import json
import requests
from tqdm import tqdm
import isodate

class YTstats:

    def __init__(self, api_key):
        self.api_key = api_key
        self.channel_statistics = None
        self.video_data = None

    def extract_all(self, channel_id):
        self.get_channel_statistics(channel_id)
        self.get_channel_video_data(channel_id)

    def get_channel_statistics(self, channel_id):
        """Extract the channel statistics"""
        print('get channel statistics...')
        url = f'https://www.googleapis.com/youtube/v3/channels?part=statistics&id={channel_id}&key={self.api_key}'
        #pbar = tqdm(total=1)
        
        json_url = requests.get(url)
        data = json.loads(json_url.text)
        try:
            data = data['items'][0]['statistics']
        except KeyError:
            print('Could not get channel statistics')
            data = {}

        self.channel_statistics = data
        #pbar.update()
        #pbar.close()
        return data

    def get_channel_video_data(self, channel_id, df_sheet, loading_bar, progress_text, item_limit=3):
        "Extract all video information of the channel"
        print('get video data...')
        channel_videos, channel_playlists = self._get_channel_content(channel_id, limit=50)

        channel_videos_out = dict()

        total_items = len(channel_videos)
        item = 0
        step_size=0
        step=0
        if total_items!=0:
            step_size=round(1/total_items,4)
        #step = step_size
        parts=["snippet", "statistics","contentDetails", "topicDetails"]
        for video_id in tqdm(channel_videos):
            if item == item_limit:
                break
            
            loading_bar.progress(step, text=progress_text)

            for part in parts:
                data = self._get_single_video_data(video_id, part)
                channel_videos[video_id].update(data)
            
            duration = isodate.parse_duration(channel_videos[video_id]['duration'])
            short_duration = isodate.parse_duration('PT4M')

            if duration > short_duration and video_id not in list(df_sheet.ID):
                item = item+1
                step = step +step_size
                channel_videos_out[video_id] = channel_videos[video_id]
                

        step=1.0
        loading_bar.progress(step, text=progress_text)
        self.video_data = channel_videos_out
        

    def _get_single_video_data(self, video_id, part):
        """
        Extract further information for a single video
        parts can be: 'snippet', 'statistics', 'contentDetails', 'topicDetails'
        """

        url = f"https://www.googleapis.com/youtube/v3/videos?part={part}&id={video_id}&key={self.api_key}"
        json_url = requests.get(url)
        data = json.loads(json_url.text)
        try:
            data = data['items'][0][part]
        except KeyError as e:
            print(f'Error! Could not get {part} part of data: \n{data}')
            data = dict()
        return data

    def _get_channel_content(self, channel_id, limit=None, check_all_pages=True):
        """
        Extract all videos and playlists, can check all available search pages
        channel_videos = videoId: title, publishedAt
        channel_playlists = playlistId: title, publishedAt
        return channel_videos, channel_playlists
        """
        url = f"https://www.googleapis.com/youtube/v3/search?key={self.api_key}&channelId={channel_id}&part=snippet,id&order=date"
        if limit is not None and isinstance(limit, int):
            url += "&maxResults=" + str(limit)

        vid, pl, npt = self._get_channel_content_per_page(url)
        idx = 0
        while(check_all_pages and npt is not None and idx < 10):
            nexturl = url + "&pageToken=" + npt
            next_vid, next_pl, npt = self._get_channel_content_per_page(nexturl)
            vid.update(next_vid)
            pl.update(next_pl)
            idx += 1

        return vid, pl

    def _get_channel_content_per_page(self, url):
        """
        Extract all videos and playlists per page
        return channel_videos, channel_playlists, nextPageToken
        """
        json_url = requests.get(url)
        data = json.loads(json_url.text)
        channel_videos = dict()
        channel_playlists = dict()
        if 'items' not in data:
            print('Error! Could not get correct channel data!\n', data)
            return channel_videos, channel_videos, None

        nextPageToken = data.get("nextPageToken", None)

        item_data = data['items']
        for item in item_data:
            try:
                kind = item['id']['kind']
                published_at = item['snippet']['publishedAt']
                title = item['snippet']['title']
                if kind == 'youtube#video':
                    video_id = item['id']['videoId']
                    channel_videos[video_id] = {'publishedAt': published_at, 'title': title}
                elif kind == 'youtube#playlist':
                    playlist_id = item['id']['playlistId']
                    channel_playlists[playlist_id] = {'publishedAt': published_at, 'title': title}
            except KeyError as e:
                print('Error! Could not extract data from item:\n', item)

        return channel_videos, channel_playlists, nextPageToken

    def dump(self, channel_id):
        """Dumps channel statistics and video data in a single json file"""
        if self.channel_statistics is None or self.video_data is None:
            print('data is missing!\nCall get_channel_statistics() and get_channel_video_data() first!')
            return

        fused_data = {channel_id: {"channel_statistics": self.channel_statistics,
                              "video_data": self.video_data}}

        channel_title = self.video_data.popitem()[1].get('channelTitle', channel_id)
        channel_title = channel_title.replace(" ", "_").lower()
        filename = channel_title + '.json'
        with open(filename, 'w') as f:
            json.dump(fused_data, f, indent=4)
        
        print('file dumped to', filename)