def get_algorithm(filename, msglen, password):
    if filename.endswith("jpeg") or filename.endswith("jpg"):
        # PQ, F5, LSB
        jpeg_data = libstegofile.jpeg_data_t()
        jpeg_int = libstegofile.jpeg_internal_data_t()
        err = libstegofile.io_jpeg_read(filename,jpeg_data, jpeg_int)
#TODO: ERROR (everywhere)

        para = libstegofile.pq_parameter()
        para.header_size = 0
        para.quality = 0

        if libstego.pq_check_capacity(jpeg_data, para) >= msglen:
            libstegofile.jpeg_cleanup_data(jpeg_data)
            libstegofile.io_jpeg_cleanup_internal(jpg_int)
            return ["PQ",para]

        para = libstegofile.f5_parameter()


        if libstego.f5_check_capacity(jpeg_data, para) >= msglen:
            libstegofile.jpeg_cleanup_data(jpeg_data)
            libstegofile.io_jpeg_cleanup_internal(jpg_int)
            return ["F5",para]

        para = libstegofile.lsb_parameter()


#        if libstego.lsb_check_capacity(jpeg_data, para) >= msglen:
#            libstegofile.jpeg_cleanup_data(jpeg_data)
#            libstegofile.io_jpeg_cleanup_internal(jpg_int)
#            return ["LSB",para]

        libstegofile.jpeg_cleanup_data(jpeg_data)
        libstegofile.io_jpeg_cleanup_internal(jpg_int)
        return

    elif filename.endswith("gif"):
        # AdvGifshuffle, Gifshuffle, Frirui, Sort/Unsort, LSB
        palette_data = libstegofile.palette_data_t()
        gif_int = libstegofile.gif_internal_data_t()
        err = libstegofile.io_gif_read(filename, palette_data, gif_int)

        para = libstegofile.gifshuffle_parameter()
        if libstego.gifshuffle_check_capacity(palette_data, para) >= msglen:
            return ["Adv. Gifshuffle", para]
# no elif gifshuffle since it has the same capacity that adv gusfhuffle has

        para = libstegofile.frirui_parameter()

        para.method = 0;
        para.size = 100;
        para.password = password
        para.pwlen = len(password)

        #para.method = 1;
        #para.threshold = 574;
        #para.password = password
        #para.pwlen = len(password)

        #para.method = 1;
        #para.threshold = 1148;
        #para.password = password
        #para.pwlen = len(password)

        #para.method = 2;
        #para.password = password
        #para.pwlen = len(password)

        #para.method = 1;
        #para.threshold = 2295;
        #para.password = password
        #para.pwlen = len(password)

        #para.method = 0;
        #para.size = 6;
        #para.password = password
        #para.pwlen = len(password)


        # DONE: multiple parameter sets for frirui from Matthias here!
        if libstego.frirui_check_capacity(palette_data, para) >= msglen:
            return ["Frirui", para]

        para = libstegofile.sortunsort_parameter()
        if libstego.sortunsort_check_capacity(palette_data, para) >= msglen:
            return ["Sort/Unsort", para]

        """para = libstegofile_lsb_parameter_t()
        #TODO: LSB Wrappers for structs like palette_data -> Jan ?
        if libstego.lsb_check_capacity(palette_data, para) >= msglen:
            return ["LSB", para]"""


    elif filename.endswith("png"):
        # CPT, Battlesteg, LSB
        rgb_data = libstegofile.rgb_data_t()
        png_int = libstegofile.png_internal_data_t()
        err = libstegofile.io_png_read(filename, rgb_data, png_int)

        for i in [2,4,6,8]:
            para = libstegofile.cpt_parameter()
            para.block_width = i;
            para.block_height = i;
            para.password = password
            para.pwlen = len(password)

            if libstegofile.cpt_check_capacity(rgb_data, para) >= msglen:
                return ["CPT", para]

        para = libstegofile.battlesteg_parameter()
        para.startbit = 7
        para.move_away = 3
        para.range = 5
        para.password = password
        para.pwlen = len(password)

        # parameter set "capacity"
        #para = libstegofile.battlesteg_parameter()
        #para.startbit = 6
        #para.move_away = 3
        #para.range = 5
        #para.password = "******"
        #para.pwlen = 8

        if libstegofile.battlesteg_check_capacity(rgb_data, para) >= msglen:
            return ["BattleSteg", para]

        """para = libstegofile.lsb_parameter()
        para.password = password
        para.pwlen = len(password)
        para.select_mode = 2


        if libstegofile.lsb_check_capacity(rgb_data, para) >= msglen:
            return ["LSB", para]"""

    elif filename.endswith("wav"):
        # Phase Coding, Echo Hiding, LSB
        pass

    elif filename.endswith("svg"):
        # SVGSteg

        svg_data = libstegofile.svg_data_t()
        svg_int = libstegofile.svg_internal_data_t()
        err = libstegofile.io_svg_read(filename, svg_data, svg_int)

        if err != 0:
            return None

        para = libstegofile.svg_parameter_t()
        para.password = password
        para.pwlen = len(password)
        para.first_embed_digit = 3

        fits = False
        if libstego.svg_check_capacity(svg_dat, para) >= msglen:
            fits = True

        libstegofile.svg_cleanup_data(svg_dat)
        libstegofile.svg_cleanup_internal(svg_int)

        if fits == True:
            return ["SVG", para]
def get_best_method(filename, filetype, msglen, password):
    # setup all methods
    setup_methods(password)

    # get methods for current file type
    num_selected, sel_method = get_methods_for_filetype(filetype)

    for i in [0, num_selected-1]:
        fits = False

        if method_to_algo[i] == "PQ":
            # prepare data strucures
            jpeg_data = libstegofile.jpeg_data_t()
            jpeg_int = libstegofile.jpeg_internal_data_t()

            # read file data
            err = libstegofile.io_jpeg_read(filename, jpeg_data, jpeg_int)
            if err != 0:
                # TODO better error handling -> detailed message what went wrong
                # by using the 'lstg_errno' code
                return None

            # check if message fits with the current params
            para = methods[i]
            if libstego.pq_check_capacity(jpeg_data, para) >= msglen:
                fits = True

            # cleanup
            libstegofile.jpeg_cleanup_data(jpeg_data)
            libstegofile.io_jpeg_cleanup_internal(jpg_int)


        if method_to_algo[i] == "F5":
            # prepare data strucures
            jpeg_data = libstegofile.jpeg_data_t()
            jpeg_int = libstegofile.jpeg_internal_data_t()

            # read file data
            err = libstegofile.io_jpeg_read(filename, jpeg_data, jpeg_int)
            if err != 0:
                # TODO better error handling -> detailed message what went wrong
                # by using the 'lstg_errno' code
                return None

            # check if message fits with the current params
            para = methods[i]
            if libstego.f5_check_capacity(jpeg_data, para) >= msglen:
                fits = True

            # cleanup
            libstegofile.jpeg_cleanup_data(jpeg_data)
            libstegofile.io_jpeg_cleanup_internal(jpg_int)


        if method_to_algo[i] in ["Adv. Gifshuffle", "Gifshuffle"]:
            # prepare data strucures
            palette_data = libstegofile.palette_data_t()
            gif_int = libstegofile.gif_internal_data_t()

            # read file data
            err = libstegofile.io_gif_read(filename, palette_data, gif_int)
            if err != 0:
                # TODO better error handling -> detailed message what went wrong
                # by using the 'lstg_errno' code
                return None

            # check if message fits with the current params
            para = methods[i]
            if libstego.gifshuffle_check_capacity(palette_data, para) >= msglen:
                fits = True

            # cleanup
            libstegofile.io_gif_cleanup_data(palette_data)
            libstegofile.io_gif_cleanup_internal(gif_int)


        if method_to_algo[i] == "Frirui":
            # prepare data strucures
            palette_data = libstegofile.palette_data_t()
            gif_int = libstegofile.gif_internal_data_t()

            # read file data
            err = libstegofile.io_gif_read(filename, palette_data, gif_int)
            if err != 0:
                # TODO better error handling -> detailed message what went wrong
                # by using the 'lstg_errno' code
                return None

            # check if message fits with the current params
            para = methods[i]
            if libstego.frirui_check_capacity(palette_data, para) >= msglen:
                fits = True

            # cleanup
            libstegofile.io_gif_cleanup_data(palette_data)
            libstegofile.io_gif_cleanup_internal(gif_int)


        if method_to_algo[i] == "Sort/Unsort":
            # prepare data strucures
            palette_data = libstegofile.palette_data_t()
            gif_int = libstegofile.gif_internal_data_t()

            # read file data
            err = libstegofile.io_gif_read(filename, palette_data, gif_int)
            if err != 0:
                # TODO better error handling -> detailed message what went wrong
                # by using the 'lstg_errno' code
                return None

            # check if message fits with the current params
            para = methods[i]
            if libstego.sortunsort_check_capacity(palette_data, para) >= msglen:
                fits = True

            # cleanup
            libstegofile.io_gif_cleanup_data(palette_data)
            libstegofile.io_gif_cleanup_internal(gif_int)

        if method_to_algo[i] == "CPT":
            # prepare data strucures
            rgb_data = libstegofile.rgb_data_t()
            png_int = libstegofile.png_internal_data_t()

            # read file data
            err = libstegofile.io_png_read(filename, rgb_data, png_int)
            if err != 0:
                # TODO better error handling -> detailed message what went wrong
                # by using the 'lstg_errno' code
                return None

            # check if message fits with the current params
            para = methods[i]
            if libstegofile.cpt_check_capacity(rgb_data, para) >= msglen:
                fits = True

            # cleanup
            libstegofile.io_png_cleanup_data(rgb_data)
            libstegofile.io_png_cleanup_internal(png_int)


        if method_to_algo[i] == "Battlesteg":
            # prepare data strucures
            rgb_data = libstegofile.rgb_data_t()
            png_int = libstegofile.png_internal_data_t()

            # read file data
            err = libstegofile.io_png_read(filename, rgb_data, png_int)
            if err != 0:
                # TODO better error handling -> detailed message what went wrong
                # by using the 'lstg_errno' code
                return None

            # check if message fits with the current params
            para = methods[i]
            if libstegofile.battlesteg_check_capacity(rgb_data, para) >= msglen:
                fits = True

            # cleanup
            libstegofile.io_png_cleanup_data(rgb_data)
            libstegofile.io_png_cleanup_internal(png_int)


        if method_to_algo[i] == "SVG Steg":
            # prepare data strucures
            svg_data = libstegofile.svg_data_t()
            svg_int = libstegofile.svg_internal_data_t()

            # read file data
            err = libstegofile.io_svg_read(filename, svg_data, svg_int)
            if err != 0:
                # TODO better error handling -> detailed message what went wrong
                # by using the 'lstg_errno' code
                return None

            # check if message fits with the current params
            para = methods[i]
            if libstego.svg_check_capacity(svg_data, para) >= msglen:
                fits = True

            # cleanup
            libstegofile.svg_cleanup_data(svg_data)
            libstegofile.svg_cleanup_internal(svg_int)

        if method_to_algo[i] == "Echo Hiding":
            # TODO implement
            pass


        if method_to_algo[i] == "Phase Coding":
            # TODO implement
            pass


        if method_to_algo[i] == "LSB":
            # TODO implement
            pass

        if fits:
            return i

    return None