text: from __future__ import unicode_literals
  
  import re
  
  from .common import InfoExtractor
  from ..compat import (
      compat_str,
      compat_urlparse,
  )
  from ..utils import (
      ExtractorError,
      int_or_none,
      urlencode_postdata,
  )
  
  
  class LyndaBaseIE(InfoExtractor):
      _SIGNIN_URL = 'https://www.lynda.com/signin/lynda'
      _PASSWORD_URL = 'https://www.lynda.com/signin/password'
      _USER_URL = 'https://www.lynda.com/signin/user'
      _ACCOUNT_CREDENTIALS_HINT = 'Use --username and --password options to provide lynda.com account credentials.'
      _NETRC_MACHINE = 'lynda'
  
      @staticmethod
      def _check_error(json_string, key_or_keys):
          keys = [key_or_keys] if isinstance(key_or_keys, compat_str) else key_or_keys
          for key in keys:
              error = json_string.get(key)
              if error:
                  raise ExtractorError('Unable to login: %s' % error, expected=True)
  
      def _perform_login_step(self, form_html, fallback_action_url, extra_form_data, note, referrer_url):
          action_url = self._search_regex(
              r'<form[^>]+action=(["\'])(?P<url>.+?)\1', form_html,
              'post url', default=fallback_action_url, group='url')
  
          if not action_url.startswith('http'):
              action_url = compat_urlparse.urljoin(self._SIGNIN_URL, action_url)
  
          form_data = self._hidden_inputs(form_html)
          form_data.update(extra_form_data)
  
          response = self._download_json(
              action_url, None, note,
              data=urlencode_postdata(form_data),
              headers={
                  'Referer': referrer_url,
                  'X-Requested-With': 'XMLHttpRequest',
              }, expected_status=(418, 500, ))
  
          self._check_error(response, ('email', 'password', 'ErrorMessage'))
  
          return response, action_url
  
      def _perform_login(self, username, password):
          # Step 1: download signin page
          signin_page = self._download_webpage(
              self._SIGNIN_URL, None, 'Downloading signin page')
  
          # Already logged in
          if any(re.search(p, signin_page) for p in (
                  r'isLoggedIn\s*:\s*true', r'logout\.aspx', r'>Log out<')):
              return
  
          # Step 2: submit email
          signin_form = self._search_regex(
              r'(?s)(<form[^>]+data-form-name=["\']signin["\'][^>]*>.+?</form>)',
              signin_page, 'signin form')
          signin_page, signin_url = self._login_step(
              signin_form, self._PASSWORD_URL, {'email': username},
              'Submitting email', self._SIGNIN_URL)
  
          # Step 3: submit password
          password_form = signin_page['body']
          self._login_step(
              password_form, self._USER_URL, {'email': username, 'password': password},
              'Submitting password', signin_url)
  
  
  class LyndaIE(LyndaBaseIE):
      IE_NAME = 'lynda'
      IE_DESC = 'lynda.com videos'
      _VALID_URL = r'''(?x)
                      https?://
                          (?:www\.)?(?:lynda\.com|educourse\.ga)/
                          (?:
                              (?:[^/]+/){2,3}(?P<course_id>\d+)|
                              player/embed
                          )/
                          (?P<id>\d+)
                      '''
  
      _TIMECODE_REGEX = r'\[(?P<timecode>\d+:\d+:\d+[\.,]\d+)\]'
  
      _TESTS = [{
          'url': 'https://www.lynda.com/Bootstrap-tutorials/Using-exercise-files/110885/114408-4.html',
          # md5 is unstable
          'info_dict': {
              'id': '114408',
              'ext': 'mp4',
              'title': 'Using the exercise files',
              'duration': 68
          }
      }, {
          'url': 'https://www.lynda.com/player/embed/133770?tr=foo=1;bar=g;fizz=rt&fs=0',
          'only_matching': True,
      }, {
          'url': 'https://educourse.ga/Bootstrap-tutorials/Using-exercise-files/110885/114408-4.html',
          'only_matching': True,
      }, {
          'url': 'https://www.lynda.com/de/Graphic-Design-tutorials/Willkommen-Grundlagen-guten-Gestaltung/393570/393572-4.html',
          'only_matching': True,
      }, {
          # Status="NotFound", Message="Transcript not found"
          'url': 'https://www.lynda.com/ASP-NET-tutorials/What-you-should-know/5034180/2811512-4.html',
          'only_matching': True,
      }]
  
      def _raise_unavailable(self, video_id):
          self.raise_login_required(
              'Video %s is only available for members' % video_id)
  
      def _real_extract(self, url):
          mobj = self._match_valid_url(url)
          video_id = mobj.group('id')
          course_id = mobj.group('course_id')
  
          query = {
              'videoId': video_id,
              'type': 'video',
          }
  
          video = self._download_json(
              'https://www.lynda.com/ajax/player', video_id,
              'Downloading video JSON', fatal=False, query=query)
  
          # Fallback scenario
          if not video:
              query['courseId'] = course_id
  
              play = self._download_json(
                  'https://www.lynda.com/ajax/course/%s/%s/play'
                  % (course_id, video_id), video_id, 'Downloading play JSON')
  
              if not play:
                  self._raise_unavailable(video_id)
  
              formats = []
              for formats_dict in play:
                  urls = formats_dict.get('urls')
                  if not isinstance(urls, dict):
                      continue
                  cdn = formats_dict.get('name')
                  for format_id, format_url in urls.items():
                      if not format_url:
                          continue
                      formats.append({
                          'url': format_url,
                          'format_id': '%s-%s' % (cdn, format_id) if cdn else format_id,
                          'height': int_or_none(format_id),
                      })
              self._sort_formats(formats)
  
              conviva = self._download_json(
                  'https://www.lynda.com/ajax/player/conviva', video_id,
                  'Downloading conviva JSON', query=query)
  
              return {
                  'id': video_id,
                  'title': conviva['VideoTitle'],
                  'description': conviva.get('VideoDescription'),
                  'release_year': int_or_none(conviva.get('ReleaseYear')),
                  'duration': int_or_none(conviva.get('Duration')),
                  'creator': conviva.get('Author'),
                  'formats': formats,
              }
  
          if 'Status' in video:
              raise ExtractorError(
                  'lynda returned error: %s' % video['Message'], expected=True)
  
          if video.get('HasAccess') is False:
              self._raise_unavailable(video_id)
  
          video_id = compat_str(video.get('ID') or video_id)
          duration = int_or_none(video.get('DurationInSeconds'))
          title = video['Title']
  
          formats = []
  
          fmts = video.get('Formats')
          if fmts:
              formats.extend([{
                  'url': f['Url'],
                  'ext': f.get('Extension'),
                  'width': int_or_none(f.get('Width')),
                  'height': int_or_none(f.get('Height')),
                  'filesize': int_or_none(f.get('FileSize')),
                  'format_id': compat_str(f.get('Resolution')) if f.get('Resolution') else None,
              } for f in fmts if f.get('Url')])
  
          prioritized_streams = video.get('PrioritizedStreams')
          if prioritized_streams:
              for prioritized_stream_id, prioritized_stream in prioritized_streams.items():
                  formats.extend([{
                      'url': video_url,
                      'height': int_or_none(format_id),
                      'format_id': '%s-%s' % (prioritized_stream_id, format_id),
                  } for format_id, video_url in prioritized_stream.items()])
  
          self._check_formats(formats, video_id)
          self._sort_formats(formats)
  
          subtitles = self.extract_subtitles(video_id)
  
          return {
              'id': video_id,
              'title': title,
              'duration': duration,
              'subtitles': subtitles,
              'formats': formats
          }
  
      def _fix_subtitles(self, subs):
          srt = ''
          seq_counter = 0
          for pos in range(0, len(subs) - 1):
              seq_current = subs[pos]
              m_current = re.match(self._TIMECODE_REGEX, seq_current['Timecode'])
              if m_current is None:
                  continue
              seq_next = subs[pos + 1]
              m_next = re.match(self._TIMECODE_REGEX, seq_next['Timecode'])
              if m_next is None:
                  continue
              appear_time = m_current.group('timecode')
              disappear_time = m_next.group('timecode')
              text = seq_current['Caption'].strip()
              if text:
                  seq_counter += 1
                  srt += '%s\r\n%s --> %s\r\n%s\r\n\r\n' % (seq_counter, appear_time, disappear_time, text)
          if srt:
              return srt
  
      def _get_subtitles(self, video_id):
          url = 'https://www.lynda.com/ajax/player?videoId=%s&type=transcript' % video_id
          subs = self._download_webpage(
              url, video_id, 'Downloading subtitles JSON', fatal=False)
          if not subs or 'Status="NotFound"' in subs:
              return {}
          subs = self._parse_json(subs, video_id, fatal=False)
          if not subs:
              return {}
          fixed_subs = self._fix_subtitles(subs)
          if fixed_subs:
              return {'en': [{'ext': 'srt', 'data': fixed_subs}]}
          return {}
  
  
  class LyndaCourseIE(LyndaBaseIE):
      IE_NAME = 'lynda:course'
      IE_DESC = 'lynda.com online courses'
  
      # Course link equals to welcome/introduction video link of same course
      # We will recognize it as course link
      _VALID_URL = r'https?://(?:www|m)\.(?:lynda\.com|educourse\.ga)/(?P<coursepath>(?:[^/]+/){2,3}(?P<courseid>\d+))-2\.html'
  
      _TESTS = [{
          'url': 'https://www.lynda.com/Graphic-Design-tutorials/Grundlagen-guten-Gestaltung/393570-2.html',
          'only_matching': True,
      }, {
          'url': 'https://www.lynda.com/de/Graphic-Design-tutorials/Grundlagen-guten-Gestaltung/393570-2.html',
          'only_matching': True,
      }]
  
      def _real_extract(self, url):
          mobj = self._match_valid_url(url)
          course_path = mobj.group('coursepath')
          course_id = mobj.group('courseid')
  
          item_template = 'https://www.lynda.com/%s/%%s-4.html' % course_path
  
          course = self._download_json(
              'https://www.lynda.com/ajax/player?courseId=%s&type=course' % course_id,
              course_id, 'Downloading course JSON', fatal=False)
  
          if not course:
              webpage = self._download_webpage(url, course_id)
              entries = [
                  self.url_result(
                      item_template % video_id, ie=LyndaIE.ie_key(),
                      video_id=video_id)
                  for video_id in re.findall(
                      r'data-video-id=["\'](\d+)', webpage)]
              return self.playlist_result(
                  entries, course_id,
                  self._og_search_title(webpage, fatal=False),
                  self._og_search_description(webpage))
  
          if course.get('Status') == 'NotFound':
              raise ExtractorError(
                  'Course %s does not exist' % course_id, expected=True)
  
          unaccessible_videos = 0
          entries = []
  
          # Might want to extract videos right here from video['Formats'] as it seems 'Formats' is not provided
          # by single video API anymore
  
          for chapter in course['Chapters']:
              for video in chapter.get('Videos', []):
                  if video.get('HasAccess') is False:
                      unaccessible_videos += 1
                      continue
                  video_id = video.get('ID')
                  if video_id:
                      entries.append({
                          '_type': 'url_transparent',
                          'url': item_template % video_id,
                          'ie_key': LyndaIE.ie_key(),
                          'chapter': chapter.get('Title'),
                          'chapter_number': int_or_none(chapter.get('ChapterIndex')),
                          'chapter_id': compat_str(chapter.get('ID')),
                      })
  
          if unaccessible_videos > 0:
              self.report_warning(
                  '%s videos are only available for members (or paid members) and will not be downloaded. '
                  % unaccessible_videos + self._ACCOUNT_CREDENTIALS_HINT)
  
          course_title = course.get('Title')
          course_description = course.get('Description')
  
          return self.playlist_result(entries, course_id, course_title, course_description)
  