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import os
import math
import random
import asyncio
import logging
from collections import defaultdict
from datetime import datetime, timedelta
from zoneinfo import ZoneInfo
from typing import List, Dict

import numpy as np
from dotenv import load_dotenv
from supabase import create_client
from sentence_transformers import SentenceTransformer
import pdb

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# Load environment variables
load_dotenv()

# Configuration
SEED = 42
random.seed(SEED)
np.random.seed(SEED)

TOP_K = 75
HISTORY_WINDOW = timedelta(days=1000)
TIMEZONE = ZoneInfo("UTC")

# Global variables
supabase_client = None
user_interactions = defaultdict(set)
post_features = {}
post_metadata = {}

if not os.path.exists('/tmp/cache'):
    os.makedirs('/tmp/cache')
sentence_model = SentenceTransformer(
    'all-MiniLM-L6-v2', cache_folder='/tmp/cache')

SUPABASE_URL = os.getenv('supabaseUrl')
SUPABASE_KEY = os.getenv('supabaseAnonKey')


def get_supabase_client():
    global supabase_client
    if supabase_client is None:
        supabase_client = create_client(SUPABASE_URL, SUPABASE_KEY)
    return supabase_client


def parse_datetime(dt_str: str) -> datetime:
    """Parse ISO datetime string and ensure correct microsecond precision."""
    try:
        if '.' in dt_str:
            date_part, time_part = dt_str.split('T')
            time_part, tz_part = time_part.split('+')
            if '.' in time_part:
                time_without_micro, micro = time_part.split('.')
                micro = micro.ljust(6, '0')
                time_part = f"{time_without_micro}.{micro}"
            dt_str = f"{date_part}T{time_part}+00:00"
        return datetime.fromisoformat(dt_str).astimezone(TIMEZONE)
    except Exception as e:
        logger.error(f"Error parsing datetime: {dt_str} - {str(e)}")
        raise


def decay_weight(interaction_time: datetime, current_time: datetime, decay_rate: float = 0.0001) -> float:
    """
    Compute an exponential decay weight for an interaction based on its age.
    The decay_rate can be tuned to control how fast interactions lose weight.
    """
    time_diff = (current_time - interaction_time).total_seconds()
    return math.exp(-decay_rate * time_diff)


def normalize_profile(profile: np.ndarray) -> np.ndarray:
    norm = np.linalg.norm(profile)
    return profile / norm if norm > 0 else profile


def compute_score(sim_score: float, popularity: float, freshness: float) -> float:
    """
    Compute a non-linear recommendation score.
    - sim_score is squared to emphasize strong similarities.
    - Popularity is log-transformed.
    - Freshness is combined linearly.
    """
    return 0.6 * (sim_score ** 2) + 0.3 * np.log1p(popularity) + 0.1 * freshness


class Recommender:
    def __init__(self, like_weight=1.0, comment_weight=0.5, comment_like_weight=0.3,
                 reply_weight=0.5, reply_like_weight=0.3):
        self.user_profiles = defaultdict(lambda: np.zeros(384))
        self.post_popularity = defaultdict(float)
        self.last_update = datetime.now(TIMEZONE) - HISTORY_WINDOW

        # Parameterized weights
        self.like_weight = like_weight
        self.comment_weight = comment_weight
        self.comment_like_weight = comment_like_weight
        self.reply_weight = reply_weight
        self.reply_like_weight = reply_like_weight

    async def fetch_all_rows(self, table_name: str, columns: str, last_update: datetime, post_id_not_null: bool):
        """Fetch all rows from a table using pagination."""
        supabase = get_supabase_client()
        page_size = 1000
        page = 0
        all_data = []

        while True:
            if post_id_not_null:
                response = await asyncio.to_thread(
                    supabase.table(table_name)
                    .select(columns)
                    .gt('created_at', last_update.isoformat())
                    .not_.is_("post_id", None)
                    .range(page * page_size, (page + 1) * page_size - 1)
                    .execute
                )
            else:
                response = await asyncio.to_thread(
                    supabase.table(table_name)
                    .select(columns)
                    .gt('created_at', last_update.isoformat())
                    .range(page * page_size, (page + 1) * page_size - 1)
                    .execute
                )

            if not response.data:
                break

            all_data.extend(response.data)
            page += 1

        return all_data

    async def update_data(self):
        # Current time for decay calculation
        current_time = datetime.now(TIMEZONE)

        # Fetch all interaction data since last update
        likes = await self.fetch_all_rows('likes', 'user_id, post_id, created_at', self.last_update, True)
        comments = await self.fetch_all_rows('comments', 'id, user_id, post_id, created_at, comment', self.last_update, True)
        commentlikes = await self.fetch_all_rows('commentlikes', 'user_id, author_id, post_id, created_at, comment_id', self.last_update, True)
        replies = await self.fetch_all_rows('replies', 'user_id, to, post_id, created_at, comment, comment_id, reply_id', self.last_update, True)
        replylikes = await self.fetch_all_rows('replylikes', 'user_id, author_id, post_id, created_at, reply_id', self.last_update, True)

        # Process likes with time decay
        for like in likes:
            user_id = like['user_id']
            post_id = like['post_id']
            interaction_time = parse_datetime(like['created_at'])
            weight = decay_weight(interaction_time, current_time)
            user_interactions[user_id].add(post_id)
            self.post_popularity[post_id] += self.like_weight * weight
            if post_id in post_features:
                self.user_profiles[user_id] += post_features[post_id] * \
                    self.like_weight * weight

        # Process comments with time decay
        for comment in comments:
            user_id = comment['user_id']
            post_id = comment['post_id']
            interaction_time = parse_datetime(comment['created_at'])
            weight = decay_weight(interaction_time, current_time)
            user_interactions[user_id].add(post_id)
            self.post_popularity[post_id] += self.comment_weight * weight
            if post_id in post_features:
                self.user_profiles[user_id] += post_features[post_id] * \
                    self.comment_weight * weight

        # Process comment likes with time decay
        for clike in commentlikes:
            user_id = clike['user_id']  # User who liked the comment
            post_id = clike['post_id']
            interaction_time = parse_datetime(clike['created_at'])
            weight = decay_weight(interaction_time, current_time)
            user_interactions[user_id].add(post_id)
            self.post_popularity[post_id] += self.comment_like_weight * weight
            if post_id in post_features:
                self.user_profiles[user_id] += post_features[post_id] * \
                    self.comment_like_weight * weight

        # Process replies with time decay
        for reply in replies:
            user_id = reply['user_id']
            post_id = reply['post_id']
            interaction_time = parse_datetime(reply['created_at'])
            weight = decay_weight(interaction_time, current_time)
            user_interactions[user_id].add(post_id)
            self.post_popularity[post_id] += self.reply_weight * weight
            if post_id in post_features:
                self.user_profiles[user_id] += post_features[post_id] * \
                    self.reply_weight * weight

        # Process reply likes with time decay
        for rlike in replylikes:
            user_id = rlike['user_id']
            post_id = rlike['post_id']
            interaction_time = parse_datetime(rlike['created_at'])
            weight = decay_weight(interaction_time, current_time)
            user_interactions[user_id].add(post_id)
            self.post_popularity[post_id] += self.reply_like_weight * weight
            if post_id in post_features:
                self.user_profiles[user_id] += post_features[post_id] * \
                    self.reply_like_weight * weight

        # OPTIONAL: Process negative feedback if available
        # for negative in negative_interactions:
        #     user_id = negative['user_id']
        #     post_id = negative['post_id']
        #     interaction_time = parse_datetime(negative['created_at'])
        #     weight = decay_weight(interaction_time, current_time)
        #     user_interactions[user_id].add(post_id)
        #     self.post_popularity[post_id] -= some_negative_weight * weight
        #     if post_id in post_features:
        #         self.user_profiles[user_id] -= post_features[post_id] * some_negative_weight * weight

        # Normalize user profiles after processing interactions
        for user_id in self.user_profiles:
            self.user_profiles[user_id] = normalize_profile(
                self.user_profiles[user_id])

        # Fetch and update post features
        posts = await self.fetch_all_rows('posts', '*', self.last_update, False)
        post_texts, post_ids = [], []
        for post in posts:
            post_id = post['id']
            text = f"{post.get('movie_name', '')} {post.get('content', '')}".strip(
            )
            post_texts.append(text)
            post_ids.append(post_id)
            post['created_at'] = parse_datetime(post['created_at'])
            post['type'] = 'post'
            post_metadata[post_id] = post

        if post_texts:
            embeddings = sentence_model.encode(
                post_texts, show_progress_bar=False, convert_to_numpy=True)
            for post_id, embedding in zip(post_ids, embeddings):
                post_features[post_id] = embedding / np.linalg.norm(embedding)

        self.last_update = datetime.now(TIMEZONE)
        total_interactions = len(likes) + len(comments) + \
            len(commentlikes) + len(replies) + len(replylikes)
        logger.info(
            f"Data updated: {len(posts)} posts, {total_interactions} interactions")

    def get_recommendations(self, user_id: str) -> List[Dict]:
        user_profile = self.user_profiles[user_id]
        seen_posts = user_interactions[user_id]
        scores = {}
        now = datetime.now(TIMEZONE)

        for post_id, feature in post_features.items():
            if post_id in seen_posts:
                continue

            sim_score = np.dot(user_profile, feature) if np.any(
                user_profile) else 0
            time_diff = now - post_metadata[post_id]['created_at']
            # Freshness is defined as an exponential decay based on weeks old
            freshness = math.exp(-time_diff.days / 7.0)
            score = compute_score(
                sim_score, self.post_popularity[post_id], freshness)
            # Adding a small random noise for exploration
            scores[post_id] = score + random.uniform(-0.1, 0.1)

        top_posts = sorted(
            scores.items(), key=lambda x: x[1], reverse=True)[:TOP_K]
        results = [post_metadata[post_id] for post_id, _ in top_posts]
        random.shuffle(results)
        return results


recommender = Recommender()


async def main():
    # pdb.set_trace()
    user_id = "d7411324-c8ea-42cb-ae59-7b8cbc61594c"
    await recommender.update_data()
    recommendations = recommender.get_recommendations(user_id)
    print(f"Recommendations for user {user_id}:")
    for post in recommendations:
        print(
            f"- Post {post['id']}: Movie: {post.get('movie_name', '')} Caption: {post.get('content', '')}")

if __name__ == "__main__":
    asyncio.run(main())