<?php
/**
 * WordPress Abilities.
 *
 * @package StandChat
 */

namespace StandChat;

defined( 'ABSPATH' ) || exit;

/**
 * Registers three abilities with the WordPress Abilities API (WordPress 6.9
 * and later), so tools such as the MCP Adapter can check the chat, read a page
 * again or switch chat on and off. They aren't public and need the plugin's
 * capability. Conversations are never exposed.
 */
final class Abilities {

	/**
	 * Connection.
	 *
	 * @var Connection
	 */
	private $connection;

	/**
	 * Stand service.
	 *
	 * @var Stand
	 */
	private $stand;

	/**
	 * Constructor.
	 *
	 * @param Connection $connection Connection.
	 * @param Stand      $stand      Stand service.
	 */
	public function __construct( Connection $connection, Stand $stand ) {
		$this->connection = $connection;
		$this->stand      = $stand;
	}

	/**
	 * Hooks, when the Abilities API exists.
	 */
	public function register(): void {
		if ( ! function_exists( 'wp_register_ability' ) || ! function_exists( 'wp_register_ability_category' ) ) {
			return;
		}
		add_action( 'wp_abilities_api_categories_init', array( $this, 'category' ) );
		add_action( 'wp_abilities_api_init', array( $this, 'abilities' ) );
	}

	/**
	 * Registers the category.
	 */
	public function category(): void {
		wp_register_ability_category(
			'stand-chat',
			array(
				'label'       => __( 'Stand Chat', 'stand-chat' ),
				'description' => __( 'Chat on this site and the AI assistant that answers it.', 'stand-chat' ),
			)
		);
	}

	/**
	 * Registers the abilities.
	 */
	public function abilities(): void {
		$permission = static function (): bool {
			return current_user_can( Admin::capability() );
		};

		wp_register_ability(
			'stand-chat/get-status',
			array(
				'label'               => __( 'Get chat status', 'stand-chat' ),
				'description'         => __( 'Whether chat is live on this site, and if not, why: off, hidden on this environment, waiting for installation, no one answering, or chats used up.', 'stand-chat' ),
				'category'            => 'stand-chat',
				'output_schema'       => array(
					'type'       => 'object',
					'properties' => array(
						'state'   => array( 'type' => 'string' ),
						'title'   => array( 'type' => 'string' ),
						'message' => array( 'type' => 'string' ),
					),
				),
				'execute_callback'    => function () {
					$status = Status::compute( $this->connection, $this->stand );
					return array(
						'state'   => $status['state'],
						'title'   => $status['title'],
						'message' => $status['message'],
					);
				},
				'permission_callback' => $permission,
				'meta'                => array(
					'annotations' => array(
						'readonly'    => true,
						'destructive' => false,
						'idempotent'  => true,
					),
				),
			)
		);

		wp_register_ability(
			'stand-chat/read-page-again',
			array(
				'label'               => __( 'Read a page again', 'stand-chat' ),
				'description'         => __( 'Asks Stand to read a page the AI assistant reads again, after it was edited.', 'stand-chat' ),
				'category'            => 'stand-chat',
				'input_schema'        => array(
					'type'       => 'object',
					'properties' => array(
						'post_id' => array(
							'type'    => 'integer',
							'minimum' => 1,
						),
					),
					'required'   => array( 'post_id' ),
				),
				'execute_callback'    => function ( $input ) {
					$id = absint( is_array( $input ) ? ( $input['post_id'] ?? 0 ) : 0 );
					if ( '' === (string) get_post_meta( $id, Knowledge::META_SOURCE, true ) ) {
						return new \WP_Error( 'stand_chat_not_picked', __( 'Your AI assistant doesn\'t read this page.', 'stand-chat' ) );
					}
					// On the connection the request began on, as a page's changes
					// are: nobody connects or disconnects until it's asked.
					$errors = $this->stand->on_loaded_connection(
						null,
						function () use ( $id ): array {
							return ( new Knowledge( $this->stand ) )->read_again( array( $id ) );
						}
					);
					if ( is_wp_error( $errors ) ) {
						return $errors;
					}
					return empty( $errors ) ? array( 'requested' => true ) : new \WP_Error( 'stand_chat_read_again', (string) reset( $errors ) );
				},
				'permission_callback' => $permission,
				'meta'                => array(
					'annotations' => array(
						'readonly'    => false,
						'destructive' => false,
						// Each call starts another reading in Stand.
						'idempotent'  => false,
					),
				),
			)
		);

		wp_register_ability(
			'stand-chat/set-chat-enabled',
			array(
				'label'               => __( 'Turn chat on or off', 'stand-chat' ),
				'description'         => __( 'Turns "Chat on this site" on or off. Settings are kept.', 'stand-chat' ),
				'category'            => 'stand-chat',
				'input_schema'        => array(
					'type'       => 'object',
					'properties' => array(
						'enabled' => array( 'type' => 'boolean' ),
					),
					'required'   => array( 'enabled' ),
				),
				'execute_callback'    => static function ( $input ) {
					$enabled = is_array( $input ) && ! empty( $input['enabled'] );
					Settings::update( array( 'chat_enabled' => $enabled ) );
					return array( 'enabled' => $enabled );
				},
				'permission_callback' => $permission,
				'meta'                => array(
					'annotations' => array(
						'readonly'    => false,
						'destructive' => false,
						'idempotent'  => true,
					),
				),
			)
		);
	}
}