<?php
/**
 * REST API Class
 * Handles all API endpoints for the AI assistant
 *
 * @package AI_Commerce_Assistant
 */

if ( !defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * REST API Class
 */
class AICA_REST_API {

	/**
	 * API namespace
	 *
	 * @var string
	 */
	private $namespace = 'ai-assistant/v1';

	/**
	 * Single instance
	 *
	 * @var AICA_REST_API
	 */
	private static $instance = null;

	/**
	 * Get instance
	 *
	 * @return AICA_REST_API
	 */
	public static function get_instance() {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Constructor
	 */
	private function __construct() {
		add_action( 'rest_api_init', array( $this, 'register_routes' ) );
	}

	/**
	 * Register REST API routes
	 *
	 * @return void
	 */
	public function register_routes() {
		// Chat endpoint
		register_rest_route(
			$this->namespace,
			'/chat',
			array(
				'methods'             => 'POST',
				'callback'            => array( $this, 'handle_chat' ),
				'permission_callback' => array( $this, 'check_chat_permission' ),
				'args'                => array(
					'message'    => array(
						'required'          => true,
						'type'              => 'string',
						'sanitize_callback' => 'sanitize_text_field',
					),
					'session_id' => array(
						'required'          => true,
						'type'              => 'string',
						'sanitize_callback' => 'sanitize_text_field',
					),
					'context'    => array(
						'required' => false,
						'type'     => 'object',
					),
				),
			)
		);

		// Product search endpoint
		register_rest_route(
			$this->namespace,
			'/products/search',
			array(
				'methods'             => 'GET',
				'callback'            => array( $this, 'search_products' ),
				'permission_callback' => array( $this, 'check_chat_permission' ),
				'args'                => array(
					'query' => array(
						'required'          => true,
						'type'              => 'string',
						'sanitize_callback' => 'sanitize_text_field',
					),
					'limit' => array(
						'required' => false,
						'type'     => 'integer',
						'default'  => 5,
					),
				),
			)
		);

		// Cart endpoints
		register_rest_route(
			$this->namespace,
			'/cart/add',
			array(
				'methods'             => 'POST',
				'callback'            => array( $this, 'add_to_cart' ),
				'permission_callback' => array( $this, 'check_cart_permission' ),
				'args'                => array(
					'product_id'   => array(
						'required' => true,
						'type'     => 'integer',
					),
					'quantity'     => array(
						'required' => false,
						'type'     => 'integer',
						'default'  => 1,
					),
					'variation_id' => array(
						'required' => false,
						'type'     => 'integer',
					),
				),
			)
		);

		register_rest_route(
			$this->namespace,
			'/cart/get',
			array(
				'methods'             => 'GET',
				'callback'            => array( $this, 'get_cart' ),
				'permission_callback' => array( $this, 'check_cart_permission' ),
			)
		);

		register_rest_route(
			$this->namespace,
			'/cart/remove',
			array(
				'methods'             => 'POST',
				'callback'            => array( $this, 'remove_from_cart' ),
				'permission_callback' => array( $this, 'check_cart_permission' ),
				'args'                => array(
					'cart_item_key' => array(
						'required' => true,
						'type'     => 'string',
					),
				),
			)
		);

		// Settings endpoint (for widget configuration)
		register_rest_route(
			$this->namespace,
			'/settings',
			array(
				'methods'             => 'GET',
				'callback'            => array( $this, 'get_settings' ),
				'permission_callback' => array( $this, 'check_public_read_permission' ),
			)
		);

		// NEW: User authentication check endpoint
		register_rest_route(
			$this->namespace,
			'/user/check',
			array(
				'methods'             => 'GET',
				'callback'            => array( $this, 'check_user_auth' ),
				'permission_callback' => array( $this, 'check_public_read_permission' ),
			)
		);
	}

	/**
	 * Check chat permission
	 *
	 * @param WP_REST_Request $request Request object
	 * @return bool
	 */
	public function check_chat_permission( $request ) {
		// Check rate limiting
		if ( !$this->check_rate_limit( $request ) ) {
			return new WP_Error(
				'rate_limit_exceeded',
				__( 'Too many requests. Please try again later.', 'aica-smart-ai-commerce-assistant' ),
				array( 'status' => 429 )
			);
		}

		return true;
	}

	/**
	 * Check cart permission
	 *
	 * @return bool
	 */
	public function check_cart_permission() {
		// Anyone can access cart endpoints
		return true;
	}

	/**
	 * Check rate limit
	 *
	 * @param WP_REST_Request $request Request object
	 * @return bool
	 */
	private function check_rate_limit( $request ) {
		$settings = get_option( 'aica_settings', array() );

		if ( !isset( $settings['rate_limit_enabled'] ) || $settings['rate_limit_enabled'] !== 'yes' ) {
			return true;
		}

		$session_id    = $request->get_param( 'session_id' );
		$transient_key = 'aica_rate_limit_' . md5( $session_id );

		$count = get_transient( $transient_key );

		if ( $count === false ) {
			set_transient( $transient_key, 1, HOUR_IN_SECONDS );
			return true;
		}

		$limit = isset( $settings['rate_limit_messages'] ) ? intval( $settings['rate_limit_messages'] ) : 50;

		if ( $count >= $limit ) {
			return false;
		}

		set_transient( $transient_key, $count + 1, HOUR_IN_SECONDS );
		return true;
	}

	/**
	 * Handle chat request
	 *
	 * @param WP_REST_Request $request Request object
	 * @return WP_REST_Response|WP_Error
	 */
	public function handle_chat( $request ) {
		$message    = sanitize_text_field( $request->get_param( 'message' ) );
		$session_id = sanitize_text_field( $request->get_param( 'session_id' ) );
		$context    = $request->get_param( 'context' ); // Context is an array/object, validated later

		// Save user message
		$this->save_message( $session_id, $message, 'user', $context );

		// Log analytics event
		$this->log_analytics(
			$session_id,
			'message_sent',
			array(
				'message_length' => strlen( $message ),
			)
		);

		try {
			// NEW: Check if this is an order tracking request
			if ( $this->is_order_tracking_request( $message ) ) {
				return $this->handle_order_tracking_request( $message, $session_id );
			}

			// Use AI Engine for intelligent response
			$ai_engine   = AICA_AI_Engine::get_instance();
			$ai_response = $ai_engine->generate_response( $message, $session_id, $context );

			// Handle cart actions if present
			if ( isset( $ai_response['actions'] ) ) {
				foreach ( $ai_response['actions'] as $action ) {
					if ( $action['type'] === 'add_to_cart' && isset( $action['product_id'] ) ) {
						$cart_manager = AICA_Cart_Manager::get_instance();
						$cart_result  = $cart_manager->add_to_cart( $action['product_id'] );

						if ( $cart_result['success'] ) {
							$ai_response['cart'] = $cart_result['cart'];
						}
					}
				}
			}

			// Save assistant response
			$this->save_message(
				$session_id,
				$ai_response['message'],
				'assistant',
				array(
					'products' => $ai_response['products'] ?? null,
					'actions'  => $ai_response['actions'] ?? null,
				)
			);

			// Log product recommendations
			if ( !empty( $ai_response['products'] ) ) {
				$this->log_analytics(
					$session_id,
					'products_recommended',
					array(
						'count'       => count( $ai_response['products'] ),
						'product_ids' => array_column( $ai_response['products'], 'id' ),
					)
				);
			}

			return new WP_REST_Response(
				array(
					'success'    => true,
					'message'    => $ai_response['message'],
					'products'   => $ai_response['products'] ?? array(),
					'actions'    => $ai_response['actions'] ?? array(),
					'cart'       => $ai_response['cart'] ?? null,
					'session_id' => $session_id,
				),
				200
			);

		} catch ( Exception $e ) {
			error_log( 'AICA Chat Error: ' . $e->getMessage() );

			return new WP_Error(
				'ai_error',
				__( 'Sorry, I encountered an error. Please try again.', 'aica-smart-ai-commerce-assistant' ),
				array( 'status' => 500 )
			);
		}
	}

	/**
	 * NEW: Check if message is about order tracking
	 *
	 * @param string $message User message
	 * @return bool
	 */
	private function is_order_tracking_request( $message ) {
		$tracking_keywords = array(
			// English
			'track',
			'order',
			'tracking',
			'where',
			'status',
			'delivery',
			'shipping',
			'package',
			'arrived',
			'when will',
			'when does',

			// Italian
			'traccia',
			'ordine',
			'tracciamento',
			'dov',
			'dove',
			'stato',
			'consegna',
			'spedizione',
			'pacco',
			'arrivato',
			'quando arriva',
			'quando sarà',
			'informazioni ordine',
			'dettagli ordine',
			'mio ordine',
		);

		$message_lower = strtolower( $message );

		foreach ( $tracking_keywords as $keyword ) {
			if ( strpos( $message_lower, $keyword ) !== false ) {
				return true;
			}
		}

		return false;
	}

	/**
	 * NEW: Handle order tracking request
	 *
	 * @param string $message User message
	 * @param string $session_id Session ID
	 * @return WP_REST_Response
	 */
	private function handle_order_tracking_request( $message, $session_id ) {
		$user_id = get_current_user_id();

		// Check if user is logged in
		if ( !$user_id ) {
			$this->save_message(
				$session_id,
				'Order tracking requested (user not logged in)',
				'assistant',
				array(
					'require_login' => true,
				)
			);

			$this->log_analytics(
				$session_id,
				'order_tracking_request',
				array(
					'authenticated' => false,
				)
			);

			return new WP_REST_Response(
				array(
					'success'       => true,
					'message'       => __( 'Per tracciare i tuoi ordini, per favore effettua il login al tuo account.', 'aica-smart-ai-commerce-assistant' ),
					'require_login' => true,
				),
				200
			);
		}

		// Get user orders
		$orders = wc_get_orders(
			array(
				'customer_id' => $user_id,
				'limit'       => 5,
				'orderby'     => 'date',
				'order'       => 'DESC',
			)
		);

		if ( empty( $orders ) ) {
			$this->save_message( $session_id, 'Order tracking requested (no orders found)', 'assistant' );

			return new WP_REST_Response(
				array(
					'success' => true,
					'message' => __( 'Non hai ordini recenti da tracciare.', 'aica-smart-ai-commerce-assistant' ),
				),
				200
			);
		}

		// Format orders for display
		$formatted_orders = array();
		$message_text     = __( 'Ecco i tuoi ordini recenti:', 'aica-smart-ai-commerce-assistant' ) . "\n\n";

		foreach ( $orders as $order ) {
			$order_id     = $order->get_id();
			$order_number = $order->get_order_number();
			$status       = $order->get_status();
			$status_name  = $this->translate_order_status( $status );
			$date         = $order->get_date_created()->date_i18n( get_option( 'date_format' ) );
			$total        = $order->get_formatted_order_total();

			// Get tracking info from order meta
			$tracking_number = $order->get_meta( '_tracking_number' );
			$tracking_url    = $order->get_meta( '_tracking_url' );

			$formatted_orders[] = array(
				'id'              => $order_id,
				'number'          => $order_number,
				'status'          => $status,
				'status_name'     => $status_name,
				'date'            => $date,
				'total'           => $total,
				'tracking_number' => $tracking_number ?: null,
				'tracking_url'    => $tracking_url ?: null,
				'view_url'        => $order->get_view_order_url(),
			);

			// Build message in Italian
			$message_text .= sprintf(
				"**Ordine #%s** - %s\n" .
				"📅 Data: %s\n" .
				"💰 Totale: %s\n" .
				"📦 Stato: %s\n",
				$order_number,
				$status_name,
				$date,
				$total,
				$status_name
			);

			if ( $tracking_number ) {
				$message_text .= sprintf( "🔍 Tracciamento: %s\n", $tracking_number );
			}

			$message_text .= "\n";
		}

		// Save assistant response
		$this->save_message(
			$session_id,
			$message_text,
			'assistant',
			array(
				'orders' => $formatted_orders,
			)
		);

		// Log event
		$this->log_analytics(
			$session_id,
			'order_tracking_viewed',
			array(
				'order_count' => count( $orders ),
				'user_id'     => $user_id,
			)
		);

		return new WP_REST_Response(
			array(
				'success' => true,
				'message' => $message_text,
				'orders'  => $formatted_orders,
			),
			200
		);
	}

	/**
	 * NEW: Translate WooCommerce order status to Italian
	 *
	 * @param string $status Order status
	 * @return string Translated status
	 */
	private function translate_order_status( $status ) {
		$status_translations = array(
			'pending'    => __( 'In Sospeso', 'aica-smart-ai-commerce-assistant' ),
			'processing' => __( 'In Elaborazione', 'aica-smart-ai-commerce-assistant' ),
			'on-hold'    => __( 'In Attesa', 'aica-smart-ai-commerce-assistant' ),
			'completed'  => __( 'Completato', 'aica-smart-ai-commerce-assistant' ),
			'cancelled'  => __( 'Cancellato', 'aica-smart-ai-commerce-assistant' ),
			'refunded'   => __( 'Rimborsato', 'aica-smart-ai-commerce-assistant' ),
			'failed'     => __( 'Non Riuscito', 'aica-smart-ai-commerce-assistant' ),
		);

		return isset( $status_translations[ $status ] )
		? $status_translations[ $status ]
		: wc_get_order_status_name( $status );
	}

	/**
	 * NEW: Check user authentication status
	 *
	 * @param WP_REST_Request $request Request object
	 * @return WP_REST_Response
	 */
	public function check_user_auth( $request ) {
		return new WP_REST_Response(
			array(
				'is_authenticated' => is_user_logged_in(),
				'user_id'          => get_current_user_id(),
				'user_email'       => is_user_logged_in() ? wp_get_current_user()->user_email : null,
			),
			200
		);
	}

	/**
	 * Get AI response (placeholder for now)
	 *
	 * @param string $message User message
	 * @param string $session_id Session ID
	 * @param array  $context Context data
	 * @return array
	 */
	private function get_ai_response( $message, $session_id, $context ) {
		// For now, return a simple response
		// We'll implement the real AI engine in Phase 4

		$message_lower = strtolower( $message );

		// Simple keyword detection
		if ( strpos( $message_lower, 'product' ) !== false || strpos( $message_lower, 'show' ) !== false ) {
			// Search for products
			$products = $this->simple_product_search( $message );

			return array(
				'message'  => sprintf(
					/* translators: %d: number of products */
					__( 'I found %d products that might interest you:', 'aica-smart-ai-commerce-assistant' ),
					count( $products )
				),
				'products' => $products,
			);
		}

		if ( strpos( $message_lower, 'cart' ) !== false ) {
			return array(
				'message' => __( 'Let me check your cart for you...', 'aica-smart-ai-commerce-assistant' ),
				'actions' => array( 'show_cart' ),
			);
		}

		// Default response
		return array(
			'message' => __( 'Hi! I\'m your AI shopping assistant. I can help you find products, answer questions, and manage your cart. What would you like to know?', 'aica-smart-ai-commerce-assistant' ),
		);
	}

	/**
	 * Simple product search (temporary implementation)
	 *
	 * @param string $query Search query
	 * @return array
	 */
	private function simple_product_search( $query ) {
		$args = array(
			'post_type'      => 'product',
			'posts_per_page' => 5,
			'post_status'    => 'publish',
			's'              => $query,
		);

		$products = wc_get_products( $args );
		$result   = array();

		foreach ( $products as $product ) {
			$result[] = array(
				'id'             => $product->get_id(),
				'name'           => $product->get_name(),
				'price'          => $product->get_price(),
				'regular_price'  => $product->get_regular_price(),
				'sale_price'     => $product->get_sale_price(),
				'image'          => wp_get_attachment_url( $product->get_image_id() ),
				'url'            => $product->get_permalink(),
				'in_stock'       => $product->is_in_stock(),
				'stock_quantity' => $product->get_stock_quantity(),
			);
		}

		return $result;
	}

	/**
	 * Search products endpoint
	 *
	 * @param WP_REST_Request $request Request object
	 * @return WP_REST_Response
	 */
	public function search_products( $request ) {
		$query = sanitize_text_field( $request->get_param( 'query' ) );
		$limit = intval( $request->get_param( 'limit' ) );
		if ( $limit <= 0 ) {
			$limit = 5;
		}

		// Use AI Engine's RAG search
		$ai_engine            = AICA_AI_Engine::get_instance();
		$ai_engine_reflection = new ReflectionClass( $ai_engine );
		$method               = $ai_engine_reflection->getMethod( 'retrieve_relevant_products' );
		$method->setAccessible( true );

		$products = $method->invoke( $ai_engine, $query );

		return new WP_REST_Response(
			array(
				'success'  => true,
				'products' => array_slice( $products, 0, $limit ),
			),
			200
		);
	}

	/**
	 * Add product to cart
	 *
	 * @param WP_REST_Request $request Request object
	 * @return WP_REST_Response|WP_Error
	 */
	public function add_to_cart( $request ) {
		$product_id   = intval( $request->get_param( 'product_id' ) );
		$quantity     = intval( $request->get_param( 'quantity' ) );
		$variation_id = !empty( $request->get_param( 'variation_id' ) ) ? intval( $request->get_param( 'variation_id' ) ) : 0;

		$cart_manager = AICA_Cart_Manager::get_instance();
		$result       = $cart_manager->add_to_cart( $product_id, $quantity, $variation_id );

		if ( $result['success'] ) {
			return new WP_REST_Response( $result, 200 );
		}

		return new WP_Error(
			'add_to_cart_failed',
			$result['message'],
			array( 'status' => 400 )
		);
	}

	/**
	 * Get cart contents
	 *
	 * @return WP_REST_Response
	 */
	public function get_cart() {
		$cart_manager = AICA_Cart_Manager::get_instance();
		$cart         = $cart_manager->get_cart_data();

		return new WP_REST_Response(
			array(
				'success' => true,
				'cart'    => $cart,
			),
			200
		);
	}

	/**
	 * Remove item from cart
	 *
	 * @param WP_REST_Request $request Request object
	 * @return WP_REST_Response|WP_Error
	 */
	public function remove_from_cart( $request ) {
		$cart_item_key = sanitize_text_field( $request->get_param( 'cart_item_key' ) );

		$cart_manager = AICA_Cart_Manager::get_instance();
		$result       = $cart_manager->remove_from_cart( $cart_item_key );

		if ( $result['success'] ) {
			return new WP_REST_Response( $result, 200 );
		}

		return new WP_Error(
			'remove_failed',
			$result['message'],
			array( 'status' => 400 )
		);
	}

	/**
	 * Format cart data
	 *
	 * @return array
	 */
	private function format_cart() {
		$cart_items = array();

		foreach ( WC()->cart->get_cart() as $cart_item_key => $cart_item ) {
			$product = $cart_item['data'];

			$cart_items[] = array(
				'key'        => $cart_item_key,
				'product_id' => $cart_item['product_id'],
				'name'       => $product->get_name(),
				'quantity'   => $cart_item['quantity'],
				'price'      => $product->get_price(),
				'subtotal'   => $cart_item['line_subtotal'],
				'image'      => wp_get_attachment_url( $product->get_image_id() ),
			);
		}

		return array(
			'items'      => $cart_items,
			'item_count' => WC()->cart->get_cart_contents_count(),
			'subtotal'   => WC()->cart->get_cart_subtotal(),
			'total'      => WC()->cart->get_cart_total(),
		);
	}

	/**
	 * Get widget settings
	 *
	 * @return WP_REST_Response
	 */
	public function get_settings() {
		$settings      = get_option( 'aica_settings', array() );
		$magic_prompts = get_option( 'aica_magic_prompts', array() );

		return new WP_REST_Response(
			array(
				'success'  => true,
				'settings' => array(
					'widget_position'  => $settings['widget_position'] ?? 'bottom-right',
					'primary_color'    => $settings['primary_color'] ?? '#0066FF',
					'widget_title'     => $settings['widget_title'] ?? __( 'AI Assistant', 'aica-smart-ai-commerce-assistant' ),
					'greeting_message' => $settings['greeting_message'] ?? __( 'Hi! How can I help you today?', 'aica-smart-ai-commerce-assistant' ),
					'magic_prompts'    => $magic_prompts,
				),
			),
			200
		);
	}

	/**
	 * Save conversation message
	 *
	 * @param string $session_id Session ID
	 * @param string $message Message content
	 * @param string $role Role (user or assistant)
	 * @param array  $metadata Additional metadata
	 * @return void
	 */
	private function save_message( $session_id, $message, $role, $metadata = null ) {
		global $wpdb;

		$table = $wpdb->prefix . 'aica_conversations';

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
		$wpdb->insert(
			$table,
			array(
				'session_id' => $session_id,
				'user_id'    => get_current_user_id(),
				'message'    => $message,
				'role'       => $role,
				'metadata'   => $metadata ? wp_json_encode( $metadata ) : null,
				'created_at' => current_time( 'mysql' ),
			),
			array( '%s', '%d', '%s', '%s', '%s', '%s' )
		);
	}

	/**
	 * Log analytics event
	 *
	 * @param string $session_id Session ID
	 * @param string $event_type Event type
	 * @param array  $event_data Event data
	 * @return void
	 */
	private function log_analytics( $session_id, $event_type, $event_data = null ) {
		global $wpdb;

		$table = $wpdb->prefix . 'aica_analytics';

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
		$wpdb->insert(
			$table,
			array(
				'session_id' => $session_id,
				'event_type' => $event_type,
				'event_data' => $event_data ? wp_json_encode( $event_data ) : null,
				'created_at' => current_time( 'mysql' ),
			),
			array( '%s', '%s', '%s', '%s' )
		);
	}

	/**
	 * Check public read permission
	 * 
	 * @return bool
	 */
	public function check_public_read_permission() {
		// These endpoints are designed to be public to support the frontend widget.
		// /settings: Publicly exposes only non-sensitive configuration needed for widget initialization.
		// /user/check: Checks strict authentication status without exposing user data.
		return true;
	}
}