<?php
/**
 * phpList REST API wrapper.
 *
 * @package WooList
 */

defined( 'ABSPATH' ) || exit;

class WooList_API {

	/**
	 * Retrieve a saved plugin option.
	 *
	 * @param string $key Option key (without prefix).
	 * @param mixed  $default Default value.
	 * @return mixed
	 */
	public function get_option( string $key, $default = '' ) {
		return get_option( 'woolist_' . $key, $default );
	}

	/**
	 * Build the full phpList REST API URL.
	 *
	 * All parameters are passed as query-string arguments because the phpList
	 * REST API reads them from $_GET regardless of the HTTP method used.
	 *
	 * @param string $cmd   phpList API command.
	 * @param array  $extra Additional query parameters.
	 * @return string|WP_Error Full URL or WP_Error when base URL is missing.
	 */
	public function build_url( string $cmd, array $extra = [] ) {
		$base = $this->get_option( 'phplist_url' );
		$base = rtrim( $base, '/' );

		if ( empty( $base ) ) {
			return new WP_Error( 'woolist_no_url', __( 'phpList base URL is not configured.', 'woolist-phplist' ) );
		}

		$params = array_merge(
			[
				'page'     => 'call',
				'pi'       => 'restapi',
				'login'    => $this->get_option( 'phplist_login' ),
				'password' => $this->get_option( 'phplist_password' ),
				'cmd'      => $cmd,
			],
			$extra
		);

		return $base . '/admin/?' . http_build_query( $params );
	}

	/**
	 * Execute an API call and return decoded JSON data.
	 *
	 * @param string $cmd   phpList API command.
	 * @param array  $extra Additional query parameters.
	 * @return array|WP_Error Decoded response data or WP_Error.
	 */
	public function call( string $cmd, array $extra = [] ) {
		$url = $this->build_url( $cmd, $extra );

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

		$response = wp_remote_post( $url, [ 'timeout' => 15 ] );

		if ( is_wp_error( $response ) ) {
			error_log( '[WooList] API request failed for cmd=' . $cmd . ': ' . $response->get_error_message() );
			return $response;
		}

		$code = wp_remote_retrieve_response_code( $response );
		$body = wp_remote_retrieve_body( $response );

		if ( $code < 200 || $code >= 300 ) {
			error_log( '[WooList] API returned HTTP ' . $code . ' for cmd=' . $cmd );
			return new WP_Error( 'woolist_http_error', 'HTTP error ' . $code );
		}

		$data = json_decode( $body, true );

		if ( json_last_error() !== JSON_ERROR_NONE ) {
			error_log( '[WooList] API returned invalid JSON for cmd=' . $cmd . ': ' . $body );
			return new WP_Error( 'woolist_json_error', 'Invalid JSON response from phpList.' );
		}

		// phpList REST API signals errors via a "status" field.
		if ( isset( $data['status'] ) && strtolower( $data['status'] ) === 'error' ) {
			$message = $data['errormessage'] ?? $data['message'] ?? 'Unknown API error';
			error_log( '[WooList] API error for cmd=' . $cmd . ': ' . $message );
			return new WP_Error( 'woolist_api_error', $message );
		}

		return $data;
	}

	/**
	 * Retrieve a subscriber by email address.
	 *
	 * @param string $email Subscriber email.
	 * @return array|WP_Error
	 */
	public function subscriber_get_by_email( string $email ) {
		return $this->call( 'subscriberGetByEmail', [ 'email' => rawurlencode( $email ) ] );
	}

	/**
	 * Add a new confirmed subscriber.
	 *
	 * @param string $email Subscriber email.
	 * @return array|WP_Error
	 */
	public function subscriber_add( string $email ) {
		return $this->call(
			'subscriberAdd',
			[
				'email'      => rawurlencode( $email ),
				'confirmed'  => 1,
				'htmlemail'  => 1,
			]
		);
	}

	/**
	 * Add a subscriber (by ID) to a phpList list.
	 *
	 * @param int $list_id       phpList list ID.
	 * @param int $subscriber_id phpList subscriber ID.
	 * @return array|WP_Error
	 */
	public function list_subscriber_add( int $list_id, int $subscriber_id ) {
		return $this->call(
			'listSubscriberAdd',
			[
				'listid'       => $list_id,
				'subscriberid' => $subscriber_id,
			]
		);
	}

	/**
	 * High-level helper: subscribe an email to a list.
	 *
	 * Gets or creates the subscriber, then adds them to the list.
	 *
	 * @param string $email   Subscriber email address.
	 * @param int    $list_id phpList list ID.
	 * @return array{success: bool, subscriber_id: int|null}
	 */
	public function subscribe_email_to_list( string $email, int $list_id ): array {
		// Try to find existing subscriber.
		$subscriber_id = null;
		$existing      = $this->subscriber_get_by_email( $email );

		if ( ! is_wp_error( $existing ) && ! empty( $existing['id'] ) ) {
			$subscriber_id = (int) $existing['id'];
		} else {
			// Create new subscriber.
			$added = $this->subscriber_add( $email );
			if ( is_wp_error( $added ) ) {
				error_log( '[WooList] Could not add subscriber ' . $email . ': ' . $added->get_error_message() );
				return [ 'success' => false, 'subscriber_id' => null ];
			}
			$subscriber_id = isset( $added['id'] ) ? (int) $added['id'] : null;
		}

		if ( ! $subscriber_id ) {
			error_log( '[WooList] Could not determine subscriber ID for ' . $email );
			return [ 'success' => false, 'subscriber_id' => null ];
		}

		// Add subscriber to the list.
		$result = $this->list_subscriber_add( $list_id, $subscriber_id );

		if ( is_wp_error( $result ) ) {
			error_log( '[WooList] Could not add subscriber ' . $subscriber_id . ' to list ' . $list_id . ': ' . $result->get_error_message() );
			return [ 'success' => false, 'subscriber_id' => $subscriber_id ];
		}

		return [ 'success' => true, 'subscriber_id' => $subscriber_id ];
	}

	/**
	 * Retrieve all lists (used for connection testing).
	 *
	 * @return array|WP_Error
	 */
	public function lists_get() {
		return $this->call( 'listsGet' );
	}
}