import os

def parse_review_line(line):
    parts = line.strip().split("|")
    return {
        "user_id": parts[0],
        "movie_title": parts[1],
        "rating": float(parts[2]),
        "review_text": parts[3],
        "watch_date": parts[4],
        "useful_votes": int(parts[5]),
        "total_votes": int(parts[6])
    }

def load_reviews(file_path):
    if not os.path.exists(file_path):
        print("Файл не найден")
        return []
    f = open(file_path, "r", encoding="utf-8")
    reviews = []
    for line in f:
        line = line.strip()
        if line != "":
            reviews.append(parse_review_line(line))
    f.close()
    return reviews

def filter_by_min_rating(reviews, min_rating):
    result = []
    for r in reviews:
        if r["rating"] >= min_rating:
            result.append(r)
    return result

def calculate_average_rating(reviews):
    if len(reviews) == 0:
        return 0
    total = sum(r["rating"] for r in reviews)
    return round(total / len(reviews), 2)

def get_movie_statistics(reviews):
    stats = {}
    for r in reviews:
        title = r["movie_title"]
        if title not in stats:
            stats[title] = {}
            stats[title]["reviews_count"] = 0
            stats[title]["total_rating"] = 0
            stats[title]["total_useful_votes"] = 0
        stats[title]["reviews_count"] = stats[title]["reviews_count"] + 1
        stats[title]["total_rating"] = stats[title]["total_rating"] + r["rating"]
        stats[title]["total_useful_votes"] = stats[title]["total_useful_votes"] + r["useful_votes"]
    
    for title in stats:
        stats[title]["average_rating"] = round(stats[title]["total_rating"] / stats[title]["reviews_count"], 2)
        del stats[title]["total_rating"]
    
    items = list(stats.items())
    items.sort(key=lambda x: x[1]["reviews_count"], reverse=True)
    
    result = {}
    for title, data in items:
        result[title] = data
    return result

def find_most_useful_review(reviews):
    if len(reviews) == 0:
        return {}
    
    best = min(reviews, key=lambda x: - (x["useful_votes"] / x["total_votes"]) if x["total_votes"] > 0 else -1)
    percent = (best["useful_votes"] / best["total_votes"]) * 100 if best["total_votes"] > 0 else 0
    
    return {
        "movie_title": best["movie_title"],
        "review_text": best["review_text"],
        "useful_percentage": round(percent, 2)
    }

def group_reviews_by_month(reviews):
    months = {}
    for r in reviews:
        month = r["watch_date"][:7]
        if month in months:
            months[month] = months[month] + 1
        else:
            months[month] = 1
    
    result = dict(sorted(months.items()))
    return result

def filter_by_keywords(reviews, keywords):
    result = []
    for r in reviews:
        text = r["review_text"].lower()
        if any(k.lower() in text for k in keywords):
            result.append(r)
    return result

def get_top_movies_by_rating(reviews, n):
    data = {}
    for r in reviews:
        title = r["movie_title"]
        if title not in data:
            data[title] = {}
            data[title]["total"] = 0
            data[title]["count"] = 0
        data[title]["total"] = data[title]["total"] + r["rating"]
        data[title]["count"] = data[title]["count"] + 1
    
    ratings = []
    for title in data:
        if data[title]["count"] >= 2:
            avg = data[title]["total"] / data[title]["count"]
            ratings.append((title, round(avg, 2)))
    
    ratings.sort(key=lambda x: x[1], reverse=True)
    return ratings[:n]

def generate_review_report(reviews, file_path):
    if len(reviews) == 0:
        return
    
    total = len(reviews)
    avg_rating = calculate_average_rating(reviews)
    movie_stats = get_movie_statistics(reviews)
    top_movies = get_top_movies_by_rating(reviews, 3)
    monthly = group_reviews_by_month(reviews)
    
    useful_list = []
    for r in reviews:
        if r["total_votes"] > 0:
            percent = (r["useful_votes"] / r["total_votes"]) * 100
            useful_list.append((r, percent))
    
    useful_list.sort(key=lambda x: x[1], reverse=True)
    
    f = open(file_path, "w", encoding="utf-8")
    f.write("ОТЧЕТ ПО РЕЦЕНЗИЯМ\n")
    f.write("\n")
    f.write("Всего рецензий: " + str(total) + "\n")
    f.write("Средний рейтинг: " + str(avg_rating) + "\n")
    f.write("\n")
    f.write("ТОП 5 ФИЛЬМОВ ПО КОЛИЧЕСТВУ РЕЦЕНЗИЙ\n")
    
    items = list(movie_stats.items())
    for i in range(min(5, len(items))):
        title, s = items[i]
        f.write(str(i + 1) + ". " + title + " - рецензий: " + str(s["reviews_count"]) + ", средний рейтинг: " + str(s["average_rating"]) + "\n")
    
    f.write("\n")
    f.write("ТОП 3 САМЫХ ПОЛЕЗНЫХ РЕЦЕНЗИЙ ()\n")
    
    for i in range(min(3, len(useful_list))):
        r, p = useful_list[i]
        f.write(str(i + 1) + ". " + r["movie_title"] + " - " + str(p) + "%\n")
        f.write("   " + r["review_text"][:100] + "\n")
    
    f.write("\n")
    f.write("ДИНАМИКА ПО МЕСЯЦАМ\n")
    
    for m in monthly:
        f.write(m + ": " + str(monthly[m]) + " рецензий\n")
    
    f.write("\n")
    f.write("ТОП 3 ФИЛЬМА ПО СРЕДНЕМУ РЕЙТИНГУ (мин 2 рецензии)\n")
    
    for i in range(len(top_movies)):
        title, rating = top_movies[i]
        f.write(str(i + 1) + ". " + title + " - " + str(rating) + "\n")
    
    f.close()
    
    if not os.path.exists("data"):
        os.makedirs("data")

def main():
    reviews = load_reviews("data/data.txt")
    
    if len(reviews) == 0:
        return
    
    print("Общее количество рецензий:", len(reviews))
    print()
    
    print("Средний рейтинг:", calculate_average_rating(reviews))
    print()
    
    print("Топ 5 фильмов по количеству рецензий:")
    stats = get_movie_statistics(reviews)
    count = 0
    for title in stats:
        if count >= 5:
            break
        s = stats[title]
        print(str(count + 1) + ".", title, "-", s["reviews_count"], "рецензий, средний рейтинг:", s["average_rating"])
        count = count + 1
    print()
    
    print("Самая полезная рецензия:")
    useful = find_most_useful_review(reviews)
    print("Фильм:", useful["movie_title"])
    print("Полезность:", useful["useful_percentage"], "%")
    print("Текст:", useful["review_text"][:100], "...")
    print()
    
    print("Топ 3 фильма по среднему рейтингу (мин 2 рецензии):")
    top = get_top_movies_by_rating(reviews, 3)
    for i in range(len(top)):
        title, rating = top[i]
        print(str(i + 1) + ".", title, "-", rating)
    print()
    
    generate_review_report(reviews, "data/report.txt")
    print("Отчет сохранен в файл data/report.txt")

if __name__ == "__main__":
    main()