<?php
/**
 * Cart Manager Class
 * Handles cart operations for AI assistant
 *
 * @package AI_Commerce_Assistant
 */

if ( !defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Cart Manager Class
 */
class AICA_Cart_Manager {

	/**
	 * Single instance
	 *
	 * @var AICA_Cart_Manager
	 */
	private static $instance = null;

	/**
	 * Get instance
	 *
	 * @return AICA_Cart_Manager
	 */
	public static function get_instance() {
		if ( null === self::$instance ) {
			self::$instance = new self();
		}
		return self::$instance;
	}

	/**
	 * Constructor
	 */
	private function __construct() {
		// Initialize WooCommerce cart if needed
		add_action( 'wp_loaded', array( $this, 'maybe_init_cart' ) );
	}

	/**
	 * Initialize cart if needed
	 *
	 * @return void
	 */
	public function maybe_init_cart() {
		if ( is_null( WC()->cart ) ) {
			wc_load_cart();
		}
	}

	/**
	 * Add product to cart with validation
	 *
	 * @param int   $product_id Product ID
	 * @param int   $quantity Quantity
	 * @param int   $variation_id Variation ID
	 * @param array $variation Variation attributes
	 * @return array Result
	 */
	public function add_to_cart( $product_id, $quantity = 1, $variation_id = 0, $variation = array() ) {
		// Validate product
		$validation = $this->validate_product( $product_id, $quantity, $variation_id );
		if ( !$validation['valid'] ) {
			return array(
				'success' => false,
				'message' => $validation['message'],
			);
		}

		// Initialize cart
		$this->maybe_init_cart();

		try {
			// Add to cart
			$cart_item_key = WC()->cart->add_to_cart(
				$product_id,
				$quantity,
				$variation_id,
				$variation
			);

			if ( $cart_item_key ) {
				$product = wc_get_product( $product_id );

				return array(
					'success'       => true,
					'message'       => sprintf(
						/* translators: %s: product name */
						__( '"%s" has been added to your cart.', 'aica-smart-ai-commerce-assistant' ),
						$product->get_name()
					),
					'cart_item_key' => $cart_item_key,
					'cart'          => $this->get_cart_data(),
				);
			}

			return array(
				'success' => false,
				'message' => __( 'Failed to add product to cart.', 'aica-smart-ai-commerce-assistant' ),
			);

		} catch ( Exception $e ) {
			return array(
				'success' => false,
				'message' => $e->getMessage(),
			);
		}
	}

	/**
	 * Update cart item quantity
	 *
	 * @param string $cart_item_key Cart item key
	 * @param int    $quantity New quantity
	 * @return array Result
	 */
	public function update_quantity( $cart_item_key, $quantity ) {
		$this->maybe_init_cart();

		if ( $quantity <= 0 ) {
			return $this->remove_from_cart( $cart_item_key );
		}

		// Validate quantity
		$cart_item = WC()->cart->get_cart_item( $cart_item_key );
		if ( !$cart_item ) {
			return array(
				'success' => false,
				'message' => __( 'Cart item not found.', 'aica-smart-ai-commerce-assistant' ),
			);
		}

		$product = $cart_item['data'];

		// Check stock
		if ( $product->managing_stock() ) {
			$stock_quantity = $product->get_stock_quantity();
			if ( $quantity > $stock_quantity ) {
				return array(
					'success' => false,
					'message' => sprintf(
						/* translators: %d: stock quantity */
						__( 'Only %d items available in stock.', 'aica-smart-ai-commerce-assistant' ),
						$stock_quantity
					),
				);
			}
		}

		// Update quantity
		WC()->cart->set_quantity( $cart_item_key, $quantity );

		return array(
			'success' => true,
			'message' => __( 'Cart updated successfully.', 'aica-smart-ai-commerce-assistant' ),
			'cart'    => $this->get_cart_data(),
		);
	}

	/**
	 * Remove item from cart
	 *
	 * @param string $cart_item_key Cart item key
	 * @return array Result
	 */
	public function remove_from_cart( $cart_item_key ) {
		$this->maybe_init_cart();

		$cart_item = WC()->cart->get_cart_item( $cart_item_key );
		if ( !$cart_item ) {
			return array(
				'success' => false,
				'message' => __( 'Cart item not found.', 'aica-smart-ai-commerce-assistant' ),
			);
		}

		$product = $cart_item['data'];

		if ( WC()->cart->remove_cart_item( $cart_item_key ) ) {
			return array(
				'success' => true,
				'message' => sprintf(
					/* translators: %s: product name */
					__( '"%s" has been removed from your cart.', 'aica-smart-ai-commerce-assistant' ),
					$product->get_name()
				),
				'cart'    => $this->get_cart_data(),
			);
		}

		return array(
			'success' => false,
			'message' => __( 'Failed to remove item from cart.', 'aica-smart-ai-commerce-assistant' ),
		);
	}

	/**
	 * Clear cart
	 *
	 * @return array Result
	 */
	public function clear_cart() {
		$this->maybe_init_cart();

		WC()->cart->empty_cart();

		return array(
			'success' => true,
			'message' => __( 'Cart has been cleared.', 'aica-smart-ai-commerce-assistant' ),
			'cart'    => $this->get_cart_data(),
		);
	}

	/**
	 * Get cart data
	 *
	 * @return array Cart data
	 */
	public function get_cart_data() {
		$this->maybe_init_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'],
				'variation_id' => $cart_item['variation_id'],
				'name'         => $product->get_name(),
				'quantity'     => $cart_item['quantity'],
				'price'        => $product->get_price(),
				'subtotal'     => $cart_item['line_subtotal'],
				'total'        => $cart_item['line_total'],
				'image'        => wp_get_attachment_url( $product->get_image_id() ),
				'url'          => $product->get_permalink(),
			);
		}

		return array(
			'items'            => $cart_items,
			'item_count'       => WC()->cart->get_cart_contents_count(),
			'subtotal'         => WC()->cart->get_subtotal(),
			'subtotal_display' => wc_price( WC()->cart->get_subtotal() ),
			'total'            => WC()->cart->get_total( 'edit' ),
			'total_display'    => WC()->cart->get_total(),
			'needs_shipping'   => WC()->cart->needs_shipping(),
			'checkout_url'     => wc_get_checkout_url(),
		);
	}

	/**
	 * Validate product before adding to cart
	 *
	 * @param int $product_id Product ID
	 * @param int $quantity Quantity
	 * @param int $variation_id Variation ID
	 * @return array Validation result
	 */
	private function validate_product( $product_id, $quantity, $variation_id = 0 ) {
		// Get product
		$product = wc_get_product( $variation_id > 0 ? $variation_id : $product_id );

		if ( !$product ) {
			return array(
				'valid'   => false,
				'message' => __( 'Product not found.', 'aica-smart-ai-commerce-assistant' ),
			);
		}

		// Check if product is purchasable
		if ( !$product->is_purchasable() ) {
			return array(
				'valid'   => false,
				'message' => __( 'This product cannot be purchased.', 'aica-smart-ai-commerce-assistant' ),
			);
		}

		// Check stock
		if ( !$product->is_in_stock() ) {
			return array(
				'valid'   => false,
				'message' => __( 'This product is out of stock.', 'aica-smart-ai-commerce-assistant' ),
			);
		}

		// Check quantity availability
		if ( $product->managing_stock() ) {
			$stock_quantity = $product->get_stock_quantity();

			if ( $quantity > $stock_quantity ) {
				return array(
					'valid'   => false,
					'message' => sprintf(
						/* translators: %d: stock quantity */
						__( 'Only %d items available in stock.', 'aica-smart-ai-commerce-assistant' ),
						$stock_quantity
					),
				);
			}
		}

		// Check if variation is valid
		if ( $product->is_type( 'variable' ) && $variation_id === 0 ) {
			return array(
				'valid'   => false,
				'message' => __( 'Please select product options.', 'aica-smart-ai-commerce-assistant' ),
			);
		}

		return array(
			'valid' => true,
		);
	}

	/**
	 * Apply coupon to cart
	 *
	 * @param string $coupon_code Coupon code
	 * @return array Result
	 */
	public function apply_coupon( $coupon_code ) {
		$this->maybe_init_cart();

		$coupon_code = sanitize_text_field( $coupon_code );

		if ( WC()->cart->apply_coupon( $coupon_code ) ) {
			return array(
				'success' => true,
				'message' => sprintf(
					/* translators: %s: coupon code */
					__( 'Coupon "%s" applied successfully.', 'aica-smart-ai-commerce-assistant' ),
					$coupon_code
				),
				'cart'    => $this->get_cart_data(),
			);
		}

		return array(
			'success' => false,
			'message' => __( 'Failed to apply coupon.', 'aica-smart-ai-commerce-assistant' ),
		);
	}

	/**
	 * Remove coupon from cart
	 *
	 * @param string $coupon_code Coupon code
	 * @return array Result
	 */
	public function remove_coupon( $coupon_code ) {
		$this->maybe_init_cart();

		if ( WC()->cart->remove_coupon( $coupon_code ) ) {
			return array(
				'success' => true,
				'message' => sprintf(
					/* translators: %s: coupon code */
					__( 'Coupon "%s" removed.', 'aica-smart-ai-commerce-assistant' ),
					$coupon_code
				),
				'cart'    => $this->get_cart_data(),
			);
		}

		return array(
			'success' => false,
			'message' => __( 'Failed to remove coupon.', 'aica-smart-ai-commerce-assistant' ),
		);
	}

	/**
	 * Get product variations for AI context
	 *
	 * @param int $product_id Product ID
	 * @return array Variations
	 */
	public function get_product_variations( $product_id ) {
		$product = wc_get_product( $product_id );

		if ( !$product || !$product->is_type( 'variable' ) ) {
			return array();
		}

		$variations           = array();
		$available_variations = $product->get_available_variations();

		foreach ( $available_variations as $variation ) {
			$variation_obj = wc_get_product( $variation['variation_id'] );

			$variations[] = array(
				'variation_id' => $variation['variation_id'],
				'attributes'   => $variation['attributes'],
				'price'        => $variation_obj->get_price(),
				'in_stock'     => $variation['is_in_stock'],
				'display_name' => implode(
					' / ',
					array_map(
						function ( $attr ) {
							return ucfirst( str_replace( 'attribute_', '', $attr ) );
						},
						$variation['attributes']
					)
				),
			);
		}

		return $variations;
	}
}