<?php
/**
 * MCP tool implementations.
 *
 * Each public method corresponds to an MCP tool that can be invoked
 * via tools/call. Eight tools: search_products, get_product_details,
 * check_inventory, get_price, get_categories, get_store_info,
 * initiate_checkout, get_checkout_status.
 *
 * @package AICommerce\Agentic
 */

declare(strict_types=1);

namespace AICommerce\Agentic;

use AICommerce\Feed\ProductDataExtractor;

/**
 * Implements MCP tool handlers.
 */
class MCPTools {

	/**
	 * Reference to the MCP server for response helpers.
	 *
	 * @var MCPServer
	 */
	private MCPServer $server;

	/**
	 * Agent bridge for checkout orchestration.
	 *
	 * @var AgentBridge|null
	 */
	private ?AgentBridge $bridge = null;

	/**
	 * Constructor.
	 *
	 * @param MCPServer $server The MCP server instance.
	 */
	public function __construct( MCPServer $server ) {
		$this->server = $server;
	}

	/**
	 * Set the agent bridge (resolves late binding).
	 *
	 * @param AgentBridge $bridge The agent bridge instance.
	 *
	 * @return void
	 */
	public function set_bridge( AgentBridge $bridge ): void {
		$this->bridge = $bridge;
	}

	/**
	 * Get tool definitions for tools/list.
	 *
	 * @return array<int, array{name: string, description: string, inputSchema: array}>
	 */
	public function get_tool_definitions(): array {
		return array(
			$this->def_search_products(),
			$this->def_get_product_details(),
			$this->def_check_inventory(),
			$this->def_get_price(),
			$this->def_get_categories(),
			$this->def_get_store_info(),
			$this->def_initiate_checkout(),
			$this->def_get_checkout_status(),
		);
	}

	// ─── Tool definitions ──────────────────────────────────────────────

	/**
	 * Definition for search_products.
	 *
	 * @return array
	 */
	private function def_search_products(): array {
		return array(
			'name'        => 'search_products',
			'description' => 'Search the WooCommerce product catalog. Returns matching products with price, availability, and key details. Use this to find products before getting full details or initiating checkout.',
			'inputSchema' => array(
				'type'       => 'object',
				'properties' => array(
					'query'         => array(
						'type'        => 'string',
						'description' => 'Search terms, e.g. \'blue coffee mug under $30\'',
					),
					'category'      => array(
						'type'        => 'string',
						'description' => 'Product category name or slug to filter by',
					),
					'min_price'     => array(
						'type'        => 'number',
						'description' => 'Minimum price in store currency',
					),
					'max_price'     => array(
						'type'        => 'number',
						'description' => 'Maximum price in store currency',
					),
					'in_stock_only' => array(
						'type'        => 'boolean',
						'description' => 'Only return in-stock products',
						'default'     => true,
					),
					'limit'         => array(
						'type'        => 'integer',
						'description' => 'Max results to return (1-20)',
						'default'     => 10,
						'minimum'     => 1,
						'maximum'     => 20,
					),
				),
				'required'   => array(),
			),
		);
	}

	/**
	 * Definition for get_product_details.
	 *
	 * @return array
	 */
	private function def_get_product_details(): array {
		return array(
			'name'        => 'get_product_details',
			'description' => 'Get complete details for a specific product including all variants, attributes, images, FAQs, and customer reviews summary.',
			'inputSchema' => array(
				'type'       => 'object',
				'properties' => array(
					'product_id' => array(
						'type'        => 'integer',
						'description' => 'WooCommerce product ID',
					),
				),
				'required'   => array( 'product_id' ),
			),
		);
	}

	/**
	 * Definition for check_inventory.
	 *
	 * @return array
	 */
	private function def_check_inventory(): array {
		return array(
			'name'        => 'check_inventory',
			'description' => 'Check real-time stock availability for a product or specific variant. Always call this before attempting to initiate a purchase.',
			'inputSchema' => array(
				'type'       => 'object',
				'properties' => array(
					'product_id'   => array(
						'type'        => 'integer',
						'description' => 'WooCommerce product ID',
					),
					'variation_id' => array(
						'type'        => 'integer',
						'description' => 'For variable products — specific variation ID',
					),
				),
				'required'   => array( 'product_id' ),
			),
		);
	}

	/**
	 * Definition for get_price.
	 *
	 * @return array
	 */
	private function def_get_price(): array {
		return array(
			'name'        => 'get_price',
			'description' => 'Get current pricing for a product including sale prices and bulk/quantity discounts if available.',
			'inputSchema' => array(
				'type'       => 'object',
				'properties' => array(
					'product_id'   => array(
						'type'        => 'integer',
						'description' => 'WooCommerce product ID',
					),
					'variation_id' => array(
						'type'        => 'integer',
						'description' => 'Specific variation ID',
					),
					'quantity'     => array(
						'type'        => 'integer',
						'description' => 'Check price for this quantity (for bulk pricing)',
						'default'     => 1,
					),
				),
				'required'   => array( 'product_id' ),
			),
		);
	}

	/**
	 * Definition for get_categories.
	 *
	 * @return array
	 */
	private function def_get_categories(): array {
		return array(
			'name'        => 'get_categories',
			'description' => 'Browse the product category tree. Use to understand store taxonomy before searching.',
			'inputSchema' => array(
				'type'       => 'object',
				'properties' => array(
					'parent_id'             => array(
						'type'        => 'integer',
						'description' => 'Get subcategories of this category ID. Omit for top-level categories.',
						'default'     => 0,
					),
					'include_product_count' => array(
						'type'    => 'boolean',
						'default' => true,
					),
				),
				'required'   => array(),
			),
		);
	}

	/**
	 * Definition for get_store_info.
	 *
	 * @return array
	 */
	private function def_get_store_info(): array {
		return array(
			'name'        => 'get_store_info',
			'description' => 'Get general store information including currency, shipping destinations, return policy, and accepted payment methods.',
			'inputSchema' => array(
				'type'       => 'object',
				'properties' => (object) array(),
				'required'   => array(),
			),
		);
	}

	/**
	 * Definition for initiate_checkout.
	 *
	 * @return array
	 */
	private function def_initiate_checkout(): array {
		return array(
			'name'        => 'initiate_checkout',
			'description' => 'Initiate a checkout session for specified products. Returns a checkout URL for the user to complete payment. The session expires in 10 minutes.',
			'inputSchema' => array(
				'type'       => 'object',
				'properties' => array(
					'items' => array(
						'type'        => 'array',
						'description' => 'Array of items to purchase',
						'items'       => array(
							'type'       => 'object',
							'properties' => array(
								'product_id'   => array(
									'type'        => 'integer',
									'description' => 'WooCommerce product ID',
								),
								'variation_id' => array(
									'type'        => 'integer',
									'description' => 'Variation ID for variable products',
								),
								'quantity'     => array(
									'type'    => 'integer',
									'default' => 1,
									'minimum' => 1,
								),
							),
							'required'   => array( 'product_id' ),
						),
					),
				),
				'required'   => array( 'items' ),
			),
		);
	}

	/**
	 * Definition for get_checkout_status.
	 *
	 * @return array
	 */
	private function def_get_checkout_status(): array {
		return array(
			'name'        => 'get_checkout_status',
			'description' => 'Check the status of a previously initiated checkout session.',
			'inputSchema' => array(
				'type'       => 'object',
				'properties' => array(
					'session_id' => array(
						'type'        => 'string',
						'description' => 'Session ID returned by initiate_checkout',
					),
				),
				'required'   => array( 'session_id' ),
			),
		);
	}

	// ─── Tool implementations ──────────────────────────────────────────

	/**
	 * Search WooCommerce products.
	 *
	 * @param string $id   JSON-RPC request ID.
	 * @param array  $args Tool arguments.
	 *
	 * @return \WP_REST_Response
	 */
	public function search_products( string $id, array $args ): \WP_REST_Response {
		$query     = sanitize_text_field( $args['query'] ?? '' );
		$category  = sanitize_text_field( $args['category'] ?? '' );
		$min_price = isset( $args['min_price'] ) ? (float) $args['min_price'] : null;
		$max_price = isset( $args['max_price'] ) ? (float) $args['max_price'] : null;
		$in_stock  = isset( $args['in_stock_only'] ) ? (bool) $args['in_stock_only'] : true;
		$limit     = min( 20, max( 1, (int) ( $args['limit'] ?? 10 ) ) );

		$query_args = array(
			'status'  => 'publish',
			'limit'   => $limit,
			'orderby' => 'relevance',
		);

		if ( $query ) {
			$query_args['s'] = $query;
		}
		if ( $in_stock ) {
			$query_args['stock_status'] = 'instock';
		}
		if ( null !== $min_price ) {
			$query_args['min_price'] = $min_price;
		}
		if ( null !== $max_price ) {
			$query_args['max_price'] = $max_price;
		}
		if ( $category ) {
			$term = get_term_by( 'name', $category, 'product_cat' );
			if ( ! $term ) {
				$term = get_term_by( 'slug', $category, 'product_cat' );
			}
			if ( $term ) {
				$query_args['category'] = array( $term->slug );
			}
		}

		$wc_query = new \WC_Product_Query( $query_args );
		$products = $wc_query->get_products();

		$results = array();
		foreach ( $products as $product ) {
			$results[] = array(
				'id'                => $product->get_id(),
				'title'             => $product->get_name(),
				'price'             => (float) $product->get_price(),
				'regular_price'     => (float) $product->get_regular_price(),
				'sale_price'        => $product->is_on_sale() ? (float) $product->get_sale_price() : null,
				'on_sale'           => $product->is_on_sale(),
				'currency'          => get_woocommerce_currency(),
				'availability'      => $product->is_in_stock() ? 'in_stock' : 'out_of_stock',
				'url'               => get_permalink( $product->get_id() ),
				'image_url'         => wp_get_attachment_image_url( $product->get_image_id(), 'woocommerce_single' ) ?: null,
				'short_description' => wp_strip_all_tags( $product->get_short_description() ),
				'category'          => implode( ', ', wp_list_pluck( wp_get_post_terms( $product->get_id(), 'product_cat' ), 'name' ) ),
				'rating'            => array(
					'value' => (float) $product->get_average_rating(),
					'count' => (int) $product->get_review_count(),
				),
				'sku'               => $product->get_sku(),
				'type'              => $product->get_type(),
			);
			unset( $product );
		}

		return $this->server->tool_result(
			$id,
			array(
				'found'    => count( $results ),
				'products' => $results,
				'currency' => function_exists( 'get_woocommerce_currency' ) ? get_woocommerce_currency() : 'USD',
				'query'    => $query ?: null,
			)
		);
	}

	/**
	 * Get detailed product information.
	 *
	 * @param string $id   JSON-RPC request ID.
	 * @param array  $args Tool arguments.
	 *
	 * @return \WP_REST_Response
	 */
	public function get_product_details( string $id, array $args ): \WP_REST_Response {
		$product_id = absint( $args['product_id'] ?? 0 );
		$product    = wc_get_product( $product_id );

		if ( ! $product || 'publish' !== $product->get_status() ) {
			return $this->server->error_response( $id, -32602, "Product {$product_id} not found or not published" );
		}

		$extractor = new ProductDataExtractor();
		$data      = $extractor->extract( $product );

		// Add AI-optimized content if active.
		if ( 'yes' === get_post_meta( $product_id, '_aicommerce_use_optimized_description', true ) ) {
			$optimized = get_post_meta( $product_id, '_aicommerce_optimized_description', true );
			if ( $optimized ) {
				$data['description'] = $optimized;
			}
		}

		// Add FAQs if active.
		if ( 'yes' === get_post_meta( $product_id, '_aicommerce_use_optimized_faqs', true ) ) {
			$faqs_raw     = get_post_meta( $product_id, '_aicommerce_faqs', true );
			$data['faqs'] = $faqs_raw ? json_decode( $faqs_raw, true ) : array();
		}

		// Add review summary.
		$data['reviews'] = array(
			'average' => (float) $product->get_average_rating(),
			'count'   => (int) $product->get_review_count(),
			'summary' => $this->get_review_summary( $product_id ),
		);

		return $this->server->tool_result( $id, $data );
	}

	/**
	 * Check real-time stock availability.
	 *
	 * @param string $id   JSON-RPC request ID.
	 * @param array  $args Tool arguments.
	 *
	 * @return \WP_REST_Response
	 */
	public function check_inventory( string $id, array $args ): \WP_REST_Response {
		$product_id   = absint( $args['product_id'] ?? 0 );
		$variation_id = absint( $args['variation_id'] ?? 0 );

		$product = $variation_id ? wc_get_product( $variation_id ) : wc_get_product( $product_id );

		if ( ! $product ) {
			$check_id = $variation_id ?: $product_id;
			return $this->server->error_response( $id, -32602, "Product {$check_id} not found" );
		}

		return $this->server->tool_result(
			$id,
			array(
				'product_id'         => $product_id,
				'variation_id'       => $variation_id ?: null,
				'in_stock'           => $product->is_in_stock(),
				'stock_status'       => $product->get_stock_status(),
				'stock_quantity'     => $product->get_manage_stock() ? $product->get_stock_quantity() : null,
				'backorders_allowed' => $product->backorders_allowed(),
				'sold_individually'  => $product->is_sold_individually(),
				'checked_at'         => current_time( 'c' ),
			)
		);
	}

	/**
	 * Get current pricing for a product.
	 *
	 * @param string $id   JSON-RPC request ID.
	 * @param array  $args Tool arguments.
	 *
	 * @return \WP_REST_Response
	 */
	public function get_price( string $id, array $args ): \WP_REST_Response {
		$product_id   = absint( $args['product_id'] ?? 0 );
		$variation_id = absint( $args['variation_id'] ?? 0 );
		$quantity     = max( 1, (int) ( $args['quantity'] ?? 1 ) );

		$product = $variation_id ? wc_get_product( $variation_id ) : wc_get_product( $product_id );

		if ( ! $product ) {
			$check_id = $variation_id ?: $product_id;
			return $this->server->error_response( $id, -32602, "Product {$check_id} not found" );
		}

		$price         = wc_get_price_including_tax( $product, array( 'qty' => $quantity ) );
		$regular_price = wc_get_price_including_tax(
			$product,
			array(
				'qty'   => $quantity,
				'price' => $product->get_regular_price(),
			)
		);

		$sale_price = null;
		if ( $product->is_on_sale() ) {
			$sale_price = (float) wc_get_price_including_tax(
				$product,
				array(
					'price' => $product->get_sale_price(),
				)
			);
		}

		return $this->server->tool_result(
			$id,
			array(
				'product_id'      => $product_id,
				'variation_id'    => $variation_id ?: null,
				'price'           => (float) $price,
				'regular_price'   => (float) $regular_price,
				'sale_price'      => $sale_price,
				'on_sale'         => $product->is_on_sale(),
				'currency'        => get_woocommerce_currency(),
				'currency_symbol' => get_woocommerce_currency_symbol(),
				'tax_included'    => wc_prices_include_tax(),
				'quantity'        => $quantity,
				'checked_at'      => current_time( 'c' ),
			)
		);
	}

	/**
	 * Browse the product category tree.
	 *
	 * @param string $id   JSON-RPC request ID.
	 * @param array  $args Tool arguments.
	 *
	 * @return \WP_REST_Response
	 */
	public function get_categories( string $id, array $args ): \WP_REST_Response {
		$parent_id = absint( $args['parent_id'] ?? 0 );

		$terms = get_terms(
			array(
				'taxonomy'   => 'product_cat',
				'parent'     => $parent_id,
				'hide_empty' => true,
				'number'     => 100,
			)
		);

		if ( is_wp_error( $terms ) ) {
			return $this->server->error_response( $id, -32603, 'Failed to retrieve categories' );
		}

		$cats = array();
		foreach ( $terms as $term ) {
			$child_count = get_terms(
				array(
					'taxonomy' => 'product_cat',
					'parent'   => $term->term_id,
					'count'    => true,
					'fields'   => 'count',
				)
			);

			$cats[] = array(
				'id'            => $term->term_id,
				'name'          => $term->name,
				'slug'          => $term->slug,
				'product_count' => $term->count,
				'has_children'  => is_numeric( $child_count ) && (int) $child_count > 0,
			);
		}

		return $this->server->tool_result(
			$id,
			array(
				'parent_id'  => $parent_id,
				'categories' => $cats,
				'total'      => count( $cats ),
			)
		);
	}

	/**
	 * Get general store information.
	 *
	 * @param string $id   JSON-RPC request ID.
	 * @param array  $args Tool arguments (unused).
	 *
	 * @return \WP_REST_Response
	 */
	public function get_store_info( string $id, array $args ): \WP_REST_Response {
		$gateway_names = array();
		if ( function_exists( 'WC' ) && WC()->payment_gateways() ) {
			$gateways = WC()->payment_gateways()->get_available_payment_gateways();
			foreach ( $gateways as $gateway ) {
				$gateway_names[] = $gateway->get_title();
			}
		}

		$shipping_countries = array();
		if ( function_exists( 'WC' ) && WC()->countries ) {
			$shipping_countries = array_keys( WC()->countries->get_shipping_countries() );
		}

		$total_products = 0;
		$counts         = wp_count_posts( 'product' );
		if ( $counts ) {
			$total_products = (int) $counts->publish;
		}

		return $this->server->tool_result(
			$id,
			array(
				'store_name'         => get_bloginfo( 'name' ),
				'store_url'          => home_url(),
				'currency'           => function_exists( 'get_woocommerce_currency' ) ? get_woocommerce_currency() : 'USD',
				'currency_symbol'    => function_exists( 'get_woocommerce_currency_symbol' ) ? get_woocommerce_currency_symbol() : '$',
				'price_format'       => function_exists( 'get_woocommerce_price_format' ) ? get_woocommerce_price_format() : '%1$s%2$s',
				'weight_unit'        => get_option( 'woocommerce_weight_unit', 'kg' ),
				'dimension_unit'     => get_option( 'woocommerce_dimension_unit', 'cm' ),
				'shipping_countries' => $shipping_countries,
				'payment_methods'    => $gateway_names,
				'return_policy_url'  => get_option( 'aicommerce_return_policy_url' ) ?: null,
				'privacy_policy_url' => function_exists( 'get_privacy_policy_url' ) ? ( get_privacy_policy_url() ?: null ) : null,
				'terms_url'          => get_option( 'aicommerce_terms_url' ) ?: null,
				'total_products'     => $total_products,
			)
		);
	}

	/**
	 * Initiate a checkout session.
	 *
	 * @param string $id   JSON-RPC request ID.
	 * @param array  $args Tool arguments.
	 *
	 * @return \WP_REST_Response
	 */
	public function initiate_checkout( string $id, array $args ): \WP_REST_Response {
		if ( ! $this->bridge ) {
			return $this->server->error_response( $id, -32603, 'Checkout service not available' );
		}

		try {
			$result = $this->bridge->initiate_checkout( $args );
			return $this->server->tool_result( $id, $result );
		} catch ( \InvalidArgumentException $e ) {
			return $this->server->error_response( $id, -32602, $e->getMessage() );
		} catch ( \RuntimeException $e ) {
			return $this->server->error_response( $id, -32603, $e->getMessage() );
		}
	}

	/**
	 * Get checkout session status.
	 *
	 * @param string $id   JSON-RPC request ID.
	 * @param array  $args Tool arguments.
	 *
	 * @return \WP_REST_Response
	 */
	public function get_checkout_status( string $id, array $args ): \WP_REST_Response {
		if ( ! $this->bridge ) {
			return $this->server->error_response( $id, -32603, 'Checkout service not available' );
		}

		$session_id = sanitize_text_field( $args['session_id'] ?? '' );
		if ( empty( $session_id ) ) {
			return $this->server->error_response( $id, -32602, 'session_id is required' );
		}

		try {
			$result = $this->bridge->get_checkout_status( $session_id );
			return $this->server->tool_result( $id, $result );
		} catch ( \InvalidArgumentException $e ) {
			return $this->server->error_response( $id, -32602, $e->getMessage() );
		}
	}

	// ─── Private helpers ───────────────────────────────────────────────

	/**
	 * Get a brief review summary (last 3 reviews, truncated).
	 *
	 * @param int $product_id Product ID.
	 *
	 * @return array Array of recent review snippets.
	 */
	private function get_review_summary( int $product_id ): array {
		$comments = get_comments(
			array(
				'post_id' => $product_id,
				'type'    => 'review',
				'status'  => 'approve',
				'number'  => 3,
				'orderby' => 'comment_date_gmt',
				'order'   => 'DESC',
			)
		);

		$summaries = array();
		foreach ( $comments as $comment ) {
			$text = wp_strip_all_tags( $comment->comment_content );
			if ( strlen( $text ) > 80 ) {
				$text = substr( $text, 0, 80 ) . '…';
			}
			$rating      = get_comment_meta( $comment->comment_ID, 'rating', true );
			$summaries[] = array(
				'rating' => $rating ? (int) $rating : null,
				'text'   => $text,
			);
		}

		return $summaries;
	}
}