# Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import logging, time

from autotest_lib.client.common_lib import error


PLAYBACK_TEST_TIME_S = 10
PLAYER_ENDED_STATE = 'Ended'
PLAYER_PAUSE_STATE = 'Paused'
PLAYER_PLAYING_STATE = 'Playing'
WAIT_TIMEOUT_S = 10


class YouTubeHelper(object):
    """A helper class contains YouTube related utility functions.

       To use this class, please call wait_for_player_state(playing) as below
       before calling set_video_duration. Please note that set_video_duration
       must be called in order to access few functions which uses the video
       length member variable.

       yh = youtube_helper.YouTubeHelper(tab)
       yh.wait_for_player_state(PLAYER_PLAYING_STATE)
       yh.set_video_duration()

    """


    def __init__(self, youtube_tab):
        self._tab = youtube_tab
        self._video_duration = 0


    def set_video_duration(self):
        """Sets the video duration."""
        self._video_duration = (int(self._tab.EvaluateJavaScript(
                'player.getDuration()')))


    def video_current_time(self):
        """Returns video's current playback time.

        Returns:
            returns the current playback location in seconds (int).

        """
        return int(self._tab.EvaluateJavaScript('player.getCurrentTime()'))


    def get_player_status(self):
        """Returns the player status."""
        return self._tab.EvaluateJavaScript('playerStatus.innerHTML')


    def set_playback_quality(self, quality):
        """Set the video quality to the quality passed in the arg.

        @param quality: video quality to set.

        """
        self._tab.ExecuteJavaScript(
                'player.setPlaybackQuality("%s")' % quality)


    def get_playback_quality(self):
        """Returns the playback quality."""
        return self._tab.EvaluateJavaScript('player.getPlaybackQuality()')


    def wait_for_player_state(self, expected_status):
        """Wait till the player status changes to expected_status.

        If the status doesn't change for long, the test will time out after
        WAIT_TIMEOUT_S and fails.

        @param expected_status: status which is expected for the test
                                to continue.

        """
        wait_time = 0 # seconds
        while self.get_player_status() != expected_status:
            time.sleep(1)
            if wait_time > WAIT_TIMEOUT_S:
                player_status = self.get_player_status()
                raise error.TestError(
                        'Video failed to load. Player expected status: %s'
                        ' and current status: %s.'
                        % (expected_status, player_status))
            wait_time += 1


    def verify_video_playback(self):
        """Verify the video playback."""
        logging.info('Verifying the YouTube video playback.')
        playback = 0 # seconds
        prev_playback = 0
        count = 0
        while (self.video_current_time() < self._video_duration
               and playback < PLAYBACK_TEST_TIME_S):
            time.sleep(1)
            if self.video_current_time() <= prev_playback:
                if (count < 2):
                    logging.info('Retrying to video playback test.')
                    self._tab.ExecuteJavaScript(
                            'player.seekTo(%d, true)'
                            % (self.video_current_time() + 2))
                    time.sleep(1)
                    count = count + 1
                else:
                    player_status = self.get_player_status()
                    raise error.TestError(
                            'Video is not playing. Player status: %s.',
                            player_status)
            prev_playback = self.video_current_time()
            playback = playback + 1


    def wait_for_expected_resolution(self, expected_quality):
        """Wait for some time for getting expected resolution.

        @param expected_quality: quality to be set.

        """
        for _ in range(WAIT_TIMEOUT_S):
            dummy_quality = self.get_playback_quality()
            if dummy_quality == expected_quality:
                logging.info('Expected resolution is set.')
                break
            else:
                logging.info('Waiting for expected resolution.')
                time.sleep(0.1)


    def verify_video_resolutions(self):
        """Verify available video resolutions.

        Video resolution should be 360p, 480p, 720p and 1080p.

        """
        logging.info('Verifying the video resolutions.')
        video_qualities = self._tab.EvaluateJavaScript(
                'player.getAvailableQualityLevels()')
        if not video_qualities:
            raise error.TestError(
                    'Player failed to return available video qualities.')
        for quality in video_qualities:
            logging.info('Playing video in %s quality.' % quality)
            self.set_playback_quality(quality)
            self.wait_for_player_state(PLAYER_PLAYING_STATE)
            self.wait_for_expected_resolution(quality)
            current_quality = self.get_playback_quality()
            if quality != current_quality:
                raise error.TestError(
                        'Expected video quality: %s. Current video quality: %s'
                        % (quality, current_quality))
            time.sleep(1)
        # setting the video resolution to 480p for rest of the tests.
        self.set_playback_quality('large')


    def verify_player_states(self):
        """Verify the player states like play, pause, ended and seek."""
        logging.info('Verifying the player states.')
        self._tab.ExecuteJavaScript('player.pauseVideo()')
        self.wait_for_player_state(PLAYER_PAUSE_STATE)
        self._tab.ExecuteJavaScript('player.playVideo()')
        self.wait_for_player_state(PLAYER_PLAYING_STATE)
        # We are seeking the player position to (video length - 2 seconds).
        # Since the player waits for WAIT_TIMEOUT_S for the status change,
        # the video should be ended before we hit the timeout.
        video_end_test_duration = (self._video_duration -
                                   self.video_current_time() - 2)
        if video_end_test_duration >= WAIT_TIMEOUT_S:
            self._tab.ExecuteJavaScript(
                    'player.seekTo(%d, true)' % (self._video_duration - 5))
            self.wait_for_player_state(PLAYER_ENDED_STATE)
        else:
            raise error.TestError(
                    'Test video is not long enough for the video end test.')
        # Verifying seek back from the end position.
        self._tab.ExecuteJavaScript('player.seekTo(%d, true)'
                                    % (self._video_duration / 2))
        self.wait_for_player_state(PLAYER_PLAYING_STATE)
        # So the playback doesn't stay at the mid.
        seek_test = False
        for _ in range(WAIT_TIMEOUT_S):
            logging.info('Waiting for seek position to change.')
            time.sleep(1)
            seek_position = self.video_current_time()
            if (seek_position > self._video_duration / 2
                    and seek_position < self._video_duration):
                seek_test = True
                break
        if not seek_test:
            raise error.TestError(
                    'Seek location is wrong. '
                    'Video length: %d, seek position: %d.' %
                    (self._video_duration, seek_position))