.database.replace_queue(self._queue)

        curses.nocbreak()
        self._stdscr.keypad(False)
        curses.echo()
        curses.endwin()

    def update_parent_dimensions(self) -> None:
        """Update _parent_x and _parent_y to the size of the console.
        """
        current_y, current_x = self._stdscr.getmaxyx()

        if current_y != self._parent_y or current_x != self._parent_x:
            self._parent_y, self._parent_x = current_y, current_x
            self._create_windows()
            self.menus_valid = False
            self.refresh()

        if self._parent_y < self.MIN_HEIGHT:
            raise DisplaySizeError("Display height is too small")
        if self._parent_x < self.MIN_WIDTH:
            raise DisplaySizeError("Display width is too small")

    def getch(self) -> int:
        """Gets an input character from the user.

        This method returns after at most INPUT_TIMEOUT ms.

        Returns:
            int: the character entered by the user, or -1
        """
        char = self._stdscr.getch()
        return char

    def change_status(self, status) -> None:
        """Changes the status message displayed in the footer.

        Args:
            status: the status message to display
        """
        assert isinstance(status, str)

        self._status = status
        self._status_timer = self.STATUS_TIMEOUT

    def update(self) -> None:
        """Updates all actively tracked components of this object.

        Should be called by the main loop after every input or input timeout.
        """
        # have the queue check if it needs to go to the next player
        self._queue.update()

        # check the status of any downloads
        try:
            self._download_queue.update()
        except OSError as e:
            self.change_status("OSError: %s" % str(e))
            return

        # update the status timer
        # If the user is not doing anything, the status message will take
        # INPUT_TIMEOUT * STATUS_TIMEOUT ms to be cleared. However, if the user
        # is performing inputs (i.e. traversing a menu) the message may be
        # cleared much quicker, since it will go away in STATUS_TIMEOUT
        # keypresses. However, this seems reasonable, since if the user is
        # actively controlling the client and not pausing to read the message,
        # they probably don't care about it anyway.
        if self._status_timer > 0:
            self._status_timer -= 1
            if self._status_timer <= 0:
                # status_timer should be reset during the next change_status()
                self._status = ""

        # write any episode modifications to the database
        if len(self._modified_episodes) > 0:
            for episode in self._modified_episodes:
                self.database.replace_episode(episode._feed, episode)
            self.menus_valid = False
            self._modified_episodes = []

    @property
    def parent_x(self) -> int:
        """int: the width of the parent screen, in characters"""
        return self._parent_x

    @property
    def parent_y(self) -> int:
        """int: the height of the parent screen, in characters"""
        return self._parent_y

    @property
    def database(self) -> Database:
        """Database: the user's database"""
        return self._database

    @property
    def perspectives(self) -> dict:
        """dict: the loaded Perspective's with id:perspective pairs"""
        return self._perspectives

    @property
    def queue(self) -> Queue:
        """Queue: the Queue of Player's"""
        return self._queue

    @property
    def menus_valid(self) -> bool:
        """bool: whether the menu contents are valid (!need_to_be_updated)"""
        return self._menus_valid

    @menus_valid.setter
    def menus_valid(self, menus_valid) -> None:
        self._menus_valid = menus_valid

    @property
    def modified_episodes(self) -> List[Episode]:
        """List[Episode]: database episodes to save on the next update"""
        return self._modified_episodes
Exemplo n.º 11
0
class Display:
    """The Display class.

    This class is used to handle all user-interaction. It creates and handles
    all aspects of the application's interface, including windows and menus. It
    retrieves input from the user and performs corresponding actions.

    This class also includes the core input loop of the application, contained
    in the loop() method.
    """
    MIN_WIDTH = 20
    MIN_HEIGHT = 8
    INPUT_TIMEOUT = 1000  # 1 second
    STATUS_TIMEOUT = 4  # multiple of INPUT_TIMEOUT
    AVAILABLE_COLORS = {
        'black': curses.COLOR_BLACK,
        'blue': curses.COLOR_BLUE,
        'cyan': curses.COLOR_CYAN,
        'green': curses.COLOR_GREEN,
        'magenta': curses.COLOR_MAGENTA,
        'red': curses.COLOR_RED,
        'white': curses.COLOR_WHITE,
        'yellow': curses.COLOR_YELLOW
    }

    def __init__(self, stdscr, config, feeds) -> None:
        """Initializes the object.

        Args:
            stdscr: a stdscr from curses.initscr()
            config: a loaded castero.Config object
            feeds: a loaded castero.Feeds object
        """
        self._stdscr = stdscr
        self._config = config
        self._feeds = feeds
        self._parent_x = -1
        self._parent_y = -1
        self._active_window = 0
        self._feed_window = None
        self._episode_window = None
        self._metadata_window = None
        self._header_window = None
        self._footer_window = None
        self._feed_menu = None
        self._episode_menu = None
        self._metadata_updated = False
        self._queue = Queue(config)
        self._status = ""
        self._status_timer = self.STATUS_TIMEOUT

        # basic preliminary operations
        self._stdscr.timeout(self.INPUT_TIMEOUT)
        curses.start_color()
        curses.noecho()
        curses.curs_set(0)
        curses.cbreak()
        self._stdscr.keypad(True)

        self.update_parent_dimensions()
        self.create_color_pairs()
        self._create_windows()
        self.create_menus()

    def create_color_pairs(self) -> None:
        """Initializes color pairs used for the display.

        Creates the following color pairs (foreground, background):
            - 1: foreground, background
            - 2: background, foreground
            - 3: background_alt, foreground_alt
            - 4: foreground_alt, background_alt
        """
        assert self._config["color_foreground"] in self.AVAILABLE_COLORS
        assert self._config["color_background"] in self.AVAILABLE_COLORS
        assert self._config["color_foreground_alt"] in self.AVAILABLE_COLORS
        assert self._config["color_background_alt"] in self.AVAILABLE_COLORS

        curses.init_pair(
            1,
            self.AVAILABLE_COLORS[self._config["color_foreground"]],
            self.AVAILABLE_COLORS[self._config["color_background"]]
        )
        curses.init_pair(
            2,
            self.AVAILABLE_COLORS[self._config["color_background"]],
            self.AVAILABLE_COLORS[self._config["color_foreground"]]
        )
        curses.init_pair(
            3,
            self.AVAILABLE_COLORS[self._config["color_background_alt"]],
            self.AVAILABLE_COLORS[self._config["color_foreground_alt"]]
        )
        curses.init_pair(
            4,
            self.AVAILABLE_COLORS[self._config["color_foreground_alt"]],
            self.AVAILABLE_COLORS[self._config["color_background_alt"]]
        )

    def _create_windows(self) -> None:
        """Creates and sets basic parameters for the windows.

        Creates the following windows:
            - _feed_window, _episode_window, _metadata_window
        Each window is set to use the default color pair (1), and each window
        takes up one-third of the display.

        If the windows already exist when this method is run, this method will
        delete them and create new ones.
        """
        third_x = helpers.third(self._parent_x)

        # delete old windows if they exist
        if self._header_window is not None:
            del self._header_window
            self._header_window = None
        if self._feed_window is not None:
            del self._feed_window
            self._feed_window = None
        if self._episode_window is not None:
            del self._episode_window
            self._episode_window = None
        if self._metadata_window is not None:
            del self._metadata_window
            self._metadata_window = None
        if self._footer_window is not None:
            del self._footer_window
            self._footer_window = None

        # create windows
        self._header_window = curses.newwin(2, self._parent_x,
                                            0, 0)
        self._feed_window = curses.newwin(self._parent_y - 2, third_x,
                                          2, 0)
        self._episode_window = curses.newwin(self._parent_y - 2, third_x,
                                             2, third_x)
        metadata_width = self._parent_x - ((third_x * 2) - 1)
        self._metadata_window = curses.newwin(self._parent_y - 2,
                                              metadata_width,
                                              2, 2 * third_x)
        self._footer_window = curses.newwin(2, self._parent_x,
                                            self._parent_y - 2, 0)

        # set window attributes
        self._feed_window.attron(curses.color_pair(1))
        self._episode_window.attron(curses.color_pair(1))
        self._metadata_window.attron(curses.color_pair(1))
        self._header_window.attron(curses.color_pair(4))
        self._footer_window.attron(curses.color_pair(4))

    def create_menus(self) -> None:
        """Creates the menus used in each window.

        Windows which have menus should be created prior to running this method
        (using _create_windows).

        If the menus already exist when this method is run, this method will
        delete them and create new ones.
        """
        assert all(window is not None for window in [
            self._feed_window, self._episode_window
        ])

        # this method could change a lot of screen content - probably
        # reasonable to simply clear the whole screen
        self.clear()

        # delete old menus if they exist
        if self._feed_menu is not None:
            del self._feed_menu
            self._feed_menu = None
        if self._episode_menu is not None:
            del self._episode_menu
            self._episode_menu = None

        feed_items = [[]]
        episode_items = []
        for key in self._feeds:
            feed = self._feeds[key]
            feed_items[0].append(
                str(feed)
            )
            episode_items.append(
                [str(ep) for ep in feed.episodes]
            )

        self._episode_menu = Menu(self._episode_window, episode_items)
        self._feed_menu = Menu(self._feed_window, feed_items,
                               child=self._episode_menu, active=True)

        # force reset active window to prevent starting in the episodes menu
        self._active_window = 0

    def _show_help(self) -> None:
        """Show the help screen.

        This method takes over the main loop, displaying the screen until a key
        is pressed. This means that typical loop actions, including checking
        the state of the current player, will not run while this screen is up.
        """
        self.clear()
        self._stdscr.refresh()

        padding_xy = (1, 4)

        help_window = curses.newwin(self._parent_y, self._parent_x, 0, 0)
        help_window.attron(curses.A_BOLD)

        # display lines from __help__
        help_lines = castero.__help__.split('\n')
        help_lines.append("Press any key to exit this screen.")
        for i in range(len(help_lines)):
            help_window.addstr(i + padding_xy[0], padding_xy[1], help_lines[i])
        help_window.refresh()

        # simply wait until any key is pressed (temporarily disable timeout)
        self._stdscr.timeout(-1)
        self._stdscr.getch()
        self._stdscr.timeout(self.INPUT_TIMEOUT)

        self.clear()

    def display(self) -> None:
        """Draws all windows and sub-features, including titles and borders.
        """
        # check if the screen size has changed
        self.update_parent_dimensions()

        # add header
        playing_str = ""
        if self._queue.first is not None:
            state = self._queue.first.state
            if state == 0:
                playing_str = " - Stopped [%s]: " % self._queue.first.time_str
            elif state == 1:
                playing_str = " - Playing [%s]: " % self._queue.first.time_str
            elif state == 2:
                playing_str = " - Paused [%s]: " % self._queue.first.time_str
            playing_str += self._queue.first.title
            if self._queue.length > 1:
                playing_str += " (+%d in queue)" % (self._queue.length - 1)

        self._header_window.attron(curses.A_BOLD)
        self._header_window.addstr(0, 0, " " * self._parent_x)
        self._header_window.addstr(0, 0, castero.__title__ + playing_str)

        # add footer
        footer_str = ""
        if self._status == "":  # always display the status instead if needed
            if len(self._feeds) > 0:
                total_feeds = len(self._feeds)
                lengths_of_feeds = [len(self._feeds[key].episodes) for key in
                                    self._feeds]
                total_episodes = sum(lengths_of_feeds)
                median_episodes = helpers.median(lengths_of_feeds)

                footer_str += "Processed %d feeds with %d total episodes (av" \
                              "g. %d episodes, med. %d)" % (
                                  total_feeds,
                                  total_episodes,
                                  total_episodes / total_feeds,
                                  median_episodes
                              )
            else:
                footer_str += "No feeds added"
        else:
            footer_str = self._status

        footer_str += " -- Press h for help"
        self._footer_window.attron(curses.A_BOLD)
        self._footer_window.addstr(
            1, 0, " " * (self._footer_window.getmaxyx()[1] - 1)
        )
        footer_str = footer_str[:self._footer_window.getmaxyx()[1] - 1]
        self._footer_window.addstr(1, 0, footer_str)

        # add window titles
        self._feed_window.attron(curses.A_BOLD)
        self._episode_window.attron(curses.A_BOLD)
        self._metadata_window.attron(curses.A_BOLD)
        self._feed_window.addstr(0, 0, "Feeds")
        self._episode_window.addstr(0, 0, "Episodes")
        self._metadata_window.addstr(0, 0, "Metadata")

        # add window borders
        self._feed_window.hline(1, 0,
                                0, self._feed_window.getmaxyx()[1] - 1)
        self._feed_window.vline(0, self._feed_window.getmaxyx()[1] - 1,
                                0, self._feed_window.getmaxyx()[0] - 2)
        self._episode_window.hline(1, 0,
                                   0, self._episode_window.getmaxyx()[1] - 1)
        self._episode_window.vline(0, self._episode_window.getmaxyx()[1] - 1,
                                   0, self._episode_window.getmaxyx()[0] - 2)
        self._metadata_window.hline(1, 0,
                                    0, self._metadata_window.getmaxyx()[1] - 1)
        self._header_window.hline(1, 0,
                                  0, self._header_window.getmaxyx()[1])
        self._footer_window.hline(0, 0,
                                  0, self._footer_window.getmaxyx()[1])

        # display menu content
        self._feed_menu.display()
        self._episode_menu.display()

        # draw metadata
        if not self._metadata_updated:
            self._draw_metadata()

    def _get_input_str(self, prompt) -> str:
        """Prompts the user for input and returns the resulting string.

        This method assumes that all input strings will be obtained in the
        footer window.

        Args:
            prompt: a string to inform the user of what they need to enter

        Returns:
            str: the user's input
        """
        assert self._footer_window is not None
        assert type(prompt) == str

        curses.echo()
        curses.curs_set(1)

        self._footer_window.addstr(
            1, 0, " " * (self._footer_window.getmaxyx()[1] - 1)
        )
        self._footer_window.addstr(1, 0, prompt)
        result = self._footer_window.getstr(1, len(prompt))

        self._footer_window.clear()
        curses.curs_set(0)
        curses.noecho()

        return result.decode("utf-8")

    def _get_y_n(self, prompt) -> bool:
        """Prompts the user for a yes or no (y/n) input.

        Args:
            prompt: a string to inform the user of what they need to enter

        Returns:
            bool: true if the user presses y, false otherwise
        """
        assert self._footer_window is not None
        assert type(prompt) == str

        curses.echo()
        curses.curs_set(1)

        self._footer_window.addstr(
            1, 0, " " * (self._footer_window.getmaxyx()[1] - 1)
        )
        self._footer_window.addstr(1, 0, prompt)
        c = self._footer_window.getch()

        self._footer_window.clear()
        curses.curs_set(0)
        curses.noecho()

        return c == ord('y')

    def handle_input(self, c) -> bool:
        """Performs action corresponding to the user's input.

        Args:
            c: the input character

        Returns:
            bool: whether or not the application should continue running
        """
        keep_running = True
        if c == ord('q'):
            self.terminate()
            keep_running = False
        elif c == ord('h'):
            self._show_help()
        elif c == curses.KEY_RIGHT:
            self._change_active_window(1)
            self._metadata_updated = False
        elif c == curses.KEY_LEFT:
            self._change_active_window(-1)
            self._metadata_updated = False
        elif c == curses.KEY_UP:
            self.get_active_menu().move(1)
            self._metadata_updated = False
        elif c == curses.KEY_DOWN:
            self.get_active_menu().move(-1)
            self._metadata_updated = False
        elif c == curses.KEY_PPAGE:  # page up
            self.get_active_menu().move_page(1)
            self._metadata_updated = False
        elif c == curses.KEY_NPAGE:  # page down
            self.get_active_menu().move_page(-1)
            self._metadata_updated = False
        elif c == 10:  # return
            self._queue.stop()
            self._queue.clear()
            self._create_player_from_selected()
            self._queue.play()
            self.get_active_menu().move(-1)
        elif c == ord(' '):  # space
            self._create_player_from_selected()
            self.get_active_menu().move(-1)
        elif c == ord('c'):
            self._queue.stop()
            self._queue.clear()
        elif c == ord('p'):
            self._queue.toggle()
        elif c == ord('n'):
            self._queue.stop()
            self._queue.next()
            self._queue.play()
        elif c == ord('f'):
            self._queue.seek(1)
        elif c == ord('b'):
            self._queue.seek(-1)
        elif c == ord('a'):
            self._add_feed()
        elif c == ord('d'):
            self._delete_feed()
        elif c == ord('r'):
            self._reload_feeds()
        elif c == ord('s'):
            self._save_episode()

        return keep_running

    def _add_feed(self) -> None:
        """Prompt the user for a feed and add it, if possible.
        """
        path = self._get_input_str("Enter the URL or path of the feed: ")
        try:
            # assume urls have http in them
            if "http" in path:
                feed = Feed(url=path)
            else:
                feed = Feed(file=path)
            if feed.validated:
                self._feeds[path] = feed
            self.create_menus()
            self._feeds.write()
            self.update_status("Feed '%s\' successfully added" % str(feed))
        except FeedError as e:
            if type(e) == FeedLoadError:
                self.update_status(
                    "Error: An error occurred while loading the file"
                )
            elif type(e) == FeedDownloadError:
                self.update_status(
                    "Error: An error occurred while downloading the feed"
                )
            elif type(e) == FeedParseError:
                self.update_status(
                    "Error: An error occurred while parsing the feed"
                )
            elif type(e) == FeedStructureError:
                self.update_status(
                    "Error: The provided feed is not a valid RSS document"
                )
            else:
                self.update_status(
                    "Error: An ambiguous error occurred while handling the"
                    " feed"
                )

    def _delete_feed(self) -> None:
        """Deletes the current selected feed.

        If the delete_feed_confirmation config option is true, this method will
        first ask for y/n confirmation before deleting the feed.
        """
        if self._active_window == 0:
            should_delete = True
            if self._config["delete_feed_confirmation"] \
                    in ['True', 'true', '1']:
                should_delete = self._get_y_n(
                    "Are you sure you want to delete this feed? (y/n): "
                )
            if should_delete:
                deleted = self._feeds.del_at(
                    self._feed_menu.selected_index)
                if deleted:
                    self.create_menus()
                    self._feeds.write()
                    self.update_status("Feed successfully deleted")

    def _reload_feeds(self) -> None:
        """Reloads the users' feeds.

        If the total number of feeds is >= the reload_feeds_threshold config
        option, this method will first ask for y/n confirmation.

        This method starts the reloading in a new un-managed thread.
        """
        should_reload = True
        if len(self._feeds) >= int(self._config["reload_feeds_threshold"]):
            should_reload = self._get_y_n(
                "Are you sure you want to reload all of your feeds?"
                " (y/n): "
            )
        if should_reload:
            t = threading.Thread(target=self._feeds.reload, args=[self])
            t.start()

    def _save_episode(self) -> None:
        """Saves the current selected episode.

        If the episode is already saved, this method will instead ask the user
        if they would like to delete the downloaded episode.
        """
        if self._active_window == 1:
            feed_index = self._feed_menu.selected_index
            feed = self._feeds.at(feed_index)
            episode_index = self._episode_menu.selected_index
            if feed is not None:
                episode = feed.episodes[episode_index]
                if episode.downloaded:
                    should_delete = self._get_y_n(
                        "Are you sure you want to delete the downloaded"
                        " episode? (y/n): ")
                    if should_delete:
                        episode.delete(self)
                else:
                    episode.download(self)

    def _create_player_from_selected(self) -> None:
        """Creates player(s) based on the selected items and adds to the queue.

        If the active menu is the feed menu, then this will create players for
        all episodes in the selected feed. If the active menu is the episode
        menu, this will simply create a single player.

        This method will not clear the queue prior to adding the new player(s),
        nor will it play the episodes after running.
        """
        feed_index = self._feed_menu.selected_index
        feed = self._feeds.at(feed_index)
        if self._active_window == 0:
            if feed is not None:
                for episode in feed.episodes:
                    player = Player(str(episode), episode.get_playable())
                    self._queue.add(player)
        elif self._active_window == 1:
            episode_index = self._episode_menu.selected_index
            if feed is not None:
                episode = feed.episodes[episode_index]
                player = Player(str(episode), episode.get_playable())
                self._queue.add(player)

    def _change_active_window(self, direction) -> None:
        """Changes _active_window to the next or previous window, if available.

        Args:
            direction: 1 to change to the next window, -1 to change to the
                previous (if it exists)
        """
        assert direction == 1 or direction == -1

        self.get_active_menu().set_active(False)
        self._active_window += direction
        if self._active_window > 1:
            self._active_window = 1
        elif self._active_window < 0:
            self._active_window = 0
        self.get_active_menu().set_active(True)

    def _append_metadata_lines(self, string, output_lines, attr=-1,
                               add_blank=False) -> None:
        """Appends properly formatted lines to the 2D output_lines array.

        Args:
            string: the string to add to output_lines
            output_lines: 2D array, each element is [attr, str]
            attr: (optional) the attribute (i.e. curses.A_BOLD)
        """
        max_lines = int(0.7 * self._metadata_window.getmaxyx()[0])
        max_line_width = self._metadata_window.getmaxyx()[1] - 1
        lines = textwrap.wrap(string, max_line_width)

        # truncate to at most 70% of the total lines on the screen
        lines = lines[:max_lines]

        # add all lines to array
        for line in lines:
            output_lines.append([attr, line])

        # add a blank line afterward, if necessary
        if add_blank:
            output_lines.append([-1, ""])

    def _draw_metadata(self) -> None:
        """Draws the metadata of the selected feed/episode onto the window.
        """
        assert self._metadata_window is not None

        output_lines = []  # 2D array, each element is [attr, str]
        max_lines = self._metadata_window.getmaxyx()[0] - 2
        max_line_width = self._metadata_window.getmaxyx()[1] - 1

        # clear the window by drawing blank lines
        for y in range(2, self._metadata_window.getmaxyx()[0]):
            self._metadata_window.addstr(y, 0, " " * max_line_width)

        if self._active_window == 0:
            # * the selected item is a feed
            selected_index = self._feed_menu.selected_index
            feed = self._feeds.at(selected_index)

            if feed is not None:
                # draw feed title
                self._append_metadata_lines(feed.title, output_lines,
                                            attr=curses.A_BOLD)
                # draw feed lastBuildDate
                self._append_metadata_lines(feed.last_build_date, output_lines,
                                            add_blank=True)
                # draw feed link
                self._append_metadata_lines(feed.link, output_lines,
                                            add_blank=True)
                # draw feed description
                self._append_metadata_lines("Description:", output_lines,
                                            attr=curses.A_BOLD)
                self._append_metadata_lines(feed.description, output_lines,
                                            add_blank=True)
                # draw feed copyright
                self._append_metadata_lines("Copyright:", output_lines,
                                            attr=curses.A_BOLD)
                self._append_metadata_lines(feed.copyright, output_lines,
                                            add_blank=True)
                # draw feed number of episodes
                num_dl = sum([episode.downloaded for episode in feed.episodes])
                self._append_metadata_lines("Episodes:", output_lines,
                                            attr=curses.A_BOLD)
                self._append_metadata_lines(
                    "Found %d episodes (%d downloaded)" % (
                        len(feed.episodes), num_dl
                    ), output_lines
                )

        elif self._active_window == 1:
            # * the selected item is an episode
            selected_feed_index = self._feed_menu.selected_index
            selected_episode_index = self._episode_menu.selected_index
            feed = self._feeds.at(selected_feed_index)

            if feed is not None:
                episode = feed.episodes[selected_episode_index]

                # draw episode title
                self._append_metadata_lines(episode.title, output_lines,
                                            attr=curses.A_BOLD)
                # draw episode pubdate
                self._append_metadata_lines(episode.pubdate, output_lines,
                                            add_blank=True)
                # draw episode link
                self._append_metadata_lines(episode.link, output_lines,
                                            add_blank=True)
                # draw episode description
                self._append_metadata_lines("Description:", output_lines,
                                            attr=curses.A_BOLD)
                self._append_metadata_lines(episode.description, output_lines,
                                            add_blank=True)
                # draw episode copyright
                self._append_metadata_lines("Copyright:", output_lines,
                                            attr=curses.A_BOLD)
                self._append_metadata_lines(episode.copyright, output_lines,
                                            add_blank=True)

                # draw episode downloaded
                self._append_metadata_lines("Downloaded:", output_lines,
                                            attr=curses.A_BOLD)
                self._append_metadata_lines(episode.downloaded_str,
                                            output_lines)

        y = 2
        for line in output_lines[:max_lines]:
            self._metadata_window.attrset(curses.color_pair(1))
            if line[0] != -1:
                self._metadata_window.attron(line[0])
            self._metadata_window.addstr(y, 0, line[1])
            y += 1 + line[1].count('\n')

    def get_active_window(self):
        """Retrieve the window object corresponding to the active window.

        Returns:
            curses.window: the active window object
        """
        assert 0 <= self._active_window < 3

        return {
            0: self._feed_window,
            1: self._episode_window,
            2: self._metadata_window
        }.get(self._active_window)

    def get_active_menu(self) -> Menu:
        """Retrieve the menu object corresponding to the active window.

        Returns:
            menu.Menu: the active menu object
        """
        assert 0 <= self._active_window < 2

        return {
            0: self._feed_menu,
            1: self._episode_menu,
        }.get(self._active_window)

    def clear(self) -> None:
        """Clear the screen.
        """
        self._stdscr.clear()

    def refresh(self) -> None:
        """Refresh the screen and all windows.
        """
        self._stdscr.refresh()
        self._feed_window.refresh()
        self._episode_window.refresh()
        self._metadata_window.refresh()
        self._header_window.refresh()
        self._footer_window.refresh()

    def terminate(self) -> None:
        """Set console settings to their normal state.

        This method does not, by itself, cause the application to exit. Nor
        does it even cause the input loop to end. It should simply be seen as
        a "wrapping up" method for any actions which need to be performed
        before the object is destroyed.
        """
        curses.nocbreak()
        self._stdscr.keypad(False)
        curses.echo()
        curses.endwin()

    def update_parent_dimensions(self) -> None:
        """Update _parent_x and _parent_y to the size of the console.
        """
        current_y, current_x = self._stdscr.getmaxyx()

        if current_y != self._parent_y or current_x != self._parent_x:
            self._parent_y, self._parent_x = current_y, current_x
            self._create_windows()
            self.create_menus()

        if self._parent_y < self.MIN_HEIGHT:
            raise DisplaySizeError("Display height is too small")
        if self._parent_x < self.MIN_WIDTH:
            raise DisplaySizeError("Display width is too small")

    def getch(self) -> int:
        """Gets an input character from the user.

        This method returns after at most INPUT_TIMEOUT ms.

        Returns:
            int: the character entered by the user, or -1
        """
        c = self._stdscr.getch()
        return c

    def update_status(self, status) -> None:
        """Updates the status message displayed in the footer.

        Args:
            status: the status message to display
        """
        assert type(status) == str

        self._status = status
        self._status_timer = self.STATUS_TIMEOUT

    def update(self) -> None:
        """Updates all actively tracked components of this object.

        Should be called by the main loop after every input or input timeout.
        """
        # have the queue check if it needs to go to the next player
        self._queue.update()

        # update the status timer
        # If the user is not doing anything, the status message will take
        # INPUT_TIMEOUT * STATUS_TIMEOUT ms to be cleared. However, if the user
        # is performing inputs (i.e. traversing a menu) the message may be
        # cleared much quicker, since it will go away in STATUS_TIMEOUT
        # keypresses. However, this seems reasonable, since if the user is
        # actively controlling the client and not pausing to read the message,
        # they probably don't care about it anyway.
        if self._status_timer > 0:
            self._status_timer -= 1
            if self._status_timer <= 0:
                # status_timer should be reset during the next update_status()
                self._status = ""
Exemplo n.º 12
0
class Display:
    """The user-facing display.

    This class is used to handle all user-interaction. It creates and handles
    all aspects of the application's interface, including windows and menus. It
    retrieves input from the user and performs corresponding actions.
    """
    MIN_WIDTH = 20
    MIN_HEIGHT = 8
    INPUT_TIMEOUT = int(Config["refresh_delay"])
    UPDATE_TIMEOUT = 2000 / INPUT_TIMEOUT  # multiple of INPUT_TIMEOUT
    STATUS_TIMEOUT = 3  # multiple of UPDATE_TIMEOUT
    COLOR_NAMES = {
        'black': curses.COLOR_BLACK,
        'blue': curses.COLOR_BLUE,
        'cyan': curses.COLOR_CYAN,
        'green': curses.COLOR_GREEN,
        'magenta': curses.COLOR_MAGENTA,
        'red': curses.COLOR_RED,
        'white': curses.COLOR_WHITE,
        'yellow': curses.COLOR_YELLOW,
        'transparent': -1
    }
    KEY_MAPPING = {chr(i): i for i in range(256)}
    KEY_MAPPING.update((name[4:], value)
                       for name, value in vars(curses).items()
                       if name.startswith('KEY_'))
    KEY_MAPPING.update({'ENTER': 10, 'SPACE': 32})
    AVAILABLE_PLAYERS = {}

    def __init__(self, stdscr, database) -> None:
        """
        Args:
            stdscr: a stdscr from curses.initscr()
            database: a connected castero.Database
        """
        self._stdscr = stdscr
        self._database = database
        self._parent_x = -1
        self._parent_y = -1
        self._perspectives = {}
        self._active_perspective = 1
        self._header_window = None
        self._footer_window = None
        self._queue = Queue(self)
        self._download_queue = DownloadQueue(self)
        self._status = ""
        self._header_str = ""
        self._footer_str = ""
        self._status_timer = self.STATUS_TIMEOUT
        self._update_timer = self.UPDATE_TIMEOUT
        self._menus_valid = True
        self._modified_episodes = []

        # basic preliminary operations
        self._stdscr.timeout(self.INPUT_TIMEOUT)
        curses.start_color()
        curses.use_default_colors()
        curses.noecho()
        self._curs_set(0)
        curses.cbreak()
        self._stdscr.keypad(True)

        self.update_parent_dimensions()
        self.create_color_pairs()
        self._load_perspectives()
        self._load_players()
        self._restore_queue()
        self._create_windows()
        self.create_menus()

    def color_number(self, color: str) -> int:
        """Convert color string to valid color number"""
        if color in self.COLOR_NAMES:
            return self.COLOR_NAMES[color]
        if color.isnumeric() and int(color) < curses.COLORS:
            return int(color)
        return -1

    def create_color_pairs(self) -> None:
        """Initializes color pairs used for the display.

        Creates the following color pairs (foreground, background):
            - 1: foreground, background
            - 2: background, foreground
            - 3: background_alt, foreground_alt
            - 4: foreground_alt, background_alt
            - 5: foreground_dim, background
        """

        curses.init_pair(
            1,
            self.color_number(Config["color_foreground"]),
            self.color_number(Config["color_background"]),
        )
        curses.init_pair(
            2,
            self.color_number(Config["color_background"]),
            self.color_number(Config["color_foreground"]),
        )
        curses.init_pair(
            3,
            self.color_number(Config["color_background_alt"]),
            self.color_number(Config["color_foreground_alt"]),
        )
        curses.init_pair(
            4,
            self.color_number(Config["color_foreground_alt"]),
            self.color_number(Config["color_background_alt"]),
        )
        curses.init_pair(
            5,
            self.color_number(Config["color_foreground_dim"]),
            self.color_number(Config["color_background"]),
        )
        curses.init_pair(
            6,
            self.color_number(Config["color_foreground_status"]),
            self.color_number(Config["color_background"]),
        )
        curses.init_pair(
            7,
            self.color_number(Config["color_foreground_heading"]),
            self.color_number(Config["color_background"]),
        )
        curses.init_pair(
            8,
            self.color_number(Config["color_foreground_dividers"]),
            self.color_number(Config["color_background"]),
        )

    def _load_perspectives(self) -> None:
        """Load instances of perspectives from the `perspectives` package.
        """
        # load a list of modules names by manually detecting .py files
        module_files = glob.glob(dirname(__file__) + "/perspectives/*.py")
        module_names = [basename(f)[:-3] for f in module_files if isfile(f)]

        for name in module_names:
            p_mod = importlib.import_module("castero.perspectives.%s" % name)
            p_cls = getattr(
                p_mod,
                dir(p_mod)[[cls.lower() == name
                            for cls in dir(p_mod)].index(True)])
            inst = p_cls(self)
            self._perspectives[inst.ID] = inst

    def _load_players(self) -> None:
        """Load player classes from the `players` package.
        """
        # load a list of modules names by manually detecting .py files
        module_files = glob.glob(dirname(__file__) + "/players/*.py")
        module_names = [basename(f)[:-3] for f in module_files if isfile(f)]

        for name in module_names:
            p_mod = importlib.import_module("castero.players.%s" % name)
            p_cls = getattr(
                p_mod,
                dir(p_mod)[[cls.lower() == name
                            for cls in dir(p_mod)].index(True)])
            self.AVAILABLE_PLAYERS[p_cls.NAME] = p_cls

    def _restore_queue(self) -> None:
        """Recreate players in queue from the database.
        """
        for episode in self.database.queue():
            player = Player.create_instance(self.AVAILABLE_PLAYERS,
                                            str(episode),
                                            episode.get_playable(), episode)
            self.queue.add(player)

    def _create_windows(self) -> None:
        """Creates and sets basic parameters for the windows.

        If the windows already exist when this method is run, this method will
        delete them and create new ones.
        """
        # delete old windows if they exist
        if self._header_window is not None:
            del self._header_window
            self._header_window = None
        if self._footer_window is not None:
            del self._footer_window
            self._footer_window = None

        # create windows
        self._header_window = curses.newwin(2, self._parent_x, 0, 0)
        self._footer_window = curses.newwin(2, self._parent_x,
                                            self._parent_y - 2, 0)

        # create windows for all perspectives
        for perspective_id in self._perspectives:
            self._perspectives[perspective_id].create_windows()

    def create_menus(self) -> None:
        """Creates the menus used in each window.

        Windows which have menus should be created prior to running this method
        (using _create_windows).
        """
        for perspective_id in self._perspectives:
            self._perspectives[perspective_id].create_menus()

    def show_help(self) -> None:
        """Show the help screen.

        This method takes over the main loop, displaying the screen until a key
        is pressed. This means that typical loop actions, including checking
        the state of the current player, will not run while this screen is up.
        """
        help_lines = castero.__help__.split('\n')

        # the first and last lines that content can be displayed, excluding
        # the final line on the screen which is reserved for the "press any
        # key to exit" line
        y_bounds = (0, self._parent_y - 2)

        # the current vertical offset set by the user with arrow keys
        cur_offset = 0

        # the max offset, which is the offset where the last line in help_lines
        # is displayed at y_bounds[1]
        max_offset = len(help_lines) - (y_bounds[1] - y_bounds[0]) - 2

        help_window = curses.newwin(self._parent_y, self._parent_x, 0, 0)
        help_window.refresh()

        running = True
        update_text = True
        while running:
            inp = self._stdscr.getch()

            if inp == self.KEY_MAPPING["DOWN"]:
                update_text = True
                cur_offset += 1

            elif inp == self.KEY_MAPPING["UP"]:
                update_text = True
                cur_offset -= 1
            elif inp != -1:
                running = False

            if cur_offset > max_offset:
                cur_offset = max_offset
            if cur_offset < 0:
                cur_offset = 0

            if update_text:
                # draw blank lines to clear the screen
                for i in range(self._parent_y):
                    help_window.addstr(i, 0, "".ljust(self._parent_x - 1))

                # add text from help_lines based on offset
                max_lineno = min(len(help_lines), cur_offset + y_bounds[1] + 1)
                for i in range(cur_offset, max_lineno):
                    help_window.addstr(i - cur_offset, 2,
                                       help_lines[i][:self._parent_x - 2])

                bottom_line = "[%d/%d] Press arrow keys to scroll, or any"\
                    " other key to exit this screen." % (
                        min(len(help_lines), cur_offset + y_bounds[1] + 2),
                        len(help_lines)
                    )
                help_window.addstr(y_bounds[1] + 1, 2, bottom_line)
                help_window.refresh()
                update_text = False

        self.clear()
        self.display_all()

    def display(self) -> None:
        """Draws all windows and sub-features, including titles and borders.
        """
        # check if the screen size has changed
        self.update_parent_dimensions()

        # decrement the update timer
        self._update_timer -= 1
        if self._update_timer <= 0:
            self._update_timer = self.UPDATE_TIMEOUT
            self.update()

        # display the header and footer
        width = self._header_window.getmaxyx()[1]
        self._header_window.addstr(0, 0, " " * width)
        self._header_window.addstr(0, 0, self._header_str,
                                   curses.color_pair(6) | curses.A_BOLD)
        self._footer_window.addstr(1, 0, self._footer_str[:width - 1],
                                   curses.color_pair(6) | curses.A_BOLD)

        # add window borders
        self._header_window.hline(1, 0, 0,
                                  self._header_window.getmaxyx()[1],
                                  curses.ACS_HLINE | curses.color_pair(8))
        self._footer_window.hline(0, 0, 0,
                                  self._footer_window.getmaxyx()[1],
                                  curses.ACS_HLINE | curses.color_pair(8))

        # refresh updated windows
        self._footer_window.refresh()
        self._header_window.refresh()

        # add display for current perspective
        self._perspectives[self._active_perspective].display()

    def display_all(self) -> None:
        """Force all perspectives to completely redraw their content.

        For more details, see the description of the method in Perspective.
        """
        self.refresh()
        self._perspectives[self._active_perspective].display_all()
        self.refresh()

    def _get_active_perspective(self) -> Perspective:
        """Retrieve the active/visible Perspective.
        """
        return self._perspectives[self._active_perspective]

    def _change_active_perspective(self, perspective_id) -> None:
        """Changes _active_perspective to the given perspective.

        Args:
            perspective_id: the ID of the perspective to change to
        """
        assert perspective_id in self._perspectives

        self.clear()
        self._active_perspective = perspective_id
        self._perspectives[perspective_id].made_active()
        self.display_all()

    def _get_input_str(self, prompt) -> str:
        """Prompts the user for input and returns the resulting string.

        This method assumes that all input strings will be obtained in the
        footer window.

        Args:
            prompt: a string to inform the user of what they need to enter

        Returns:
            str: the user's input
        """
        assert self._footer_window is not None
        assert isinstance(prompt, str)

        self._curs_set(1)
        self._stdscr.timeout(-1)  # disable timeouts while waiting for entry

        # display input prompt
        self._footer_window.addstr(
            1, 0, " " * (self._footer_window.getmaxyx()[1] - 1))
        self._footer_window.addstr(1, 0, prompt)

        entry_pad = curses.newpad(1, 999)
        current_x = 0
        scroll_x = 0
        input_char = None
        while input_char not in [curses.KEY_ENTER, 10]:
            if input_char is not None:
                # manually handle backspace
                if input_char in [curses.KEY_BACKSPACE, 127]:
                    if current_x > 0:
                        entry_pad.delch(0, current_x - 1)
                        current_x -= 1
                        if scroll_x > 0:
                            scroll_x -= 1
                else:
                    # scroll the input pad if necessary
                    if current_x + len(prompt) > \
                            self._footer_window.getmaxyx()[1] - 1:
                        scroll_x += 1

                    # add the entered character to the pad
                    entry_pad.addch(0, current_x, input_char)
                    current_x += 1

                # display current portion of pad
                entry_pad.refresh(0, scroll_x, self._parent_y - 1, len(prompt),
                                  self._parent_y - 1,
                                  self._footer_window.getmaxyx()[1] - 1)

            # get the next input character
            input_char = self._footer_window.getch()

        self._stdscr.timeout(self.INPUT_TIMEOUT)
        self._footer_window.clear()
        self._curs_set(0)

        return entry_pad.instr(0, 0, entry_pad.getmaxyx()[1]) \
            .decode('utf-8').strip()

    def _get_y_n(self, prompt) -> bool:
        """Prompts the user for a yes or no (y/n) input.

        Args:
            prompt: a string to inform the user of what they need to enter

        Returns:
            bool: true if the user presses y, false otherwise
        """
        assert self._footer_window is not None
        assert isinstance(prompt, str)

        curses.echo()
        self._curs_set(1)

        self._footer_window.addstr(
            1, 0, " " * (self._footer_window.getmaxyx()[1] - 1))
        self._footer_window.addstr(1, 0, prompt)
        char = self._footer_window.getch()

        self._footer_window.clear()
        self._curs_set(0)
        curses.noecho()

        return char == ord('y')

    def _curs_set(self, visibility: int) -> None:
        """Safely set the appearance of the cursor.

        Args:
            visibility: 0 (invisible), 1 (normal mode) or 2 (high visibility)
        """
        if hasattr(curses, 'curs_set'):
            try:
                curses.curs_set(visibility)
            except curses.error:
                pass

    def handle_input(self, c) -> bool:
        """Performs action corresponding to the user's input.

        Args:
            c: the input character

        Returns:
            bool: whether or not the application should continue running
        """
        for perspective_id in self._perspectives:
            if c == self.KEY_MAPPING[str(perspective_id)]:
                self._change_active_perspective(perspective_id)

        return self._get_active_perspective().handle_input(c)

    def add_feed(self) -> None:
        """Prompt the user for a feed and add it, if possible.
        """
        path = self._get_input_str("Enter the URL or path of the feed: ")
        try:
            # assume urls have http in them
            if "http" in path:
                feed = Feed(url=path)
            else:
                feed = Feed(file=path)
            if feed.validated:
                self.database.replace_feed(feed)
                self.database.replace_episodes(feed, feed.parse_episodes())
            self.menus_valid = False
            self.change_status("Feed '%s\' successfully added" % str(feed))
        except FeedError as e:
            if isinstance(e, FeedLoadError):
                self.change_status("FeedLoadError: %s" % str(e))
            elif isinstance(e, FeedDownloadError):
                self.change_status("FeedDownloadError: %s" % str(e))
            elif isinstance(e, FeedParseError):
                self.change_status("FeedParseError: %s" % str(e))
            elif isinstance(e, FeedStructureError):
                self.change_status("FeedStructureError: %s" % str(e))
            else:
                self.change_status("FeedError [ambiguous]: %s" % str(e))

    def delete_feed(self, feed: Feed) -> None:
        """Deletes the given feed from the database.

        If the delete_feed_confirmation config option is true, this method will
        first ask for y/n confirmation before deleting the feed.

        Deleting a feed also deletes all downloaded/saved episodes.

        Args:
            feed: the Feed to delete, which can be None
        """
        if feed is not None:
            should_delete = True
            if helpers.is_true(Config["delete_feed_confirmation"]):
                should_delete = self._get_y_n(
                    "Are you sure you want to delete this feed? (y/n): ")
            if should_delete:
                self.database.delete_feed(feed)
                self.menus_valid = False
                self.change_status("Feed successfully deleted")

    def reload_feeds(self) -> None:
        """Reloads the users' feeds.

        If the total number of feeds is >= the reload_feeds_threshold config
        option, this method will first ask for y/n confirmation.

        This method starts the reloading in a new un-managed thread.
        """
        should_reload = True
        if len(self.database.feeds()) >= int(Config["reload_feeds_threshold"]):
            should_reload = self._get_y_n(
                "Are you sure you want to reload all of your feeds?"
                " (y/n): ")
        if should_reload:
            t = threading.Thread(target=self.database.reload, args=[self])
            t.start()

    def reload_selected_feed(self, feed: Feed) -> None:
        """Reloads the selected feed.

        This method starts the reloading in a new un-managed thread.
        """
        t = threading.Thread(target=self.database.reload, args=[self, [feed]])
        t.start()

    def save_episodes(self, feed=None, episode=None) -> None:
        """Save a feed or episode.

        Exactly one of either feed or episode must be given.

        Args:
            feed: (optional) a feed to download all episodes of
            episode: (optional) an episode to download
        """
        assert (feed is None or episode is None) and (feed is not episode)

        if feed is not None:
            num_to_save = 0
            for episode in self.database.episodes(feed):
                if not episode.downloaded:
                    num_to_save += 1

            if num_to_save == 0:
                return

            should_delete = self._get_y_n(
                "Are you sure you want to download %d"
                " episodes from this feed? (y/n): " % num_to_save)
            if should_delete:
                for episode in self.database.episodes(feed):
                    if not episode.downloaded:
                        self._download_queue.add(episode)
        else:
            if not episode.downloaded:
                self._download_queue.add(episode)

    def delete_episodes(self, feed=None, episode=None) -> None:
        """Delete a downloaded episode, or all of those from a feed.

        Exactly one of either feed or episode must be given.

        Args:
            feed: (optional) a feed to delete all episodes of
            episode: (optional) an episode or delete
        """
        assert (feed is None or episode is None) and (feed is not episode)

        if feed is not None:
            num_deleted = 0
            num_to_delete = 0
            for episode in self.database.episodes(feed):
                if episode.downloaded:
                    num_to_delete += 1

            if num_to_delete == 0:
                return

            should_delete = self._get_y_n(
                "Are you sure you want to delete %d downloaded"
                " episodes from this feed? (y/n): " % num_to_delete)
            if should_delete:
                for episode in self.database.episodes(feed):
                    if episode.downloaded:
                        episode.delete(self)
                        num_deleted += 1
                self.menus_valid = False
                self.change_status("Successfully deleted %d episodes" %
                                   num_deleted)
        else:
            if episode.downloaded:
                should_delete = self._get_y_n(
                    "Are you sure you want to delete the downloaded"
                    " episode? (y/n): ")
                if should_delete:
                    episode.delete(self)

    def filter_menu(self, menu: Menu) -> None:
        menu.filter_text = self._get_input_str("Filter: ")
        self.menus_valid = False

    def execute_command(self, episode: Episode) -> None:
        """Execute a system command on an episode's enclosure.

        The command to run is set by the user with the execute_command config
        setting. See the description in the config file above that setting for
        details about how it may be formatted.

        Args:
            episode: episode to execute the command on
        """
        command = Config["execute_command"]\
            .replace("{file}", episode.enclosure)\
            .replace("{title}", episode.title)\
            .replace("{description}", episode.description)\
            .replace("{link}", episode.link)\
            .replace("{pubdate}", episode.pubdate)\
            .replace("{copyright}", episode.copyright)
        subprocess.Popen(command, shell=True)

    def show_episode_url(self, episode: Episode) -> None:
        """Show episode URL in status line.

        Args:
            episode: episode to show URL for
        """
        if episode is not None:
            max_width = self._footer_window.getmaxyx()[1] - 1
            self._footer_window.addstr(1, 0, " " * max_width)
            self.change_status(episode.enclosure)

    def clear(self) -> None:
        """Clear the screen.
        """
        self._stdscr.clear()

    def refresh(self) -> None:
        """Refresh the screen and all windows in all perspectives.
        """
        self._stdscr.refresh()

        for perspective_id in self._perspectives:
            self._perspectives[perspective_id].refresh()

        self._header_window.refresh()
        self._footer_window.refresh()

    def terminate(self) -> None:
        """Set console settings to their normal state.

        This method does not, by itself, cause the application to exit. Nor
        does it even cause the input loop to end. It should simply be seen as
        a "wrapping up" method for any actions which need to be performed
        before the object is destroyed.
        """
        self._queue.stop()

        self.database.replace_queue(self._queue)
        self.database.close()

        curses.nocbreak()
        self._stdscr.keypad(False)
        curses.echo()
        curses.endwin()

    def update_parent_dimensions(self) -> None:
        """Update _parent_x and _parent_y to the size of the console.
        """
        current_y, current_x = self._stdscr.getmaxyx()

        if current_y != self._parent_y or current_x != self._parent_x:
            self._parent_y, self._parent_x = current_y, current_x
            self._create_windows()
            self.menus_valid = False
            self._update_timer = 0

        if self._parent_y < self.MIN_HEIGHT:
            raise DisplaySizeError("Display height is too small")
        if self._parent_x < self.MIN_WIDTH:
            raise DisplaySizeError("Display width is too small")

    def getch(self) -> int:
        """Gets an input character from the user.

        This method returns after at most INPUT_TIMEOUT ms.

        Returns:
            int: the character entered by the user, or -1
        """
        char = self._stdscr.getch()
        return char

    def change_status(self, status) -> None:
        """Changes the status message displayed in the footer.

        Args:
            status: the status message to display
        """
        assert isinstance(status, str)

        self._status = status
        self._status_timer = self.STATUS_TIMEOUT

    def update(self) -> None:
        """Updates all actively tracked components of this object.

        Should be called by the main loop after every input or input timeout.
        """
        # have the queue check if it needs to go to the next player
        self._queue.update()

        # check the status of any downloads
        try:
            self._download_queue.update()
        except OSError as e:
            self.change_status("OSError: %s" % str(e))
            return

        # check to see if menu contents have been invalidated
        if not self.menus_valid:
            for perspective_id in self._perspectives:
                self._perspectives[perspective_id].update_menus()
            self.menus_valid = True

        # update the header text
        max_width = self._header_window.getmaxyx()[1]
        header_str = "%s " % castero.__title__
        stats_str = "[%d%%]" % self._queue.volume
        if self._queue.first is not None:
            state = self._queue.first.state
            header_str += ["Stopped", "Playing", "Paused"][state] + \
                ": %s" % self._queue.first.title
            if self._queue.length > 1:
                header_str += " (+%d in queue)" % (self._queue.length - 1)

            # the stats section of the header contains the volume and, if
            # something is playing, time/duration of the media
            stats_str += " [%s]" % self._queue.first.time_str

        # truncate the header string to ensure there is always space for
        # the stats to be displayed
        header_str = header_str[:max_width - len(stats_str)]
        header_str += stats_str.rjust(max_width - len(header_str))
        self._header_str = header_str[:max_width]

        # update the footer text
        footer_str = "%sPress %s for help" % (self._status + " -- " if len(
            self._status) > 0 else "", Config["key_help"])
        max_width = self._footer_window.getmaxyx()[1] - 1
        footer_str = footer_str[:max_width]
        self._footer_str = footer_str.ljust(max_width)[:max_width]

        # decrement the status timer
        if self._status_timer > 0:
            self._status_timer -= 1
            if self._status_timer <= 0:
                # status_timer should be reset during the next change_status()
                self._status = ""

        # write any episode modifications to the database
        if len(self._modified_episodes) > 0:
            for episode in self._modified_episodes:
                self.database.replace_episode(episode._feed, episode)
                if episode.progress is None:
                    self.database.delete_progress(episode, episode.progress)
                else:
                    self.database.replace_progress(episode, episode.progress)

            self.menus_valid = False
            self._modified_episodes = []

    @property
    def parent_x(self) -> int:
        """int: the width of the parent screen, in characters"""
        return self._parent_x

    @property
    def parent_y(self) -> int:
        """int: the height of the parent screen, in characters"""
        return self._parent_y

    @property
    def database(self) -> Database:
        """Database: the user's database"""
        return self._database

    @property
    def perspectives(self) -> dict:
        """dict: the loaded Perspective's with id:perspective pairs"""
        return self._perspectives

    @property
    def queue(self) -> Queue:
        """Queue: the Queue of Player's"""
        return self._queue

    @property
    def menus_valid(self) -> bool:
        """bool: whether the menu contents are valid (!need_to_be_updated)"""
        return self._menus_valid

    @menus_valid.setter
    def menus_valid(self, menus_valid) -> None:
        self._menus_valid = menus_valid

    @property
    def modified_episodes(self) -> List[Episode]:
        """List[Episode]: database episodes to save on the next update"""
        return self._modified_episodes