import json
import numpy as np
import random
import streamlit as st
from sentence_transformers import SentenceTransformer

@st.cache_resource
def load_youtube_data(base_path, embedding_model_name, chunk_tokens, overlap_tokens):
    embedding_space_file_name = f'{base_path}/yt_embedding_space_{embedding_model_name}_tpc{chunk_tokens}_o{overlap_tokens}.json'
    with open(embedding_space_file_name, 'r') as json_file:
        loaded_data = json.load(json_file)
    
    embedding_space = np.array(loaded_data['embedding_space'])
    return loaded_data['chunks'], embedding_space

@st.cache_resource
def load_book_data(base_path, embedding_model_name, chunk_tokens, overlap_tokens):
    embedding_space_file_name = f'{base_path}/latex_embedding_space_by_sections_{embedding_model_name}_tpc{chunk_tokens}_o{overlap_tokens}.json'
    with open(embedding_space_file_name, 'r') as json_file:
        loaded_data = json.load(json_file)
    
    embedding_space = np.array(loaded_data['embedding_space'])
    return loaded_data['chunks'], embedding_space

@st.cache_resource
def load_summary(file_path):
    with open(file_path, 'r') as file:
        transcripts = json.load(file)
    return transcripts

def embed_question_sentence_transformer(texts, model_name="sentence-transformers/all-MiniLM-L6-v2"):
    model = SentenceTransformer(model_name)
    embeddings = model.encode(texts)
    
    return embeddings.tolist()

def fixed_knn_retrieval(question_embedding, context_embeddings, top_k=5, min_k=1):
    
    question_embedding = np.array(question_embedding)

    # Normalize 
    question_embedding = question_embedding / np.linalg.norm(question_embedding)
    context_embeddings = context_embeddings / np.linalg.norm(context_embeddings, axis=1, keepdims=True)
    
    # Calculate cosine similarities between the question embedding and all context embeddings.
    similarities = np.dot(context_embeddings, question_embedding)
    # Sort the similarities in descending order and get the corresponding indices.
    sorted_indices = np.argsort(similarities)[::-1]
    # Select the top_k most similar contexts, ensuring at least min_k contexts are selected.
    selected_indices = sorted_indices[:max(top_k, min_k)].tolist()
    return selected_indices


def get_random_question(text_file):
    with open(text_file, "r") as file:
        questions = [line.strip() for line in file]
    return random.choice(questions)