<?php
/**
 * Base class for a grid entity (products, orders, coupons).
 *
 * @package CodeCraft\Gridsmith
 */

defined( 'ABSPATH' ) || exit;

/**
 * One kind of record the grid can list and edit.
 */
abstract class BDBE_Entity {

	/**
	 * Field definitions cache.
	 *
	 * @var array|null
	 */
	protected $fields = null;

	/**
	 * Entity key, e.g. "product".
	 *
	 * @return string
	 */
	abstract public function key();

	/**
	 * Plural label.
	 *
	 * @return string
	 */
	abstract public function label();

	/**
	 * Build the field definitions.
	 *
	 * @return array
	 */
	abstract protected function build_fields();

	/**
	 * Query one page of records.
	 *
	 * @param array $args Sanitised query args (page, per_page, orderby, order, filters).
	 * @return array { objects: object[], total: int }
	 */
	abstract public function query( array $args );

	/**
	 * Load one record.
	 *
	 * @param int $id ID.
	 * @return object|null
	 */
	abstract public function load( $id );

	/**
	 * Persist a record.
	 *
	 * @param object $object Record.
	 */
	abstract public function save( $object );

	/**
	 * Allowed filter keys and how to sanitise them.
	 *
	 * @return array key => 'key'|'text'|'bool'
	 */
	public function filter_keys() {
		return array( 'search' => 'text' );
	}

	/**
	 * Field definitions, filterable.
	 *
	 * @return array
	 */
	public function fields() {
		if ( null === $this->fields ) {
			$this->fields = (array) apply_filters( 'bdbe_' . $this->key() . '_fields', $this->build_fields(), $this );
		}
		return $this->fields;
	}

	/**
	 * One field definition.
	 *
	 * @param string $key Field key.
	 * @return array|null
	 */
	public function field( $key ) {
		$fields = $this->fields();
		return isset( $fields[ $key ] ) ? $fields[ $key ] : null;
	}

	/**
	 * Whether the current user can edit this record.
	 *
	 * @param object $object Record.
	 * @return bool
	 */
	public function can_edit( $object ) {
		unset( $object );
		return current_user_can( 'manage_woocommerce' );
	}

	/**
	 * Cross-field validation after values are set (before saving).
	 *
	 * @param object $object  Record with new values applied.
	 * @param array  $touched Field keys that changed.
	 * @return array field => error message.
	 */
	public function validate( $object, array $touched ) {
		unset( $object, $touched );
		return array();
	}

	/**
	 * Called once after a batch of records was saved.
	 *
	 * @param object[] $objects Saved records.
	 */
	public function after_save( array $objects ) {
		unset( $objects );
	}

	/**
	 * Row identity and links for the grid.
	 *
	 * @param object $object Record.
	 * @return array
	 */
	abstract protected function row_meta( $object );

	/**
	 * Row payload for the grid.
	 *
	 * @param object $object Record.
	 * @return array
	 */
	public function row( $object ) {
		$row = array_merge(
			array(
				'id'      => 0,
				'kind'    => $this->key(),
				'parent'  => 0,
				'title'   => '',
				'edit'    => '',
				'view'    => '',
				'cells'   => array(),
				'locked'  => array(),
				'display' => array(),
			),
			$this->row_meta( $object )
		);
		foreach ( $this->fields() as $key => $def ) {
			if ( isset( $def['column'] ) && false === $def['column'] ) {
				continue;
			}
			$value                = isset( $def['get'] ) && is_callable( $def['get'] ) ? call_user_func( $def['get'], $object ) : '';
			$row['cells'][ $key ] = null === $value ? '' : (string) $value;
			if ( ! BDBE_Fields::editable( $def, $object ) ) {
				$row['locked'][] = $key;
			}
			if ( isset( $def['display'] ) && is_callable( $def['display'] ) ) {
				$text = call_user_func( $def['display'], $object );
				if ( null !== $text && '' !== $text ) {
					$row['display'][ $key ] = (string) $text;
				}
			}
		}
		return $row;
	}

	/**
	 * Expand a page of objects into rows (Pro adds variation rows here).
	 *
	 * @param object[] $objects Records.
	 * @param array    $args    Query args.
	 * @return array Rows.
	 */
	public function rows( array $objects, array $args ) {
		$rows = array();
		foreach ( $objects as $object ) {
			$rows[] = $this->row( $object );
		}
		return (array) apply_filters( 'bdbe_' . $this->key() . '_rows', $rows, $objects, $args, $this );
	}

	/**
	 * IDs matching a filter (for bulk actions), oldest first.
	 *
	 * @param array $filters Sanitised filters.
	 * @return int[]
	 */
	public function matching_ids( array $filters ) {
		unset( $filters );
		return array();
	}
}