from flask import Flask, request, render_template, redirect, url_for, session
import json
import numpy as np
import random
import math
from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.metrics.pairwise import cosine_similarity

app = Flask(__name__)
app.secret_key = 'your_secret_key_here'  # Replace with a secure key in production

# Load movies from top_movies.json with UTF-8 encoding
with open('top_movies.json', 'r', encoding='utf-8') as f:
    movies = json.load(f)

# Preprocess each movie
for i, movie in enumerate(movies):
    movie['id'] = i  # Unique ID
    # Combine genres and tags into one feature string.
    movie['features'] = ' '.join(movie.get('genres', [])) + ' ' + ' '.join(movie.get('tags', []))
    # Ensure numeric values for year and runtime:
    try:
        movie['year_num'] = int(movie.get('year', '0'))
    except:
        movie['year_num'] = 0
    try:
        movie['runtime_num'] = float(movie.get('runtime')) if movie.get('runtime') else 0
    except:
        movie['runtime_num'] = 0
    # Ensure vote_count is numeric.
    try:
        count = movie.get('vote_count', 0)
        if isinstance(count, str):
            count = count.replace(',', '')
            if 'M' in count:
                count = float(count.replace('M', '')) * 1e6
            else:
                count = int(count)
        movie['vote_count'] = int(count)
    except:
        movie['vote_count'] = 0

# Build the TF‑IDF vectorizer on movie features.
vectorizer = TfidfVectorizer(stop_words='english')
movie_features = [movie['features'] for movie in movies]
movie_vectors = vectorizer.fit_transform(movie_features)

# Precompute overall ranges for numeric features.
years = [m['year_num'] for m in movies if m['year_num'] > 0]
runtimes = [m['runtime_num'] for m in movies if m['runtime_num'] > 0]
max_vote = max([m['vote_count'] for m in movies]) if movies else 1

min_year, max_year = (min(years), max(years)) if years else (0, 1)
min_runtime, max_runtime = (min(runtimes), max(runtimes)) if runtimes else (0, 1)
year_range = max_year - min_year if max_year != min_year else 1
runtime_range = max_runtime - min_runtime if max_runtime != min_runtime else 1
rating_range = 10.0  # Assuming ratings are on a 0–10 scale

def get_predicted_movies(num=10):
    """
    Return up to `num` movies that haven't been shown yet.
    Uses the user's past ratings to predict which unseen movies they might like.
    If no ratings exist, falls back to random selection.
    """
    asked = session.get('asked_movies', [])
    available = [m for m in movies if m['id'] not in asked]
    if not available:
        return []
    rated = session.get('rated_movies', {})
    # Fallback to random selection if there are no like/dislike ratings.
    if not rated or not any(r in ['like', 'dislike'] for r in rated.values()):
        random.shuffle(available)
        return available[:num]
    
    # Build prediction profiles.
    liked_ids = [int(mid) for mid, rating in rated.items() if rating == 'like']
    disliked_ids = [int(mid) for mid, rating in rated.items() if rating == 'dislike']
    
    if liked_ids:
        liked_profile = np.asarray(movie_vectors[liked_ids].mean(axis=0))
    else:
        liked_profile = np.zeros((1, movie_vectors.shape[1]))
    if disliked_ids:
        disliked_profile = np.asarray(movie_vectors[disliked_ids].mean(axis=0))
    else:
        disliked_profile = np.zeros((1, movie_vectors.shape[1]))
    
    # Compute numeric averages for liked movies.
    liked_years = [movies[i]['year_num'] for i in liked_ids if movies[i]['year_num'] > 0]
    liked_runtimes = [movies[i]['runtime_num'] for i in liked_ids if movies[i]['runtime_num'] > 0]
    liked_ratings = [movies[i].get('imdb_rating', 0) for i in liked_ids if movies[i].get('imdb_rating', 0)]
    
    avg_year = np.mean(liked_years) if liked_years else None
    avg_runtime = np.mean(liked_runtimes) if liked_runtimes else None
    avg_rating = np.mean(liked_ratings) if liked_ratings else None
    
    predictions = []
    # Tunable weights.
    w_text = 0.5
    w_year = 0.1
    w_runtime = 0.1
    w_rating = 0.15
    w_popularity = 0.15
    
    for movie in available:
        i = movie['id']
        # TEXT SIMILARITY.
        movie_vector = movie_vectors[i].toarray()
        like_sim = cosine_similarity(movie_vector, liked_profile)[0][0] if np.linalg.norm(liked_profile) != 0 else 0
        dislike_sim = cosine_similarity(movie_vector, disliked_profile)[0][0] if np.linalg.norm(disliked_profile) != 0 else 0
        text_score = like_sim - dislike_sim
        
        # YEAR SIMILARITY.
        year_score = 0
        if avg_year is not None and movie['year_num'] > 0:
            diff_year = abs(movie['year_num'] - avg_year)
            year_score = 1 - (diff_year / year_range)
        
        # RUNTIME SIMILARITY.
        runtime_score = 0
        if avg_runtime is not None and movie['runtime_num'] > 0:
            diff_runtime = abs(movie['runtime_num'] - avg_runtime)
            runtime_score = 1 - (diff_runtime / runtime_range)
        
        # RATING SIMILARITY.
        rating_score = 0
        movie_rating = movie.get('imdb_rating', 0)
        if avg_rating is not None and movie_rating:
            diff_rating = abs(movie_rating - avg_rating)
            rating_score = 1 - (diff_rating / rating_range)
        
        # POPULARITY SCORE.
        popularity_score = 0
        if movie['vote_count'] > 0:
            popularity_score = math.log(movie['vote_count'] + 1) / math.log(max_vote + 1)
        
        # Final prediction score.
        final_score = (w_text * text_score +
                       w_year * year_score +
                       w_runtime * runtime_score +
                       w_rating * rating_score +
                       w_popularity * popularity_score)
        predictions.append((movie, final_score))
    
    predictions.sort(key=lambda x: x[1], reverse=True)
    return [pred[0] for pred in predictions[:num]]

def enough_info():
    """
    Check if the user has rated at least 3 movies (like/dislike).
    """
    rated = session.get('rated_movies', {})
    count = sum(1 for rating in rated.values() if rating in ['like', 'dislike'])
    return count >= 3

@app.route('/')
def home():
    session.setdefault('rated_movies', {})  # {movie_id: rating}
    session.setdefault('asked_movies', [])    # list of movie IDs already shown
    return redirect(url_for('questionnaire'))

@app.route('/questionnaire', methods=['GET', 'POST'])
def questionnaire():
    if request.method == 'POST':
        current_ids = request.form.getlist("movie_id")
        for movie_id in current_ids:
            rating = request.form.get(f"rating_{movie_id}")
            session['rated_movies'][movie_id] = rating
            if int(movie_id) not in session['asked_movies']:
                session['asked_movies'].append(int(movie_id))
        remaining = [m for m in movies if m['id'] not in session['asked_movies']]
        if enough_info() or not remaining:
            return redirect(url_for('recommend'))
        else:
            return redirect(url_for('questionnaire'))
    else:
        # Use prediction to select movies for the questionnaire.
        selected_movies = get_predicted_movies(num=10)
        if not selected_movies:
            return redirect(url_for('recommend'))
        return render_template('questionnaire.html', movies=selected_movies)

def advanced_recommendations():
    """
    Compute an advanced hybrid recommendation score on unseen movies.
    Only movies not already shown (asked) are considered.
    Combines:
      1. Text similarity (TF‑IDF) between liked/disliked profiles.
      2. Year similarity.
      3. Runtime similarity.
      4. Rating similarity.
      5. Popularity (log-scaled vote count).
    Returns the top 20 recommendations.
    """
    rated = session.get('rated_movies', {})
    asked = set(session.get('asked_movies', []))
    # Only consider movies that haven't been shown to the user.
    available = [m for m in movies if m['id'] not in asked]
    if not available:
        available = movies  # Fallback if all movies have been shown.

    liked_ids = [int(mid) for mid, rating in rated.items() if rating == 'like']
    disliked_ids = [int(mid) for mid, rating in rated.items() if rating == 'dislike']
    
    if liked_ids:
        liked_profile = np.asarray(movie_vectors[liked_ids].mean(axis=0))
    else:
        liked_profile = np.zeros((1, movie_vectors.shape[1]))
    if disliked_ids:
        disliked_profile = np.asarray(movie_vectors[disliked_ids].mean(axis=0))
    else:
        disliked_profile = np.zeros((1, movie_vectors.shape[1]))
    
    liked_years = [movies[i]['year_num'] for i in liked_ids if movies[i]['year_num'] > 0]
    liked_runtimes = [movies[i]['runtime_num'] for i in liked_ids if movies[i]['runtime_num'] > 0]
    liked_ratings = [movies[i].get('imdb_rating', 0) for i in liked_ids if movies[i].get('imdb_rating', 0)]
    avg_year = np.mean(liked_years) if liked_years else None
    avg_runtime = np.mean(liked_runtimes) if liked_runtimes else None
    avg_rating = np.mean(liked_ratings) if liked_ratings else None
    
    recommendations = []
    w_text = 0.5
    w_year = 0.1
    w_runtime = 0.1
    w_rating = 0.15
    w_popularity = 0.15
    
    for movie in available:
        i = movie['id']
        movie_vector = movie_vectors[i].toarray()
        like_sim = cosine_similarity(movie_vector, liked_profile)[0][0] if np.linalg.norm(liked_profile) != 0 else 0
        dislike_sim = cosine_similarity(movie_vector, disliked_profile)[0][0] if np.linalg.norm(disliked_profile) != 0 else 0
        text_score = like_sim - dislike_sim
        
        year_score = 0
        if avg_year is not None and movie['year_num'] > 0:
            diff_year = abs(movie['year_num'] - avg_year)
            year_score = 1 - (diff_year / year_range)
        
        runtime_score = 0
        if avg_runtime is not None and movie['runtime_num'] > 0:
            diff_runtime = abs(movie['runtime_num'] - avg_runtime)
            runtime_score = 1 - (diff_runtime / runtime_range)
        
        rating_score = 0
        movie_rating = movie.get('imdb_rating', 0)
        if avg_rating is not None and movie_rating:
            diff_rating = abs(movie_rating - avg_rating)
            rating_score = 1 - (diff_rating / rating_range)
        
        popularity_score = 0
        if movie['vote_count'] > 0:
            popularity_score = math.log(movie['vote_count'] + 1) / math.log(max_vote + 1)
        
        final_score = (w_text * text_score +
                       w_year * year_score +
                       w_runtime * runtime_score +
                       w_rating * rating_score +
                       w_popularity * popularity_score)
        recommendations.append((movie, final_score))
    
    recommendations.sort(key=lambda x: x[1], reverse=True)
    return recommendations[:20]

@app.route('/recommend')
def recommend():
    recommendations = advanced_recommendations()
    return render_template('recommendations.html', recommendations=recommendations)

if __name__ == '__main__':
    app.run(debug=True)