<?php
/**
 * Quick stock.
 *
 * @package AdminPowerups
 */

namespace SmartWP\AdminPowerups\Modules\QuickStock;

use SmartWP\AdminPowerups\Admin\AdminPage;
use SmartWP\AdminPowerups\Admin\Lookup;
use SmartWP\AdminPowerups\Modules\AbstractModule;
use SmartWP\AdminPowerups\Support\Assets;
use SmartWP\AdminPowerups\Support\Cleanup;
use SmartWP\AdminPowerups\Support\Paging;
use WC_Product;
use WP_Error;
use WP_REST_Request;
use WP_REST_Server;

defined( 'ABSPATH' ) || exit;

/**
 * A Stock tab listing every product and variation with its stock, editable in place: type a
 * number and press Enter. Products that don't track stock show their status (editable) and can
 * start tracking from the row. Nothing runs outside the tab and its REST routes.
 *
 * @since 1.0.0
 */
class Module extends AbstractModule {

	/**
	 * Per-page choices.
	 */
	const PER_PAGE = array( 20, 50, 100, 200 );

	/**
	 * Sort columns.
	 */
	const SORTS = StockQuery::SORTS;

	/**
	 * Stock filters.
	 */
	const STOCK_FILTERS = StockQuery::STOCK_FILTERS;

	/**
	 * List query (shared by the tab and REST answers).
	 *
	 * @var StockQuery|null
	 */
	private $query = null;

	/**
	 * {@inheritDoc}
	 */
	public function id() {
		return 'quick-stock';
	}

	/**
	 * {@inheritDoc}
	 */
	public function title() {
		return __( 'Quick stock', 'admin-powerups-for-woocommerce' );
	}

	/**
	 * {@inheritDoc}
	 */
	public function description() {
		return __( 'See and change stock for every product and variation on one screen. Type a number and press Enter.', 'admin-powerups-for-woocommerce' );
	}

	/**
	 * {@inheritDoc}
	 */
	public function category() {
		return 'operations';
	}

	/**
	 * {@inheritDoc}
	 */
	public function location() {
		return __( 'Stock tab', 'admin-powerups-for-woocommerce' );
	}

	/**
	 * {@inheritDoc}
	 */
	public function icon() {
		return 'package';
	}

	/**
	 * {@inheritDoc} No settings.
	 */
	public function autoload_settings() {
		return false;
	}

	/**
	 * {@inheritDoc}
	 */
	public function unmet_requirement() {
		if ( 'yes' !== get_option( 'woocommerce_manage_stock' ) ) {
			return __( 'Needs stock management. Turn on “Enable stock management” in WooCommerce → Settings → Products → Inventory.', 'admin-powerups-for-woocommerce' );
		}
		return '';
	}

	/**
	 * {@inheritDoc}
	 *
	 * @since 1.0.0
	 * @return array<int, array<string, mixed>>
	 */
	public function data() {
		return array_merge(
			parent::data(),
			array(
				Cleanup::record( 'stock', __( 'Stock changes', 'admin-powerups-for-woocommerce' ), __( 'Quantities and statuses you change are saved on the products in WooCommerce. They stay when the power-up is off or removed.', 'admin-powerups-for-woocommerce' ) ),
				array(
					'id'          => 'edit-locks',
					'kind'        => 'cache',
					'label'       => __( 'Edit locks', 'admin-powerups-for-woocommerce' ),
					'description' => __( 'Short-lived rows that stop two saves of the same product overlapping. Only left behind if a request stopped half way.', 'admin-powerups-for-woocommerce' ),
					'count'       => array( StockEditor::class, 'count_locks' ),
					'delete'      => array( StockEditor::class, 'delete_locks' ),
				),
			)
		);
	}

	/**
	 * {@inheritDoc}
	 */
	public function boot() {
		add_action( 'rest_api_init', array( $this, 'register_routes' ) );
	}

	/**
	 * {@inheritDoc}
	 */
	public function views() {
		return array( 'stock' => __( 'Stock', 'admin-powerups-for-woocommerce' ) );
	}

	/**
	 * {@inheritDoc}
	 */
	public function shortcut() {
		return 'stock';
	}

	/**
	 * The list query.
	 *
	 * @since 1.0.0
	 * @return StockQuery
	 */
	public function query() {
		if ( null === $this->query ) {
			$this->query = new StockQuery();
		}
		return $this->query;
	}

	/**
	 * Stock tab URL.
	 *
	 * @since 1.0.0
	 * @param array<string, mixed> $args Query args (s, stock, type, cat, parent, orderby, order, paged, per_page).
	 * @return string
	 */
	public static function url( array $args = array() ) {
		return add_query_arg( array_filter( $args, static fn( $v ) => '' !== $v && null !== $v && 0 !== $v ), AdminPage::url( 'quick-stock', 'stock' ) );
	}

	/**
	 * Columns of the table.
	 *
	 * @since 1.0.0
	 * @return array<string, string> Key => label.
	 */
	public static function columns() {
		$columns = array(
			'product' => __( 'Product', 'admin-powerups-for-woocommerce' ),
			'sku'     => __( 'SKU', 'admin-powerups-for-woocommerce' ),
			'stock'   => __( 'Stock', 'admin-powerups-for-woocommerce' ),
			'status'  => __( 'Status', 'admin-powerups-for-woocommerce' ),
		);
		/**
		 * Filter the Quick stock columns. Draw an added column's cells with the
		 * `apwc_quick_stock_column` action.
		 *
		 * @since 1.0.0
		 * @param array<string, string> $columns Key => label.
		 */
		$filtered = (array) apply_filters( 'apwc_quick_stock_columns', $columns );
		$out      = array();
		foreach ( $filtered as $key => $label ) {
			if ( is_string( $key ) && is_string( $label ) ) {
				$out[ sanitize_key( $key ) ] = $label;
			}
		}
		return $out ? $out : $columns;
	}

	/**
	 * {@inheritDoc}
	 *
	 * @since 1.0.0
	 * @param string $view View ID.
	 */
	public function render_view( $view ) {
		// phpcs:disable WordPress.Security.NonceVerification.Recommended -- read-only screen filters.
		$get    = static fn( $key ) => isset( $_GET[ $key ] ) && is_string( $_GET[ $key ] ) ? sanitize_text_field( wp_unslash( $_GET[ $key ] ) ) : '';
		$num    = static fn( $key ) => max( 0, (int) $get( $key ) ); // Not absint(): "-3" must not mean 3.
		$types  = $this->type_choices();
		$per    = in_array( $num( 'per_page' ), self::PER_PAGE, true ) ? $num( 'per_page' ) : 50;
		$filter = array(
			's'        => $get( 's' ),
			'stock'    => in_array( $get( 'stock' ), self::STOCK_FILTERS, true ) ? $get( 'stock' ) : '',
			'type'     => isset( $types[ sanitize_key( $get( 'type' ) ) ] ) ? sanitize_key( $get( 'type' ) ) : '',
			'cat'      => $num( 'cat' ),
			'parent'   => $num( 'parent' ),
			'orderby'  => in_array( $get( 'orderby' ), self::SORTS, true ) ? $get( 'orderby' ) : 'name',
			'order'    => 'desc' === $get( 'order' ) ? 'desc' : 'asc',
			'paged'    => Paging::page( $get( 'paged' ), $per ),
			'per_page' => $per,
		);
		// phpcs:enable
		$query       = new StockQuery(); // Fresh per screen (type terms are memoized per instance).
		$this->query = $query;
		$total       = $query->count( $filter );
		$last        = max( 1, (int) ceil( $total / $filter['per_page'] ) );
		if ( $total > 0 && $filter['paged'] > $last ) {
			$filter['paged'] = $last; // Past the end (old link, fewer products): show the last page.
		}
		$rows       = $total > 0 ? $query->rows( $query->ids( $filter ) ) : array();
		$columns    = self::columns();
		$categories = $this->categories();
		$rebuilding = function_exists( 'wc_update_product_lookup_tables_is_running' ) && wc_update_product_lookup_tables_is_running();
		$parent     = $filter['parent'] ? get_post( $filter['parent'] ) : null;
		include __DIR__ . '/views/stock.php';
	}

	/**
	 * Product types offered in the filter.
	 *
	 * @since 1.0.0
	 * @return array<string, string>
	 */
	public function type_choices() {
		$types = Lookup::product_types();
		foreach ( array_merge( array( 'virtual', 'downloadable' ), StockQuery::excluded_types() ) as $drop ) {
			unset( $types[ $drop ] );
		}
		return array_map( 'strval', $types );
	}

	/**
	 * Product categories for the filter, parents first with children indented.
	 *
	 * @since 1.0.0
	 * @return array<int, array{id: int, name: string, depth: int}>
	 */
	public function categories() {
		$terms = array_slice( $this->query()->categories(), 0, 1000 ); // A longer list isn't usable as a dropdown.
		$ids   = array_flip( array_column( $terms, 'id' ) );
		$under = array();
		foreach ( $terms as $term ) {
			// A parent beyond the first 1,000: show the category at the top level.
			$under[ isset( $ids[ $term['parent'] ] ) ? $term['parent'] : 0 ][] = $term;
		}
		$out  = array();
		$seen = array();
		$walk = static function ( $parent_id, $depth ) use ( &$walk, &$out, &$seen, $under ) {
			foreach ( $under[ $parent_id ] ?? array() as $term ) {
				if ( isset( $seen[ $term['id'] ] ) ) {
					continue;
				}
				$seen[ $term['id'] ] = true;
				$out[]               = array(
					'id'    => $term['id'],
					'name'  => $term['name'],
					'depth' => $depth,
				);
				if ( $depth < 10 ) {
					$walk( $term['id'], $depth + 1 );
				}
			}
		};
		$walk( 0, 0 );
		return $out;
	}

	/**
	 * One row's HTML.
	 *
	 * @since 1.0.0
	 * @param array<string, mixed>       $row     Row from StockQuery::rows().
	 * @param array<string, string>|null $columns Columns (null = read them; pass them when drawing many rows).
	 * @return string Markup, for REST responses.
	 */
	public function row_html( array $row, $columns = null ) {
		ob_start();
		$this->render_row( $row, $columns );
		return (string) ob_get_clean();
	}

	/**
	 * Print one row's HTML.
	 *
	 * @since 1.0.0
	 * @param array<string, mixed>       $row     Row from StockQuery::rows().
	 * @param array<string, string>|null $columns Columns (null = read them; pass them when drawing many rows).
	 * @return void
	 */
	public function render_row( array $row, $columns = null ) {
		$columns = is_array( $columns ) ? $columns : self::columns();
		include __DIR__ . '/views/row.php';
	}

	/**
	 * A product's row HTML, read fresh ('' when it isn't listed any more).
	 *
	 * @since 1.0.0
	 * @param int $id Product or variation ID.
	 * @return string
	 */
	public function row_html_for( $id ) {
		// A fresh query: types and categories are memoized per instance, and a save can add a term.
		$rows = ( new StockQuery() )->rows( array( (int) $id ) );
		return $rows ? $this->row_html( $rows[0] ) : '';
	}

	/**
	 * {@inheritDoc}
	 *
	 * @since 1.0.0
	 * @param string $view View ID.
	 */
	public function enqueue_view_assets( $view ) {
		wp_enqueue_script( 'apwc-quick-stock', Assets::url( 'assets/js/quick-stock.js' ), array( 'wp-api-fetch', 'wp-i18n' ), Assets::ver( 'assets/js/quick-stock.js' ), true );
		wp_set_script_translations( 'apwc-quick-stock', 'admin-powerups-for-woocommerce' );
	}

	/* ------------------------------------------------------------------ REST */

	/**
	 * REST routes.
	 *
	 * @since 1.0.0
	 * @return void
	 */
	public function register_routes() {
		$routes = array(
			'stock'  => array(
				'callback' => array( $this, 'rest_stock' ),
				'args'     => array(
					'quantity' => array( 'required' => true ),
					'expected' => array( 'required' => true ),
				),
			),
			'status' => array(
				'callback' => array( $this, 'rest_status' ),
				'args'     => array(
					'status'   => array(
						'required' => true,
						'type'     => 'string',
					),
					'expected' => array(
						'type'    => 'string',
						'default' => '',
					),
				),
			),
			'manage' => array(
				'callback' => array( $this, 'rest_manage' ),
				'args'     => array(
					'quantity' => array( 'required' => true ),
				),
			),
		);
		foreach ( $routes as $path => $route ) {
			register_rest_route(
				'apwc/v1',
				'/quick-stock/(?P<id>\d+)/' . $path,
				array(
					'methods'             => WP_REST_Server::CREATABLE,
					'callback'            => $route['callback'],
					'permission_callback' => array( $this, 'can_use' ),
					'args'                => $route['args'],
				)
			);
		}
	}

	/**
	 * Who may use the routes at all (each product is checked again in StockEditor).
	 *
	 * @since 1.0.0
	 * @return bool
	 */
	public function can_use() {
		return current_user_can( 'manage_woocommerce' ) && current_user_can( 'edit_products' );
	}

	/**
	 * The editor.
	 *
	 * @since 1.0.0
	 * @return StockEditor
	 */
	private function editor() {
		return new StockEditor( fn( $id ) => $this->row_html_for( (int) $id ) );
	}

	/**
	 * POST /quick-stock/{id}/stock.
	 *
	 * @since 1.0.0
	 * @param WP_REST_Request $request Request.
	 * @return \WP_REST_Response|WP_Error
	 */
	public function rest_stock( WP_REST_Request $request ) {
		$editor = $this->editor();
		$result = $editor->set_quantity( (int) $request['id'], $request['quantity'], $request['expected'] );
		if ( is_wp_error( $result ) ) {
			return $result;
		}
		$name = $this->name( $result['product'] );
		if ( ! $result['changed'] ) {
			/* translators: %s: product name. */
			$message = sprintf( __( '%s: no change', 'admin-powerups-for-woocommerce' ), $name );
		} elseif ( abs( (float) $result['new'] - (float) $request['quantity'] ) > 1e-9 ) {
			/* translators: 1: product name, 2: stock before, 3: stock now. */
			$message = sprintf( __( '%1$s: %2$s → %3$s (another change came in while saving)', 'admin-powerups-for-woocommerce' ), $name, $editor->number( $result['old'] ), $editor->number( $result['new'] ) );
		} else {
			/* translators: 1: product name, 2: stock before, 3: stock now. */
			$message = sprintf( __( '%1$s: %2$s → %3$s', 'admin-powerups-for-woocommerce' ), $name, $editor->number( $result['old'] ), $editor->number( $result['new'] ) );
		}
		return $this->answer( $result, $message );
	}

	/**
	 * POST /quick-stock/{id}/status.
	 *
	 * @since 1.0.0
	 * @param WP_REST_Request $request Request.
	 * @return \WP_REST_Response|WP_Error
	 */
	public function rest_status( WP_REST_Request $request ) {
		$result = $this->editor()->set_status( (int) $request['id'], $request['status'], (string) $request['expected'] );
		if ( is_wp_error( $result ) ) {
			return $result;
		}
		$options = (array) wc_get_product_stock_status_options();
		$label   = static fn( $key ) => (string) ( $options[ $key ] ?? $key );
		$message = $result['changed']
			/* translators: 1: product name, 2: status before, 3: status now. */
			? sprintf( __( '%1$s: %2$s → %3$s', 'admin-powerups-for-woocommerce' ), $this->name( $result['product'] ), $label( $result['old'] ), $label( $result['new'] ) )
			/* translators: %s: product name. */
			: sprintf( __( '%s: no change', 'admin-powerups-for-woocommerce' ), $this->name( $result['product'] ) );
		return $this->answer( $result, $message );
	}

	/**
	 * POST /quick-stock/{id}/manage.
	 *
	 * @since 1.0.0
	 * @param WP_REST_Request $request Request.
	 * @return \WP_REST_Response|WP_Error
	 */
	public function rest_manage( WP_REST_Request $request ) {
		$editor = $this->editor();
		$result = $editor->start_tracking( (int) $request['id'], $request['quantity'] );
		if ( is_wp_error( $result ) ) {
			return $result;
		}
		/* translators: 1: product name, 2: stock amount. */
		$message = sprintf( __( '%1$s: tracking stock, %2$s in stock', 'admin-powerups-for-woocommerce' ), $this->name( $result['product'] ), $editor->number( $result['new'] ) );
		return $this->answer( $result, $message );
	}

	/**
	 * Success answer: the redrawn row (and its parent's, for a variation).
	 *
	 * @since 1.0.0
	 * @param array<string, mixed> $result  Editor result.
	 * @param string               $message Plain text.
	 * @return \WP_REST_Response
	 */
	private function answer( array $result, $message ) {
		$product = $result['product'];
		$parent  = $product instanceof WC_Product && $product->is_type( 'variation' ) ? $product->get_parent_id() : 0;
		$html    = $product instanceof WC_Product ? $this->row_html_for( $product->get_id() ) : '';
		return rest_ensure_response(
			array(
				'row_html'    => $html,
				'parent_html' => $parent ? $this->row_html_for( $parent ) : null,
				'message'     => $message,
				'old'         => $result['old'],
				'new'         => $result['new'],
				'changed'     => (bool) $result['changed'],
			)
		);
	}

	/**
	 * Product name for messages (plain text; the page shows it with textContent).
	 *
	 * @since 1.0.0
	 * @param WC_Product|null $product Product.
	 * @return string
	 */
	private function name( $product ) {
		return $product instanceof WC_Product ? wp_specialchars_decode( (string) $product->get_name(), ENT_QUOTES ) : '';
	}
}