<?php
if (!defined('ABSPATH')) {
    exit;
}

class Beep_Magic_Links {

    const TABLE = 'beep_magic_links';
    const TOKEN_LENGTH = 32;
    const EXPIRY_HOURS = 24;

    public static function init() {
        // Auto-create table on first load if needed
        self::maybe_create_table();

        add_action('rest_api_init', [__CLASS__, 'register_rest_routes']);
        add_action('init', [__CLASS__, 'handle_magic_link_login']);
        add_action('wp', [__CLASS__, 'cleanup_expired_tokens']);
    }

    private static function maybe_create_table() {
        static $checked = false;
        if ($checked) {
            return;
        }
        $checked = true;

        global $wpdb;
        $table = $wpdb->prefix . self::TABLE;
        if ($wpdb->get_var("SHOW TABLES LIKE '$table'") !== $table) {
            self::create_table();
        }
    }

    public static function create_table() {
        global $wpdb;
        $table = $wpdb->prefix . self::TABLE;
        $charset = $wpdb->get_charset_collate();

        $sql = "CREATE TABLE IF NOT EXISTS {$table} (
            id bigint(20) unsigned NOT NULL auto_increment,
            user_id bigint(20) unsigned NOT NULL,
            token varchar(64) NOT NULL,
            email varchar(100) NOT NULL,
            created_at datetime NOT NULL default CURRENT_TIMESTAMP,
            expires_at datetime NOT NULL,
            used_at datetime DEFAULT NULL,
            PRIMARY KEY (id),
            UNIQUE KEY token (token),
            KEY user_id (user_id),
            KEY expires_at (expires_at)
        ) {$charset};";

        require_once(ABSPATH . 'wp-admin/includes/upgrade.php');
        dbDelta($sql);
    }

    public static function register_rest_routes() {
        register_rest_route('beep/v1', '/magic-link', [
            'methods'  => 'POST',
            'callback'  => [__CLASS__, 'request_magic_link'],
            'permission_callback' => '__return_true',
        ]);
    }

    public static function request_magic_link($request) {
        $email = sanitize_email($request->get_param('email'));

        if (!$email || !is_email($email)) {
            return new WP_Error('invalid_email', 'Please enter a valid email address.', ['status' => 400]);
        }

        $user = get_user_by('email', $email);
        if (!$user) {
            // Don't reveal whether an email exists
            return ['success' => true, 'message' => 'If that email is registered, a login link has been sent.'];
        }

        // Check rate limit (one request per 5 minutes per email)
        $rate_key = 'beep_ml_' . md5($email);
        $last_request = get_transient($rate_key);
        if ($last_request) {
            return new WP_Error(
                'rate_limited',
                'Please wait a few minutes before requesting another login link.',
                ['status' => 429]
            );
        }

        // Generate token
        $token = wp_generate_password(self::TOKEN_LENGTH, false);
        $hashed_token = hash('sha256', $token);
        $expires_at = date('Y-m-d H:i:s', time() + (self::EXPIRY_HOURS * 3600));

        // Store in database
        global $wpdb;
        $table = $wpdb->prefix . self::TABLE;

        $wpdb->insert($table, [
            'user_id'    => $user->ID,
            'token'      => $hashed_token,
            'email'      => $email,
            'expires_at' => $expires_at,
        ]);

        // Set rate limit
        set_transient($rate_key, true, 5 * 60);

        // Build magic link
        $login_url = add_query_arg([
            'beep_magic' => $token,
            'uid'        => $user->ID,
        ], home_url('/'));

        // Email content
        $site_name = get_bloginfo('name');
        $subject = sprintf('[%s] Your login link', $site_name);
        $message = sprintf(
            "Hi %s,\n\nClick the link below to sign in to %s:\n\n%s\n\nThis link expires in %d hours.\n\nIf you didn't request this, you can ignore this email.\n\n— The %s team",
            $user->display_name,
            $site_name,
            $login_url,
            self::EXPIRY_HOURS,
            $site_name
        );

        // Send email
        $sent = wp_mail($email, $subject, $message);

        if (!$sent) {
            return new WP_Error('email_failed', 'Failed to send email. Please try again.', ['status' => 500]);
        }

        return ['success' => true, 'message' => 'Check your email for the login link!'];
    }

    public static function handle_magic_link_login() {
        if (!isset($_GET['beep_magic']) || !isset($_GET['uid'])) {
            return;
        }

        $token = sanitize_text_field($_GET['beep_magic']);
        $user_id = (int) $_GET['uid'];

        if (!$token || !$user_id) {
            return;
        }

        // Verify token
        global $wpdb;
        $table = $wpdb->prefix . self::TABLE;
        $hashed_token = hash('sha256', $token);

        $record = $wpdb->get_row($wpdb->prepare(
            "SELECT * FROM {$table} WHERE token = %s AND user_id = %d AND used_at IS NULL AND expires_at > %s",
            $hashed_token,
            $user_id,
            current_time('mysql')
        ));

        if (!$record) {
            wp_die('This login link is invalid or has expired. Please request a new one.');
        }

        // Mark as used
        $wpdb->update(
            $table,
            ['used_at' => current_time('mysql')],
            ['id' => $record->id]
        );

        // Log the user in
        $user = get_user_by('id', $user_id);
        if ($user) {
            wp_set_current_user($user_id);
            wp_set_auth_cookie($user_id);
            do_action('wp_login', $user->user_login, $user);

            // Redirect to home or beep page
            $redirect_url = isset($_GET['redirect_to']) ? esc_url_raw($_GET['redirect_to']) : home_url('/');
            wp_redirect($redirect_url);
            exit;
        }
    }

    public static function cleanup_expired_tokens() {
        // Run once per session
        static $run = false;
        if ($run) {
            return;
        }
        $run = true;

        global $wpdb;
        $table = $wpdb->prefix . self::TABLE;
        $wpdb->query($wpdb->prepare(
            "DELETE FROM {$table} WHERE expires_at < %s OR (used_at IS NOT NULL AND DATE_ADD(used_at, INTERVAL 1 HOUR) < %s)",
            current_time('mysql'),
            current_time('mysql')
        ));
    }

    public static function render_login_form() {
        ob_start();
        ?>
        <div class="beep-magic-login">
            <div class="beep-magic-login-card">
                <div class="beep-magic-login-header">
                    <svg viewBox="0 0 24 24" width="32" height="32" fill="#1D9BF0">
                        <path d="M12 1.726c-6.585 0-10 5.589-10 7.5S5.415 16.726 12 16.726s10-2.589 10-7.5S18.585 1.726 12 1.726zM12 15.726c-5.33 0-8-2.91-8-4.5S6.67 6.726 12 6.726s8 2.91 8 4.5-2.67 4.5-8 4.5z"/>
                    </svg>
                    <h3>Sign in to Beep</h3>
                    <p>Enter your email to receive a magic login link</p>
                </div>
                <form class="beep-magic-login-form" data-beep-magic-form>
                    <input type="email" name="email" class="beep-magic-email" placeholder="your@email.com" required>
                    <button type="submit" class="beep-button beep-magic-submit" data-beep-magic-submit>
                        <span class="beep-magic-btn-text">Send Login Link</span>
                        <span class="beep-magic-loading" hidden>Sending...</span>
                    </button>
                </form>
                <div class="beep-magic-success" data-beep-magic-success hidden>
                    <svg viewBox="0 0 24 24" width="24" height="24" fill="#00BA7C">
                        <path d="M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z"/>
                    </svg>
                    <span>Check your email for the login link!</span>
                </div>
                <div class="beep-magic-error" data-beep-magic-error hidden></div>
            </div>
        </div>
        <?php
        return ob_get_clean();
    }
}