<?php
/**
 * REST controller for the v1 Plugin Command Interface.
 *
 * @package ActionPanelAI
 */

namespace ActionPanelAI\Rest;

use ActionPanelAI\Grammar\CommandPolicy;
use ActionPanelAI\Grammar\CommandBatchRuntime;
use ActionPanelAI\Grammar\CommandRuntime;
use ActionPanelAI\Services\SettingsRepository;
use WP_REST_Request;
use WP_REST_Response;

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

/**
 * Exposes the v1 command grammar catalog and executes command batches.
 */
class CommandController {
	/**
	 * Maximum commands accepted per batch. Sized above the largest batch the
	 * Backend translator composes (a ~100-command content-occurrence sweep).
	 */
	public const MAX_BATCH_COMMANDS = 120;

	/**
	 * Plugin command grammar runtime.
	 *
	 * @var CommandRuntime
	 */
	private CommandRuntime $grammar_runtime;

	/**
	 * Ordered command batch runtime.
	 *
	 * @var CommandBatchRuntime
	 */
	private CommandBatchRuntime $batch_runtime;

	/**
	 * Plugin settings repository.
	 *
	 * @var SettingsRepository
	 */
	private SettingsRepository $settings;

	/**
	 * Create the controller.
	 *
	 * @param SettingsRepository|null $settings        Plugin settings repository.
	 * @param CommandRuntime|null     $grammar_runtime Grammar runtime.
	 */
	public function __construct( ?SettingsRepository $settings = null, ?CommandRuntime $grammar_runtime = null ) {
		$this->settings        = $settings ?? new SettingsRepository();
		$this->grammar_runtime = $grammar_runtime ?? new CommandRuntime( null, null, null, null, null, null, new CommandPolicy( $this->settings ) );
		$this->batch_runtime   = new CommandBatchRuntime(
			fn(): array => array( 'site_shape' => $this->grammar_runtime->site_shape() )
		);
	}

	/**
	 * Return installed-runtime command grammar discovery.
	 *
	 * @param WP_REST_Request $request REST request.
	 */
	public function capabilities( WP_REST_Request $request ): WP_REST_Response {
		unset( $request );
		// One canonical discovery shape for both gate states: `enabled` reports
		// the WordPress-to-ActionPanel request gate, and a disabled site simply
		// advertises an empty capability catalog.
		return new WP_REST_Response(
			array(
				'plugin_version' => defined( 'ACTIONPANEL_AI_PLUGIN_VERSION' ) ? ACTIONPANEL_AI_PLUGIN_VERSION : '1.0.0',
				'enabled'        => $this->settings->get_allow_requests(),
				'site_identity'  => array(
					'site_url'  => get_site_url(),
					'home_url'  => get_home_url(),
					'admin_url' => admin_url(),
				),
				'grammar'        => $this->grammar_runtime->discovery(),
			)
		);
	}

	/**
	 * Execute a flat command batch and return one terminal result per command.
	 *
	 * @param WP_REST_Request $request REST request.
	 */
	public function execute( WP_REST_Request $request ): WP_REST_Response {
		if ( ! $this->settings->get_allow_requests() ) {
			return new WP_REST_Response(
				array(
					'error'   => 'actionpanel_ai_requests_disabled',
					'message' => __( 'Allow WordPress to send requests to ActionPanel AI before executing assistant commands.', 'actionpanel-ai' ),
				),
				403
			);
		}

		$commands = $request->get_param( 'commands' );
		if ( ! is_array( $commands ) ) {
			return new WP_REST_Response(
				array(
					'error'   => 'invalid_command_batch',
					'message' => '`commands` must be an array.',
				),
				400
			);
		}
		if ( count( $commands ) > self::MAX_BATCH_COMMANDS ) {
			return new WP_REST_Response(
				array(
					'error'   => 'command_batch_limit_exceeded',
					'message' => 'Command batches are limited to ' . self::MAX_BATCH_COMMANDS . ' commands; split the work into smaller batches.',
					'max'     => self::MAX_BATCH_COMMANDS,
				),
				400
			);
		}

		return new WP_REST_Response(
			array(
				'batch_id' => $request->get_param( 'batch_id' ),
				'results'  => $this->batch_runtime->run(
					$commands,
					fn( array $command ): array => $this->grammar_runtime->run( $command )
				),
			)
		);
	}
}