<?php
declare( strict_types = 1 );

namespace Automattic\WooCommerce\Blocks\BlockTypes;

use Automattic\WooCommerce\Blocks\BlockTypes\ProductCollection\Utils as ProductCollectionUtils;
use Automattic\WooCommerce\Internal\ProductFilters\FilterDataProvider;
use Automattic\WooCommerce\Internal\ProductFilters\QueryClauses;
use Automattic\WooCommerce\Internal\ProductFilters\TaxonomyHierarchyData;

/**
 * Product Filter: Taxonomy Block.
 */
final class ProductFilterTaxonomy extends AbstractBlock {

	/**
	 * Block name.
	 *
	 * @var string
	 */
	protected $block_name = 'product-filter-taxonomy';

	/**
	 * Prepare the active filter items.
	 *
	 * @internal For exclusive usage of WooCommerce core, backwards compatibility not guaranteed.
	 *
	 * @param array $items  The active filter items.
	 * @param array $params The query param parsed from the URL.
	 * @return array Active filters items.
	 */
	public function prepare_selected_filters( $items, $params ) {
		$container      = wc_get_container();
		$params_handler = $container->get( \Automattic\WooCommerce\Internal\ProductFilters\Params::class );

		// Use centralized parameter mapping to avoid hardcoding URL parameter formats.
		$taxonomy_params = $params_handler->get_param( 'taxonomy' );

		$active_taxonomies = array();
		$all_term_slugs    = array();

		foreach ( $taxonomy_params as $taxonomy_slug => $param_key ) {
			if ( ! empty( $params[ $param_key ] ) && is_string( $params[ $param_key ] ) ) {
				$term_slugs                          = array_map( 'sanitize_title', explode( ',', $params[ $param_key ] ) );
				$active_taxonomies[ $taxonomy_slug ] = $term_slugs;
				$all_term_slugs                      = array_merge( $all_term_slugs, $term_slugs );
			}//end if
		}

		if ( empty( $active_taxonomies ) ) {
			return $items;
		}

		// Single query for all taxonomies and terms to avoid N+1 query problem.
		$terms = get_terms(
			array(
				'taxonomy'   => array_keys( $active_taxonomies ),
				'slug'       => array_unique( $all_term_slugs ),
				'hide_empty' => false,
			)
		);

		if ( is_wp_error( $terms ) || empty( $terms ) ) {
			return $items;
		}

		foreach ( $terms as $term ) {
			$taxonomy_object = get_taxonomy( $term->taxonomy );
			if ( $taxonomy_object ) {
				$term_name = wp_specialchars_decode( $term->name, ENT_QUOTES );
				$items[]   = array(
					'type'        => 'taxonomy/' . $term->taxonomy,
					'value'       => $term->slug,
					'activeLabel' => $taxonomy_object->labels->singular_name . ': ' . $term_name,
				);
			}//end if
		}

		return $items;
	}

	/**
	 * Initialize this block type.
	 *
	 * - Hook into WP lifecycle.
	 * - Register the block with WordPress.
	 */
	protected function initialize() {
		parent::initialize();

		add_filter( 'woocommerce_blocks_product_filters_selected_items', array( $this, 'prepare_selected_filters' ), 10, 2 );

		// Register REST field for menu_order on sortable taxonomies.
		$this->register_taxonomy_menu_order_rest_field();
	}

	/**
	 * Register a REST field to expose the menu_order meta for sortable taxonomies.
	 * This allows the editor to display terms in menu order.
	 */
	private function register_taxonomy_menu_order_rest_field(): void {
		/**
		 * Filters the list of taxonomies that support custom ordering. Filter was introduced long
		 * ago is only documented in 10.6.0.
		 *
		 * First instance in plugins/woocommerce/includes/admin/class-wc-admin-assets.php.
		 *
		 * @since 1.0
		 *
		 * @param array $sortable_taxonomies List of taxonomy slugs that support custom ordering.
		 * @return array List of taxonomy slugs that support custom ordering.
		 */
		$sortable_taxonomies = apply_filters( 'woocommerce_sortable_taxonomies', array( 'product_cat' ) );

		foreach ( $sortable_taxonomies as $taxonomy ) {
			register_rest_field(
				$taxonomy,
				'menu_order',
				array(
					'get_callback' => function ( $term ) {
						$menu_order = get_term_meta( $term['id'], 'order', true );
						return is_numeric( $menu_order ) ? (int) $menu_order : 0;
					},
					'schema'       => array(
						'description' => __( 'Menu order, used to custom sort the term.', 'woocommerce' ),
						'type'        => 'integer',
						'context'     => array( 'view', 'edit' ),
						'readonly'    => true,
					),
				)
			);
		}
	}

	/**
	 * Extra data passed through from server to client for block.
	 *
	 * @param array $attributes  Any attributes that currently are available from the block.
	 *                           Note, this will be empty in the editor context when the block is
	 *                           not in the post content on editor load.
	 */
	protected function enqueue_data( array $attributes = array() ) {
		parent::enqueue_data( $attributes );

		if ( is_admin() ) {
			$this->asset_data_registry->add( 'filterableProductTaxonomies', $this->get_taxonomies() );
			// Expose sortable taxonomies so the editor can show/hide "Menu order" option.
			$this->asset_data_registry->add(
				'sortableTaxonomies',
				/**
				 * Filters the list of taxonomies that support custom ordering. Filter was introduced long
				 * ago is only documented in 10.6.0.
				 *
				 * First instance in plugins/woocommerce/includes/admin/class-wc-admin-assets.php.
				 *
				 * @since 1.0
				 *
				 * @param array $sortable_taxonomies List of taxonomy slugs that support custom ordering.
				 * @return array List of taxonomy slugs that support custom ordering.
				 */
				apply_filters( 'woocommerce_sortable_taxonomies', array( 'product_cat' ) )
			);
		}
	}

	/**
	 * Get the frontend script handle for this block type.
	 *
	 * @see $this->register_block_type()
	 * @param string $key Data to get, or default to everything.
	 * @return array|string|null
	 */
	protected function get_block_type_script( $key = null ) {
		return null;
	}

	/**
	 * Render the block.
	 *
	 * @param array    $block_attributes Block attributes.
	 * @param string   $content          Block content.
	 * @param WP_Block $block            Block instance.
	 * @return string Rendered block type output.
	 */
	protected function render( $block_attributes, $content, $block ) {
		// Skip rendering in admin or during AJAX requests.
		if ( is_admin() || wp_doing_ajax() || empty( $block_attributes['taxonomy'] ) ) {
			return '';
		}

		$taxonomy        = $block_attributes['taxonomy'];
		$taxonomy_object = get_taxonomy( $taxonomy );

		if ( ! $taxonomy_object || ! taxonomy_exists( $taxonomy ) ) {
			return '';
		}

		// Validate that this taxonomy is configured in the parameter map.
		$container       = wc_get_container();
		$params_handler  = $container->get( \Automattic\WooCommerce\Internal\ProductFilters\Params::class );
		$taxonomy_params = $params_handler->get_param( 'taxonomy' );

		if ( ! isset( $taxonomy_params[ $taxonomy ] ) ) {
			return '';
		}

		// Pass taxonomy parameter mapping to frontend via interactivity config.
		wp_interactivity_config(
			'woocommerce/product-filters',
			array(
				'taxonomyParamsMap' => $taxonomy_params,
			)
		);

		$filter_context  = array(
			'items'          => array(),
			'selectionMode'  => 'multiple',
			'storeNamespace' => 'woocommerce/product-filters',
			'groupLabel'     => $taxonomy_object->labels->singular_name,
		);
		$taxonomy_counts = $this->get_taxonomy_term_counts( $block, $taxonomy );

		if ( ! empty( $taxonomy_counts ) ) {
			$hide_empty     = $block_attributes['hideEmpty'] ?? true;
			$orderby        = $block_attributes['sortOrder'] ? explode( '-', $block_attributes['sortOrder'] )[0] : 'name';
			$order          = $block_attributes['sortOrder'] ? strtoupper( explode( '-', $block_attributes['sortOrder'] )[1] ) : 'DESC';
			$taxonomy_terms = $this->get_sorted_terms( $taxonomy, $taxonomy_counts, $hide_empty, $orderby, $order );

			if ( is_wp_error( $taxonomy_terms ) ) {
				return '';
			}

			// Get selected terms from filter params.
			$filter_params  = $block->context['filterParams'] ?? array();
			$selected_terms = array();
			$param_key      = $taxonomy_params[ $taxonomy ];

			if ( $filter_params && ! empty( $filter_params[ $param_key ] ) && is_string( $filter_params[ $param_key ] ) ) {
				$selected_terms = array_filter( array_map( 'sanitize_title', explode( ',', $filter_params[ $param_key ] ) ) );
			}

			$show_counts      = $block_attributes['showCounts'] ?? false;
			$taxonomy_options = array_map(
				function ( $term ) use ( $taxonomy_counts, $selected_terms, $taxonomy, $show_counts ) {
					$term          = (array) $term;
					$term['count'] = $taxonomy_counts[ $term['term_id'] ] ?? 0;
					$term_name     = wp_specialchars_decode( $term['name'], ENT_QUOTES );

					$type   = 'taxonomy/' . $taxonomy;
					$option = array(
						'id'        => $type . '-' . $term['slug'],
						'label'     => $term_name,
						'ariaLabel' => $term_name,
						'value'     => $term['slug'],
						'selected'  => in_array( $term['slug'], $selected_terms, true ),
						'type'      => $type,
					);

					if ( $show_counts ) {
						$option['count'] = $term['count'];
					}

					if ( is_taxonomy_hierarchical( $taxonomy ) ) {
						$option['termId'] = $term['term_id'];

						if ( isset( $term['depth'] ) && $term['depth'] > 0 ) {
							$option['depth'] = $term['depth'];
						}
						if ( isset( $term['parent'] ) && $term['parent'] > 0 ) {
							$option['parent'] = $term['parent'];
						}
					}

					return $option;
				},
				$taxonomy_terms
			);

			$filter_context['items'] = array_values( $taxonomy_options );
		}//end if

		$wrapper_attributes = array(
			'data-wp-interactive' => 'woocommerce/product-filters',
			'data-wp-key'         => wp_unique_prefixed_id( $this->get_full_block_name() ),
			'data-wp-context'     => wp_json_encode(
				array(
					'activeLabelTemplate' => $taxonomy_object->labels->singular_name . ': {{label}}',
					'filterType'          => 'taxonomy/' . $taxonomy,
					'items'               => $filter_context['items'],
				),
				JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT | JSON_HEX_AMP
			),
		);

		if ( empty( $filter_context['items'] ) ) {
			$wrapper_attributes['hidden'] = true;
			$wrapper_attributes['class']  = 'wc-block-product-filter--hidden';
		}

		return sprintf(
			'<div %1$s>%2$s</div>',
			get_block_wrapper_attributes( $wrapper_attributes ),
			array_reduce(
				$block->parsed_block['innerBlocks'],
				function ( $carry, $parsed_block ) use ( $filter_context ) {
					$carry .= ( new \WP_Block( $parsed_block, array( 'woocommerce/selectableItems' => $filter_context ) ) )->render();
					return $carry;
				},
				''
			)
		);
	}

	/**
	 * Get terms sorted based on taxonomy type (hierarchical vs flat).
	 *
	 * @param string $taxonomy        Taxonomy slug.
	 * @param array  $taxonomy_counts Term counts with term_id as key.
	 * @param bool   $hide_empty      Whether to hide empty terms.
	 * @param string $orderby         Sort field (name, count, menu_order).
	 * @param string $order           Sort direction (ASC, DESC).
	 * @return array Sorted terms array.
	 */
	private function get_sorted_terms( $taxonomy, $taxonomy_counts, $hide_empty, $orderby, $order ) {
		if ( ! is_taxonomy_hierarchical( $taxonomy ) ) {
			$args = array(
				'taxonomy'   => $taxonomy,
				'hide_empty' => false,
			);

			if ( $hide_empty ) {
				$args['include'] = array_keys( $taxonomy_counts );
			}

			$terms = get_terms( $args );

			if ( is_wp_error( $terms ) || empty( $terms ) ) {
				return array();
			}

			// Add menu_order to flat terms for sorting.
			if ( 'menu_order' === $orderby ) {
				// Prime term meta cache in single query to avoid N+1.
				update_termmeta_cache( wp_list_pluck( $terms, 'term_id' ) );
				$terms = array_map(
					function ( $term ) {
						$term               = (array) $term;
						$menu_order         = get_term_meta( $term['term_id'], 'order', true );
						$term['menu_order'] = is_numeric( $menu_order ) ? (int) $menu_order : 0;
						return (object) $term;
					},
					$terms
				);
			}

			return $this->sort_terms_by_criteria( $terms, $orderby, $order, $taxonomy_counts );
		}//end if

		return $this->get_hierarchical_terms( $taxonomy, $taxonomy_counts, $hide_empty, $orderby, $order );
	}

	/**
	 * Retrieve the taxonomy term counts for current block.
	 *
	 * @param WP_Block $block    Block instance.
	 * @param string   $taxonomy Taxonomy slug.
	 * @return array Term counts with term_id as key and count as value.
	 */
	private function get_taxonomy_term_counts( $block, $taxonomy ) {
		if ( ! isset( $block->context['filterParams'] ) ) {
			return array();
		}

		$query_vars = ProductCollectionUtils::get_query_vars( $block, 1 );

		// Remove current taxonomy from query vars to avoid circular counting.
		$container       = wc_get_container();
		$params_handler  = $container->get( \Automattic\WooCommerce\Internal\ProductFilters\Params::class );
		$taxonomy_params = $params_handler->get_param( 'taxonomy' );

		if ( isset( $taxonomy_params[ $taxonomy ] ) ) {
			$param_key = $taxonomy_params[ $taxonomy ];
			unset( $query_vars[ $param_key ] );
		}

		/**
		 * Prevent circular counting when calculating filter counts with active attribute filters.
		 * Removes product attribute taxonomy filters to ensure accurate cross-filter counting.
		 *
		 * @see https://github.com/woocommerce/woocommerce/pull/52759
		 */
		if ( isset( $query_vars['taxonomy'] ) && false !== strpos( $query_vars['taxonomy'], 'pa_' ) ) {
			unset(
				$query_vars['taxonomy'],
				$query_vars['term']
			);
		}

		// Remove from tax_query if present.
		if ( ! empty( $query_vars['tax_query'] ) ) {
			// phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_tax_query
			$query_vars['tax_query'] = ProductCollectionUtils::remove_query_array( $query_vars['tax_query'], 'taxonomy', $taxonomy );
		}

		$counts = $container->get( FilterDataProvider::class )->with( $container->get( QueryClauses::class ) )->get_taxonomy_counts( $query_vars, $taxonomy );

		return $counts;
	}

	/**
	 * Get product taxonomies for the block.
	 *
	 * @return array
	 */
	private function get_taxonomies() {
		$container       = wc_get_container();
		$params_handler  = $container->get( \Automattic\WooCommerce\Internal\ProductFilters\Params::class );
		$taxonomy_params = $params_handler->get_param( 'taxonomy' );
		$taxonomy_data   = array();

		foreach ( array_keys( $taxonomy_params ) as $taxonomy_slug ) {
			$taxonomy = get_taxonomy( $taxonomy_slug );

			if ( ! $taxonomy ) {
				continue;
			}

			$taxonomy_data[] = array(
				'label' => $taxonomy->labels->singular_name,
				'name'  => $taxonomy->name,
			);
		}

		return $taxonomy_data;
	}

	/**
	 * Sort hierarchical terms recursively maintaining parent-child relationships.
	 *
	 * @param array  $terms           Hierarchical terms array with children.
	 * @param string $orderby         Sort field (name, count, menu_order).
	 * @param string $order           Sort direction (ASC, DESC).
	 * @param array  $taxonomy_counts Context-aware term counts.
	 * @return array Sorted hierarchical terms.
	 */
	private function sort_hierarchy_terms( $terms, $orderby, $order, $taxonomy_counts ) {
		foreach ( $terms as $term ) {
			if ( ! empty( $term['children'] ) ) {
				$term['children'] = $this->sort_terms_by_criteria( $term['children'], $orderby, $order, $taxonomy_counts );
			}//end if
		}//end foreach
		$sorted = $this->sort_terms_by_criteria( $terms, $orderby, $order, $taxonomy_counts );
		return $sorted;
	}

	/**
	 * Flatten hierarchical term tree into flat array maintaining depth-first order.
	 *
	 * @param array $terms  Hierarchical terms with children structure.
	 * @param array $result Reference to result array being built.
	 * @param array $visited_ids Reference to array tracking visited term IDs to prevent circular references.
	 * @param int   $depth Current recursion depth for bounds checking.
	 */
	private function flatten_terms_list( $terms, &$result, &$visited_ids = array(), $depth = 0 ) {
		/**
		 * This is the safeguard to prevent the memory limit issue. We choose 10 as it
		 * should cover most of the cases. Typical e-commerce stores have two or three
		 * levels of category. Extreme cases like Amazon has about 7 levels.
		 *
		 * @see https://github.com/woocommerce/woocommerce/pull/60142/files#r2250287050
		 */
		if ( $depth > 10 ) {
			return;
		}

		if ( ! is_array( $terms ) ) {
			return;
		}

		foreach ( $terms as $term ) {
			// Validate term structure.
			if ( ! is_array( $term ) || ! isset( $term['term_id'] ) ) {
				continue;
			}

			$term_id = $term['term_id'];

			// Prevent circular references.
			if ( isset( $visited_ids[ $term_id ] ) ) {
				continue;
			}

			$visited_ids[ $term_id ] = true;
			$result[ $term_id ]      = $term;

			if ( ! empty( $term['children'] ) && is_array( $term['children'] ) ) {
				$this->flatten_terms_list( $term['children'], $result, $visited_ids, $depth + 1 );
				unset( $result[ $term_id ]['children'] );
			}
		}//end foreach
	}

	/**
	 * Get taxonomy terms ordered hierarchically.
	 *
	 * @param string $taxonomy        Taxonomy slug.
	 * @param array  $taxonomy_counts Term counts with term_id as key.
	 * @param bool   $hide_empty      Whether to hide empty terms.
	 * @param string $orderby         Sort field for siblings (name, count, menu_order).
	 * @param string $order           Sort direction (ASC, DESC).
	 * @return array|\WP_Error Hierarchically ordered terms or error.
	 */
	private function get_hierarchical_terms( string $taxonomy, array $taxonomy_counts, bool $hide_empty, string $orderby, string $order ) {
		// Use TaxonomyHierarchyData for hierarchy operations.
		$container      = wc_get_container();
		$hierarchy_data = $container->get( TaxonomyHierarchyData::class )->get_hierarchy_map( $taxonomy );

		$sorted_term = $this->sort_hierarchy_terms( $hierarchy_data['tree'], $orderby, $order, $taxonomy_counts );

		$flat_list = array();
		$this->flatten_terms_list( $sorted_term, $flat_list );

		if ( ! $hide_empty ) {
			return $flat_list;
		}

		return array_filter(
			$flat_list,
			function ( $term ) use ( $taxonomy_counts ) {
				return ! empty( $taxonomy_counts[ $term['term_id'] ] );
			}
		);
	}

	/**
	 * Sort terms by the specified criteria (name, count, or menu_order).
	 *
	 * @param array  $terms           Array of term objects to sort.
	 * @param string $orderby         Sort field (name, count, menu_order).
	 * @param string $order           Sort direction (ASC, DESC).
	 * @param array  $taxonomy_counts Context-aware term counts.
	 * @return array Sorted terms.
	 */
	private function sort_terms_by_criteria( array $terms, string $orderby, string $order, array $taxonomy_counts ): array {
		$sort_order = 'DESC' === strtoupper( $order ) ? -1 : 1;

		usort(
			$terms,
			function ( $a, $b ) use ( $orderby, $sort_order, $taxonomy_counts ) {
				$a = (object) $a;
				$b = (object) $b;
				switch ( $orderby ) {
					case 'count':
						$count_a    = $taxonomy_counts[ $a->term_id ] ?? 0;
						$count_b    = $taxonomy_counts[ $b->term_id ] ?? 0;
						$comparison = $count_a <=> $count_b;
						break;

					case 'menu_order':
						$order_a    = $a->menu_order ?? 0;
						$order_b    = $b->menu_order ?? 0;
						$comparison = $order_a <=> $order_b;
						// Secondary sort by name when menu_order is equal.
						if ( 0 === $comparison ) {
							$comparison = strcasecmp( $a->name, $b->name );
						}
						break;

					case 'name':
					default:
						$comparison = strcasecmp( $a->name, $b->name );
						break;
				}//end switch

				return $comparison * $sort_order;
			}
		);

		return $terms;
	}
}
