import bcrypt
from db import get_db_connection
import base64
import secrets
import time
import json


# USER MANAGEMENT FUNCTIONS
def register_user(email, display_name, password):
    hashed_password = bcrypt.hashpw(password.encode(), bcrypt.gensalt()).decode()
    conn = get_db_connection()
    cursor = conn.cursor()
    try:
        cursor.execute(
            "INSERT INTO users (email, display_name, password_hash) VALUES (%s, %s, %s) RETURNING uid;",
            (email, display_name, hashed_password)
        )
        uid = cursor.fetchone()["uid"]
        conn.commit()
        return uid
    except Exception as e:
        conn.rollback()
        raise e
    finally:
        cursor.close()
        conn.close()

def authenticate_user(email, password):
    conn = get_db_connection()
    cursor = conn.cursor()
    try:
        cursor.execute("SELECT uid, password_hash FROM users WHERE email = %s;", (email,))
        user = cursor.fetchone()
        if user and bcrypt.checkpw(password.encode(), user["password_hash"].encode()):
            epoch_timestamp = int(time.time()) 
            random_int = secrets.randbelow(1000000)
            token_data = f"{email}:{password}:{epoch_timestamp}:{random_int}"
            encoded_token = base64.b64encode(token_data.encode()).decode()
            cursor.execute("UPDATE users SET session_token = %s WHERE email = %s;", (encoded_token, email))
            conn.commit() 
            return encoded_token
        return None
    
    finally:
        cursor.close()
        conn.close()
        
        
def add_friend(token, friend_uid):
    conn = get_db_connection()
    cursor = conn.cursor()
    try:
        cursor.execute("SELECT friend_list FROM users WHERE session_token = %s;", (token,))
        result = cursor.fetchone()
        if result:
            friends = result["friend_list"] or {}  
        else:
            friends = {}

        if friend_uid in friends.values():
            return "Friend already in the list."

        index = len(friends)
        friend_key = f"friend{index}"
        friends[friend_key] = friend_uid 
        friends_json = json.dumps(friends)

        cursor.execute(
            "UPDATE users SET friend_list = %s WHERE session_token = %s;",
            (friends_json, token) 
        )
        conn.commit()

        return True
    except Exception as e:
        conn.rollback()
        raise e
    finally:
        cursor.close()
        conn.close()


# MATCHMAKING ENDPOINTS

def get_leaderboard():
    conn = get_db_connection()
    cursor = conn.cursor()
    try:
        cursor.execute("SELECT display_name, current_elo, uid FROM users WHERE current_elo IS NOT NULL ORDER BY current_elo DESC;")
        players = cursor.fetchall()
        player_elo_list = [{"player_name": player["display_name"], "elo_rating": player["current_elo"], "friend_code": player["uid"]} for player in players]
        return player_elo_list
    finally:
        cursor.close()
        conn.close()
        
def update_elo(player1_display_name, player2_display_name, player1_score, player2_score, winner):
    conn = get_db_connection()
    cursor = conn.cursor()
    K = 32

    try:
        cursor.execute("""
            SELECT display_name, current_elo 
            FROM users 
            WHERE display_name IN (%s, %s);
        """, (player1_display_name, player2_display_name))

        players = cursor.fetchall()
        if len(players) != 2:
            return {"error": "Both players must exist in the database."}

        player1_elo = players[0]["current_elo"]
        player2_elo = players[1]["current_elo"]
        expected_player1 = 1 / (1 + 10 ** ((player2_elo - player1_elo) / 400))
        expected_player2 = 1 / (1 + 10 ** ((player1_elo - player2_elo) / 400))
        

        if winner == player1_display_name:
            actual_player1 = 1
            actual_player2 = 0
        elif winner == player2_display_name:
            actual_player1 = 0
            actual_player2 = 1
        else:
            actual_player1 = 0.5
            actual_player2 = 0.5 

        new_player1_elo = player1_elo + K * (actual_player1 - expected_player1)
        new_player2_elo = player2_elo + K * (actual_player2 - expected_player2)

        cursor.execute("""
            UPDATE users 
            SET current_elo = %s 
            WHERE display_name = %s;
        """, (new_player1_elo, player1_display_name))

        cursor.execute("""
            UPDATE users 
            SET current_elo = %s 
            WHERE display_name = %s;
        """, (new_player2_elo, player2_display_name))

        conn.commit()  
        
        return {
            "player1_display_name": player1_display_name,
            "new_player1_elo": new_player1_elo,
            "player2_display_name": player2_display_name,
            "new_player2_elo": new_player2_elo
        }

    finally:
        cursor.close()
        conn.close()