<?php
require_once 'vendor/autoload.php';
require_once 'db/config.php';
session_start();

$social_logins = require 'config/social_logins.php';
$google_config = $social_logins['google'];

$client = new Google_Client();
$client->setClientId($google_config['client_id']);
$client->setClientSecret($google_config['client_secret']);
$client->setRedirectUri($google_config['redirect_uri']);

if (isset($_GET['code'])) {
    $token = $client->fetchAccessTokenWithAuthCode($_GET['code']);
    $client->setAccessToken($token['access_token']);

    // get profile info
    $google_oauth = new Google_Service_Oauth2($client);
    $google_account_info = $google_oauth->userinfo->get();
    $email =  $google_account_info->email;
    $name =  $google_account_info->name;
    $google_id = $google_account_info->id;

    try {
        $pdo = db();

        // Check if user exists with this google id
        $stmt = $pdo->prepare('SELECT u.* FROM users u JOIN user_social_logins usl ON u.id = usl.user_id WHERE usl.provider = ? AND usl.provider_id = ?');
        $stmt->execute(['google', $google_id]);
        $user = $stmt->fetch();

        if ($user) {
            // User exists, log them in
            $_SESSION['user_id'] = $user['id'];
            $_SESSION['username'] = $user['username'];
            $_SESSION['role'] = $user['role'];
        } else {
            // User does not exist, create a new user
            $stmt = $pdo->prepare('SELECT * FROM users WHERE username = ?');
            $stmt->execute([$email]);
            $user_exists = $stmt->fetch();

            if ($user_exists) {
                // A user with this email already exists, but not linked to this google id.
                // For simplicity, we will just link them.
                $user_id = $user_exists['id'];
            } else {
                // Create a new user
                $stmt = $pdo->prepare("INSERT INTO users (username, role) VALUES (?, ?)");
                $stmt->execute([$email, 'customer']);
                $user_id = $pdo->lastInsertId();
            }

            // Link the social login
            $stmt = $pdo->prepare("INSERT INTO user_social_logins (user_id, provider, provider_id) VALUES (?, ?, ?)");
            $stmt->execute([$user_id, 'google', $google_id]);

            // Log the new user in
            $_SESSION['user_id'] = $user_id;
            $_SESSION['username'] = $email;
            $_SESSION['role'] = 'customer';
        }

        header('Location: profile.php');
        exit;

    } catch (PDOException $e) {
        $_SESSION['flash_message'] = ['type' => 'danger', 'message' => 'Database error: ' . $e->getMessage()];
        header('Location: login.php');
        exit;
    }
} else {
    header('Location: login.php');
    exit;
}