import os
import csv
import json
import logging
from operator import attrgetter
from collections import namedtuple
import requests
import arrow
import settings
import keys
from pprint import pprint

Track = namedtuple(
    'Track',
    ['timestamp', 'artist', 'album', 'title', 'artistid', 'albumid', 'img']
)


class cached_property(object):
    """ extermely simple cached_property decorator:
    whenever something is called as @cached_property, on first run, the
    result is calculated, then the class method is overwritten to be
    a property, contaning the result from the method
    """

    def __init__(self, method, name=None):
        self.method = method
        self.name = name or method.__name__

    def __get__(self, inst, cls):
        if inst is None:
            return self
        result = self.method(inst)
        setattr(inst, self.name, result)
        return result


class LastFM(object):
    url = 'http://ws.audioscrobbler.com/2.0/'

    def __init__(self):
        self.params = {
            'method': 'user.getrecenttracks',
            'user': keys.lastfm.get('username'),
            'api_key': keys.lastfm.get('key'),
            'format': 'json',
            'limit': '200'
        }
        if os.path.isfile(self.target):
            mtime = os.path.getmtime(self.target)
            self.params.update({'from': mtime})

    @property
    def target(self):
        return os.path.join(
            settings.paths.get('archive'),
            'lastfm.csv'
        )

    @cached_property
    def existing(self):
        timestamps = []
        with open(self.target, 'r') as f:
            r = csv.reader(f)
            for row in r:
                try:
                    timestamps.append(arrow.get(row[0]).timestamp)
                except Exception as e:
                    logging.error('arrow failed on row %s', row)
                    continue
        return timestamps

    @property
    def exists(self):
        return os.path.isfile(self.target)

    def extracttracks(self, data):
        tracks = []
        if not data:
            return tracks
        for track in data.get('track', []):
            if 'date' not in track:
                continue
            ts = arrow.get(int(track.get('date').get('uts')))
            if ts.timestamp in self.existing:
                continue
            entry = Track(
                ts.format('YYYY-MM-DDTHH:mm:ssZ'),
                track.get('artist').get('#text', ''),
                track.get('album').get('#text', ''),
                track.get('name', ''),
                track.get('artist').get('mbid', ''),
                track.get('album').get('mbid', ''),
                track.get('image', [])[-1].get('#text', ''),
            )
            tracks.append(entry)
        return tracks

    def fetch(self):
        r = requests.get(self.url, params=self.params)
        return  json.loads(r.text).get('recenttracks')


    def run(self):
        try:
            data = self.fetch()
            tracks = self.extracttracks(data)
            total = int(data.get('@attr').get('totalPages'))
            current = int(data.get('@attr').get('page'))
            cntr = total - current
        except Exception as e:
            logging.error('Something went wrong: %s', e)
            return

        if not len(tracks):
            return

        while cntr > 0:
            current = current + 1
            cntr = total - current
            logging.info('requesting page #%d of paginated results', current)
            self.params.update({
                'page': current
            })
            data = self.fetch()
            tracks = tracks + self.extracttracks(data)

        if not self.exists:
            with open(self.target, 'w') as f:
                writer = csv.DictWriter(f, fieldnames=Track._fields)
                writer.writeheader()

        if len(tracks):
            with open(self.target, 'a') as f:
                writer = csv.writer(f, quoting=csv.QUOTE_NONNUMERIC)
                writer.writerows(sorted(tracks, key=attrgetter('timestamp')))


if __name__ == '__main__':
    lfm = LastFM()
    lfm.run()