import requests as rq
import json
from datetime import datetime, timedelta


COUNTTYPE_DAYS = 'days'
COUNTTYPE_TRACKS = 'tracks'


class PlaylistUpdater:
    def __init__(self, db, auth_token, spotify_api_endpoint='https://api.spotify.com/v1'):
        self._db = db
        self._tracks = []
        self._auth_token = auth_token
        self._spotify_api_endpoint = spotify_api_endpoint

        self._update_tracks()

    def _update_tracks(self):
        self._tracks = []
        rnext = f"{self._spotify_api_endpoint}/me/tracks?limit=50"
        while rnext is not None:
            r = self._fetch(rnext);
            self._tracks += r['items']
            rnext = r['next']

    def _fetch(self, url):
        headers = { 'Authorization': f"Bearer {self._auth_token}" }
        while True:
            r = rq.get(f"{url}", headers=headers)
            if 200 <= r.status_code <= 299:
                return r.json()
            # slow down if spotify is applying rate limiting
            if r.status_code == 429:
                time.sleep(30)
            # don't try again in a crazy fast loop to avoid rate limits
            time.sleep(1)

    def update_playlist(self, playlist_id):
        pltracks = []
        newtracklist = []
        count = self._db.get_user_playlist_count(playlist_id)
        counttype = self._db.get_user_playlist_counttype(playlist_id)
        headers = { 'Authorization': f"Bearer {self._auth_token}" }
        added_at_dict = {}

        r = self._fetch(f"{self._spotify_api_endpoint}/playlists/{playlist_id}?fields=tracks,snapshot_id")
        snapshot_id = r['snapshot_id']
        pltracks = [t['track']['id'] for t  in r['tracks']['items']]
        rnext = r['tracks']['next']
        while rnext is not None:
            r = self._fetch(rnext)
            for track in  r['items']:
                pltracks.append(track['track']['id'])
            rnext = r['next']

        for i, track in enumerate(self._tracks):
            # for some reason, python datetime doesn't support utc zulu timezone
            added_at = datetime.fromisoformat(track['added_at'].replace('Z', '+00:00')).timestamp()
            added_at_dict[track['track']['id']] = added_at

            if counttype == COUNTTYPE_DAYS:
                if added_at < (datetime.now() - timedelta(days=count)).timestamp():
                    break

            if counttype == COUNTTYPE_TRACKS and i >= count:
                break

            newtracklist.append(track['track']['id'])


        pltracks = set(pltracks)
        newtracklist = set(newtracklist)

        toremove = list(pltracks - newtracklist)
        toadd = sorted(list(newtracklist - pltracks), key = lambda t: added_at_dict[t])

        print(f"{pltracks=}")
        print(f"{newtracklist=}")
        print(f"{toremove=}")
        print(f"{toadd=}")
        print(f"{count=}")
        print(f"{counttype=}")
        print(f"{COUNTTYPE_TRACKS=}")
        print(f"{counttype==COUNTTYPE_TRACKS=}")

        while toremove:
            tracks = []
            for i in range(100):
                if not toremove:
                    break
                tracks.append({
                    'uri': f"spotify:track:{toremove.pop()}"
                })

            r = rq.delete(
                f"{self._spotify_api_endpoint}/playlists/{playlist_id}/tracks",
                headers = headers,
                json = {
                    'tracks': tracks,
                    'snapshot_id': snapshot_id
                }
            ).json()
            print(f"{json.dumps(r, indent=2)=}")

        while toadd:
            tracks = []
            for i in range(100):
                if not toadd:
                    break
                tracks.append(f"spotify:track:{toadd.pop()}")

            r = rq.post(
                f"{self._spotify_api_endpoint}/playlists/{playlist_id}/tracks",
                headers = headers,
                json = {
                    'uris': tracks,
                    'position': 0
                }
            )
            print(f"{r.text=}")