views.py

import os
import datetime
from hashlib import md5
import json
from PIL import Image
from StringIO import StringIO

from werkzeug.wrappers import Response
from werkzeug.utils import redirect

from sqlalchemy import desc, or_
from sqlalchemy.exc import IntegrityError
from sqlalchemy.orm.exc import NoResultFound

import exc
import util
from util import render_template, escape_html
import model
from model import tag, post, user, identity
from config import Configuration

from wtforms import Form, TextField, FileField, PasswordField, TextAreaField,\
    validators


def authorized(function):
    """
    checks if the username in the is identic to <username>, raises
    Exception('InsufficientPrivileges') otherwise.
    """
    def inner(*args, **kwargs):
        environment = args[1]
        try:
            username = kwargs['username']
        except KeyError:
            raise Exception('NoUsernamePassed')

        if environment['beaker.session']['username'] == username:
            return function(*args, **kwargs)
        else:
            raise Exception("InsufficientPrivileges")

    return inner


def admin(function):
    """
    checks if the username in the session is 'admin', raises
    Exception('InsufficientPrivileges') otherwise.
    """
    def inner(*args, **kwargs):
        environment = args[1]
        try:
            if environment['beaker.session']['username'] == "admin":
                return function(*args, **kwargs)
            else:
                raise Exception("InsufficientPrivileges")
        except KeyError:
            raise Exception("InsufficientPrivileges")

    return inner


def get_user_obj(username, session):
    """
    returns the user object with the name <username>.

    Raises Exception('NoSuchUser') if <username> is not known to the system.
    """
    try:
        u = session.query(user).join(identity).\
            filter(identity.username == username).one()

    except Exception:
        raise exc.NoSuchUser
    if not u:
        raise exc.NoSuchUser
    return u


def web_logout(request, environment, session):
    """
    Deletes the client's session
    """
    session = environment['beaker.session']
    session.delete()
    return redirect('/')


def web_login(request, environment, session):
    """
    verifies username and password, sets the username attribute of the session
    accordingly.

    Possible errortype values:
     * 'LoginInvalid' if the the login was not successful.
    """
    class LoginForm(Form):
        username = TextField('username', [validators.Required()])
        password = PasswordField('password', [validators.Required()])

    if request.method == "POST":
        form = LoginForm(request.form)
        if form.validate():
            try:
                user_obj = get_user_obj(form.username.data, session)
            # TODO be more specific
            except exc.NoSuchUser:
                return render_template("web_login.htmljinja", environment,
                                       form=form, error="Error: Username \
                                       and password do not match!")
            #TODO hash
            if user_obj.passwordhash == form.password.data:
                http_session = environment['beaker.session']
                http_session['username'] = user_obj.identity.username
                http_session.save()
                return redirect('/')
            else:
                return render_template("web_login.htmljinja", environment,
                                       form=form, error="Error: Username \
                                       and password do not match!")

        else:
            return render_template("web_login.htmljinja", environment,
                                   form=form)
    else:
        form = LoginForm()
        return render_template("web_login.htmljinja", environment, form=form)


def json_since(request, environment, session, username, timestamp):
    """
    returns json representations of <username>'s posts since <timestamp>, in
    consequence an empty array if there are none. if an error occurs, a json
    representation of the error handling is returned.

    Possible errortype values:
     * 'NoSuchUser'
    """
    try:
        u = get_user_obj(username, session)
    except Exception:
        return Response(json.dumps(
                        {'success':     False,
                         'errortype':   'NoSuchUser'}
                        ), content_type="text/json")

    posts = session.query(post).filter(post.owner == u).\
        filter(post.timestamp >= int(timestamp)).all()
    dicts = [x.to_serializable_dict() for x in posts]
    return Response(json.dumps(dicts, encoding="utf-8"),
                    content_type="text/json")


def json_last(request, environment, session, username, count):
    """
    returns json representations of <username>'s last <count> posts,
    in consequence an empty array if there are none.
    if an error occurs, a json representation of the error handling is
    returned.

    Possible errortype values:
     * 'NoSuchUser'
    """
    try:
        u = get_user_obj(username, session)
    except Exception:
        return Response(json.dumps(
                        {'success': False, 'errortype': 'NoSuchUser'}),
                        content_type="text/json")

    posts = session.query(post).filter(post.owner == u).\
        order_by(desc(post.timestamp)).limit(int(count)).all()
    dicts = [x.to_serializable_dict() for x in posts]
    return Response(json.dumps(dicts, encoding="utf-8"),
                    content_type="text/json")


def json_user_info(request, environment, session, username):
    """
    retunrns a json representation of some of <username>'s user data.
    if an error occurs, a json representation of the standard error handling
    is returned.

    Possible errortype values:
     * 'NoSuchUser' if the <username> is unknown to the system.

    """
    try:
        user = get_user_obj(username, session)
    except Exception:
        return Response(json.dumps(
                        {'success': False, 'errortype': 'NoSuchUser'}),
                        content_type="text/json")

    userdict = user.to_serializable_dict()
    return Response(json.dumps(userdict, encoding="utf-8"),
                    content_type="text/json")


def web_view_user_posts(request, environment, session, username, page=1,
                        posts_per_page=15):
    """
    returns the <page> <posts_per_page> posts created by <username> as 'posts',
    <username>'s user object as 'user', an empty array if there aren't any.

    Possible errortype values are:
    * 'NoSuchUser' if <username> is unknown to the system.

    May raise the following Exceptions:
    * Exception('NoSuchUser')
    """

    u = get_user_obj(username, session)

    own = session.query(post.id).filter(post.owner == u.identity).subquery()
    reposts = session.query(post.id).filter(
        post.reposters.contains(u.identity)).subquery()
    total_num = session.query(model.post).filter(or_(post.id.in_(reposts), post.id.in_(own))).count()
    allposts = session.query(model.post).filter(
        or_(post.id.in_(reposts), post.id.in_(own))).order_by(desc(post.timestamp)).offset((page-1)*posts_per_page).limit(posts_per_page).all()

    posts = [p.downcast() for p in allposts]

    return render_template("web_view_user_posts.htmljinja", environment,
                           posts=posts, page_num=page, total_num=total_num,
                           posts_per_page=posts_per_page, user=u)


@authorized
def web_view_stream(request, environment, session, username, page=1,
                    posts_per_page=15):
    """
    returns the <page> <posts_per_page> posts created by <username> as 'posts',
    <username>'s user object as 'user', an empty array if there aren't any.

    Possible errortype values are:
     * 'InputMakesNoSense' if at least one of <page> or <posts_per_page> is
       negative

    May raise the following Exceptions:
     * Exception('NoSuchUser')
     * Exception('InsufficientPrivileges')
    """

    # may raise Exception('NoSuchUser')
    u = get_user_obj(username, session)
    friend_ids = [f.id for f in u.friends]

    # one more time... with subqueries

    # friends' posts
    friendposts = session.query(model.post.id).\
        filter(model.post.owner_id.in_(friend_ids)).subquery()

    # friends' reposts
    friendreposts = session.query(model.post.id).join(model.post_reposters).\
        filter(model.post_reposters.c.identity_id.in_(friend_ids)).subquery()

    # now put it together

    posts = session.query(model.post).\
        filter(or_(model.post.id.in_(friendposts),
                   model.post.id.in_(friendreposts))).\
        order_by(desc(post.timestamp)).\
        offset((page-1)*posts_per_page).limit(posts_per_page).all()

    total_num = session.query(model.post).\
        filter(or_(model.post.id.in_(friendposts),
                   model.post.id.in_(friendreposts))).\
        count()

    posts = [p.downcast() for p in posts]

    return render_template("web_view_stream.htmljinja", environment,
                           posts=posts, user=u, page_num=page, total_num=total_num,
                           posts_per_page=posts_per_page)


@authorized
def web_view_stream_tag(request, environment, session, username, tagstr,
                        page=1, posts_per_page=15):
    """
    returns the <page> <posts_per_page> posts owned by <username> and tagged
    with <tagstr> as 'posts' and the <username>'s user object as 'user'

    Possible errortype values are:
     *

    May raise the following Exceptions:
     * Exception('NoSuchUser')
     * Exception('InsufficientPrivileges')
     * Exception('InputMakesNoSense')
     * Exception('TagNotFound')
    """

    u = get_user_obj(username, session)

    #identify tag
    res = session.query(tag).filter(tag.tag == tagstr).all()
    if res:
        tag_found = res[0]
        posts = tag_found.posts[(page-1)*posts_per_page:page*posts_per_page]
        posts = [p.downcast() for p in posts]
        posts = sorted(posts, key = lambda p: p.timestamp, reverse=True)
        total_num = len(tag_found.posts)
    else:
        raise Exception("TagNotFound")
    return render_template("web_view_stream_tag.htmljinja", environment,
                           posts=posts, tag=tag_found, show_tags=True, user=u,
                           page_num=page, total_num=total_num,
                           posts_per_page=posts_per_page)


@authorized
def web_insert_post(request, environment, session, username, plugin_str=None):
    """
    Saves a post to <username>'s wurstgulasch.

    Possible errortypes are:
     *
    May raise the following Exceptions:
     *
    """
    if not request.method == "POST":
        if plugin_str is None:
            # list all available plugins
            pluginlist = environment['content_plugins'].keys()
            return render_template("web_choose_post_plugin.htmljinja",
                                   environment, pluginlist=pluginlist)
        else:
            # check if plugin actually exists
            if plugin_str not in environment['content_plugins'].keys():
                raise Exception('Content Plugin not found :(')
            # show the specific form
            else:
                form = environment['content_plugins'][plugin_str].\
                    CreatePostForm()
                return render_template("web_insert_post.htmljinja",
                                       environment, form=form)
    else:
        if not plugin_str is None:
            # check if plugin actually exists
            if plugin_str not in environment['content_plugins'].keys():
                raise Exception('Content Plugin not found :(')
            form = environment['content_plugins'][plugin_str].CreatePostForm(request.form)
            # create post object
            if form.validate():
                plugin_class = environment['content_plugins'][plugin_str]
                post_obj = plugin_class.from_request(form, request)

                # set user and time
                u = get_user_obj(username, session)
                post_obj.owner = u.identity
                # add tags
                tag_strings = [ t.strip() for t in escape_html(request.form['tags']).split(',') ]
                for tag_str in tag_strings:
                    res = session.query(tag).filter(tag.tag == tag_str).all()
                    if res:
                        post_obj.tags.append(res[0])
                    else:
                        new_tag = tag(tag_str)
                        session.add(new_tag)
                        post_obj.tags.append(new_tag)

                # insert into database
                session.add(post_obj)
                session.commit()

                # return to Stream
                return redirect('/' + username + '/stream')
            else:
                return render_template("web_insert_post.htmljinja",
                                       environment, form=form)
  
        else:
            # this should not happen
            pass


@authorized
def json_repost(request, environment, session, username, post_id):
    u = get_user_obj(username, session)
    p = session.query(model.post).filter(model.post.post_id == post_id).one()
    p.reposters.append(u.identity)
    session.commit()
    return Response('{\'success\'=True}')


@authorized
def web_repost(request, environment, session, username, post_id):
    u = get_user_obj(environment['beaker.session']['username'], session)
    p = session.query(model.post).filter(model.post.post_id == post_id).one()
    if u.identity.username == p.owner.username:
        raise Exception('Cannot Repost your own posts.')

    #p.reposters.append(u.identity)

    stmt = model.post_reposters.insert().values(post_id = p.id,
            identity_id=u.identity.id, repost_date=datetime.datetime.now())
    session.execute(stmt)
    session.commit()
    return redirect("/" + username + "/post/" + str(post_id))


def web_view_post_detail(request, environment, session, username, postid):
    """
    Saves a post to <username>'s wurstgulasch.

    Possible errortypes are:
     *
    May raise the following Exceptions:
     *
    """
    u = get_user_obj(username, session)

    p = session.query(model.post).filter(post.post_id == int(postid),).all()[0]
    p = p.downcast()
    return render_template("web_view_post_detail.htmljinja", environment,
                           post=p, user=u, show_tags=True)


@authorized
def web_view_friends(request, environment, session, username):
    """
    Saves a post to <username>'s wurstgulasch.

    Possible errortypes are:
     *
    May raise the following Exceptions:
     *
    """
    u = get_user_obj(username, session)

    friends = u.friends
    return render_template("web_view_friends.htmljinja", environment,
                           friends=friends)


@authorized
def web_add_friend(request, environment, session, username):
    """
    Saves a post to <username>'s wurstgulasch.

    Possible errortypes are:
     *
    May raise the following Exceptions:
     *
    """
    class AddFriendForm(Form):
        handle = TextField("FriendHandle", [validators.Required()])

    u = get_user_obj(username, session)

    if request.method == "POST":
        form = AddFriendForm(request.form)
        if form.validate():
            # check if identity exists
            name, wurstgulasch = form.handle.data.split("@")
            if session.query(identity).\
                    filter(identity.username == name,
                           identity.wurstgulasch == wurstgulasch).\
                    count() != 0:
                new_friend = session.query(identity).\
                    filter(identity.username == name,
                           identity.wurstgulasch == wurstgulasch).one()
            else:
                new_friend = identity(name, wurstgulasch=wurstgulasch)
                session.add(new_friend)

            u.friends.append(new_friend)
            session.commit()

            return redirect('/' + username + '/friends')

    else:
        form = AddFriendForm()
        return render_template("web_add_friends.htmljinja",
                               environment, form=form)


@authorized
def web_delete_friend(request, environment, session, username, friendid):
    user_obj = get_user_obj(username, session)
    friend_obj = session.query(identity).filter(identity.id == friendid).one()
    user_obj.friends.remove(friend_obj)

    session.commit()

    return redirect('/' + username + '/friends')


def web_view_profile(request, environment, session, username):
    """
    Saves a post to <username>'s wurstgulasch.

    Possible errortypes are:
     *
    May raise the following Exceptions:
     *
    """
    u = get_user_obj(username, session)
    return render_template("web_view_profile.htmljinja", environment, user=u)


@authorized
def web_change_profile(request, environment, session, username):
    """
    makes changes to <username>'s user object

    Possible errortypes are:
     *
    May raise the following Exceptions:
     *
    """
    class changeProfileForm(Form):
        tagline = TextField("Tagline")
        bio = TextAreaField("Something about yourself")
        avatar = FileField("Your Avatar")
        password = PasswordField("New Password (leave empty if you \
                                  don't want to change it")
        password_confirm = PasswordField("Confirm new password")

    u = get_user_obj(username, session)

    if request.method == 'POST':
        form = changeProfileForm(request.form)
 
        u.identity.tagline = escape_html(form.tagline.data)
        u.identity.bio = escape_html(form.bio.data)

        # avatar
        uploaded = request.files.get('avatar')
        if uploaded:
            mimetype = uploaded.content_type
            try:
                filetype = util.check_mimetype(mimetype, ["image"],
                                               ["jpeg", "png", "gif", "tiff"])
            except Exception:
                # TODO no valid filetype
                pass
            else:
                buf_image = uploaded.read()
                image = util.force_quadratic(Image.open(StringIO(buf_image)))
                thumbnail = util.generate_thumbnail(image, 50)

                assetspath = os.path.join(Configuration().base_path, 'assets')
                filename = "avatar_" + md5(buf_image).hexdigest() + "." +\
                           filetype
                imagepath = os.path.join(assetspath, filename)
                thumbnailpath = os.path.join(assetspath, "thumb_" + filename)

                image.save(imagepath)
                thumbnail.save(thumbnailpath)

                u.identity.avatar_url = Configuration().base_url + 'assets/' +\
                    filename

                u.identity.avatar_small_url = Configuration().base_url +\
                    'assets/thumb_' + filename

        # TODO: use hash
        if form.password.data != "" and form.password.data == form.password_confirm.data:
            u.passwordhash = form.password.data

        session.commit()
        return render_template("web_change_profile.htmljinja", environment,
                               success=True, user=u)
    else:
        form = changeProfileForm()
        form.bio.data = escape_html(u.identity.bio)
        form.tagline.data = escape_html(u.identity.tagline)
        return render_template("web_change_profile.htmljinja", environment,
                               user=u, form=form)


@admin
def admin_view_users(request, environment, session):
    """
    returns all user objects known to the system.

    Possible errortypes are:
     *
    May raise the following Exceptions:
     *
    """

    users = session.query(model.user).all()

    return render_template("admin_view_users.htmljinja", environment,
                           users=users)


@admin
def admin_create_user(request, environment, session):
    """
    creates a new user and adds it to the database.

    Possible errortypes are:
     *
    May raise the following Exceptions:
     *
    """
    class CreateUserForm(Form):
        username = TextField('Username', [validators.Required()])
        password = TextField('Password', [validators.Required()])

    if request.method == 'POST':
        form = CreateUserForm(request.form)
        if form.validate():
            username = form.username.data.strip()
            password = form.password.data
            #TODO: hash password
            u = model.user(username, password)
            session.add(u)
            try:
                session.commit()
            except IntegrityError:
                return render_template("admin_create_user.htmljinja",
                                       environment, success=False, form=form)

            return redirect('/admin/users/view')
        else:
            return render_template("admin_create_user.htmljinja", environment,
                                   success=False, form=form)
    else:
        form = CreateUserForm()
        return render_template("admin_create_user.htmljinja", environment,
                               form=form)


@admin
def admin_reset_password(request, environment, session, username):
    """
    resets  <username>'s password

    Possible errortypes are:
     *
    May raise the following Exceptions:
     *
    """
    class ResetPasswordForm(Form):
        password = TextField("password",
                             [validators.Required()])

    u = get_user_obj(username, session)

    if request.method == 'POST':
        form = ResetPasswordForm(request.form)
        if form.validate():
            u.passwordhash = form.password.data
            session.commit()
            return redirect('/admin/users/view')
    else:
        form = ResetPasswordForm()
        return render_template("admin_reset_password.htmljinja", environment,
                               success=False, user=u, form=form)


@admin
def admin_delete_user(request, environment, session, username):
    """
    deletes <username>'s user object from the database

    Possible errortypes are:
     *
    1May raise the following Exceptions:
     *
    """
    # don't delete admin user
    if username == 'admin':
        return render_template("admin_delete_user.htmljinja", environment,
                               success=False)

    try:
        user = get_user_obj(username, session)
    except NoResultFound:
        return render_template("admin_delete_user.htmljinja", environment,
                               success=False)  # delete all posts by user
    posts = session.query(model.post).filter(model.post.owner == user).all()
    for post in posts:
        session.delete(post)
    # delete friends
    #for friend in user.friends:
        #session.delete(friend)
    session.delete(user)
    session.commit()

    return redirect('/admin/users/view')


def default(request, environment, session):
    """
    returns an empty dictionary.

    Possible errortypes are:
     *
    May raise the following Exceptions:
     *
    """
    return render_template("default.htmljinja", environment)