<?php
/**
 * UCP cart and checkout handlers for WooCommerce guest sessions.
 *
 * @package Agentmatica
 */

declare(strict_types=1);

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

final class Agentmatica_Ucp_Cart {
	public static function cart_gid( string $session_key ): string {
		return 'gid://woocommerce/Cart/' . $session_key;
	}

	public static function checkout_gid( string $session_key ): string {
		return 'gid://woocommerce/Checkout/' . $session_key;
	}

	/**
	 * Parse cart id GID or session_key from UCP arguments.
	 */
	public static function read_session_key( array $arguments ): string {
		if ( isset( $arguments['id'] ) && is_string( $arguments['id'] ) ) {
			$id = trim( $arguments['id'] );
			if ( preg_match( '/gid:\/\/woocommerce\/Cart\/(.+)/', $id, $matches ) ) {
				return Agentmatica_WooCommerce_Cart::sanitize_session_key( $matches[1] );
			}
		}

		$cart = isset( $arguments['cart'] ) && is_array( $arguments['cart'] )
			? $arguments['cart']
			: array();

		if ( isset( $cart['session_key'] ) ) {
			return Agentmatica_WooCommerce_Cart::sanitize_session_key( (string) $cart['session_key'] );
		}

		if ( isset( $cart['id'] ) && is_string( $cart['id'] ) ) {
			$id = trim( $cart['id'] );
			if ( preg_match( '/gid:\/\/woocommerce\/Cart\/(.+)/', $id, $matches ) ) {
				return Agentmatica_WooCommerce_Cart::sanitize_session_key( $matches[1] );
			}
		}

		return '';
	}

	/**
	 * @param array<string, mixed> $arguments
	 * @return array<string, mixed>
	 */
	public static function create_cart( array $arguments ): array {
		$session_key = self::resolve_session_key( $arguments );
		if ( $session_key === '' ) {
			return self::error_response( __( 'A valid chat session id is required in cart context.', 'agentmatica-mcp-connector' ) );
		}

		$line_items = self::read_line_items( $arguments );
		if ( empty( $line_items ) ) {
			return self::error_response( __( 'cart.line_items is required.', 'agentmatica-mcp-connector' ) );
		}

		foreach ( $line_items as $line ) {
			$result = Agentmatica_WooCommerce_Cart::add_item(
				array(
					'session_key'  => $session_key,
					'product_id'   => (int) ( $line['product_id'] ?? 0 ),
					'variation_id' => (int) ( $line['variation_id'] ?? 0 ),
					'quantity'     => (int) ( $line['quantity'] ?? 1 ),
				)
			);

			if ( empty( $result['success'] ) ) {
				return self::error_response( (string) ( $result['message'] ?? __( 'Failed to add item to cart.', 'agentmatica-mcp-connector' ) ) );
			}
		}

		$attributes = self::read_cart_attributes( $arguments );
		if ( ! empty( $attributes ) ) {
			Agentmatica_Order_Attribution::merge_cart_attributes( $session_key, $attributes );
		}

		return self::cart_response( $session_key );
	}

	/**
	 * @param array<string, mixed> $arguments
	 * @return array<string, mixed>
	 */
	public static function update_cart( array $arguments ): array {
		$session_key = self::read_session_key( $arguments );
		if ( $session_key === '' ) {
			return self::error_response( __( 'A valid chat session id is required in cart context.', 'agentmatica-mcp-connector' ) );
		}

		$remove_items = self::read_remove_line_items( $arguments );
		foreach ( $remove_items as $line ) {
			$result = Agentmatica_WooCommerce_Cart::remove_item(
				array(
					'session_key'  => $session_key,
					'product_id'   => (int) ( $line['product_id'] ?? 0 ),
					'variation_id' => (int) ( $line['variation_id'] ?? 0 ),
				)
			);

			if ( empty( $result['success'] ) ) {
				return self::error_response( (string) ( $result['message'] ?? __( 'Failed to remove item from cart.', 'agentmatica-mcp-connector' ) ) );
			}
		}

		$line_items = self::read_line_items( $arguments );
		foreach ( $line_items as $line ) {
			$result = Agentmatica_WooCommerce_Cart::add_item(
				array(
					'session_key'  => $session_key,
					'product_id'   => (int) ( $line['product_id'] ?? 0 ),
					'variation_id' => (int) ( $line['variation_id'] ?? 0 ),
					'quantity'     => (int) ( $line['quantity'] ?? 1 ),
				)
			);

			if ( empty( $result['success'] ) ) {
				return self::error_response( (string) ( $result['message'] ?? __( 'Failed to add item to cart.', 'agentmatica-mcp-connector' ) ) );
			}
		}

		if ( empty( $remove_items ) && empty( $line_items ) ) {
			return self::error_response( __( 'cart.line_items or cart.remove_line_items is required.', 'agentmatica-mcp-connector' ) );
		}

		$attributes = self::read_cart_attributes( $arguments );
		if ( ! empty( $attributes ) ) {
			Agentmatica_Order_Attribution::merge_cart_attributes( $session_key, $attributes );
		}

		return self::cart_response( $session_key );
	}

	/**
	 * @return list<array{product_id:int, variation_id:int}>
	 */
	private static function read_remove_line_items( array $arguments ): array {
		$cart       = isset( $arguments['cart'] ) && is_array( $arguments['cart'] )
			? $arguments['cart']
			: $arguments;
		$line_items = isset( $cart['remove_line_items'] ) && is_array( $cart['remove_line_items'] )
			? $cart['remove_line_items']
			: array();

		$parsed = array();
		foreach ( $line_items as $line ) {
			if ( ! is_array( $line ) ) {
				continue;
			}

			$item    = isset( $line['item'] ) && is_array( $line['item'] ) ? $line['item'] : $line;
			$item_id = isset( $item['id'] ) ? (string) $item['id'] : '';

			$product_id   = 0;
			$variation_id = 0;

			if ( preg_match( '/gid:\/\/woocommerce\/ProductVariation\/(\d+)/', $item_id, $matches ) ) {
				$maybe_id  = (int) $matches[1];
				$variation = wc_get_product( $maybe_id );
				if ( $variation instanceof WC_Product_Variation ) {
					$variation_id = $maybe_id;
					$product_id   = (int) $variation->get_parent_id();
				}
			} elseif ( preg_match( '/gid:\/\/woocommerce\/Product\/(\d+)/', $item_id, $matches ) ) {
				$product_id = (int) $matches[1];
			} elseif ( preg_match( '/^\d+$/', $item_id ) ) {
				$product_id = (int) $item_id;
			}

			if ( $product_id > 0 ) {
				$parsed[] = array(
					'product_id'   => $product_id,
					'variation_id' => $variation_id,
				);
			}
		}

		return $parsed;
	}

	/**
	 * @param array<string, mixed> $arguments
	 * @return array<string, mixed>
	 */
	public static function get_cart( array $arguments ): array {
		$session_key = self::read_session_key( $arguments );
		if ( $session_key === '' ) {
			return self::error_response( __( 'cart id is required.', 'agentmatica-mcp-connector' ) );
		}

		return self::cart_response( $session_key );
	}

	/**
	 * @param array<string, mixed> $arguments
	 * @return array<string, mixed>
	 */
	public static function create_checkout( array $arguments ): array {
		$session_key = self::read_session_key( $arguments );

		$checkout = isset( $arguments['checkout'] ) && is_array( $arguments['checkout'] )
			? $arguments['checkout']
			: array();

		if ( $session_key === '' && isset( $checkout['cart_id'] ) ) {
			$session_key = self::read_session_key(
				array( 'id' => (string) $checkout['cart_id'] )
			);
		}

		if ( $session_key === '' ) {
			$session_key = self::resolve_session_key( $arguments );
		}

		if ( $session_key === '' ) {
			return self::error_response( __( 'cart id is required for checkout.', 'agentmatica-mcp-connector' ) );
		}

		$result = Agentmatica_WooCommerce_Cart::checkout_url(
			array( 'session_key' => $session_key )
		);

		if ( empty( $result['success'] ) ) {
			return self::error_response( (string) ( $result['message'] ?? __( 'Checkout unavailable.', 'agentmatica-mcp-connector' ) ) );
		}

		$checkout_url = (string) ( $result['checkout_url'] ?? '' );

		return array(
			'ucp'      => array(
				'version' => Agentmatica_Ucp_Profile::UCP_VERSION,
			),
			'checkout' => array(
				'id'           => self::checkout_gid( $session_key ),
				'cart_id'      => self::cart_gid( $session_key ),
				'checkout_url' => $checkout_url,
			),
		);
	}

	/**
	 * @return list<array{product_id:int, variation_id:int, quantity:int}>
	 */
	private static function read_line_items( array $arguments ): array {
		$cart       = isset( $arguments['cart'] ) && is_array( $arguments['cart'] )
			? $arguments['cart']
			: $arguments;
		$line_items = isset( $cart['line_items'] ) && is_array( $cart['line_items'] )
			? $cart['line_items']
			: array();

		$parsed = array();
		foreach ( $line_items as $line ) {
			if ( ! is_array( $line ) ) {
				continue;
			}

			$quantity = isset( $line['quantity'] ) ? max( 1, (int) $line['quantity'] ) : 1;
			$item     = isset( $line['item'] ) && is_array( $line['item'] ) ? $line['item'] : $line;
			$item_id  = isset( $item['id'] ) ? (string) $item['id'] : '';

			$product_id   = 0;
			$variation_id = 0;

			if ( preg_match( '/gid:\/\/woocommerce\/ProductVariation\/(\d+)/', $item_id, $matches ) ) {
				$maybe_id  = (int) $matches[1];
				$variation = wc_get_product( $maybe_id );
				if ( $variation instanceof WC_Product_Variation ) {
					$variation_id = $maybe_id;
					$product_id   = (int) $variation->get_parent_id();
				} elseif ( $variation instanceof WC_Product ) {
					$product_id   = $maybe_id;
					$variation_id = 0;
				}
			} elseif ( preg_match( '/gid:\/\/woocommerce\/Product\/(\d+)/', $item_id, $matches ) ) {
				$product_id = (int) $matches[1];
			} elseif ( preg_match( '/^\d+$/', $item_id ) ) {
				$product_id = (int) $item_id;
			}

			if ( $product_id > 0 ) {
				$parsed[] = array(
					'product_id'   => $product_id,
					'variation_id' => $variation_id,
					'quantity'     => $quantity,
				);
			}
		}

		return $parsed;
	}

	private static function resolve_session_key( array $arguments ): string {
		$existing = self::read_session_key( $arguments );
		if ( $existing !== '' ) {
			return $existing;
		}

		$cart    = isset( $arguments['cart'] ) && is_array( $arguments['cart'] )
			? $arguments['cart']
			: array();
		$context = isset( $cart['context'] ) && is_array( $cart['context'] )
			? $cart['context']
			: array();

		if ( isset( $context['session_key'] ) ) {
			return Agentmatica_WooCommerce_Cart::sanitize_session_key( (string) $context['session_key'] );
		}

		if ( isset( $arguments['session_key'] ) ) {
			return Agentmatica_WooCommerce_Cart::sanitize_session_key( (string) $arguments['session_key'] );
		}

		return '';
	}

	/**
	 * @return array<string, mixed>
	 */
	private static function cart_response( string $session_key ): array {
		$result = Agentmatica_WooCommerce_Cart::checkout_url(
			array( 'session_key' => $session_key )
		);

		if ( empty( $result['success'] ) ) {
			return self::error_response( (string) ( $result['message'] ?? __( 'Cart is empty.', 'agentmatica-mcp-connector' ) ) );
		}

		$line_items = array();
		foreach ( (array) ( $result['line_items'] ?? array() ) as $item ) {
			if ( ! is_array( $item ) ) {
				continue;
			}

			$product_id   = (int) ( $item['product_id'] ?? 0 );
			$variation_id = (int) ( $item['variation_id'] ?? 0 );
			$quantity     = (int) ( $item['quantity'] ?? 0 );
			if ( $product_id <= 0 || $quantity <= 0 ) {
				continue;
			}

			$item_id = $variation_id > 0
				? Agentmatica_Ucp_Catalog::variant_gid( $variation_id )
				: Agentmatica_Ucp_Catalog::product_gid( $product_id );

			$title     = (string) ( $item['title'] ?? '' );
			$image_url = isset( $item['image_url'] ) ? trim( (string) $item['image_url'] ) : '';

			$item_payload = array(
				'id'      => $item_id,
				'title'   => $title,
				'product' => array(
					'id'    => Agentmatica_Ucp_Catalog::product_gid( $product_id ),
					'title' => $title,
				),
			);
			if ( $image_url !== '' ) {
				$item_payload['image_url'] = $image_url;
			}

			$line_items[] = array(
				'quantity' => $quantity,
				'item'     => $item_payload,
			);
		}

		return array(
			'ucp'  => array(
				'version' => Agentmatica_Ucp_Profile::UCP_VERSION,
			),
			'cart' => array(
				'id'           => self::cart_gid( $session_key ),
				'line_items'   => $line_items,
				'checkout_url' => (string) ( $result['checkout_url'] ?? '' ),
			),
		);
	}

	/**
	 * @return list<array{key:string, value:string}>
	 */
	private static function read_cart_attributes( array $arguments ): array {
		$cart = isset( $arguments['cart'] ) && is_array( $arguments['cart'] )
			? $arguments['cart']
			: $arguments;
		$raw  = isset( $cart['attributes'] ) && is_array( $cart['attributes'] )
			? $cart['attributes']
			: array();

		$attributes = array();
		foreach ( $raw as $entry ) {
			if ( ! is_array( $entry ) ) {
				continue;
			}
			$key = isset( $entry['key'] ) ? trim( (string) $entry['key'] ) : '';
			if ( $key === '' ) {
				continue;
			}
			$attributes[] = array(
				'key'   => $key,
				'value' => isset( $entry['value'] ) ? (string) $entry['value'] : '',
			);
		}

		return $attributes;
	}

	/**
	 * @return array<string, mixed>
	 */
	private static function error_response( string $message ): array {
		return array(
			'ucp'      => array(
				'version' => Agentmatica_Ucp_Profile::UCP_VERSION,
				'status'  => 'error',
			),
			'messages' => array(
				array(
					'severity' => 'error',
					'text'     => $message,
				),
			),
		);
	}
}