<?php
/**
 * DataLoader - WC_Db_Loader
 *
 * Loads Models for WooCommerce objects defined in custom DB tables.
 *
 * @package WPGraphQL\WooCommerce\Data\Loader
 * @since 0.5.0
 */

namespace WPGraphQL\WooCommerce\Data\Loader;

use GraphQL\Error\UserError;
use WPGraphQL\Data\Loader\AbstractDataLoader;
use WPGraphQL\WooCommerce\Data\Factory;
use WPGraphQL\WooCommerce\Model\Shipping_Method;
use WPGraphQL\WooCommerce\Model\Shipping_Zone;
use WPGraphQL\WooCommerce\Model\Tax_Rate;

/**
 * Class WC_Db_Loader
 */
class WC_Db_Loader extends AbstractDataLoader {
	/**
	 * Stores loaded data objects.
	 *
	 * @var array
	 */
	protected $loaded_objects;

	/**
	 * Loader type
	 *
	 * @var string
	 */
	protected $loader_type;

	/**
	 * WC_Db_Loader constructor
	 *
	 * @param \WPGraphQL\AppContext $context      AppContext instance.
	 * @param string                $loader_type  Type of loader be initialized.
	 */
	public function __construct( $context, $loader_type ) {
		$this->loader_type = $loader_type;

		parent::__construct( $context );
	}

	/**
	 * Given array of keys, loads and returns a map consisting of keys from `keys` array and loaded
	 * posts as the values
	 *
	 * @param array $keys - array of IDs.
	 *
	 * @return array
	 * @throws \Exception Invalid loader type.
	 */
	public function loadKeys( array $keys ) {
		$loader = null;
		switch ( $this->loader_type ) {
			case 'CART_ITEM':
				$loader = [ $this, 'load_cart_item_from_key' ];
				break;
			case 'DOWNLOADABLE_ITEM':
				$loader = [ $this, 'load_downloadable_item_from_id' ];
				break;
			case 'TAX_CLASS':
				$loader = [ $this, 'load_tax_class_from_slug' ];
				break;
			case 'TAX_RATE':
				$loader = [ $this, 'load_tax_rate_from_id' ];
				break;
			case 'ORDER_ITEM':
				$loader = [ $this, 'load_order_item_from_id' ];
				break;
			case 'SHIPPING_METHOD':
				$loader = [ $this, 'load_shipping_method_from_id' ];
				break;
			case 'SHIPPING_ZONE':
				$loader = [ $this, 'load_shipping_zone_from_id' ];
				break;
			default:
				/**
				 * For adding custom key types to this loader
				 *
				 * @param callable|null $loader       Callback that gets entry from key.
				 * @param string        $loader_type  Used to determine loader being used for this instance of the loader.
				 */
				$loader = apply_filters( 'woographql_db_loader_func', null, $this->loader_type );

				if ( empty( $loader ) ) {
					throw new \Exception(
						/* translators: %s: Loader Type */
						sprintf( __( 'Loader type invalid: %s', 'graphql-for-ecommerce' ), $this->loader_type )
					);
				}
		}//end switch

		$loaded_items = [];

		/**
		 * Loop over the keys and return an array of items.
		 */
		foreach ( $keys as $key ) {
			$loaded_items[ $key ] = call_user_func( $loader, $key );
		}

		return ! empty( $loaded_items ) ? $loaded_items : [];
	}

	/**
	 * Returns the cart item connected the provided key.
	 *
	 * @param string $key - Cart item key.
	 *
	 * @return array
	 */
	public function load_cart_item_from_key( $key ) {
		// Add the cart item's product and product variation to WC-CPT buffer.
		return Factory::resolve_cart()->get_cart_item( $key );
	}

	/**
	 * Returns the downloadable item connected the provided IDs.
	 *
	 * @param int $id - Downloadable item ID.
	 *
	 * @return \WC_Customer_Download|null
	 */
	public function load_downloadable_item_from_id( $id ) {
		$node = new \WC_Customer_Download( $id );
		return 0 === $node->get_id() ? $node : null;
	}

	/**
	 * Returns the tax class connected the provided IDs.
	 *
	 * @param int $slug - Tax class slug.
	 *
	 * @return array|null
	 */
	public function load_tax_class_from_slug( $slug ) {
		if ( 'standard' === $slug ) {
			return [
				'slug' => 'standard',
				'name' => __( 'Standard rate', 'graphql-for-ecommerce' ),
			];
		} else {
			$tax_class = \WC_Tax::get_tax_class_by( 'slug', $slug );
			return is_array( $tax_class ) && ! empty( $tax_class ) ? $tax_class : null;
		}
	}

	/**
	 * Returns the tax rate connected the provided IDs.
	 *
	 * @param int $id - Tax rate IDs.
	 *
	 * @return \WPGraphQL\WooCommerce\Model\Tax_Rate|null
	 */
	public function load_tax_rate_from_id( $id ) {
		global $wpdb;

		/**
		 * Get tax rate from WooCommerce.
		 *
		 * @var \stdClass&object{
		 *  tax_rate_id: int,
		 *  tax_rate_class: string,
		 *  tax_rate_country: string,
		 *  tax_rate_state: string,
		 *  tax_rate: string,
		 *  tax_rate_name: string,
		 *  tax_rate_priority: int,
		 *  tax_rate_compound: bool,
		 *  tax_rate_shipping: bool,
		 *  tax_rate_order: int,
		 *  tax_rate_city: string,
		 *  tax_rate_postcode: string,
		 *  tax_rate_postcodes: string,
		 *  tax_rate_cities: string
		 *  } $rate
		 */
		$rate = \WC_Tax::_get_tax_rate( $id, OBJECT );
		if ( ! empty( $rate ) && is_object( $rate ) ) {
			$rate->tax_rate_city      = '';
			$rate->tax_rate_postcode  = '';
			$rate->tax_rate_postcodes = '';
			$rate->tax_rate_cities    = '';

			// Get locales from a tax rate.
			// phpcs:ignore WordPress.DB.DirectDatabaseQuery
			$locales = $wpdb->get_results(
				$wpdb->prepare(
					"
					SELECT location_code, location_type
					FROM {$wpdb->prefix}woocommerce_tax_rate_locations
					WHERE tax_rate_id = %d
					",
					$rate->tax_rate_id
				)
			);

			$cities    = [];
			$postcodes = [];
			foreach ( $locales as $locale ) {
				if ( 'city' === $locale->location_type ) {
					$cities[] = $locale->location_code;
				} elseif ( 'postcode' === $locale->location_type ) {
					$postcodes[] = $locale->location_code;
				} else {
					$rate->{'tax_rate_' . $locale->location_type} = $locale->location_code;
				}
			}

			if ( ! empty( $cities ) ) {
				$rate->tax_rate_cities = implode( ';', $cities );
				$rate->tax_rate_city   = end( $cities );
			}

			if ( ! empty( $postcodes ) ) {
				$rate->tax_rate_postcodes = implode( ';', $postcodes );
				$rate->tax_rate_postcode  = end( $postcodes );
			}
			return new Tax_Rate( $rate );
		} else {
			return null;
		}//end if
	}

	/**
	 * Returns the shipping method Model for the shipping method ID.
	 *
	 * @param int $id - Shipping method ID.
	 *
	 * @return \WPGraphQL\WooCommerce\Model\Shipping_Method
	 *
	 * @throws \GraphQL\Error\UserError Invalid object.
	 */
	public function load_shipping_method_from_id( $id ) {
		$wc_shipping = \WC_Shipping::instance();
		$methods     = $wc_shipping->get_shipping_methods();
		if ( empty( $methods[ $id ] ) ) {
			throw new UserError(
			/* translators: shipping method ID */
				sprintf( __( 'No Shipping Method assigned to ID %s was found ', 'graphql-for-ecommerce' ), $id )
			);
		}

		$method = $methods[ $id ];

		return new Shipping_Method( $method );
	}

	/**
	 * Returns the shipping zone connected the provided IDs.
	 *
	 * @param int $id - Shipping zone IDs.
	 *
	 * @return \WPGraphQL\WooCommerce\Model\Shipping_Zone|null
	 */
	public function load_shipping_zone_from_id( $id ) {
		/** @var \WC_Shipping_Zone|false $zone */
		$zone = \WC_Shipping_Zones::get_zone( $id );

		if ( false === $zone ) {
			return null;
		}

		$zone = new Shipping_Zone( $zone );

		return $zone;
	}

	/**
	 * Returns the order item connected the provided IDs.
	 *
	 * @param int $id - Order item IDs.
	 *
	 * @return \WPGraphQL\WooCommerce\Model\Order_Item|null
	 */
	public function load_order_item_from_id( $id ) {
		$item = \WC()->order_factory::get_order_item( $id );

		if ( false === $item ) {
			return null;
		}

		$item = new \WPGraphQL\WooCommerce\Model\Order_Item( $item );

		return $item;
	}
}