<?php
/**
 * Field helpers: sanitising and comparing cell values.
 *
 * @package CodeCraft\Gridsmith
 */

defined( 'ABSPATH' ) || exit;

/**
 * Static helpers shared by every entity.
 *
 * A field definition is an array with:
 *  - label    (string)  Column title.
 *  - type     (string)  text|textarea|price|int|select|date|terms|readonly|image.
 *  - options  (array)   value => label, for select fields.
 *  - column   (bool)    Show as a grid column (default true).
 *  - default  (bool)    Visible by default (default true).
 *  - sortable (string)  Orderby key understood by the entity, or empty.
 *  - width    (int)     Column width in px.
 *  - get      (callable) function( $object ): string.
 *  - set      (callable) function( $object, $value ): void|WP_Error.
 *  - editable (callable) function( $object ): bool. Optional.
 *  - display  (callable) function( $object ): string. Text shown when locked. Optional.
 */
class BDBE_Fields {

	/**
	 * Types that can never be edited.
	 *
	 * @var string[]
	 */
	const READONLY_TYPES = array( 'readonly', 'image' );

	/**
	 * Sanitise and validate one raw value for a field.
	 *
	 * @param array $def   Field definition.
	 * @param mixed $value Raw value from the request.
	 * @return string|WP_Error Clean value, or an error.
	 */
	public static function sanitize( array $def, $value ) {
		$type  = isset( $def['type'] ) ? $def['type'] : 'text';
		$value = is_scalar( $value ) ? trim( (string) $value ) : '';

		switch ( $type ) {
			case 'price':
				if ( '' === $value ) {
					return '';
				}
				$clean = wc_format_decimal( $value );
				if ( '' === $clean || ! is_numeric( $clean ) || (float) $clean < 0 ) {
					return new WP_Error( 'bdbe_price', __( 'Enter a price of 0 or more, e.g. 19.99.', 'gridsmith' ) );
				}
				return (string) $clean;

			case 'int':
				if ( '' === $value ) {
					return '';
				}
				if ( ! preg_match( '/^-?\d+$/', $value ) ) {
					return new WP_Error( 'bdbe_int', __( 'Enter a whole number.', 'gridsmith' ) );
				}
				return (string) (int) $value;

			case 'select':
				$options = isset( $def['options'] ) ? (array) $def['options'] : array();
				if ( ! array_key_exists( $value, $options ) ) {
					return new WP_Error( 'bdbe_select', __( 'Choose one of the listed values.', 'gridsmith' ) );
				}
				return $value;

			case 'date':
				if ( '' === $value ) {
					return '';
				}
				$parts = explode( '-', $value );
				if ( 3 !== count( $parts ) || ! checkdate( (int) $parts[1], (int) $parts[2], (int) $parts[0] ) ) {
					return new WP_Error( 'bdbe_date', __( 'Enter a date as YYYY-MM-DD.', 'gridsmith' ) );
				}
				return sprintf( '%04d-%02d-%02d', (int) $parts[0], (int) $parts[1], (int) $parts[2] );

			case 'textarea':
				return wp_kses_post( $value );

			case 'terms':
				$names = array_filter( array_map( 'trim', explode( ',', sanitize_text_field( $value ) ) ), 'strlen' );
				return implode( ', ', array_unique( $names ) );

			case 'readonly':
			case 'image':
				return new WP_Error( 'bdbe_readonly', __( 'This column is read-only.', 'gridsmith' ) );

			default:
				return sanitize_text_field( $value );
		}
	}

	/**
	 * Whether two stored values are the same for a field type.
	 *
	 * @param array  $def Field definition.
	 * @param string $a   First value.
	 * @param string $b   Second value.
	 * @return bool
	 */
	public static function same( array $def, $a, $b ) {
		$a = (string) $a;
		$b = (string) $b;
		if ( $a === $b ) {
			return true;
		}
		$type = isset( $def['type'] ) ? $def['type'] : 'text';
		if ( in_array( $type, array( 'price', 'int' ), true ) && '' !== $a && '' !== $b && is_numeric( $a ) && is_numeric( $b ) ) {
			return abs( (float) $a - (float) $b ) < 0.000001;
		}
		return false;
	}

	/**
	 * Whether a field may be edited on an object.
	 *
	 * @param array  $def    Field definition.
	 * @param object $object Object.
	 * @return bool
	 */
	public static function editable( array $def, $object ) {
		$type = isset( $def['type'] ) ? $def['type'] : 'text';
		if ( in_array( $type, self::READONLY_TYPES, true ) || empty( $def['set'] ) ) {
			return false;
		}
		if ( isset( $def['editable'] ) && is_callable( $def['editable'] ) ) {
			return (bool) call_user_func( $def['editable'], $object );
		}
		return true;
	}

	/**
	 * Column metadata sent to the browser (no callables).
	 *
	 * @param array $fields Field definitions keyed by field key.
	 * @return array
	 */
	public static function columns( array $fields ) {
		$out = array();
		foreach ( $fields as $key => $def ) {
			if ( isset( $def['column'] ) && false === $def['column'] ) {
				continue;
			}
			$type  = isset( $def['type'] ) ? $def['type'] : 'text';
			$out[] = array(
				'key'      => (string) $key,
				'label'    => isset( $def['label'] ) ? (string) $def['label'] : (string) $key,
				'type'     => $type,
				'options'  => 'select' === $type && isset( $def['options'] ) ? self::options_list( (array) $def['options'] ) : array(),
				'editable' => ! in_array( $type, self::READONLY_TYPES, true ) && ! empty( $def['set'] ),
				'default'  => ! isset( $def['default'] ) || (bool) $def['default'],
				'sortable' => isset( $def['sortable'] ) ? (string) $def['sortable'] : '',
				'width'    => isset( $def['width'] ) ? (int) $def['width'] : 0,
				'hint'     => isset( $def['hint'] ) ? (string) $def['hint'] : '',
			);
		}
		return $out;
	}

	/**
	 * Select options as an ordered list (keeps order in JSON).
	 *
	 * @param array $options value => label.
	 * @return array
	 */
	private static function options_list( array $options ) {
		$list = array();
		foreach ( $options as $value => $label ) {
			$list[] = array(
				'value' => (string) $value,
				'label' => (string) $label,
			);
		}
		return $list;
	}
}