'''
Recommendation Engine Example
1 Nov 2017, 0x2620
'''

from collections import defaultdict
import json
import os
import random

import ox

from utils import run_async

class Engine:

    def __init__(self, path, **kwargs):
        self.path = path
        self.pandora = Pandora(
            url=kwargs.get('pandora', 'http://pandora.dmp/api/'),
            username=kwargs.get('username', 'dd.re'),
            password=kwargs.get('password', 'dd.re')
        )
        filename = os.path.join(self.path, 'playlists.json') 
        if os.path.exists(filename):
            with open(filename) as f:
                self.playlists = json.loads(f.read())
        else:
            self.playlists = []

    def _patch_clips(self, clips):
        inpoints = {}
        for index, clip in enumerate(clips):
            video_id = clip['id'].split('/')[0]
            inpoints[video_id] = inpoints.get(video_id, []) + [{
                'index': index,
                'position': clip['in']
            }]
        for video_id in inpoints:
            for i, inpoint in enumerate(sorted(
                inpoints[video_id], key=lambda inpoint: inpoint['position']
            )):
                if i < len(inpoints[video_id]) - 1:
                    clips[inpoint['index']]['out'] = inpoints[video_id][i + 1]['position']
                else:
                    clips[inpoint['index']]['out'] = self.pandora.get(video_id, ['duration'])['duration']
        return clips

    def get_videos(self, user):
        channels = {'keywords': 7, 'screenings': 7, 'random': 2}
        sliders = {'dau': -1, 'physics': 0, 'sex': 1}
        # For each playlist, compute keyword score
        score = {}
        for playlist in self.playlists:
            score[playlist['name']] = random.random()
            for tag in [tag for tag in playlist['tags'] if tag in sliders]:
                score[playlist['name']] += sliders[tag]
        # Select highest scoring playlists
        playlists = sorted(
            self.playlists,
            key=lambda playlist: -score[playlist['name']]
        )
        videos = playlists[:channels['keywords']]
        playlists = playlists[channels['keywords']:]
        # Count tags for the user
        count = defaultdict(lambda: 0)
        for event in user.get('events', []):
            count[event['data']['product']] += 1
        # For each tag in playlist, increment score by count
        for playlist in playlists:
            score[playlist['name']] = random.random()
            for tag in [tag for tag in playlist['tags'] if tag not in sliders]:
                score[playlist['name']] += count[tag]
        # Select highest scoring playlists
        videos += sorted(
            playlists,
            key=lambda playlist: -score[playlist['name']]
        )[:16 - channels['keywords']]
        # Shuffle playlists (randomize layout) and shift clips (randomize start)
        random.shuffle(videos)
        return [{
            'clips': video['clips'],
            'position': random.randrange(len(video['clips'])),
            'name': video['name']
        } for video in videos]

    def update(self):
        # Get all storylines with tags
        storylines = [{
            'id': entity['id'],
            'name': entity['name'],
            'nodename': entity['nodename'],
            'tags': entity['tags']
        } for entity in self.pandora.find_entities({
            'conditions': [
                {'key': 'type', 'operator': '==', 'value': 'storylines'},
            ],
            'operator': '&'
        }, ['id', 'name', 'tags', 'nodename']) if entity.get('tags', [])]
        # Get list of storyline names
        names = list(set([storyline['name'] for storyline in storylines]))
        # Get all clips annotated with storyline references
        clips = [clip for clip in self.pandora.find_annotations({
            'conditions': [
                {'key': 'layer', 'operator': '==', 'value': 'storylines'}
            ],
            'operator': '&'
        }, ['id', 'in', 'out', 'value']) if clip['value'] in names]
        # Get list of ids for videos with clips
        ids = list(set([clip['id'].split('/')[0] for clip in clips]))
        # Get and cache video data
        filename = os.path.join(self.path, 'videos.json')
        if os.path.exists(filename):
            with open(filename) as f:
                videos_ = json.loads(f.read())
                ids_ = [video['id'] for video in videos_]
        else:
            videos_, ids_ = [], []
        videos = sorted(videos_ + [
            self.pandora.get(id, ['code', 'id', 'order', 'title'])
            for id in ids if not id in ids_
        ], key=lambda video: video['order'])
        with open(filename, 'w') as f:
            f.write(json.dumps(videos, indent=4, sort_keys=True))
        # Get video order
        order = {video['id']: video['order'] for video in videos}
        # Sort clips
        clips = sorted(
            clips,
            key=lambda clip: order[clip['id'].split('/')[0]] * 1000000 + clip['in']
        )
        # Get and cache playlists
        self.playlists = [playlist for playlist in [{
            'id': storyline['id'],
            'name': storyline['nodename'],
            'tags': storyline['tags'],
            'clips': self._patch_clips([{
                'id': clip['id'],
                'in': clip['in'],
                'out': clip['out']
            } for clip in clips if clip['value'] == storyline['name']])
        } for storyline in storylines] if playlist['clips']]
        with open(os.path.join(self.path, 'playlists.json'), 'w') as f:
            f.write(json.dumps(self.playlists, indent=4, sort_keys=True))

    @run_async
    def update_async(self):
        self.update()


class Pandora:

    # pan.do/ra API wrapper

    def __init__(self, url, username, password):
        self.api = ox.API(url)
        self.api.signin(username=username, password=password)

    def find_annotations(self, query, keys):
        # print('FIND ANNOTATIONS', query, keys)
        return self.api.findAnnotations({
            'keys': keys,
            'query': query,
            'range': [0, 1000000]
        })['data']['items']

    def find_entities(self, query, keys):
        # print('FIND ENTITIES', query, keys)
        return self.api.findEntities({
            'keys': keys,
            'query': query,
            'range': [0, 1000000]
        })['data']['items']

    def get(self, id, keys):
        # print('GET', id, keys)
        return self.api.get({
            'id': id,
            'keys': keys
        })['data']


if __name__ == '__main__':
    engine = Engine('json')
    engine.update()