<?php
/**
 * REST API — public and authenticated endpoints.
 *
 * @package AdsdReferralCouponcoreEcosystem
 */

defined( 'ABSPATH' ) || exit;

class ADSD_RCC_REST_API {

    private static ?ADSD_RCC_REST_API $instance = null;
    private const NAMESPACE = 'adsd-rcc/v1';

    public static function instance(): self {
        if ( null === self::$instance ) {
            self::$instance = new self();
        }
        return self::$instance;
    }

    private function __construct() {
        add_action( 'rest_api_init', [ $this, 'register_routes' ] );
    }

    public function register_routes(): void {
        // Generate referral link
        register_rest_route( self::NAMESPACE, '/generate-link', [
            'methods'             => 'POST',
            'callback'            => [ $this, 'generate_link' ],
            'permission_callback' => [ $this, 'require_login' ],
        ] );

        // Get user rewards
        register_rest_route( self::NAMESPACE, '/rewards', [
            'methods'             => 'GET',
            'callback'            => [ $this, 'get_rewards' ],
            'permission_callback' => [ $this, 'require_login' ],
        ] );

        // Get dashboard data
        register_rest_route( self::NAMESPACE, '/dashboard', [
            'methods'             => 'GET',
            'callback'            => [ $this, 'get_dashboard' ],
            'permission_callback' => [ $this, 'require_login' ],
        ] );

        // Checker: validate reward code
        register_rest_route( self::NAMESPACE, '/check-reward', [
            'methods'             => 'POST',
            'callback'            => [ $this, 'check_reward' ],
            'permission_callback' => '__return_true',
        ] );

        // Checker: mark reward as used
        register_rest_route( self::NAMESPACE, '/mark-used', [
            'methods'             => 'POST',
            'callback'            => [ $this, 'mark_used' ],
            'permission_callback' => '__return_true',
        ] );
    }

    public function require_login(): bool {
        return is_user_logged_in();
    }

    // ─── Handlers ─────────────────────────────────────────────────────────────

    public function generate_link( WP_REST_Request $req ): WP_REST_Response {
        $user_id = get_current_user_id();
        $result  = ADSD_RCC_Referral_Engine::instance()->generate_link( $user_id );

        if ( is_wp_error( $result ) ) {
            return new WP_REST_Response( [ 'error' => $result->get_error_message() ], 400 );
        }

        return new WP_REST_Response( $result, 200 );
    }

    public function get_rewards( WP_REST_Request $req ): WP_REST_Response {
        $user_id = get_current_user_id();
        $rewards = ADSD_RCC_DB::instance()->get_rewards_for_user( $user_id );

        $formatted = array_map( function( $r ) {
            $r->reward_display = ADSD_RCC_Reward_Engine::format_value( $r );
            return $r;
        }, $rewards );

        return new WP_REST_Response( $formatted, 200 );
    }

    public function get_dashboard( WP_REST_Request $req ): WP_REST_Response {
        $user_id = get_current_user_id();
        $data    = ADSD_RCC_Referral_Engine::instance()->get_dashboard_data( $user_id );
        return new WP_REST_Response( $data, 200 );
    }

    public function check_reward( WP_REST_Request $req ): WP_REST_Response {
        $params   = $req->get_json_params();
        $passkey  = sanitize_text_field( $params['passkey']     ?? '' );
        $code     = sanitize_text_field( $params['reward_code'] ?? '' );

        if ( ! ADSD_RCC_DB::instance()->validate_passkey( $passkey ) ) {
            return new WP_REST_Response( [ 'error' => __( 'Invalid passkey.', 'adsd-referral-couponcore' ) ], 403 );
        }

        $reward = ADSD_RCC_DB::instance()->get_reward_by_code( $code );
        if ( ! $reward ) {
            return new WP_REST_Response( [ 'error' => __( 'Reward code not found.', 'adsd-referral-couponcore' ) ], 404 );
        }

        $user = get_user_by( 'id', (int) $reward->user_id );

        return new WP_REST_Response( [
            'reward_code'    => $reward->reward_code,
            'reward_value'   => ADSD_RCC_Reward_Engine::format_value( $reward ),
            'status'         => $reward->status,
            'expires_at'     => $reward->expires_at,
            'user_email'     => $user ? $user->user_email : '',
            'can_mark_used'  => $reward->status === 'active',
        ], 200 );
    }

    public function mark_used( WP_REST_Request $req ): WP_REST_Response {
        $params  = $req->get_json_params();
        $passkey = sanitize_text_field( $params['passkey']     ?? '' );
        $code    = sanitize_text_field( $params['reward_code'] ?? '' );

        if ( ! ADSD_RCC_DB::instance()->validate_passkey( $passkey ) ) {
            return new WP_REST_Response( [ 'error' => __( 'Invalid passkey.', 'adsd-referral-couponcore' ) ], 403 );
        }

        $db     = ADSD_RCC_DB::instance();
        $reward = $db->get_reward_by_code( $code );

        if ( ! $reward ) {
            return new WP_REST_Response( [ 'error' => __( 'Reward not found.', 'adsd-referral-couponcore' ) ], 404 );
        }

        if ( $reward->status !== 'active' ) {
            return new WP_REST_Response( [
                /* translators: %s: current status of the reward (e.g. expired, used) */
                'error' => sprintf( __( 'Reward is already %s.', 'adsd-referral-couponcore' ), $reward->status ),
            ], 409 );
        }

        $db->update_reward( (int) $reward->id, [
            'status'          => 'used',
            'used_at'         => current_time( 'mysql', true ),
            'used_by'         => 'local_shop',
            'shopkeeper_used' => 1,
        ] );

        $user = get_user_by( 'id', (int) $reward->user_id );
        if ( $user ) {
            ADSD_RCC_Reward_Engine::instance()->send_used_email( $user, $reward );
        }

        $db->log( 'reward_used_local', (int) $reward->user_id, (int) $reward->id, 'Reward marked as used by local shopkeeper.' );

        return new WP_REST_Response( [ 'success' => true ], 200 );
    }
}