import collections
import itertools
import os
import qwarc
import qwarc.utils


responseHandler = qwarc.utils.handle_response_limit_error_retries(5)


class Comments(qwarc.Item):
	itemType = 'comments'
	# itemValue = '{videoId}'

	@classmethod
	def generate(cls):
		yield os.environ['YOUTUBE_VIDEOID']

	async def process(self):
		videoPageUrl = f'https://www.youtube.com/watch?v={self.itemValue}'
		response, _ = await self.fetch(videoPageUrl, responseHandler = responseHandler)
		if not response or response.status != 200:
			self.logger.error('Could not fetch video page')
			return
		content = await response.read()

		sessionToken = qwarc.utils.str_get_between(content, b'"XSRF_TOKEN":"', b'"')
		if not sessionToken:
			self.logger.error('Could not find session token')
			return
		if sessionToken.lstrip(b'0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-') not in (b'', b'=', b'==', b'%3D', b'%3D%3D'):
			self.logger.error(f'Unexpected session token value: {sessionToken!r}')
			return
		sessionToken = sessionToken.decode('ascii')

		sectionIdentifierPos = content.find(b'"comment-item-section"')
		if sectionIdentifierPos < 0:
			self.logger.error('Could not find comment section identifier')
			return
		continuationStartPos = content.rfind(b'"continuation":', 0, sectionIdentifierPos)
		if continuationStartPos < 0:
			self.logger.error('Could not find continuation start position')
			return
		section = content[continuationStartPos:sectionIdentifierPos]
		continuationToken = qwarc.utils.str_get_between(section, b'"continuation":"', b'"')
		if continuationToken.lstrip(b'0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-') not in (b'', b'=', b'==', b'%3D', b'%3D%3D'):
			self.logger.error(f'Unexpected continuation token value: {continuationToken!r}')
			return
		continuationToken = continuationToken.decode('ascii')
		itct = qwarc.utils.str_get_between(section, b'"clickTrackingParams":"', b'"')
		if itct.lstrip(b'0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_-') not in (b'', b'=', b'==', b'%3D', b'%3D%3D'):
			self.logger.error(f'Unexpected itct value: {itct!r}')
			return
		itct = itct.decode('ascii')

		queue = collections.deque() # of (continuationToken, itct, nested) where nested indicates that it's a comment's replies ("View N replies" or "Show more comments")
		queue.append((continuationToken, itct, False))
		first = True
		while queue:
			continuationToken, itct, nested = queue.popleft()
			response, _ = await self.fetch(
				f'https://www.youtube.com/comment_service_ajax?action_get_{"comments" if not nested else "comment_replies"}=1&pbj=1&ctoken={continuationToken}&continuation={continuationToken}&itct={itct}',
				method = 'POST',
				data = {'session_token': sessionToken},
				headers = [('X-YouTube-Client-Name', '1'), ('X-YouTube-Client-Version', '2.20191212.06.02'), ('X-SPF-Referer', videoPageUrl), ('X-SPF-Previous', videoPageUrl)],
				responseHandler = responseHandler,
			  )
			if not response or response.status != 200 or (await response.read(16) == b'{"reload":"now"}'):
				self.logger.error('Error fetching comments, skipping')
				continue
			obj = await response.json()

			if first:
				sortMenu = obj['response']['continuationContents']['itemSectionContinuation']['header']['commentsHeaderRenderer']['sortMenu']
				for subMenuItem in sortMenu['sortFilterSubMenuRenderer']['subMenuItems']:
					if subMenuItem['title'] != 'Newest first':
						continue
					subContinuation = subMenuItem['continuation']['reloadContinuationData']
					queue.append((subContinuation['continuation'], subContinuation['clickTrackingParams'], False))
					break
				else:
					self.logger.error('Could not find newest first sort continuation')
				first = False
			else:
				if not nested:
					o = obj
					continuationKey = 'itemSectionContinuation'
				else:
					# Of course the data format is different here...
					for o in obj:
						if 'response' in o:
							break
					continuationKey = 'commentRepliesContinuation'
				if 'continuationContents' not in o['response']:
					# Empty response
					continue
				for reply in o['response']['continuationContents'][continuationKey]['contents']:
					if 'commentThreadRenderer' in reply and 'replies' in reply['commentThreadRenderer']:
						# Nested continuations
						continuations = reply['commentThreadRenderer']['replies']['commentRepliesRenderer']['continuations']
						assert len(continuations) == 1
						queue.append((continuations[0]['nextContinuationData']['continuation'], continuations[0]['nextContinuationData']['clickTrackingParams'], True))
				if 'continuations' in o['response']['continuationContents'][continuationKey]:
					assert len(o['response']['continuationContents'][continuationKey]['continuations']) == 1
					continuation = o['response']['continuationContents'][continuationKey]['continuations'][0]['nextContinuationData']
					queue.append((continuation['continuation'], continuation['clickTrackingParams'], nested))


specDependencies = qwarc.utils.SpecDependencies(extra = (('videoId', os.environ['YOUTUBE_VIDEOID']),))