# -*- coding: utf-8 -*-
#
#         PySceneDetect: Python-Based Video Scene Detector
#   ---------------------------------------------------------------
#     [  Site: http://www.bcastell.com/projects/pyscenedetect/   ]
#     [  Github: https://github.com/Breakthrough/PySceneDetect/  ]
#     [  Documentation: http://pyscenedetect.readthedocs.org/    ]
#
# Copyright (C) 2012-2018 Brandon Castellano <http://www.bcastell.com>.
#
# PySceneDetect is licensed under the BSD 3-Clause License; see the included
# LICENSE file, or visit one of the following pages for details:
#  - https://github.com/Breakthrough/PySceneDetect/
#  - http://www.bcastell.com/projects/pyscenedetect/
#
# This software uses the Numpy, OpenCV, click, tqdm, and pytest libraries.
# See the included LICENSE files or one of the above URLs for more information.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
# AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#

""" PySceneDetect scenedetect.cli.context Module

This file contains the implementation of the PySceneDetect command-line
interface (CLI) context class CliContext, used for the main application
state/context and logic to run the PySceneDetect CLI.
"""

# Standard Library Imports
from __future__ import print_function
import logging
import os
import time
import math
from string import Template

# Third-Party Library Imports
#import click
import cv2
from scenedetect.platform import tqdm

# PySceneDetect Library Imports
import scenedetect.detectors

from scenedetect.scene_manager import SceneManager
from scenedetect.scene_manager import write_scene_list

from scenedetect.stats_manager import StatsManager
from scenedetect.stats_manager import StatsFileCorrupt
from scenedetect.stats_manager import StatsFileFramerateMismatch

from scenedetect.video_manager import VideoManager
from scenedetect.video_manager import VideoOpenFailure
from scenedetect.video_manager import VideoFramerateUnavailable
from scenedetect.video_manager import VideoParameterMismatch
from scenedetect.video_manager import InvalidDownscaleFactor

from scenedetect.video_splitter import is_mkvmerge_available
from scenedetect.video_splitter import is_ffmpeg_available
from scenedetect.video_splitter import split_video_mkvmerge
from scenedetect.video_splitter import split_video_ffmpeg

from scenedetect.platform import get_cv2_imwrite_params
from scenedetect.platform import check_opencv_ffmpeg_dll


def get_plural(val_list):
    """ Get Plural: Helper function to return 's' if a list has more than one (1)
    element, otherwise returns ''.

    Returns:
        str: String of 's' if the length of val_list is greater than 1, otherwise ''.
    """
    return 's' if len(val_list) > 1 else ''


class CliContext(object):
    """ Context of the command-line interface passed between the various sub-commands.

    Pools all options, processing the main program options as they come in (e.g. those
    not passed to a command), followed by parsing each sub-command's options, preparing
    the actions to be executed in the process_input() method, which is called after the
    whole command line has been processed (successfully nor not).

    This class and the cli.__init__ module make up the bulk of the PySceneDetect
    application logic for the command line.
    """

    def __init__(self):
        # Properties for main scenedetect command options (-i, -s, etc...) and CliContext logic.
        self.options_processed = False          # True when CLI option parsing is complete.
        self.scene_manager = None               # detect-content, detect-threshold, etc...
        self.video_manager = None               # -i/--input, -d/--downscale
        self.base_timecode = None               # -f/--framerate
        self.start_frame = 0                    # time -s/--start
        self.stats_manager = None               # -s/--stats
        self.stats_file_path = None             # -s/--stats
        self.output_directory = None            # -o/--output
        self.quiet_mode = False                 # -q/--quiet or -v/--verbosity quiet
        self.frame_skip = 0                     # -fs/--frame-skip
        # Properties for save-images command.
        self.save_images = False                # save-images command
        self.image_extension = 'jpg'            # save-images -j/--jpeg, -w/--webp, -p/--png
        self.image_directory = None             # save-images -o/--output

        self.image_param = None                 # save-images -q/--quality if -j/-w,
                                                #   -c/--compression if -p


        self.image_name_format = (              # save-images -f/--name-format
            '$VIDEO_NAME-Scene-$SCENE_NUMBER-$IMAGE_NUMBER')
        self.num_images = 2                     # save-images -n/--num-images
        self.imwrite_params = get_cv2_imwrite_params()
        # Properties for split-video command.
        self.split_video = False                # split-video command
        self.split_mkvmerge = False             # split-video -c/--copy
        self.split_args = None                  # split-video -a/--override-args
        self.split_directory = None             # split-video -o/--output
        self.split_name_format = '$VIDEO_NAME-Scene-$SCENE_NUMBER'  # split-video -f/--filename
        self.split_quiet = False                # split-video -q/--quiet
        # Properties for list-scenes command.
        self.list_scenes = False                # list-scenes command
        self.print_scene_list = False           # list-scenes --quiet/-q
        self.scene_list_directory = None        # list-scenes -o/--output
        self.scene_list_name_format = None      # list-scenes -f/--filename
        self.scene_list_output = False          # list-scenes -n/--no-output


    def cleanup(self):
        # type: () -> None
        """ Cleanup: Releases all resources acquired by the CliContext (esp. the VideoManager). """
        try:
            logging.debug('Cleaning up...\n\n')
        finally:
            if self.video_manager is not None:
                self.video_manager.release()


    def _generate_images(self, scene_list, video_name,
                         image_name_template='$VIDEO_NAME-Scene-$SCENE_NUMBER-$IMAGE_NUMBER',
                         output_dir=None):
        # type: (List[Tuple[FrameTimecode, FrameTimecode]) -> None

        if not scene_list:
            return
        if not self.options_processed:
            return
        if self.num_images <= 0:
            raise ValueError()
        self.check_input_open()

        imwrite_param = []
        if self.image_param is not None:
            imwrite_param = [self.imwrite_params[self.image_extension], self.image_param]

        # Reset video manager and downscale factor.
        self.video_manager.release()
        self.video_manager.reset()
        self.video_manager.set_downscale_factor(1)
        self.video_manager.start()

        # Setup flags and init progress bar if available.
        completed = True
        logging.info('Generating output images (%d per scene)...', self.num_images)
        progress_bar = None
        if tqdm and not self.quiet_mode:
            progress_bar = tqdm(
                total=len(scene_list) * self.num_images, unit='images')

        filename_template = Template(image_name_template)


        scene_num_format = '%0'
        scene_num_format += str(max(3, math.floor(math.log(len(scene_list), 10)) + 1)) + 'd'
        image_num_format = '%0'
        image_num_format += str(math.floor(math.log(self.num_images, 10)) + 2) + 'd'

        timecode_list = dict()

        for i in range(len(scene_list)):
            timecode_list[i] = []

        if self.num_images == 1:
            for i, (start_time, end_time) in enumerate(scene_list):
                duration = end_time - start_time
                timecode_list[i].append(start_time + int(duration.get_frames() / 2))

        else:
            middle_images = self.num_images - 2
            for i, (start_time, end_time) in enumerate(scene_list):
                timecode_list[i].append(start_time)

                if middle_images > 0:
                    duration = (end_time.get_frames() - 1) - start_time.get_frames()
                    duration_increment = None
                    duration_increment = int(duration / (middle_images + 1))
                    for j in range(middle_images):
                        timecode_list[i].append(start_time + ((j+1) * duration_increment))

                # End FrameTimecode is always the same frame as the next scene's start_time
                # (one frame past the end), so we need to subtract 1 here.
                timecode_list[i].append(end_time - 1)

        for i in timecode_list:
            for j, image_timecode in enumerate(timecode_list[i]):
                self.video_manager.seek(image_timecode)
                self.video_manager.grab()
                ret_val, frame_im = self.video_manager.retrieve()
                if ret_val:
                    cv2.imwrite(
                        self.get_output_file_path(
                            '%s.%s' % (filename_template.safe_substitute(
                                VIDEO_NAME=video_name,
                                SCENE_NUMBER=scene_num_format % (i+1),
                                IMAGE_NUMBER=image_num_format % (j+1)
                            ), self.image_extension),
                            output_dir=output_dir), frame_im, imwrite_param)
                else:
                    completed = False
                    break
                if progress_bar:
                    progress_bar.update(1)

        if not completed:
            logging.error('Could not generate all output images.')


    def get_output_file_path(self, file_path, output_dir=None):
        # type: (str, Optional[str]) -> str
        """ Get Output File Path: Gets full path to output file passed as argument, in
        the specified global output directory (scenedetect -o/--output) if set, creating
        any required directories along the way.

        Arguments:
            file_path (str): File name to get path for.  If file_path is an absolute
                path (e.g. starts at a drive/root), no modification of the path
                is performed, only ensuring that all output directories are created.
            output_dir (Optional[str]): An optional output directory to override the
                global output directory option, if set.

        Returns:
            (str) Full path to output file suitable for writing.

        """
        if file_path is None:
            return None
        output_dir = self.output_directory if output_dir is None else output_dir
        # If an output directory is defined and the file path is a relative path, open
        # the file handle in the output directory instead of the working directory.
        if output_dir is not None and not os.path.isabs(file_path):
            file_path = os.path.join(output_dir, file_path)
        # Now that file_path is an absolute path, let's make sure all the directories
        # exist for us to start writing files there.
        try:
            os.makedirs(os.path.split(os.path.abspath(file_path))[0])
        except OSError:
            pass
        return file_path

    def _open_stats_file(self):

        if self.stats_manager is None:
            self.stats_manager = StatsManager()

        if self.stats_file_path is not None:
            if os.path.exists(self.stats_file_path):
                logging.info('Loading frame metrics from stats file: %s',
                             os.path.basename(self.stats_file_path))
                try:
                    with open(self.stats_file_path, 'rt') as stats_file:
                        self.stats_manager.load_from_csv(stats_file, self.base_timecode)
                except StatsFileCorrupt:
                    error_strs = [
                        'Could not load stats file.', 'Failed to parse stats file:',
                        'Could not load frame metrics from stats file - file is corrupt or not a'
                        ' valid PySceneDetect stats file. If the file exists, ensure that it is'
                        ' a valid stats file CSV, otherwise delete it and run PySceneDetect again'
                        ' to re-generate the stats file.']
                    logging.error('\n'.join(error_strs))
                    raise click.BadParameter(
                        '\n  Could not load given stats file, see above output for details.',
                        param_hint='input stats file')
                except StatsFileFramerateMismatch as ex:
                    error_strs = [
                        'could not load stats file.', 'Failed to parse stats file:',
                        'Framerate differs between stats file (%.2f FPS) and input'
                        ' video%s (%.2f FPS)' % (
                            ex.stats_file_fps,
                            's' if self.video_manager.get_num_videos() > 1 else '',
                            ex.base_timecode_fps),
                        'Ensure the correct stats file path was given, or delete and re-generate'
                        ' the stats file.']
                    logging.error('\n'.join(error_strs))
                    raise click.BadParameter(
                        'framerate differs between given stats file and input video(s).',
                        param_hint='input stats file')


    def process_input(self):
        # type: () -> None
        """ Process Input: Processes input video(s) and generates output as per CLI commands.

        Run after all command line options/sub-commands have been parsed.
        """
        logging.debug('Processing input...')
        if not self.options_processed:
            logging.debug('Skipping processing, CLI options were not parsed successfully.')
            return
        self.check_input_open()
        if not self.scene_manager.get_num_detectors() > 0:
            logging.error(
                'No scene detectors specified (detect-content, detect-threshold, etc...),\n'
                '  or failed to process all command line arguments.')
            return

        # Handle scene detection commands (detect-content, detect-threshold, etc...).
        self.video_manager.start()
        base_timecode = self.video_manager.get_base_timecode()

        start_time = time.time()
        logging.info('Detecting scenes...')

        num_frames = self.scene_manager.detect_scenes(
            frame_source=self.video_manager, frame_skip=self.frame_skip,
            show_progress=not self.quiet_mode)

        duration = time.time() - start_time
        logging.info('Processed %d frames in %.1f seconds (average %.2f FPS).',
                     num_frames, duration, float(num_frames)/duration)

        # Handle -s/--statsfile option.
        if self.stats_file_path is not None:
            if self.stats_manager.is_save_required():
                with open(self.stats_file_path, 'wt') as stats_file:
                    logging.info('Saving frame metrics to stats file: %s',
                                 os.path.basename(self.stats_file_path))
                    self.stats_manager.save_to_csv(
                        stats_file, base_timecode)
            else:
                logging.debug('No frame metrics updated, skipping update of the stats file.')

        # Get list of detected cuts and scenes from the SceneManager to generate the required output
        # files with based on the given commands (list-scenes, split-video, save-images, etc...).
        cut_list = self.scene_manager.get_cut_list(base_timecode)
        scene_list = self.scene_manager.get_scene_list(base_timecode)
        video_paths = self.video_manager.get_video_paths()
        video_name = os.path.basename(video_paths[0])
        if video_name.rfind('.') >= 0:
            video_name = video_name[:video_name.rfind('.')]

        # Ensure we don't divide by zero.
        if scene_list:
            logging.info('Detected %d scenes, average shot length %.1f seconds.',
                         len(scene_list),
                         sum([(end_time - start_time).get_seconds()
                              for start_time, end_time in scene_list]) / float(len(scene_list)))
        else:
            logging.info('No scenes detected.')

        # Handle list-scenes command.
        if self.scene_list_output:
            scene_list_filename = Template(self.scene_list_name_format).safe_substitute(
                VIDEO_NAME=video_name)
            if not scene_list_filename.lower().endswith('.csv'):
                scene_list_filename += '.csv'
            scene_list_path = self.get_output_file_path(
                scene_list_filename, self.scene_list_directory)
            logging.info('Writing scene list to CSV file:\n  %s', scene_list_path)
            with open(scene_list_path, 'wt') as scene_list_file:
                write_scene_list(scene_list_file, scene_list, cut_list)
        # Handle `list-scenes`.
        if self.print_scene_list:
            logging.info("""Scene List:
-----------------------------------------------------------------------
 | Scene # | Start Frame |  Start Time  |  End Frame  |   End Time   |
-----------------------------------------------------------------------
%s
-----------------------------------------------------------------------
""", '\n'.join(
    [' |  %5d  | %11d | %s | %11d | %s |' % (
        i+1,
        start_time.get_frames(), start_time.get_timecode(),
        end_time.get_frames(), end_time.get_timecode())
     for i, (start_time, end_time) in enumerate(scene_list)]))


        if cut_list:
            logging.info('Comma-separated timecode list:\n  %s',
                         ','.join([cut.get_timecode() for cut in cut_list]))

        # Handle save-images command.
        if self.save_images:
            self._generate_images(scene_list=scene_list, video_name=video_name,
                                  image_name_template=self.image_name_format,
                                  output_dir=self.image_directory)

        # Handle split-video command.
        if self.split_video:
            # Add proper extension to filename template if required.
            dot_pos = self.split_name_format.rfind('.')
            if self.split_mkvmerge and not self.split_name_format.endswith('.mkv'):
                self.split_name_format += '.mkv'
            # Don't add if we find an extension between 2 and 4 characters
            elif not (dot_pos >= 0) or (
                    dot_pos >= 0 and not
                    ((len(self.split_name_format) - (dot_pos+1) <= 4 >= 2))):
                self.split_name_format += '.mp4'

            output_file_prefix = self.get_output_file_path(
                self.split_name_format, output_dir=self.split_directory)
            mkvmerge_available = is_mkvmerge_available()
            ffmpeg_available = is_ffmpeg_available()
            if mkvmerge_available and (self.split_mkvmerge or not ffmpeg_available):
                if not self.split_mkvmerge:
                    logging.warning(
                        'ffmpeg not found, falling back to fast copy mode (split-video -c/--copy).')
                logging.info('Splitting input video%s using mkvmerge, output path template:\n  %s',
                             's' if len(video_paths) > 1 else '', output_file_prefix)
                split_video_mkvmerge(video_paths, scene_list, output_file_prefix, video_name,
                                     suppress_output=self.quiet_mode or self.split_quiet)
            elif ffmpeg_available:
                if self.split_mkvmerge:
                    logging.warning('mkvmerge not found, falling back to normal splitting'
                                    ' mode (split-video).')
                logging.info(
                    'Splitting input video%s using ffmpeg, output path template:\n  %s',
                    's' if len(video_paths) > 1 else '', output_file_prefix)
                split_video_ffmpeg(video_paths, scene_list, output_file_prefix,
                                   video_name, arg_override=self.split_args,
                                   hide_progress=self.quiet_mode,
                                   suppress_output=self.quiet_mode or self.split_quiet)
            else:
                if not (mkvmerge_available or ffmpeg_available):
                    error_strs = ["ffmpeg/mkvmerge is required for split-video [-c/--copy]."]
                else:
                    error_strs = [
                        "{EXTERN_TOOL} is required for split-video{EXTRA_ARGS}.".format(
                            EXTERN_TOOL='mkvmerge' if self.split_mkvmerge else 'ffmpeg',
                            EXTRA_ARGS=' -c/--copy' if self.split_mkvmerge else '')]
                error_strs += ["Install one of the above tools to enable the split-video command."]
                error_str = '\n'.join(error_strs)
                logging.debug(error_str)
                raise click.BadParameter(error_str, param_hint='split-video')

            logging.info('Video splitting completed, individual scenes written to disk.')



    def check_input_open(self):
        # type: () -> None
        """ Check Input Open: Ensures that the CliContext's VideoManager was initialized,
        started, and at *least* one input video was successfully opened - otherwise, an
        exception is raised.

        Raises:
            click.BadParameter
        """
        if self.video_manager is None or not self.video_manager.get_num_videos() > 0:
            error_strs = ["No input video(s) specified.",
                          "Make sure '--input VIDEO' is specified at the start of the command."]
            error_str = '\n'.join(error_strs)
            logging.debug(error_str)
            raise click.BadParameter(error_str, param_hint='input video')


    def add_detector(self, detector):
        """ Add Detector: Adds a detection algorithm to the CliContext's SceneManager. """
        self.check_input_open()
        options_processed_orig = self.options_processed
        self.options_processed = False
        try:
            self.scene_manager.add_detector(detector)
        except scenedetect.stats_manager.FrameMetricRegistered:
            raise click.BadParameter(message='Cannot specify detection algorithm twice.',
                                     param_hint=detector.cli_name)
        self.options_processed = options_processed_orig


    def _init_video_manager(self, input_list, framerate, downscale):

        self.base_timecode = None

        logging.debug('Initializing VideoManager.')
        video_manager_initialized = False
        try:
            self.video_manager = VideoManager(
                video_files=input_list, framerate=framerate, logger=logging)
            video_manager_initialized = True
            self.base_timecode = self.video_manager.get_base_timecode()
            self.video_manager.set_downscale_factor(downscale)
        except VideoOpenFailure as ex:
            error_strs = [
                'could not open video%s.' % get_plural(ex.file_list),
                'Failed to open the following video file%s:' % get_plural(ex.file_list)]
            error_strs += ['  %s' % file_name[0] for file_name in ex.file_list]
            dll_okay, dll_name = check_opencv_ffmpeg_dll()
            if not dll_okay:
                error_strs += [
                    'Error: OpenCV dependency %s not found.' % dll_name,
                    'Ensure that you installed the Python OpenCV module, and that the',
                    '%s file can be found to enable video support.' % dll_name]
            logging.debug('\n'.join(error_strs[1:]))
            if not dll_okay:
                click.echo(click.style(
                    '\nOpenCV dependency missing, video input/decoding not available.\n', fg='red'))
            raise click.BadParameter('\n'.join(error_strs), param_hint='input video')
        except VideoFramerateUnavailable as ex:
            error_strs = ['could not get framerate from video(s)',
                          'Failed to obtain framerate for video file %s.' % ex.file_name]
            error_strs.append('Specify framerate manually with the -f / --framerate option.')
            logging.debug('\n'.join(error_strs))
            raise click.BadParameter('\n'.join(error_strs), param_hint='input video')
        except VideoParameterMismatch as ex:
            error_strs = ['video parameters do not match.', 'List of mismatched parameters:']
            for param in ex.file_list:
                if param[0] == cv2.CAP_PROP_FPS:
                    param_name = 'FPS'
                if param[0] == cv2.CAP_PROP_FRAME_WIDTH:
                    param_name = 'Frame width'
                if param[0] == cv2.CAP_PROP_FRAME_HEIGHT:
                    param_name = 'Frame height'
                error_strs.append('  %s mismatch in video %s (got %.2f, expected %.2f)' % (
                    param_name, param[3], param[1], param[2]))
            error_strs.append(
                'Multiple videos may only be specified if they have the same framerate and'
                ' resolution. -f / --framerate may be specified to override the framerate.')
            logging.debug('\n'.join(error_strs))
            raise click.BadParameter('\n'.join(error_strs), param_hint='input videos')
        except InvalidDownscaleFactor as ex:
            error_strs = ['Downscale value is not > 0.', str(ex)]
            logging.debug('\n'.join(error_strs))
            raise click.BadParameter('\n'.join(error_strs), param_hint='downscale factor')
        return video_manager_initialized


    def parse_options(self, input_list, framerate, stats_file, downscale, frame_skip):
        # type: (List[str], float, str, int, int) -> None
        """ Parse Options: Parses all global options/arguments passed to the main
        scenedetect command, before other sub-commands (e.g. this function processes
        the [options] when calling scenedetect [options] [commands [command options]].

        This method calls the _init_video_manager(), _open_stats_file(), and
        check_input_open() methods, which may raise a click.BadParameter exception.

        Raises:
            click.BadParameter
        """
        if not input_list:
            return

        logging.debug('Parsing program options.')

        self.frame_skip = frame_skip

        video_manager_initialized = self._init_video_manager(
            input_list=input_list, framerate=framerate, downscale=downscale)

        # Ensure VideoManager is initialized, and open StatsManager if --stats is specified.
        if not video_manager_initialized:
            self.video_manager = None
            logging.info('VideoManager not initialized.')
        else:
            logging.debug('VideoManager initialized.')
            self.stats_file_path = self.get_output_file_path(stats_file)
            if self.stats_file_path is not None:
                self.check_input_open()
                self._open_stats_file()

        # Init SceneManager.
        self.scene_manager = SceneManager(self.stats_manager)

        self.options_processed = True


    def time_command(self, start=None, duration=None, end=None):
        # type: (Optional[str], Optional[str], Optional[str]) -> None
        """ Time Command: Parses all options/arguments passed to the time command,
        or with respect to the CLI, this function processes [time options] when calling:
        scenedetect [global options] time [time options] [other commands...].

        Raises:
            click.BadParameter, VideoDecodingInProgress
        """
        logging.debug('Setting video time:\n    start: %s, duration: %s, end: %s',
                      start, duration, end)

        self.check_input_open()

        if duration is not None and end is not None:
            raise click.BadParameter(
                'Only one of --duration/-d or --end/-e can be specified, not both.',
                param_hint='time')

        self.video_manager.set_duration(start_time=start, duration=duration, end_time=end)

        if start is not None:
            self.start_frame = start.get_frames()


    def list_scenes_command(self, output_path, filename_format, no_output_mode, quiet_mode):
        # type: (str, str, bool, bool) -> None
        """ List Scenes Command: Parses all options/arguments passed to the list-scenes command,
        or with respect to the CLI, this function processes [list-scenes options] when calling:
        scenedetect [global options] list-scenes [list-scenes options] [other commands...].

        Raises:
            click.BadParameter
        """
        self.check_input_open()

        self.print_scene_list = True if quiet_mode is None else not quiet_mode
        self.scene_list_directory = output_path
        self.scene_list_name_format = filename_format
        if self.scene_list_name_format is not None and not no_output_mode:
            logging.info('Scene list CSV file name format:\n  %s', self.scene_list_name_format)
        self.scene_list_output = False if no_output_mode else True
        if self.scene_list_directory is not None:
            logging.info('Scene list output directory set:\n  %s', self.scene_list_directory)


    def save_images_command(self, num_images, output, name_format, jpeg, webp, quality,
                            png, compression):
        # type: (int, str, str, bool, bool, int, bool, int) -> None
        """ Save Images Command: Parses all options/arguments passed to the save-images command,
        or with respect to the CLI, this function processes [save-images options] when calling:
        scenedetect [global options] save-images [save-images options] [other commands...].

        Raises:
            click.BadParameter
        """
        self.check_input_open()

        num_flags = sum([True if flag else False for flag in [jpeg, webp, png]])
        if num_flags <= 1:

            # Ensure the format exists.
            extension = 'jpg'   # Default is jpg.
            if png:
                extension = 'png'
            elif webp:
                extension = 'webp'
            if not extension in self.imwrite_params or self.imwrite_params[extension] is None:
                error_strs = [
                    'Image encoder type %s not supported.' % extension.upper(),
                    'The specified encoder type could not be found in the current OpenCV module.',
                    'To enable this output format, please update the installed version of OpenCV.',
                    'If you build OpenCV, ensure the the proper dependencies are enabled. ']
                logging.debug('\n'.join(error_strs))
                raise click.BadParameter('\n'.join(error_strs), param_hint='save-images')

            self.save_images = True
            self.image_directory = output
            self.image_extension = extension
            self.image_param = compression if png else quality
            self.image_name_format = name_format
            self.num_images = num_images

            image_type = 'JPEG' if self.image_extension == 'jpg' else self.image_extension.upper()
            image_param_type = ''
            if self.image_param:
                image_param_type = 'Compression' if image_type == 'PNG' else 'Quality'
                image_param_type = ' [%s: %d]' % (image_param_type, self.image_param)
            logging.info('Image output format set: %s%s', image_type, image_param_type)
            if self.image_directory is not None:
                logging.info('Image output directory set:\n  %s',
                             os.path.abspath(self.image_directory))
        else:
            self.options_processed = False
            logging.error('Multiple image type flags set for save-images command.')
            raise click.BadParameter(
                'Only one image type (JPG/PNG/WEBP) can be specified.', param_hint='save-images')

