<?php
/**
 * MCP tool registry and gateway execution.
 *
 * @package AgentdeskSiteOperations
 */

defined( 'ABSPATH' ) || exit;

/**
 * Class Agentdesk_Registry
 */
class Agentdesk_Registry {

	/**
	 * Singleton instance.
	 *
	 * @var Agentdesk_Registry|null
	 */
	private static $instance = null;

	/**
	 * Registered tools.
	 *
	 * @var array<string, array>
	 */
	private $tools = array();

	/**
	 * Get singleton.
	 *
	 * @return Agentdesk_Registry
	 */
	public static function instance() {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Load tool modules.
	 */
	public function load_tools() {
		$tool_files = array(
			'includes/tools/core/site.php',
			'includes/tools/core/content.php',
			'includes/tools/core/media.php',
			'includes/tools/core/taxonomies.php',
			'includes/tools/core/users.php',
			'includes/tools/core/comments.php',
			'includes/tools/core/plugins.php',
			'includes/tools/core/themes.php',
			'includes/tools/core/options.php',
			'includes/tools/core/diagnostics.php',
			'includes/tools/core/debug.php',
			'includes/tools/core/gateway.php',
			'includes/tools/woocommerce/products.php',
			'includes/tools/woocommerce/orders.php',
			'includes/tools/elementor/basic.php',
			'includes/tools/elementor/deep.php',
			'includes/tools/integrations/acf-seo-cache.php',
		);

		foreach ( $tool_files as $relative ) {
			$path = AGENTDESK_PLUGIN_DIR . $relative;
			if ( file_exists( $path ) ) {
				require_once $path;
			}
		}

		/**
		 * Register additional MCP tools.
		 *
		 * @param Agentdesk_Registry $registry Registry instance.
		 */
		do_action( 'agentdesk_register_tools', $this );

		$this->register_gateway_tools();
	}

	/**
	 * Register a tool.
	 *
	 * @param string   $name Tool name.
	 * @param array    $schema Tool schema (description, inputSchema, domain, etc.).
	 * @param callable $callback Execution callback.
	 */
	public function register( $name, $schema, $callback ) {
		$this->tools[ $name ] = array_merge(
			$schema,
			array(
				'name'     => $name,
				'callback' => $callback,
			)
		);
	}

	/**
	 * Get all tools.
	 *
	 * @return array<string, array>
	 */
	public function all() {
		return $this->tools;
	}

	/**
	 * Get a tool by name.
	 *
	 * @param string $name Tool name.
	 * @return array|null
	 */
	public function get( $name ) {
		return isset( $this->tools[ $name ] ) ? $this->tools[ $name ] : null;
	}

	/**
	 * Tools exposed directly in tools/list (gateway + essentials).
	 *
	 * @return array
	 */
	public function get_public_tools() {
		$always = array( 'site_info', 'health_check', 'audit_recent', 'agentdesk_discover', 'agentdesk_info', 'agentdesk_run', 'agentdesk_batch' );
		$result = array();

		foreach ( $always as $name ) {
			if ( isset( $this->tools[ $name ] ) ) {
				$result[] = $this->format_tool_for_mcp( $this->tools[ $name ] );
			}
		}

		return $result;
	}

	/**
	 * Discover tools by query/domain.
	 *
	 * @param array $args Arguments.
	 * @return array
	 */
	public function discover( $args ) {
		$query  = isset( $args['query'] ) ? strtolower( (string) $args['query'] ) : '';
		$domain = isset( $args['domain'] ) ? strtolower( (string) $args['domain'] ) : '';
		$limit  = isset( $args['limit'] ) ? max( 1, min( 100, absint( $args['limit'] ) ) ) : 50;

		$matches = array();
		foreach ( $this->tools as $name => $tool ) {
			if ( in_array( $name, array( 'agentdesk_discover', 'agentdesk_info', 'agentdesk_run', 'agentdesk_batch' ), true ) ) {
				continue;
			}

			$tool_domain = isset( $tool['domain'] ) ? strtolower( (string) $tool['domain'] ) : 'core';
			if ( $domain && $tool_domain !== $domain ) {
				continue;
			}

			$haystack = strtolower( $name . ' ' . ( $tool['description'] ?? '' ) . ' ' . $tool_domain );
			if ( $query && false === strpos( $haystack, $query ) ) {
				continue;
			}

			$matches[] = array(
				'name'        => $name,
				'description' => $tool['description'] ?? '',
				'domain'      => $tool_domain,
				'power_mode'  => ! empty( $tool['power_mode'] ),
			);

			if ( count( $matches ) >= $limit ) {
				break;
			}
		}

		return array(
			'tools'  => $matches,
			'total'  => count( $matches ),
			'domains'=> $this->get_domains(),
		);
	}

	/**
	 * Get tool info/schema.
	 *
	 * @param string $name Tool name.
	 * @return array|WP_Error
	 */
	public function info( $name ) {
		$tool = $this->get( $name );
		if ( ! $tool ) {
			/* translators: %s: MCP tool name. */
			return new WP_Error( 'agentdesk_tool_not_found', sprintf( __( 'Tool not found: %s', 'agentdesk-site-operations' ), $name ) );
		}

		return array(
			'name'               => $name,
			'description'        => $tool['description'] ?? '',
			'domain'             => $tool['domain'] ?? 'core',
			'inputSchema'        => $tool['inputSchema'] ?? array( 'type' => 'object' ),
			'capability'         => $tool['capability'] ?? 'read',
			'power_mode'         => ! empty( $tool['power_mode'] ),
			'blocked_in_safe_mode'=> ! empty( $tool['blocked_in_safe_mode'] ),
		);
	}

	/**
	 * Execute a tool.
	 *
	 * @param string $name Tool name.
	 * @param array  $args Arguments.
	 * @param bool   $dry_run Dry run flag.
	 * @return mixed|WP_Error
	 */
	public function run( $name, $args = array(), $dry_run = false ) {
		$tool = $this->get( $name );
		if ( ! $tool ) {
			/* translators: %s: MCP tool name. */
			return new WP_Error( 'agentdesk_tool_not_found', sprintf( __( 'Tool not found: %s', 'agentdesk-site-operations' ), $name ) );
		}

		$cap_check = Agentdesk_Security::validate_capability( $tool );
		if ( is_wp_error( $cap_check ) ) {
			Agentdesk_Audit::log( $name, $args, 'blocked', $cap_check->get_error_message() );
			return $cap_check;
		}

		$mode_check = Agentdesk_Security::validate_tool_mode( $tool );
		if ( is_wp_error( $mode_check ) ) {
			Agentdesk_Audit::log( $name, $args, 'blocked', $mode_check->get_error_message() );
			return $mode_check;
		}

		if ( $dry_run && ! empty( $tool['supports_dry_run'] ) ) {
			return array(
				'dry_run' => true,
				'tool'    => $name,
				'message' => __( 'Dry run — no changes applied.', 'agentdesk-site-operations' ),
				'args'    => $args,
			);
		}

		$start = microtime( true );
		try {
			$result = call_user_func( $tool['callback'], $args );
		} catch ( Throwable $e ) {
			$duration = (int) round( ( microtime( true ) - $start ) * 1000 );
			Agentdesk_Audit::log( $name, $args, 'error', $e->getMessage(), $duration );
			return new WP_Error( 'agentdesk_tool_exception', $e->getMessage() );
		}

		$duration = (int) round( ( microtime( true ) - $start ) * 1000 );

		if ( is_wp_error( $result ) ) {
			Agentdesk_Audit::log( $name, $args, 'error', $result->get_error_message(), $duration );
			return $result;
		}

		Agentdesk_Audit::log( $name, $args, 'success', '', $duration );
		return $result;
	}

	/**
	 * Run batch of tools.
	 *
	 * @param array $steps Steps with name/arguments.
	 * @param bool  $stop_on_error Stop on first error.
	 * @return array
	 */
	public function batch( $steps, $stop_on_error = true ) {
		$results = array();

		// Cap batch size: one authenticated request must not be able to run an
		// unbounded number of operations against a per-minute budget.
		$steps = array_slice( (array) $steps, 0, 25 );

		foreach ( $steps as $index => $step ) {
			$name    = isset( $step['name'] ) ? (string) $step['name'] : '';
			$args    = isset( $step['arguments'] ) && is_array( $step['arguments'] ) ? $step['arguments'] : array();
			$dry_run = ! empty( $step['dry_run'] );

			$result = $this->run( $name, $args, $dry_run );
			$results[] = array(
				'index'  => $index,
				'name'   => $name,
				'result' => is_wp_error( $result ) ? array( 'error' => $result->get_error_message() ) : $result,
			);

			if ( is_wp_error( $result ) && $stop_on_error ) {
				break;
			}
		}

		return array( 'results' => $results );
	}

	/**
	 * Format tool for MCP tools/list response.
	 *
	 * @param array $tool Tool definition.
	 * @return array
	 */
	public function format_tool_for_mcp( $tool ) {
		return array(
			'name'        => $tool['name'],
			'description' => $tool['description'] ?? '',
			'inputSchema' => $tool['inputSchema'] ?? array( 'type' => 'object' ),
		);
	}

	/**
	 * Get unique domains.
	 *
	 * @return array
	 */
	private function get_domains() {
		$domains = array();
		foreach ( $this->tools as $tool ) {
			$domains[] = $tool['domain'] ?? 'core';
		}
		return array_values( array_unique( $domains ) );
	}

	/**
	 * Register gateway meta-tools.
	 */
	private function register_gateway_tools() {
		// Gateway tools are registered in includes/tools/core/gateway.php via hooks.
	}
}