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

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 reauth_user(token):
    conn = get_db_connection()
    cursor = conn.cursor()
    try:
        cursor.execute("SELECT email, display_name, current_elo, session_token FROM users WHERE session_token = %s;", (token,))
        user = cursor.fetchone()
        if user:
                user_data = {
                    "email": user["email"],
                    "display_name": user["display_name"],
                    "elo": user["current_elo"]
                }
                return user_data
        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 = {}

        index = len(friends)

        friend_key = f"friend{index}"
        if friend_key not in friends:
            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()
        else:
            return False

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


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 send_match_invite(sender_uid, receiver_uid):
    conn = get_db_connection()
    cursor = conn.cursor()
    try:
        cursor.execute(
            "INSERT INTO matches (player1_uid, player2_uid) VALUES (%s, %s) RETURNING match_id;",
            (sender_uid, receiver_uid)
        )
        match_id = cursor.fetchone()["match_id"]
        conn.commit()
        return match_id
    except Exception as e:
        conn.rollback()
        raise e
    finally:
        cursor.close()
        conn.close()

def accept_match_invite(match_id, player2_uid):
    conn = get_db_connection()
    cursor = conn.cursor()
    try:
        cursor.execute(
            "UPDATE matches SET match_date = CURRENT_TIMESTAMP WHERE match_id = %s AND player2_uid = %s;",
            (match_id, player2_uid)
        )
        conn.commit()
        return True
    except Exception as e:
        conn.rollback()
        raise e
    finally:
        cursor.close()
        conn.close()


def get_all_matches():
    conn = get_db_connection()
    cursor = conn.cursor()
    try:
        query = """
        SELECT 
            m.match_id,
            u1.display_name AS player1_name,
            u2.display_name AS player2_name,
            m.player1_score,
            m.player2_score,
            CASE
                WHEN m.player1_score IS NULL AND m.player2_score IS NULL THEN 'upcoming'
                WHEN m.player1_score IS NOT NULL AND m.player2_score IS NOT NULL THEN 'completed'
                ELSE 'ongoing'
            END AS status,
            m.match_date
        FROM matches m
        LEFT JOIN users u1 ON m.player1_uid = u1.uid
        LEFT JOIN users u2 ON m.player2_uid = u2.uid
        ORDER BY 
            CASE
                WHEN m.player1_score IS NULL AND m.player2_score IS NULL THEN 2 -- Upcoming
                WHEN m.player1_score IS NOT NULL AND m.player2_score IS NOT NULL THEN 3 -- Completed
                ELSE 1 -- Ongoing
            END,
            m.match_date;
        """
        cursor.execute(query)
        matches = cursor.fetchall()
        return matches
    finally:
        cursor.close()
        conn.close()


def get_elo(auth_header):
    if not auth_header.startswith('Basic '):
        raise ValueError("Invalid Authorization header")

    encoded_credentials = auth_header.split(' ', 1)[1]
    decoded_credentials = base64.b64decode(encoded_credentials).decode()

    try:
        email, password = decoded_credentials.split(':', 1)
    except ValueError:
        raise ValueError("Invalid credentials format")

    conn = get_db_connection()
    cursor = conn.cursor()
    try:
        cursor.execute("SELECT email, display_name, password_hash, elo FROM users WHERE email = %s;", (email,))
        user = cursor.fetchone()

        if not user:
            raise ValueError("User not found")

        if not bcrypt.checkpw(password.encode(), user["password_hash"].encode()):
            raise ValueError("Invalid password")
        return {
            "email": user["email"],
            "elo": user["elo"],
            "display_name": user["display_name"]
        }

    except Exception as e:
        raise e

    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()