<?php

/**
 * MCP Resource component.
 *
 * @package McpAdapter
 */
declare (strict_types=1);
namespace Bluehost\Plugin\WP\MCP\Domain\Resources;

use Bluehost\Plugin\WP\MCP\Domain\Contracts\McpComponentInterface;
use Bluehost\Plugin\WP\MCP\Domain\Utils\McpValidator;
use Bluehost\Plugin\WP\MCP\Infrastructure\ErrorHandling\Contracts\McpErrorHandlerInterface;
use Bluehost\Plugin\WP\MCP\Infrastructure\Observability\FailureReason;
use Bluehost\Plugin\WP\McpSchema\Common\Protocol\DTO\Annotations;
use Bluehost\Plugin\WP\McpSchema\Server\Resources\DTO\Resource as ResourceDto;
use WP_Error;
/**
 * Resource component providing unified execution and permission checks.
 *
 * This class supports multiple ways to register resources:
 *
 * 1. Array configuration:
 * ```php
 * $resource = McpResource::fromArray([
 *     'uri'         => 'WordPress://local/readme',
 *     'title'       => 'README',
 *     'description' => 'Example resource',
 *     'handler'     => fn() => 'Hello',
 *     'permission'  => fn() => true,
 * ]);
 * ```
 *
 * 2. From WordPress Ability (ability-backed):
 * ```php
 * $resource = McpResource::fromAbility($ability);
 * ```
 *
 * McpResource wraps a protocol-only ResourceDto for MCP serialization. Internal
 * adapter metadata and execution wiring live on this class and are never
 * exposed to MCP clients. Use get_protocol_dto() for protocol responses.
 *
 * @since 0.5.0
 */
final class McpResource implements McpComponentInterface
{
    // =========================================================================
    // Runtime Properties
    // =========================================================================
    /**
     * Clean Resource DTO (protocol-only).
     *
     * @var \WP\McpSchema\Server\Resources\DTO\Resource
     */
    private ResourceDto $mcp_resource_dto;
    /**
     * Ability used for execution/permission checks (ability-backed resources).
     *
     * @var \WP_Ability|null
     */
    private ?\WP_Ability $ability = null;
    /**
     * Direct execution handler (callable-backed resources).
     *
     * @var callable|null
     */
    private $handler = null;
    /**
     * Direct permission callback (callable-backed resources).
     *
     * @var callable|null
     */
    private $permission_callback = null;
    /**
     * Internal adapter metadata (never exposed to clients).
     *
     * @var array<string, mixed>
     */
    private array $adapter_meta = array();
    /**
     * Observability context tags for logging/metrics.
     *
     * @var array<string, mixed>
     */
    private array $observability_context = array();
    // =========================================================================
    // Constructor
    // =========================================================================
    /**
     * Private constructor - use factory methods.
     *
     * @param \WP\McpSchema\Server\Resources\DTO\Resource $resource_dto The Resource DTO.
     */
    private function __construct(ResourceDto $resource_dto)
    {
        $this->mcp_resource_dto = $resource_dto;
    }
    // =========================================================================
    // Factory Methods
    // =========================================================================
    /**
     * @param array $config The resource configuration array.
     *
     * @return self|\WP_Error
     */
    public static function fromArray(array $config)
    {
        if (empty($config['uri'])) {
            return new WP_Error('mcp_resource_missing_uri', 'Resource configuration must include a "uri" field.');
        }
        if (!isset($config['handler']) || !is_callable($config['handler'])) {
            return new WP_Error('mcp_resource_missing_handler', 'Resource configuration must include a callable "handler" field.');
        }
        $uri = trim($config['uri']);
        if (!McpValidator::validate_resource_uri($uri)) {
            return new WP_Error('mcp_resource_invalid_uri', 'Resource "uri" must be a valid RFC 3986 URI with a scheme.');
        }
        $name = isset($config['name']) ? trim($config['name']) : $uri;
        if ('' === $name) {
            return new WP_Error('mcp_resource_missing_name', 'Resource "name" cannot be empty.');
        }
        $resource_data = array('name' => $name, 'uri' => $uri);
        if (isset($config['title'])) {
            $resource_data['title'] = $config['title'];
        }
        if (isset($config['description'])) {
            $resource_data['description'] = $config['description'];
        }
        // Include mimeType only when valid.
        if (isset($config['mimeType'])) {
            $mime_type = trim($config['mimeType']);
            if ('' !== $mime_type && McpValidator::validate_mime_type($mime_type)) {
                $resource_data['mimeType'] = $mime_type;
            }
        }
        // Include size only when > 0.
        if (isset($config['size']) && $config['size'] > 0) {
            $resource_data['size'] = $config['size'];
        }
        // Validate and include icons if set.
        if (isset($config['icons']) && is_array($config['icons']) && !empty($config['icons'])) {
            $icons_result = McpValidator::validate_icons_array($config['icons']);
            if (!empty($icons_result['valid'])) {
                $resource_data['icons'] = $icons_result['valid'];
            }
        }
        if (isset($config['meta']) && is_array($config['meta']) && !empty($config['meta'])) {
            $resource_data['_meta'] = $config['meta'];
        }
        // Create the Resource DTO - wrap in try-catch since Annotations::fromArray() and ResourceDto::fromArray() can throw.
        try {
            // Process annotations inside try-catch since Annotations::fromArray() can throw.
            if (isset($config['annotations']) && is_array($config['annotations']) && !empty($config['annotations'])) {
                $resource_data['annotations'] = Annotations::fromArray($config['annotations']);
            }
            $resource = ResourceDto::fromArray($resource_data);
        } catch (\Throwable $e) {
            return new WP_Error('mcp_resource_dto_creation_failed', sprintf(
                /* translators: %s: error message */
                __('Failed to create Resource DTO: %s', 'mcp-adapter'),
                $e->getMessage()
            ), array('exception' => $e));
        }
        // Optional deep validation if enabled.
        $mcp_validation_enabled = apply_filters('mcp_adapter_validation_enabled', \false);
        if ($mcp_validation_enabled) {
            $validation_result = McpResourceValidator::validate_resource_dto($resource);
            if (is_wp_error($validation_result)) {
                return $validation_result;
            }
        }
        $instance = new self($resource);
        $instance->handler = $config['handler'];
        if (isset($config['permission']) && is_callable($config['permission'])) {
            $instance->permission_callback = $config['permission'];
        }
        $instance->observability_context = array('component_type' => 'resource', 'resource_uri' => $uri, 'source' => 'array');
        return $instance;
    }
    /**
     * Create an ability-backed MCP resource.
     *
     * @param \WP_Ability $ability WordPress ability.
     * @param \WP\MCP\Infrastructure\ErrorHandling\Contracts\McpErrorHandlerInterface|null $error_handler Optional error handler.
     *
     * @return self|\WP_Error
     */
    public static function fromAbility(\WP_Ability $ability, ?McpErrorHandlerInterface $error_handler = null)
    {
        $resource_data = RegisterAbilityAsMcpResource::build($ability, $error_handler);
        if ($resource_data instanceof WP_Error) {
            return $resource_data;
        }
        $instance = new self($resource_data['resource']);
        $instance->adapter_meta = $resource_data['adapter_meta'];
        $instance->ability = $ability;
        $instance->observability_context = array('component_type' => 'resource', 'resource_uri' => $resource_data['resource']->getUri(), 'ability_name' => $ability->get_name(), 'source' => 'ability');
        return $instance;
    }
    // =========================================================================
    // McpComponentInterface Implementation
    // =========================================================================
    /**
     * Get the clean protocol DTO for MCP responses.
     *
     * @return \WP\McpSchema\Server\Resources\DTO\Resource
     */
    public function get_protocol_dto(): ResourceDto
    {
        return $this->mcp_resource_dto;
    }
    /**
     * Execute the resource read.
     *
     * @param mixed $arguments Read arguments (may be empty).
     *
     * @return mixed
     */
    public function execute($arguments)
    {
        // Ability-backed resources match existing behavior: no args passed to abilities.
        if (null !== $this->ability) {
            try {
                return $this->ability->execute();
            } catch (\Throwable $throwable) {
                return new WP_Error('mcp_execution_failed', $throwable->getMessage(), array('error_type' => get_class($throwable)));
            }
        }
        if (null !== $this->handler) {
            try {
                return call_user_func($this->handler, $arguments);
            } catch (\Throwable $throwable) {
                return new WP_Error('mcp_execution_failed', $throwable->getMessage(), array('error_type' => get_class($throwable)));
            }
        }
        return new WP_Error('mcp_resource_no_handler', 'No resource execution strategy configured.');
    }
    /**
     * Check whether the current request has permission to read this resource.
     *
     * @param mixed $arguments Read arguments (may be empty).
     *
     * @return bool|\WP_Error
     */
    public function check_permission($arguments)
    {
        // Ability-backed resources match existing behavior: no args passed to abilities.
        if (null !== $this->ability) {
            try {
                return $this->ability->check_permissions();
            } catch (\Throwable $throwable) {
                return new WP_Error('mcp_permission_check_failed', $throwable->getMessage(), array('error_type' => get_class($throwable)));
            }
        }
        if (null !== $this->permission_callback) {
            try {
                $result = call_user_func($this->permission_callback, $arguments);
                return $result instanceof WP_Error ? $result : (bool) $result;
            } catch (\Throwable $throwable) {
                return new WP_Error('mcp_permission_check_failed', $throwable->getMessage(), array('error_type' => get_class($throwable)));
            }
        }
        return new WP_Error('mcp_permission_denied', 'Access denied.', array('failure_reason' => FailureReason::NO_PERMISSION_STRATEGY));
    }
    /**
     * Get internal adapter metadata for this resource.
     *
     * @return array<string, mixed>
     */
    public function get_adapter_meta(): array
    {
        return $this->adapter_meta;
    }
    /**
     * Get observability context tags for logging/metrics.
     *
     * @return array<string, mixed>
     */
    public function get_observability_context(): array
    {
        return $this->observability_context;
    }
}
