<?php
/**
 * API Client for AgentShop backend.
 *
 * @package AgentShop
 */

namespace AgentShop\Api;

defined( 'ABSPATH' ) || exit;

/**
 * API Client class.
 */
class Client {

	/**
	 * Request timeout in seconds.
	 *
	 * @var int
	 */
	private $timeout = 30;

	/**
	 * Rate limit: requests per minute.
	 *
	 * @var int
	 */
	private $rate_limit = 60;

	/**
	 * Rate limit window in seconds.
	 *
	 * @var int
	 */
	private $rate_limit_window = 60;

	/**
	 * Constructor.
	 */
	public function __construct() {
		/**
		 * Filter the API rate limit (requests per minute).
		 *
		 * @since 1.0.0
		 * @param int $rate_limit Number of requests allowed per minute. Default 60.
		 */
		$this->rate_limit = apply_filters( 'agentshop_api_rate_limit', $this->rate_limit );

		/**
		 * Filter the API rate limit window in seconds.
		 *
		 * @since 1.0.0
		 * @param int $rate_limit_window Time window in seconds. Default 60.
		 */
		$this->rate_limit_window = apply_filters( 'agentshop_api_rate_limit_window', $this->rate_limit_window );
	}

	/**
	 * Check if rate limit is exceeded.
	 *
	 * @return bool True if rate limited, false otherwise.
	 */
	private function is_rate_limited() {
		$transient_key = 'agentshop_api_requests';
		$requests      = get_transient( $transient_key );

		if ( false === $requests ) {
			return false;
		}

		return $requests >= $this->rate_limit;
	}

	/**
	 * Increment rate limit counter.
	 */
	private function increment_rate_limit() {
		$transient_key = 'agentshop_api_requests';
		$requests      = get_transient( $transient_key );

		if ( false === $requests ) {
			set_transient( $transient_key, 1, $this->rate_limit_window );
		} else {
			$timeout   = get_option( '_transient_timeout_' . $transient_key );
			$remaining = $timeout ? $timeout - time() : $this->rate_limit_window;

			set_transient( $transient_key, $requests + 1, max( 1, $remaining ) );
		}
	}

	/**
	 * Make an API request.
	 *
	 * @param string $method  HTTP method.
	 * @param string $path    API path.
	 * @param array  $data    Request data.
	 * @param array  $headers Additional headers.
	 * @return array|\WP_Error
	 */
	public function request( $method, $path, $data = array(), $headers = array() ) {
		// Check rate limiting.
		if ( $this->is_rate_limited() ) {
			agentshop()->log( 'API rate limit exceeded', 'warning' );
			return new \WP_Error(
				'agentshop_rate_limited',
				__( 'API rate limit exceeded. Please try again later.', 'agentshop' ),
				array( 'status' => 429 )
			);
		}

		$endpoint = agentshop()->get_api_endpoint();
		$url      = trailingslashit( $endpoint ) . ltrim( $path, '/' );

		// Validate HTTPS.
		if ( strpos( $url, 'https://' ) !== 0 && ! ( defined( 'WP_DEBUG' ) && WP_DEBUG ) ) {
			return new \WP_Error(
				'agentshop_insecure_endpoint',
				__( 'API endpoint must use HTTPS.', 'agentshop' )
			);
		}

		$default_headers = array(
			'Content-Type' => 'application/json',
			'User-Agent'   => 'AgentShop-WooCommerce/' . AGENTSHOP_VERSION,
			'X-Site-URL'   => get_site_url(),
		);

		$options = agentshop()->get_options();
		if ( ! empty( $options['pixel_token'] ) ) {
			$default_headers['X-AgentShop-Token'] = $options['pixel_token'];
		}

		$headers = array_merge( $default_headers, $headers );

		$args = array(
			'method'  => $method,
			'headers' => $headers,
			'timeout' => $this->timeout,
		);

		if ( in_array( $method, array( 'POST', 'PUT', 'PATCH' ), true ) && ! empty( $data ) ) {
			$args['body'] = wp_json_encode( $data );
		}

		agentshop()->log( "API Request: {$method} {$path}", 'debug', array( 'data' => $data ) );

		// Increment rate limit counter.
		$this->increment_rate_limit();

		$response = wp_remote_request( $url, $args );

		if ( is_wp_error( $response ) ) {
			agentshop()->log( 'API Error: ' . $response->get_error_message(), 'error' );
			return $response;
		}

		$code    = wp_remote_retrieve_response_code( $response );
		$body    = wp_remote_retrieve_body( $response );
		$decoded = json_decode( $body, true );

		if ( $code >= 400 ) {
			$error_message = isset( $decoded['message'] ) ? $decoded['message'] : __( 'Unknown error', 'agentshop' );
			agentshop()->log( "API Error ({$code}): {$error_message}", 'error' );

			return new \WP_Error(
				'agentshop_api_error',
				$error_message,
				array(
					'status'   => $code,
					'response' => $decoded,
				)
			);
		}

		return array(
			'status' => $code,
			'data'   => $decoded,
		);
	}

	/**
	 * GET request.
	 *
	 * @param string $path   API path.
	 * @param array  $params Query parameters.
	 * @return array|\WP_Error
	 */
	public function get( $path, $params = array() ) {
		if ( ! empty( $params ) ) {
			$path .= '?' . http_build_query( $params );
		}
		return $this->request( 'GET', $path );
	}

	/**
	 * POST request.
	 *
	 * @param string $path API path.
	 * @param array  $data Request body.
	 * @return array|\WP_Error
	 */
	public function post( $path, $data = array() ) {
		return $this->request( 'POST', $path, $data );
	}

	/**
	 * Send pixel event.
	 *
	 * @param array $event_data Event data.
	 * @return array|\WP_Error
	 */
	public function send_pixel_event( $event_data ) {
		$options = agentshop()->get_options();

		$payload = array_merge(
			array(
				'pixel_version' => AGENTSHOP_VERSION,
				'store_url'     => agentshop()->get_store_url(),
				'pixel_token'   => $options['pixel_token'] ?? '',
				'session_id'    => agentshop()->get_session_id(),
				'customer_id'   => agentshop()->get_customer_id(),
				'event_source'  => 'server',
				'timestamp'     => gmdate( 'c' ),
				'url'           => $this->get_current_url(),
				'referrer'      => wp_get_referer() ?: '',
			),
			$event_data
		);

		return $this->post( 'api/woocommerce/pixel/events', $payload );
	}

	/**
	 * Verify connection.
	 *
	 * @return array|\WP_Error
	 */
	public function verify_connection() {
		return $this->get( 'api/woocommerce/verify' );
	}

	/**
	 * Disconnect.
	 *
	 * @return array|\WP_Error
	 */
	public function disconnect() {
		return $this->post( 'api/woocommerce/disconnect' );
	}

	/**
	 * Check plugin status.
	 *
	 * @return array|\WP_Error
	 */
	public function check_plugin_status() {
		return $this->get(
			'api/woocommerce/plugin/status',
			array( 'site' => agentshop()->get_store_url() )
		);
	}

	/**
	 * Send WordPress credentials (snake_case).
	 *
	 * @param string $username Username.
	 * @param string $password Password.
	 * @return array|\WP_Error
	 */
	public function send_wordpress_credentials( $username, $password ) {
		return $this->post(
			'api/woocommerce/plugin/wordpress-credentials',
			array(
				'wp_username'     => $username,
				'wp_app_password' => $password,
			)
		);
	}

	/**
	 * Fetch llms.txt content.
	 *
	 * @param string $version Version: 'standard' or 'full'.
	 * @return array|\WP_Error
	 */
	public function fetch_llms_txt( $version = 'standard' ) {
		$params = array( 'site' => agentshop()->get_store_url() );

		if ( 'full' === $version ) {
			$params['version'] = 'full';
		}

		return $this->get( 'api/woocommerce/llms-txt/proxy', $params );
	}

	/**
	 * Get current URL.
	 *
	 * @return string
	 */
	private function get_current_url() {
		global $wp;

		if ( is_admin() ) {
			return admin_url( add_query_arg( array(), $GLOBALS['pagenow'] ) );
		}

		return home_url( add_query_arg( array(), $wp->request ) );
	}
}