# -*- coding: utf-8 -*-
#
#            PySceneDetect: Python-Based Video Scene Detector
#   -------------------------------------------------------------------
#     [  Site:    https://scenedetect.com                           ]
#     [  Docs:    https://scenedetect.com/docs/                     ]
#     [  Github:  https://github.com/Breakthrough/PySceneDetect/    ]
#
# Copyright (C) 2014-2022 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 above pages for details.
#
"""Test for compatibility with v0.5 API.

Do not use this file as examples or in production code - see `test_api.py` instead.

The whole API is not compatible, but the compatibility layer makes the high level examples
work without modification.
"""

import logging
import os

from scenedetect import SceneManager, StatsManager, VideoManager, ContentDetector
from scenedetect.platform import init_logger


def validate_backwards_compatibility(test_video_file: str, stats_file_path: str):
    """Validate backwards compatibility wrapper for VideoManager.

    This is equivalent to the tests/api_test.py file from v0.5 with additional assertions.
    Do not following this test for writing applications - see test_api.py for examples
    using the current API. This test is equivalent to `test_api_stats_manager`.
    """
    # Suppress errors generated by using deprecated classes/arguments below.
    init_logger(log_level=logging.CRITICAL)
    video_manager = VideoManager([test_video_file])
    stats_file_path = test_video_file + '.csv'
    stats_manager = StatsManager()
    scene_manager = SceneManager(stats_manager)
    scene_manager.add_detector(ContentDetector())
    base_timecode = video_manager.get_base_timecode()
    scene_list = []
    try:
        start_time = base_timecode + 20 # 00:00:00.667
        end_time = base_timecode + 10.0 # 00:00:10.000

        if os.path.exists(stats_file_path):
            with open(stats_file_path, 'r') as stats_file:
                stats_manager.load_from_csv(stats_file)
            # ContentDetector requires at least 1 frame before it can calculate any metrics.
            assert stats_manager.metrics_exist(start_time.get_frames() + 1,
                                               [ContentDetector.FRAME_SCORE_KEY])
            # Correct end frame # for presentation duration.
            assert stats_manager.metrics_exist(end_time.get_frames() - 1,
                                               [ContentDetector.FRAME_SCORE_KEY])

        video_manager.set_duration(start_time=start_time, end_time=end_time)
        video_manager.set_downscale_factor()
        video_manager.start()
        assert video_manager.get_current_timecode().get_frames() == start_time.get_frames()

        scene_manager.detect_scenes(frame_source=video_manager)
        scene_list = scene_manager.get_scene_list()

        # Correct end frame # for presentation duration.
        assert video_manager.get_current_timecode().get_frames() == end_time.get_frames() + 1

        print('List of scenes obtained:')
        for i, scene in enumerate(scene_list):
            print('    Scene %2d: Start %s / Frame %d, End %s / Frame %d' % (
                i + 1,
                scene[0].get_timecode(),
                scene[0].get_frames(),
                scene[1].get_timecode(),
                scene[1].get_frames(),
            ))

        if stats_manager.is_save_required():
            with open(stats_file_path, 'w') as stats_file:
                stats_manager.save_to_csv(stats_file, base_timecode=base_timecode)
    finally:
        video_manager.release()
    return scene_list


def test_backwards_compatibility_with_stats(test_video_file: str):
    """Runs equivalent code to `tests/api_test.py` from v0.5 twice to also
    exercise loading a statsfile from disk."""
    stats_file_path = test_video_file + '.csv'
    try:
        os.remove(stats_file_path)
    except FileNotFoundError:
        pass
    scenes = validate_backwards_compatibility(test_video_file, stats_file_path)
    assert scenes
    assert os.path.exists(stats_file_path)
    # Make sure run with statsfile matches previous results.
    assert validate_backwards_compatibility(test_video_file, stats_file_path) == scenes
    os.remove(stats_file_path)