import pickle
import pandas as pd
import numpy as np
from sklearn.preprocessing import LabelEncoder
from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.metrics.pairwise import cosine_similarity
from tensorflow.keras.models import load_model
import streamlit as st

# Load datasets
books = pd.read_csv("./dataset/books.csv")
ratings = pd.read_csv("./dataset/ratings.csv")

# Preprocess data
user_encoder = LabelEncoder()
book_encoder = LabelEncoder()

ratings["user_id"] = ratings["user_id"].astype(str)
ratings["user_id"] = user_encoder.fit_transform(ratings["user_id"])
ratings["book_id"] = book_encoder.fit_transform(ratings["book_id"])

# Load TF-IDF models
with open("tfidf_model_authors.pkl", "rb") as f:
    tfidf_model_authors = pickle.load(f)

with open("tfidf_model_titles.pkl", "rb") as f:
    tfidf_model_titles = pickle.load(f)

# Load collaborative filtering model
model_cf = load_model("recommendation_model.keras")


# Content-Based Recommendation
def content_based_recommendation(
    query, books, tfidf_model_authors, tfidf_model_titles, num_recommendations=10
):
    # Transform book author, title, and description into TF-IDF vectors
    query_author_tfidf = tfidf_model_authors.transform([query])
    query_title_tfidf = tfidf_model_titles.transform([query])

    # Compute cosine similarity for authors and titles separately
    similarity_scores_authors = cosine_similarity(
        query_author_tfidf, tfidf_model_authors.transform(books["authors"])
    )
    similarity_scores_titles = cosine_similarity(
        query_title_tfidf, tfidf_model_titles.transform(books["original_title"])
    )

    # Combine similarity scores for authors and titles
    similarity_scores_combined = (
        similarity_scores_authors + similarity_scores_titles
    ) / 2

    # Get indices of recommended books
    recommended_indices = np.argsort(similarity_scores_combined.flatten())[
        -num_recommendations:
    ][::-1]

    # Get recommended books
    recommended_books = books.iloc[recommended_indices]

    return recommended_books


# Collaborative Recommendation
def collaborative_recommendation(user_id, model_cf, ratings, num_recommendations=10):
    # Get unrated books for the user
    unrated_books = ratings[
        ~ratings["book_id"].isin(ratings[ratings["user_id"] == user_id]["book_id"])
    ]["book_id"].unique()

    # Predict ratings for unrated books
    predictions = model_cf.predict(
        [np.full_like(unrated_books, user_id), unrated_books]
    ).flatten()

    # Get top indices based on predictions
    top_indices = np.argsort(predictions)[-num_recommendations:][::-1]

    # Get recommended books
    recommended_books = books.iloc[top_indices][["original_title", "authors"]]
    return recommended_books


# Hybrid Recommendation
def hybrid_recommendation(
    user_id,
    query,
    model_cf,
    books,
    ratings,
    tfidf_model_authors,
    tfidf_model_titles,
    num_recommendations=10,
):
    content_based_rec = content_based_recommendation(
        query,
        books,
        tfidf_model_authors,
        tfidf_model_titles,
        num_recommendations=num_recommendations,
    )
    collaborative_rec = collaborative_recommendation(
        user_id, model_cf, ratings, num_recommendations=num_recommendations
    )

    # Combine recommendations from different approaches
    hybrid_rec = pd.concat([content_based_rec, collaborative_rec]).drop_duplicates(
        subset="book_id", keep="first"
    )
    return hybrid_rec


# Streamlit App
st.title("Book Recommendation System")

# Sidebar for user input
user_input = st.text_input("Enter book name or author:", "")

# Get recommendations on button click
if st.button("Get Recommendations"):
    st.write("Content-Based Recommendation:")
    content_based_rec = content_based_recommendation(
        user_input, books, tfidf_model_authors, tfidf_model_titles
    )
    st.write(content_based_rec)

    # Example user ID for collaborative recommendation
    USER_ID = 0

    st.write("Collaborative Recommendation:")
    collaborative_rec = collaborative_recommendation(USER_ID, model_cf, ratings)
    st.write(collaborative_rec)

    st.write("Hybrid Recommendation:")
    hybrid_rec = hybrid_recommendation(
        USER_ID,
        user_input,
        model_cf,
        books,
        ratings,
        tfidf_model_authors,
        tfidf_model_titles,
    )
    st.write(hybrid_rec)