<?php
/**
 * REST API for remote management.
 *
 * All routes require an authenticated user with the manage_woocommerce
 * capability (e.g. via a WordPress Application Password over HTTPS).
 * There is deliberately no token-in-code or unauthenticated access.
 *
 * @package WC_Email_Discount_Manager
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Registers wc-edm/v1 REST routes for groups, emails and shipping rules.
 */
class WC_EDM_REST_API {

	/**
	 * REST namespace.
	 */
	const REST_NAMESPACE = 'wc-edm/v1';

	/**
	 * Hook route registration.
	 */
	public function __construct() {
		add_action( 'rest_api_init', array( $this, 'register_routes' ) );
		add_filter( 'rest_request_after_callbacks', array( $this, 'log_request' ), 10, 3 );
	}

	/**
	 * Permission check shared by all routes.
	 *
	 * Rate limiting runs before the capability check so that unauthenticated
	 * floods are throttled too.
	 *
	 * @param WP_REST_Request|null $request Current request.
	 * @return bool|WP_Error
	 */
	public function permission_check( $request = null ) {
		$method = $request instanceof WP_REST_Request ? $request->get_method() : 'GET';
		$rate   = WC_EDM_Rate_Limiter::check( $method );

		if ( $rate['limited'] ) {
			return new WP_Error(
				'wc_edm_rate_limited',
				__( 'Too many requests. Please slow down.', 'wc-email-discount' ),
				array(
					'status'      => 429,
					'retry_after' => $rate['retry_after'],
				)
			);
		}

		if ( current_user_can( 'manage_woocommerce' ) ) {
			return true;
		}

		return new WP_Error(
			'wc_edm_forbidden',
			__( 'You are not allowed to manage email discounts.', 'wc-email-discount' ),
			array( 'status' => rest_authorization_required_code() )
		);
	}

	/**
	 * Write an audit entry for wc-edm requests.
	 *
	 * Runs after the route callback (and also when a permission check failed),
	 * so both successful writes and rejected attempts are recorded. Successful
	 * reads are skipped to keep the log signal-heavy.
	 *
	 * @param WP_REST_Response|WP_HTTP_Response|WP_Error $response Result to send.
	 * @param array                                      $handler  Route handler.
	 * @param WP_REST_Request                            $request  Current request.
	 * @return mixed The unmodified response.
	 */
	public function log_request( $response, $handler, $request ) {
		if ( ! $request instanceof WP_REST_Request ) {
			return $response;
		}

		$route = $request->get_route();

		if ( 0 !== strpos( ltrim( $route, '/' ), self::REST_NAMESPACE ) ) {
			return $response;
		}

		$method  = $request->get_method();
		$is_write = WC_EDM_Rate_Limiter::is_write_method( $method );
		$details = array();
		$outcome = 'allowed';
		$status  = 200;

		if ( is_wp_error( $response ) ) {
			$error_data = $response->get_error_data();
			$status     = is_array( $error_data ) && isset( $error_data['status'] ) ? (int) $error_data['status'] : 500;
			$outcome    = 'wc_edm_rate_limited' === $response->get_error_code() ? 'rate_limited' : 'denied';

			$details['code'] = $response->get_error_code();
		} elseif ( $response instanceof WP_HTTP_Response ) {
			$status = $response->get_status();

			if ( $status >= 400 ) {
				$outcome         = 'denied';
				$data            = $response->get_data();
				$details['code'] = is_array( $data ) && isset( $data['code'] ) ? $data['code'] : 'error';
			}
		}

		// Successful reads are noise; everything else is worth keeping.
		if ( 'allowed' === $outcome && ! $is_write ) {
			return $response;
		}

		// Don't let a blocked caller flood the log with identical rows.
		if ( 'rate_limited' === $outcome && ! WC_EDM_Rate_Limiter::should_log_limit_hit() ) {
			return $response;
		}

		WC_EDM_Audit_Log::record( $outcome, $method, $route, $status, $details );

		return $response;
	}

	/**
	 * Register all routes.
	 */
	public function register_routes() {
		$perm = array( $this, 'permission_check' );

		register_rest_route(
			self::REST_NAMESPACE,
			'/status',
			array(
				'methods'             => WP_REST_Server::READABLE,
				'callback'            => array( $this, 'get_status' ),
				'permission_callback' => $perm,
			)
		);

		register_rest_route(
			self::REST_NAMESPACE,
			'/groups',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_groups' ),
					'permission_callback' => $perm,
				),
				array(
					'methods'             => WP_REST_Server::CREATABLE,
					'callback'            => array( $this, 'create_group' ),
					'permission_callback' => $perm,
				),
			)
		);

		register_rest_route(
			self::REST_NAMESPACE,
			'/groups/(?P<id>\d+)',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_group' ),
					'permission_callback' => $perm,
				),
				array(
					'methods'             => WP_REST_Server::EDITABLE,
					'callback'            => array( $this, 'update_group' ),
					'permission_callback' => $perm,
				),
				array(
					'methods'             => WP_REST_Server::DELETABLE,
					'callback'            => array( $this, 'delete_group' ),
					'permission_callback' => $perm,
				),
			)
		);

		register_rest_route(
			self::REST_NAMESPACE,
			'/emails',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_emails' ),
					'permission_callback' => $perm,
				),
				array(
					'methods'             => WP_REST_Server::CREATABLE,
					'callback'            => array( $this, 'create_email' ),
					'permission_callback' => $perm,
				),
			)
		);

		register_rest_route(
			self::REST_NAMESPACE,
			'/emails/(?P<id>\d+)',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_email' ),
					'permission_callback' => $perm,
				),
				array(
					'methods'             => WP_REST_Server::EDITABLE,
					'callback'            => array( $this, 'update_email' ),
					'permission_callback' => $perm,
				),
				array(
					'methods'             => WP_REST_Server::DELETABLE,
					'callback'            => array( $this, 'delete_email' ),
					'permission_callback' => $perm,
				),
			)
		);

		register_rest_route(
			self::REST_NAMESPACE,
			'/shipping-methods',
			array(
				'methods'             => WP_REST_Server::READABLE,
				'callback'            => array( $this, 'get_shipping_methods' ),
				'permission_callback' => $perm,
			)
		);

		register_rest_route(
			self::REST_NAMESPACE,
			'/groups/(?P<id>\d+)/shipping-rules',
			array(
				array(
					'methods'             => WP_REST_Server::READABLE,
					'callback'            => array( $this, 'get_shipping_rules' ),
					'permission_callback' => $perm,
				),
				array(
					'methods'             => WP_REST_Server::EDITABLE,
					'callback'            => array( $this, 'update_shipping_rules' ),
					'permission_callback' => $perm,
				),
			)
		);

		register_rest_route(
			self::REST_NAMESPACE,
			'/audit-log',
			array(
				'methods'             => WP_REST_Server::READABLE,
				'callback'            => array( $this, 'get_audit_log' ),
				'permission_callback' => $perm,
				'args'                => array(
					'limit'   => array(
						'type'    => 'integer',
						'default' => 50,
					),
					'offset'  => array(
						'type'    => 'integer',
						'default' => 0,
					),
					'outcome' => array(
						'type' => 'string',
						'enum' => array( 'allowed', 'denied', 'rate_limited' ),
					),
				),
			)
		);

		register_rest_route(
			self::REST_NAMESPACE,
			'/match',
			array(
				'methods'             => WP_REST_Server::READABLE,
				'callback'            => array( $this, 'match_email' ),
				'permission_callback' => $perm,
				'args'                => array(
					'email' => array(
						'required' => true,
						'type'     => 'string',
					),
				),
			)
		);
	}

	/*
	|--------------------------------------------------------------------------
	| Formatters
	|--------------------------------------------------------------------------
	*/

	/**
	 * Format a group row for API output.
	 *
	 * @param object $group Group row.
	 * @return array
	 */
	private function format_group( $group ) {
		return array(
			'id'               => (int) $group->id,
			'name'             => $group->name,
			'discount_percent' => (float) $group->discount_percent,
			'category_ids'     => WC_EDM_DB::get_group_category_ids( (int) $group->id ),
			'created_at'       => $group->created_at,
			'updated_at'       => $group->updated_at,
		);
	}

	/**
	 * Format an email assignment row for API output.
	 *
	 * @param object $assignment Email row.
	 * @return array
	 */
	private function format_email( $assignment ) {
		return array(
			'id'              => (int) $assignment->id,
			'email_pattern'   => $assignment->email_pattern,
			'assignment_type' => $assignment->assignment_type,
			'group_id'        => $assignment->group_id ? (int) $assignment->group_id : null,
			'coupon_code'     => $assignment->coupon_code,
			'custom_discount' => null !== $assignment->custom_discount ? (float) $assignment->custom_discount : null,
			'is_active'       => (bool) $assignment->is_active,
			'free_shipping'   => ! empty( $assignment->free_shipping ),
			'created_at'      => $assignment->created_at,
			'updated_at'      => $assignment->updated_at,
		);
	}

	/**
	 * Standard 404 error.
	 *
	 * @return WP_Error
	 */
	private function not_found() {
		return new WP_Error( 'wc_edm_not_found', __( 'Resource not found.', 'wc-email-discount' ), array( 'status' => 404 ) );
	}

	/*
	|--------------------------------------------------------------------------
	| Status
	|--------------------------------------------------------------------------
	*/

	/**
	 * GET /status — connectivity test plus quick stats.
	 *
	 * @return WP_REST_Response
	 */
	public function get_status() {
		return rest_ensure_response(
			array(
				'plugin'             => 'woocommerce-email-discount-manager',
				'version'            => WC_EDM_VERSION,
				'woocommerce'        => defined( 'WC_VERSION' ) ? WC_VERSION : null,
				'groups'             => WC_EDM_DB::count_groups(),
				'email_assignments'  => WC_EDM_DB::count_emails(),
				'active_assignments' => WC_EDM_DB::count_emails( true ),
			)
		);
	}

	/*
	|--------------------------------------------------------------------------
	| Groups
	|--------------------------------------------------------------------------
	*/

	/**
	 * GET /groups
	 *
	 * @return WP_REST_Response
	 */
	public function get_groups() {
		return rest_ensure_response( array_map( array( $this, 'format_group' ), WC_EDM_DB::get_groups() ) );
	}

	/**
	 * GET /groups/{id}
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function get_group( $request ) {
		$group = WC_EDM_DB::get_group( (int) $request['id'] );
		return $group ? rest_ensure_response( $this->format_group( $group ) ) : $this->not_found();
	}

	/**
	 * POST /groups
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function create_group( $request ) {
		$name = sanitize_text_field( (string) $request['name'] );

		if ( '' === $name ) {
			return new WP_Error( 'wc_edm_invalid', __( 'A group name is required.', 'wc-email-discount' ), array( 'status' => 400 ) );
		}

		$id = WC_EDM_DB::insert_group(
			array(
				'name'             => $name,
				'discount_percent' => WC_EDM_Helpers::sanitize_percent( $request['discount_percent'] ?? 0 ),
			)
		);

		if ( ! $id ) {
			return new WP_Error( 'wc_edm_db_error', __( 'Could not create the group.', 'wc-email-discount' ), array( 'status' => 500 ) );
		}

		if ( is_array( $request['category_ids'] ) ) {
			WC_EDM_DB::set_group_categories( $id, array_map( 'absint', $request['category_ids'] ) );
		}

		return rest_ensure_response( $this->format_group( WC_EDM_DB::get_group( $id ) ) );
	}

	/**
	 * PUT/PATCH /groups/{id}
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function update_group( $request ) {
		$id    = (int) $request['id'];
		$group = WC_EDM_DB::get_group( $id );

		if ( ! $group ) {
			return $this->not_found();
		}

		$name    = null !== $request['name'] ? sanitize_text_field( (string) $request['name'] ) : $group->name;
		$percent = null !== $request['discount_percent'] ? WC_EDM_Helpers::sanitize_percent( $request['discount_percent'] ) : (float) $group->discount_percent;

		if ( '' === $name ) {
			return new WP_Error( 'wc_edm_invalid', __( 'A group name is required.', 'wc-email-discount' ), array( 'status' => 400 ) );
		}

		WC_EDM_DB::update_group(
			$id,
			array(
				'name'             => $name,
				'discount_percent' => $percent,
			)
		);

		if ( is_array( $request['category_ids'] ) ) {
			WC_EDM_DB::set_group_categories( $id, array_map( 'absint', $request['category_ids'] ) );
		}

		return rest_ensure_response( $this->format_group( WC_EDM_DB::get_group( $id ) ) );
	}

	/**
	 * DELETE /groups/{id}
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function delete_group( $request ) {
		$id = (int) $request['id'];

		if ( ! WC_EDM_DB::get_group( $id ) ) {
			return $this->not_found();
		}

		WC_EDM_DB::delete_group( $id );

		return rest_ensure_response( array( 'deleted' => true, 'id' => $id ) );
	}

	/*
	|--------------------------------------------------------------------------
	| Email assignments
	|--------------------------------------------------------------------------
	*/

	/**
	 * GET /emails
	 *
	 * @return WP_REST_Response
	 */
	public function get_emails() {
		return rest_ensure_response( array_map( array( $this, 'format_email' ), WC_EDM_DB::get_emails() ) );
	}

	/**
	 * GET /emails/{id}
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function get_email( $request ) {
		$assignment = WC_EDM_DB::get_email( (int) $request['id'] );
		return $assignment ? rest_ensure_response( $this->format_email( $assignment ) ) : $this->not_found();
	}

	/**
	 * Validate and normalize email assignment input.
	 *
	 * @param WP_REST_Request $request  Request.
	 * @param object|null     $existing Existing row when updating.
	 * @return array|WP_Error
	 */
	private function prepare_email_data( $request, $existing = null ) {
		$pattern = null !== $request['email_pattern']
			? strtolower( sanitize_text_field( (string) $request['email_pattern'] ) )
			: ( $existing ? $existing->email_pattern : '' );

		$type = null !== $request['assignment_type']
			? sanitize_key( (string) $request['assignment_type'] )
			: ( $existing ? $existing->assignment_type : 'group' );

		if ( '' === $pattern ) {
			return new WP_Error( 'wc_edm_invalid', __( 'An email pattern is required.', 'wc-email-discount' ), array( 'status' => 400 ) );
		}

		if ( ! in_array( $type, array( 'group', 'coupon', 'custom' ), true ) ) {
			return new WP_Error( 'wc_edm_invalid', __( 'assignment_type must be one of: group, coupon, custom.', 'wc-email-discount' ), array( 'status' => 400 ) );
		}

		$data = array(
			'email_pattern'   => $pattern,
			'assignment_type' => $type,
			'group_id'        => null,
			'coupon_code'     => null,
			'custom_discount' => null,
			'is_active'       => null !== $request['is_active']
				? ( rest_sanitize_boolean( $request['is_active'] ) ? 1 : 0 )
				: ( $existing ? (int) $existing->is_active : 1 ),
			'free_shipping'   => null !== $request['free_shipping']
				? ( rest_sanitize_boolean( $request['free_shipping'] ) ? 1 : 0 )
				: ( $existing ? (int) ! empty( $existing->free_shipping ) : 0 ),
		);

		switch ( $type ) {
			case 'group':
				$group_id = null !== $request['group_id']
					? absint( $request['group_id'] )
					: ( $existing && $existing->group_id ? (int) $existing->group_id : 0 );

				if ( ! $group_id || ! WC_EDM_DB::get_group( $group_id ) ) {
					return new WP_Error( 'wc_edm_invalid', __( 'A valid group_id is required for group assignments.', 'wc-email-discount' ), array( 'status' => 400 ) );
				}

				$data['group_id'] = $group_id;
				break;

			case 'coupon':
				$coupon = null !== $request['coupon_code']
					? wc_format_coupon_code( (string) $request['coupon_code'] )
					: ( $existing ? (string) $existing->coupon_code : '' );

				if ( '' === $coupon ) {
					return new WP_Error( 'wc_edm_invalid', __( 'A coupon_code is required for coupon assignments.', 'wc-email-discount' ), array( 'status' => 400 ) );
				}

				$data['coupon_code'] = $coupon;
				break;

			case 'custom':
				$data['custom_discount'] = null !== $request['custom_discount']
					? WC_EDM_Helpers::sanitize_percent( $request['custom_discount'] )
					: ( $existing && null !== $existing->custom_discount ? (float) $existing->custom_discount : 0 );
				break;
		}

		return $data;
	}

	/**
	 * POST /emails
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function create_email( $request ) {
		$data = $this->prepare_email_data( $request );

		if ( is_wp_error( $data ) ) {
			return $data;
		}

		$id = WC_EDM_DB::insert_email( $data );

		if ( ! $id ) {
			return new WP_Error( 'wc_edm_db_error', __( 'Could not create the assignment.', 'wc-email-discount' ), array( 'status' => 500 ) );
		}

		return rest_ensure_response( $this->format_email( WC_EDM_DB::get_email( $id ) ) );
	}

	/**
	 * PUT/PATCH /emails/{id}
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function update_email( $request ) {
		$id       = (int) $request['id'];
		$existing = WC_EDM_DB::get_email( $id );

		if ( ! $existing ) {
			return $this->not_found();
		}

		$data = $this->prepare_email_data( $request, $existing );

		if ( is_wp_error( $data ) ) {
			return $data;
		}

		WC_EDM_DB::update_email( $id, $data );

		return rest_ensure_response( $this->format_email( WC_EDM_DB::get_email( $id ) ) );
	}

	/**
	 * DELETE /emails/{id}
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function delete_email( $request ) {
		$id = (int) $request['id'];

		if ( ! WC_EDM_DB::get_email( $id ) ) {
			return $this->not_found();
		}

		WC_EDM_DB::delete_email( $id );

		return rest_ensure_response( array( 'deleted' => true, 'id' => $id ) );
	}

	/*
	|--------------------------------------------------------------------------
	| Shipping
	|--------------------------------------------------------------------------
	*/

	/**
	 * GET /shipping-methods — all shipping method instances across zones.
	 *
	 * @return WP_REST_Response
	 */
	public function get_shipping_methods() {
		return rest_ensure_response( array_values( WC_EDM_Helpers::get_all_shipping_methods() ) );
	}

	/**
	 * GET /groups/{id}/shipping-rules
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function get_shipping_rules( $request ) {
		$group_id = (int) $request['id'];

		if ( ! WC_EDM_DB::get_group( $group_id ) ) {
			return $this->not_found();
		}

		$rules = array();

		foreach ( WC_EDM_DB::get_shipping_rules( $group_id ) as $rule ) {
			$rules[] = array(
				'shipping_method_id' => $rule->shipping_method_id,
				'action'             => $rule->action,
				'sort_order'         => (int) $rule->sort_order,
			);
		}

		return rest_ensure_response( $rules );
	}

	/**
	 * PUT /groups/{id}/shipping-rules — replace all rules for the group.
	 *
	 * Body: { "rules": [ { "shipping_method_id": "flat_rate:3", "action": "show" }, ... ] }
	 * Sort order follows array order. An empty rules array clears all rules.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response|WP_Error
	 */
	public function update_shipping_rules( $request ) {
		$group_id = (int) $request['id'];

		if ( ! WC_EDM_DB::get_group( $group_id ) ) {
			return $this->not_found();
		}

		$raw = $request['rules'];

		if ( ! is_array( $raw ) ) {
			return new WP_Error( 'wc_edm_invalid', __( 'A rules array is required.', 'wc-email-discount' ), array( 'status' => 400 ) );
		}

		$rules = array();

		foreach ( array_values( $raw ) as $index => $rule ) {
			$method_id = isset( $rule['shipping_method_id'] ) ? sanitize_text_field( (string) $rule['shipping_method_id'] ) : '';
			$action    = isset( $rule['action'] ) ? sanitize_key( (string) $rule['action'] ) : '';

			if ( '' === $method_id || ! in_array( $action, array( 'show', 'hide', 'only' ), true ) ) {
				return new WP_Error(
					'wc_edm_invalid',
					__( 'Each rule needs a shipping_method_id and an action of "show", "hide" or "only".', 'wc-email-discount' ),
					array( 'status' => 400 )
				);
			}

			$rules[] = array(
				'shipping_method_id' => $method_id,
				'action'             => $action,
				'sort_order'         => $index,
			);
		}

		WC_EDM_DB::replace_shipping_rules( $group_id, $rules );

		return $this->get_shipping_rules( $request );
	}

	/*
	|--------------------------------------------------------------------------
	| Audit log
	|--------------------------------------------------------------------------
	*/

	/**
	 * GET /audit-log — recent REST activity, newest first.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response
	 */
	public function get_audit_log( $request ) {
		$limit   = min( 200, max( 1, (int) $request['limit'] ) );
		$offset  = max( 0, (int) $request['offset'] );
		$outcome = $request['outcome'] ? sanitize_key( (string) $request['outcome'] ) : '';

		$entries = array();

		foreach ( WC_EDM_DB::get_audit_entries( $limit, $offset, $outcome ) as $entry ) {
			$entries[] = array(
				'id'         => (int) $entry->id,
				'created_at' => $entry->created_at,
				'user_id'    => (int) $entry->user_id,
				'user_login' => $entry->user_login,
				'ip'         => $entry->ip,
				'method'     => $entry->method,
				'route'      => $entry->route,
				'status'     => (int) $entry->status,
				'outcome'    => $entry->outcome,
				'details'    => $entry->details ? json_decode( $entry->details, true ) : null,
			);
		}

		$response = rest_ensure_response( $entries );
		$response->header( 'X-WP-Total', (string) WC_EDM_DB::count_audit_entries( $outcome ) );

		return $response;
	}

	/*
	|--------------------------------------------------------------------------
	| Match test
	|--------------------------------------------------------------------------
	*/

	/**
	 * GET /match?email=... — test which assignment an email would get.
	 *
	 * @param WP_REST_Request $request Request.
	 * @return WP_REST_Response
	 */
	public function match_email( $request ) {
		$email = sanitize_email( (string) $request['email'] );
		$match = $email ? WC_EDM_Helpers::find_email_match( $email ) : null;

		return rest_ensure_response(
			array(
				'email'   => $email,
				'matched' => (bool) $match,
				'match'   => $match ? $this->format_email( $match ) : null,
			)
		);
	}
}