<?php
/**
 * Search sources for the `search` settings field (AJAX multi-select).
 *
 * @package AdminPowerups
 */

namespace SmartWP\AdminPowerups\Admin;

use WC_Data_Store;

defined( 'ABSPATH' ) || exit;

/**
 * Looks up products, categories and add-on sources by text, and resolves saved IDs to labels.
 *
 * Add a source with the `apwc_lookup_sources` filter: key => [ 'search' => callable( $term, $limit ),
 * 'labels' => callable( int[] $ids ) ]. Both return a list of [ id, label, meta ].
 *
 * @since 1.0.0
 */
final class Lookup {

	/**
	 * Max results per search.
	 */
	const LIMIT = 20;

	/**
	 * Registered sources.
	 *
	 * @since 1.0.0
	 * @return array<string, array{search: callable, labels: callable}>
	 */
	public static function sources() {
		/**
		 * Filter the lookup sources available to `search` settings fields.
		 *
		 * @since 1.0.0
		 * @param array $sources Key => [ search => callable, labels => callable, string? => bool,
		 *                       capability? => string (extra capability `GET apwc/v1/lookup` needs) ].
		 */
		return (array) apply_filters(
			'apwc_lookup_sources',
			array(
				'products'         => array(
					'search' => array( __CLASS__, 'search_products' ),
					'labels' => array( __CLASS__, 'label_products' ),
				),
				'product_cat'      => array(
					'search' => static fn( $term, $limit ) => self::search_terms( 'product_cat', $term, $limit ),
					'labels' => static fn( $ids ) => self::label_terms( 'product_cat', $ids ),
				),
				'product_tag'      => array(
					'search' => static fn( $term, $limit ) => self::search_terms( 'product_tag', $term, $limit ),
					'labels' => static fn( $ids ) => self::label_terms( 'product_tag', $ids ),
				),
				'shipping_classes' => array(
					'search' => static fn( $term, $limit ) => self::search_terms( 'product_shipping_class', $term, $limit ),
					'labels' => static fn( $ids ) => self::label_terms( 'product_shipping_class', $ids ),
				),
				'users'            => array(
					'search' => array( __CLASS__, 'search_users' ),
					'labels' => array( __CLASS__, 'label_users' ),
				),
				// Text keys: fixed lists searched in memory.
				'countries'        => self::fixed( array( __CLASS__, 'countries' ) ),
				'states'           => self::fixed( array( __CLASS__, 'states' ) ),
				'roles'            => self::fixed( array( __CLASS__, 'roles' ) ),
				'gateways'         => self::fixed( array( __CLASS__, 'gateways' ) ),
				'shipping_methods' => self::fixed( array( __CLASS__, 'shipping_methods' ) ),
				'product_types'    => self::fixed( array( __CLASS__, 'product_types' ) ),
			)
		);
	}

	/**
	 * Search a source.
	 *
	 * @since 1.0.0
	 * @param string $source Source key.
	 * @param string $term   Search text ('' = first results).
	 * @return array<int, array{id: int|string, label: string, meta: string}>
	 */
	public static function search( $source, $term ) {
		$sources = self::sources();
		if ( ! isset( $sources[ $source ]['search'] ) || ! is_callable( $sources[ $source ]['search'] ) ) {
			return array();
		}
		return array_values( (array) call_user_func( $sources[ $source ]['search'], (string) $term, self::LIMIT ) );
	}

	/**
	 * Labels for saved IDs, in the given order; unknown IDs are dropped.
	 *
	 * @since 1.0.0
	 * @param string            $source Source key.
	 * @param array<int|string> $ids    IDs.
	 * @return array<int, array{id: int|string, label: string, meta: string}>
	 */
	public static function labels( $source, array $ids ) {
		$ids     = self::clean_ids( $source, $ids );
		$sources = self::sources();
		if ( ! $ids || ! isset( $sources[ $source ]['labels'] ) || ! is_callable( $sources[ $source ]['labels'] ) ) {
			return array();
		}
		$found = array();
		foreach ( (array) call_user_func( $sources[ $source ]['labels'], $ids ) as $item ) {
			$found[ (string) $item['id'] ] = $item;
		}
		$ordered = array();
		foreach ( $ids as $id ) {
			if ( isset( $found[ (string) $id ] ) ) {
				$ordered[] = $found[ (string) $id ];
			}
		}
		return $ordered;
	}

	/**
	 * IDs that exist in the source.
	 *
	 * @since 1.0.0
	 * @param string            $source Source key.
	 * @param array<int|string> $ids    IDs.
	 * @return array<int, int|string>
	 */
	public static function existing( $source, array $ids ) {
		$string = ! empty( self::sources()[ $source ]['string'] );
		return array_map( static fn( $item ) => $string ? (string) $item['id'] : (int) $item['id'], self::labels( $source, $ids ) );
	}

	/**
	 * Clean IDs for a source: numbers, or text keys for fixed lists.
	 *
	 * @since 1.0.0
	 * @param string       $source Source key.
	 * @param array<mixed> $ids    Raw IDs.
	 * @return array<int, int|string>
	 */
	public static function clean_ids( $source, array $ids ) {
		if ( ! empty( self::sources()[ $source ]['string'] ) ) {
			return array_values( array_unique( array_filter( array_map( static fn( $id ) => sanitize_text_field( (string) $id ), $ids ), static fn( $id ) => '' !== $id ) ) );
		}
		return array_values( array_unique( array_filter( array_map( 'absint', $ids ) ) ) );
	}

	/**
	 * A source over a fixed key => label list (searched in memory, text keys).
	 *
	 * @since 1.0.0
	 * @param callable $options Returns key => label.
	 * @return array{string: true, search: callable, labels: callable}
	 */
	public static function fixed( callable $options ) {
		return array(
			'string' => true,
			'search' => static function ( $term, $limit ) use ( $options ) {
				$term  = strtolower( trim( (string) $term ) );
				$ranks = array( array(), array(), array() ); // Exact, starts with, contains.
				foreach ( (array) call_user_func( $options ) as $key => $label ) {
					$name = strtolower( (string) $label );
					$code = strtolower( (string) $key );
					if ( '' === $term || $name === $term || $code === $term ) {
						$rank = 0;
					} elseif ( 0 === strpos( $name, $term ) ) {
						$rank = 1;
					} elseif ( false !== strpos( $name . ' ' . $code, $term ) ) {
						$rank = 2;
					} else {
						continue;
					}
					$ranks[ $rank ][] = array(
						'id'    => (string) $key,
						'label' => (string) $label,
						'meta'  => (string) $key,
					);
				}
				return array_slice( array_merge( ...$ranks ), 0, $limit );
			},
			'labels' => static function ( $ids ) use ( $options ) {
				$all = (array) call_user_func( $options );
				$out = array();
				foreach ( $ids as $id ) {
					if ( isset( $all[ $id ] ) ) {
						$out[] = array(
							'id'    => (string) $id,
							'label' => (string) $all[ $id ],
							'meta'  => (string) $id,
						);
					}
				}
				return $out;
			},
		);
	}

	/**
	 * Countries.
	 *
	 * @since 1.0.0
	 * @return array<string, string>
	 */
	public static function countries() {
		return function_exists( 'WC' ) ? (array) WC()->countries->get_countries() : array();
	}

	/**
	 * States as "CC:ST" => "State, Country".
	 *
	 * @since 1.0.0
	 * @return array<string, string>
	 */
	public static function states() {
		if ( ! function_exists( 'WC' ) ) {
			return array();
		}
		$countries = WC()->countries->get_countries();
		$out       = array();
		foreach ( (array) WC()->countries->get_states() as $cc => $states ) {
			foreach ( (array) $states as $code => $name ) {
				$out[ $cc . ':' . $code ] = html_entity_decode( $name ) . ', ' . ( $countries[ $cc ] ?? $cc );
			}
		}
		return $out;
	}

	/**
	 * Roles, plus "guest" for shoppers without an account on this site (logged out, or no role here).
	 *
	 * @since 1.0.0
	 * @return array<string, string>
	 */
	public static function roles() {
		$roles = array( 'guest' => __( 'Guest (no account on this site)', 'admin-powerups-for-woocommerce' ) );
		foreach ( wp_roles()->get_names() as $key => $name ) {
			$roles[ $key ] = translate_user_role( $name );
		}
		return $roles;
	}

	/**
	 * Payment gateways.
	 *
	 * @since 1.0.0
	 * @return array<string, string>
	 */
	public static function gateways() {
		$out = array();
		if ( function_exists( 'WC' ) ) {
			foreach ( WC()->payment_gateways()->payment_gateways() as $id => $gateway ) {
				$title      = wp_strip_all_tags( (string) ( $gateway->get_method_title() ? $gateway->get_method_title() : $gateway->get_title() ) );
				$out[ $id ] = 'yes' === $gateway->enabled ? $title : sprintf( /* translators: %s: payment method. */ __( '%s (off)', 'admin-powerups-for-woocommerce' ), $title );
			}
		}
		return $out;
	}

	/**
	 * Shipping methods: each type ("any Flat rate") and each method in each zone ("flat_rate:3").
	 *
	 * @since 1.0.0
	 * @return array<string, string>
	 */
	public static function shipping_methods() {
		if ( ! function_exists( 'WC' ) || ! class_exists( '\WC_Shipping_Zones' ) ) {
			return array();
		}
		$out = array();
		foreach ( WC()->shipping()->get_shipping_methods() as $id => $method ) {
			/* translators: %s: shipping method type, e.g. "Flat rate". */
			$out[ $id ] = sprintf( __( 'Any %s', 'admin-powerups-for-woocommerce' ), $method->get_method_title() );
		}
		$zones   = \WC_Shipping_Zones::get_zones();
		$zones[] = array(
			'zone_name'        => __( 'Rest of the world', 'admin-powerups-for-woocommerce' ),
			'shipping_methods' => ( new \WC_Shipping_Zone( 0 ) )->get_shipping_methods(),
		);
		foreach ( $zones as $zone ) {
			foreach ( (array) $zone['shipping_methods'] as $method ) {
				$out[ $method->id . ':' . $method->instance_id ] = $method->get_title() . ' · ' . $zone['zone_name'];
			}
		}
		return $out;
	}

	/**
	 * Product types and flags.
	 *
	 * @since 1.0.0
	 * @return array<string, string>
	 */
	public static function product_types() {
		$types = function_exists( 'wc_get_product_types' ) ? (array) wc_get_product_types() : array();
		return $types + array(
			'virtual'      => __( 'Virtual', 'admin-powerups-for-woocommerce' ),
			'downloadable' => __( 'Downloadable', 'admin-powerups-for-woocommerce' ),
		);
	}

	/**
	 * Users by name, email or login.
	 *
	 * @since 1.0.0
	 * @param string $term  Text.
	 * @param int    $limit Max.
	 * @return array<int, array{id: int, label: string, meta: string}>
	 */
	public static function search_users( $term, $limit ) {
		$args = array(
			'number'  => $limit,
			'fields'  => array( 'ID', 'display_name', 'user_email' ),
			'orderby' => 'display_name',
		);
		if ( '' !== trim( (string) $term ) ) {
			$args['search']         = '*' . trim( (string) $term ) . '*';
			$args['search_columns'] = array( 'user_login', 'user_email', 'display_name' );
		}
		return array_map(
			static fn( $u ) => array(
				'id'    => (int) $u->ID,
				'label' => (string) $u->display_name,
				'meta'  => (string) $u->user_email,
			),
			( new \WP_User_Query( $args ) )->get_results()
		);
	}

	/**
	 * Users by ID.
	 *
	 * @since 1.0.0
	 * @param int[] $ids IDs.
	 * @return array<int, array{id: int, label: string, meta: string}>
	 */
	public static function label_users( array $ids ) {
		return array_map(
			static fn( $u ) => array(
				'id'    => (int) $u->ID,
				'label' => (string) $u->display_name,
				'meta'  => (string) $u->user_email,
			),
			get_users(
				array(
					'include' => $ids,
					'fields'  => array( 'ID', 'display_name', 'user_email' ),
				)
			)
		);
	}

	/**
	 * Products and variations by name, SKU or ID.
	 *
	 * @since 1.0.0
	 * @param string $term  Text.
	 * @param int    $limit Max.
	 * @return array<int, array{id: int, label: string, meta: string}>
	 */
	public static function search_products( $term, $limit ) {
		$term = trim( $term );
		if ( '' === $term ) {
			$ids = wc_get_products(
				array(
					'limit'   => $limit,
					'return'  => 'ids',
					'orderby' => 'title',
					'order'   => 'ASC',
					'status'  => array( 'publish', 'private', 'draft' ),
				)
			);
		} else {
			// WC_Data_Store forwards search_products() to the product data store through __call().
			$ids = (array) call_user_func( array( WC_Data_Store::load( 'product' ), 'search_products' ), $term, '', true, true, $limit );
			if ( ctype_digit( $term ) && wc_get_product( (int) $term ) ) {
				array_unshift( $ids, (int) $term );
			}
		}
		return self::label_products( array_slice( array_values( array_unique( array_filter( array_map( 'absint', $ids ) ) ) ), 0, $limit ) );
	}

	/**
	 * Product labels: "Name – attributes", meta "SKU · #ID".
	 *
	 * @since 1.0.0
	 * @param int[] $ids IDs.
	 * @return array<int, array{id: int, label: string, meta: string}>
	 */
	public static function label_products( array $ids ) {
		$items = array();
		foreach ( $ids as $id ) {
			$product = wc_get_product( $id );
			if ( ! $product ) {
				continue;
			}
			$meta    = array_filter( array( $product->get_sku(), '#' . $product->get_id() ) );
			$items[] = array(
				'id'    => $product->get_id(),
				'label' => wp_strip_all_tags( $product->get_name() ),
				'meta'  => implode( ' · ', $meta ),
			);
		}
		return $items;
	}

	/**
	 * Terms by name, with their parent path.
	 *
	 * @since 1.0.0
	 * @param string $taxonomy Taxonomy.
	 * @param string $term     Text.
	 * @param int    $limit    Max.
	 * @return array<int, array{id: int, label: string, meta: string}>
	 */
	public static function search_terms( $taxonomy, $term, $limit ) {
		$terms = get_terms(
			array(
				'taxonomy'   => $taxonomy,
				'search'     => trim( $term ),
				'number'     => $limit,
				'hide_empty' => false,
				'orderby'    => 'name',
			)
		);
		return is_wp_error( $terms ) ? array() : array_map( array( __CLASS__, 'term_item' ), $terms );
	}

	/**
	 * Term labels.
	 *
	 * @since 1.0.0
	 * @param string $taxonomy Taxonomy.
	 * @param int[]  $ids      IDs.
	 * @return array<int, array{id: int, label: string, meta: string}>
	 */
	public static function label_terms( $taxonomy, array $ids ) {
		$terms = get_terms(
			array(
				'taxonomy'   => $taxonomy,
				'include'    => $ids,
				'hide_empty' => false,
			)
		);
		return is_wp_error( $terms ) ? array() : array_map( array( __CLASS__, 'term_item' ), $terms );
	}

	/**
	 * Item for a term: label "Parent › Child", meta "N products".
	 *
	 * @since 1.0.0
	 * @param \WP_Term $term Term.
	 * @return array{id: int, label: string, meta: string}
	 */
	private static function term_item( $term ) {
		$path = array();
		foreach ( array_reverse( get_ancestors( $term->term_id, $term->taxonomy, 'taxonomy' ) ) as $ancestor_id ) {
			$ancestor = get_term( $ancestor_id, $term->taxonomy );
			if ( $ancestor && ! is_wp_error( $ancestor ) ) {
				$path[] = $ancestor->name;
			}
		}
		$path[] = $term->name;
		return array(
			'id'    => (int) $term->term_id,
			'label' => implode( ' › ', $path ),
			/* translators: %d: number of products. */
			'meta'  => sprintf( _n( '%d product', '%d products', (int) $term->count, 'admin-powerups-for-woocommerce' ), (int) $term->count ),
		);
	}
}