<?php
$rootPath = dirname(__FILE__);
require_once($rootPath . "/src/config/env.php");
require_once($rootPath . "/src/config/session.php");
require_once($rootPath . "/src/config/connection.php");
require_once($rootPath . "/src/config/functions.php");
require_once($rootPath . '/google-client/vendor/autoload.php'); // Add this line for Google Client
require_once($rootPath . "/src/helpers/notification_helper.php");


// Check if connection is established
if (!$conn) {
    json_encode(['status' => 'error', 'message' => 'Database connection failed.']);
    exit();
}

// Google Client Setup
$client = new Google_Client();
$client->setClientId($_ENV['GOOGLE_CLIENT_ID']);
$client->setClientSecret($_ENV['GOOGLE_CLIENT_SECRET']);
$client->setRedirectUri($_ENV['HOST'] . '/validate_login.php');
$client->addScope("email");
$client->addScope("profile");
// 👇 Add this to force the account picker
$client->setPrompt('select_account');

// Check if Google login code is set
if (isset($_GET['code'])) {
    $token = $client->fetchAccessTokenWithAuthCode($_GET['code']);
    if (!isset($token["error"])) {
        $client->setAccessToken($token['access_token']);
        $google_oauth = new Google_Service_Oauth2($client);
        $google_account_info = $google_oauth->userinfo->get();

        // Get user info from Google
        $email = $google_account_info->email;
        $name = $google_account_info->name;
        $first_name = $google_account_info->given_name;
        $last_name = $google_account_info->family_name;
        $picture = $google_account_info->picture;

        

        // Check if the user exists in the database
        $query = "SELECT * FROM users WHERE email = ?";
        $stmt = $conn->prepare($query);
        $stmt->bind_param("s", $email);
        $stmt->execute();
        $result = $stmt->get_result();

        if ($result->num_rows == 0) {
            // User does not exist, so register them
            $password = null; // No password for Google login
            $query = "INSERT INTO users (email, first_name, last_name, profile_pic, password, is_verified) VALUES (?, ?, ?, ?, ?, ?)";
            $stmt = $conn->prepare($query);
            $is_verified = 1; // Assuming Google users are considered verified
            $stmt->bind_param("sssssi", $email, $first_name, $last_name, $picture, $password, $is_verified);
            if ($stmt->execute()) {
                // User successfully registered, set session and redirect
                $_SESSION['user_id'] = $conn->insert_id;
                $_SESSION['first_name'] = $first_name;
                $_SESSION['profile_pic'] = $picture;

                // Send Notification
                $event = 'user_login';
                $sub_feed = 'logins';
                $data = [
                    'actor_id' => $conn->insert_id,
                    'actor_avatar' => $picture,  // used by UI to show avatar
                    'title' => "User Login by {$first_name} {$last_name}"
                ];
                addNotification(null, $event, $sub_feed, $data, null);

                header("Location: index.php");
                exit();
            } else {
                // echo json_encode(['status' => 'error', 'message' => 'Failed to register user.']);
                header("Location: index.php");
                exit();
            }
        } else {
            // User exists, set session and redirect
            $row = $result->fetch_assoc();
            $_SESSION['user_id'] = $row['user_id'];
            $_SESSION['first_name'] = $row['first_name'];
            $_SESSION['profile_pic'] = $row['profile_pic'];

            // Send Notification
            $event = 'user_login';
            $sub_feed = 'logins';
            $data = [
                'actor_id' => $_SESSION['user_id'],
                'actor_avatar' => $_SESSION['profile_pic'],  // used by UI to show avatar
                'title' => "User Login by {$first_name} {$last_name}"
            ];
            addNotification(null, $event, $sub_feed, $data, null);

            header("Location: index.php");
            exit();
        }

        $stmt->close();
    } else {
        echo "Login failed.";
        exit();
    }
}

// Check if email and password login is requested
if (isset($_POST['email']) && isset($_POST['password'])) {
    // CSRF Token Validation
    if (!isset($_POST['csrf_token']) || !validateCSRFToken($_POST['csrf_token'])) {
        auditLog(null, 'CSRF_VALIDATION_FAILED', 'users', null, ['endpoint' => 'validate_login.php']);
        echo json_encode(['status' => 'error', 'message' => 'Security token validation failed. Please try again.']);
        exit();
    }
    
    // Retrieve and validate email input
    $email = validateEmail($_POST['email']);
    if ($email === false) {
        auditLog(null, 'INVALID_EMAIL_FORMAT', 'users', null, ['email' => $_POST['email']]);
        echo json_encode(['status' => 'error', 'message' => 'Invalid email format.']);
        exit();
    }
    
    // Retrieve and sanitize password
    $password = isset($_POST['password']) ? trim($_POST['password']) : '';
    
    // Basic validation
    if (empty($email) || empty($password)) {
        echo json_encode(['status' => 'error', 'message' => 'Please enter both email and password.']);
        exit();
    }
    
    // Check for account lockout
    $lockoutStatus = checkAccountLockout($email);
    if ($lockoutStatus['is_locked']) {
        auditLog(null, 'LOGIN_ATTEMPT_LOCKED_ACCOUNT', 'users', null, [
            'email' => $email,
            'locked_until' => $lockoutStatus['locked_until']
        ]);
        echo json_encode([
            'status' => 'error',
            'message' => 'Account is temporarily locked due to multiple failed login attempts. Please try again in ' . $lockoutStatus['minutes_remaining'] . ' minutes.'
        ]);
        exit();
    }
    
    // Check recent failed attempts
    $recentFailedAttempts = countRecentFailedAttempts($email);
    if ($recentFailedAttempts >= 5) {
        // Lock account for 15 minutes
        lockAccount($email, 15);
        auditLog(null, 'ACCOUNT_LOCKED_THRESHOLD', 'users', null, [
            'email' => $email,
            'failed_attempts' => $recentFailedAttempts
        ]);
        echo json_encode([
            'status' => 'error',
            'message' => 'Account locked due to multiple failed login attempts. Please try again in 15 minutes.'
        ]);
        exit();
    }

    // Prepare SQL statement to fetch user details
    $query = "SELECT * FROM users WHERE email = ?";
    $stmt = $conn->prepare($query);

    if (!$stmt) {
        echo json_encode(['status' => 'error', 'message' => 'Database query preparation failed.']);
        exit();
    }

    $stmt->bind_param("s", $email);
    $stmt->execute();
    $result = $stmt->get_result();

    // Check if user exists and verify password
    if ($result->num_rows == 1) {
        $row = $result->fetch_assoc();

        // Check if the user is verified
        if ($row['is_verified'] == 0) {
            recordLoginAttempt($email, false);
            auditLog(null, 'LOGIN_ATTEMPT_UNVERIFIED_ACCOUNT', 'users', $row['user_id']);
            echo json_encode(['status' => 'error', 'message' => 'Your account is not verified. Please check your email for the verification link.']);
            exit();
        }

        if (password_verify($password, $row['password'])) {
            // Record successful attempt
            recordLoginAttempt($email, true);
            
            // Regenerate session ID to prevent session fixation attacks
            session_regenerate_id(true);
            
            // Password is correct, set up session
            $_SESSION['user_id'] = $row['user_id'];
            $_SESSION['first_name'] = $row['first_name'];
            $_SESSION['profile_pic'] = $row['profile_pic'];
            
            // Set session timeout (30 minutes)
            $_SESSION['login_time'] = time();
            $_SESSION['session_timeout'] = 1800; // 30 minutes in seconds

            // Send Notification
            $event = 'user_login';
            $sub_feed = 'logins';
            $data = [
                'actor_id' => $_SESSION['user_id'],
                'actor_avatar' => $_SESSION['profile_pic'],  // used by UI to show avatar
                'title' => "User Login by {$first_name} {$last_name}"
            ];
            addNotification(null, $event, $sub_feed, $data, null);
            
            auditLog($row['user_id'], 'LOGIN_SUCCESS', 'users', $row['user_id']);
            echo json_encode(['status' => 'success', 'message' => 'Successful Login']);
        } else {
            // Password is incorrect - record failed attempt
            recordLoginAttempt($email, false);
            auditLog(null, 'LOGIN_FAILED_INVALID_PASSWORD', 'users', null, ['email' => $email]);
            
            // Check if this was the threshold failure
            $newFailureCount = countRecentFailedAttempts($email);
            if ($newFailureCount >= 5) {
                lockAccount($email, 15);
                echo json_encode([
                    'status' => 'error',
                    'message' => 'Too many failed login attempts. Account locked for 15 minutes.'
                ]);
            } else {
                $attemptsRemaining = 5 - $newFailureCount;
                echo json_encode([
                    'status' => 'error',
                    'message' => 'Invalid password. ' . $attemptsRemaining . ' attempts remaining before account lockout.'
                ]);
            }
        }
    } else {
        // User does not exist - still record attempt
        recordLoginAttempt($email, false);
        auditLog(null, 'LOGIN_FAILED_USER_NOT_FOUND', 'users', null, ['email' => $email]);
        echo json_encode(['status' => 'error', 'message' => 'User with that email does not exist.']);
    }

    // Close the statement and connection
    $stmt->close();
}

// Close connection
$conn->close();
exit();
?>