<?php
/**
 * HTTP client for the UmamiEngine integration API (phase-1 contract).
 *
 * Every request identifies the plugin version. Timeouts are short, one retry
 * is attempted on transport-level failures, and all failures are mapped to
 * WP_Error with admin-safe messages (never raw bodies or credentials).
 *
 * @package OSSEngine
 */

defined( 'ABSPATH' ) || exit;

class OSSEngine_Api {

	const TIMEOUT_SECONDS = 10;

	/**
	 * @var OSSEngine_Options
	 */
	private $options;

	/**
	 * @param OSSEngine_Options $options Options.
	 */
	public function __construct( OSSEngine_Options $options ) {
		$this->options = $options;
	}

	/**
	 * Exchange an authorization code for a site token (public endpoint).
	 *
	 * @param string $code     Single-use authorization code.
	 * @param string $site_url Site URL the code was issued for.
	 * @param string $state    CSRF state value.
	 * @return array|WP_Error Array with integration_id, site_token, site_url.
	 */
	public function complete( $code, $site_url, $state ) {
		return $this->post(
			'/api/v1/integrations/complete',
			array(
				'code'     => $code,
				'siteUrl'  => $site_url,
				'state'    => $state,
			),
			''
		);
	}

	/**
	 * Create/select the Umami website for an integration.
	 *
	 * @param string $token          Site token.
	 * @param string $integration_id Integration UUID.
	 * @param string $site_name      Optional human-readable site name.
	 * @return array|WP_Error
	 */
	public function register_website( $token, $integration_id, $site_name = '' ) {
		return $this->post(
			'/api/v1/integrations/' . $integration_id . '/websites',
			array(
				'siteName' => $site_name,
			),
			$token
		);
	}

	/**
	 * Get connection status.
	 *
	 * @param string $token          Site token.
	 * @param string $integration_id Integration UUID.
	 * @return array|WP_Error
	 */
	public function get_status( $token, $integration_id ) {
		return $this->get( '/api/v1/integrations/' . $integration_id . '/status', $token );
	}

	/**
	 * Get tracking configuration (script URL + website id).
	 *
	 * @param string $token          Site token.
	 * @param string $integration_id Integration UUID.
	 * @return array|WP_Error
	 */
	public function get_config( $token, $integration_id ) {
		return $this->get( '/api/v1/integrations/' . $integration_id . '/config', $token );
	}

	/**
	 * Disconnect and permanently delete the Umami website and its analytics data.
	 *
	 * The backend requires the exact typed confirmation "DELETE"; without it
	 * the request is rejected and nothing is deleted.
	 *
	 * @param string $token          Site token.
	 * @param string $integration_id Integration UUID.
	 * @param string $confirmation   Typed confirmation, must be "DELETE".
	 * @return array|WP_Error
	 */
	public function disconnect( $token, $integration_id, $confirmation = '' ) {
		return $this->post(
			'/api/v1/integrations/' . $integration_id . '/disconnect',
			array( 'confirmation' => $confirmation ),
			$token
		);
	}

	/**
	 * POST helper with one retry on transport failure.
	 *
	 * @param string $path  API path.
	 * @param array  $body  JSON body.
	 * @param string $token Optional site token.
	 * @return array|WP_Error
	 */
	private function post( $path, array $body, $token ) {
		$response = $this->request_with_retry(
			$this->url( $path ),
			array(
				'method'  => 'POST',
				'timeout' => self::TIMEOUT_SECONDS,
				'headers' => $this->headers( $token ),
				'body'    => wp_json_encode( $body ),
			)
		);
		return $this->parse( $response );
	}

	/**
	 * GET helper with one retry on transport failure.
	 *
	 * @param string $path  API path.
	 * @param string $token Site token.
	 * @return array|WP_Error
	 */
	private function get( $path, $token ) {
		$response = $this->request_with_retry(
			$this->url( $path ),
			array(
				'method'  => 'GET',
				'timeout' => self::TIMEOUT_SECONDS,
				'headers' => $this->headers( $token ),
			)
		);
		return $this->parse( $response );
	}

	/**
	 * Perform the request, retrying once on transport-level failure.
	 *
	 * @param string $url  Full URL.
	 * @param array  $args wp_remote_* args.
	 * @return array|WP_Error
	 */
	private function request_with_retry( $url, array $args ) {
		$response = wp_remote_request( $url, $args );
		if ( is_wp_error( $response ) ) {
			ossengine_log( 'UmamiEngine API request failed, retrying once.' );
			$response = wp_remote_request( $url, $args );
		}
		return $response;
	}

	/**
	 * Build request headers.
	 *
	 * @param string $token Optional site token.
	 * @return array
	 */
	private function headers( $token ) {
		$headers = array(
			'Content-Type'    => 'application/json',
			'Accept'          => 'application/json',
			'X-Plugin-Version' => OSSENGINE_VERSION,
		);
		if ( '' !== (string) $token ) {
			$headers['Authorization'] = 'Bearer ' . $token;
		}
		return $headers;
	}

	/**
	 * Absolute API URL.
	 *
	 * @param string $path API path.
	 * @return string
	 */
	private function url( $path ) {
		return $this->options->backend_url() . $path;
	}

	/**
	 * Map a transport response to data or an admin-safe WP_Error.
	 *
	 * @param array|WP_Error $response Transport response.
	 * @return array|WP_Error
	 */
	private function parse( $response ) {
		if ( is_wp_error( $response ) ) {
			ossengine_log( 'UmamiEngine API transport failure.' );
			return new WP_Error(
				'ossengine_unreachable',
				__( 'Unable to connect to UmamiEngine. Please try again.', 'ossengine-analytics-connector' )
			);
		}
		$code = (int) wp_remote_retrieve_response_code( $response );
		$data = json_decode( (string) wp_remote_retrieve_body( $response ), true );

		if ( 401 === $code ) {
			return new WP_Error(
				'ossengine_expired',
				__( 'Your analytics connection has expired. Reconnect to continue tracking.', 'ossengine-analytics-connector' )
			);
		}
		if ( 404 === $code ) {
			return new WP_Error(
				'ossengine_not_found',
				__( 'Your analytics connection was not found. Reconnect to continue tracking.', 'ossengine-analytics-connector' )
			);
		}
		if ( 429 === $code ) {
			return new WP_Error(
				'ossengine_rate_limited',
				__( 'Too many requests. Please wait a minute and try again.', 'ossengine-analytics-connector' )
			);
		}
		if ( $code >= 400 && $code < 500 ) {
			$message = is_array( $data ) && isset( $data['error'] )
				? $data['error']
				: __( 'The request was rejected. Please check your settings and try again.', 'ossengine-analytics-connector' );
			// Backend 400s may carry the plugin-update notice; pass through, it is admin-safe by contract.
			return new WP_Error( 'ossengine_rejected', (string) $message );
		}
		if ( $code >= 500 || ! is_array( $data ) ) {
			ossengine_log( 'UmamiEngine API server failure.' );
			return new WP_Error(
				'ossengine_unavailable',
				__( 'Analytics is temporarily unavailable. Your website is unaffected.', 'ossengine-analytics-connector' )
			);
		}
		return $data;
	}
}