<?php
/**
 * Validation of the advanced XML settings: attributes and repeated element names.
 *
 * @package FeedWeaver
 */

namespace FeedWeaver\Mapping;

defined( 'ABSPATH' ) || exit;

/**
 * Pure PHP. Every message names the row it is about so the editor and the preview can point at it.
 */
class Xml_Options_Validator {

	const MAX_ATTRIBUTES   = 50;
	const MAX_REPEAT_NAMES = 20;
	const MAX_STATIC       = 200;

	/**
	 * Element paths an attribute may attach to: the item element ('') and every mapping path
	 * together with its ancestors (a group such as "media" exists because "media/thumbnail" does).
	 *
	 * @param array $mappings Mappings.
	 * @return string[]
	 */
	public static function element_paths( array $mappings ): array {
		$paths = array( '' );
		foreach ( $mappings as $mapping ) {
			$path = isset( $mapping['path'] ) && is_string( $mapping['path'] ) ? trim( $mapping['path'] ) : '';
			if ( '' === $path ) {
				continue;
			}
			$segments = explode( '/', $path );
			$prefix   = array();
			foreach ( $segments as $segment ) {
				$prefix[] = $segment;
				$paths[]  = implode( '/', $prefix );
			}
		}
		return array_values( array_unique( $paths ) );
	}

	/**
	 * Validates attribute definitions.
	 *
	 * @param array    $attributes List of array{element:string,name:string,type:string,value:string}.
	 * @param array    $mappings   Mappings (for the element paths).
	 * @param string[] $prefixes   Declared namespace prefixes.
	 * @return string[]
	 */
	public static function validate_attributes( array $attributes, array $mappings, array $prefixes ): array {
		if ( count( $attributes ) > self::MAX_ATTRIBUTES ) {
			/* translators: %d: maximum number of attributes. */
			return array( sprintf( __( 'Define at most %d attributes.', 'feedweaver' ), self::MAX_ATTRIBUTES ) );
		}
		$errors = array();
		$paths  = self::element_paths( $mappings );
		$seen   = array();
		foreach ( array_values( $attributes ) as $i => $row ) {
			$n       = $i + 1;
			$element = isset( $row['element'] ) && is_string( $row['element'] ) ? $row['element'] : null;
			$name    = isset( $row['name'] ) ? $row['name'] : '';
			$type    = isset( $row['type'] ) ? $row['type'] : '';
			$value   = isset( $row['value'] ) ? $row['value'] : '';

			if ( null === $element || ! in_array( $element, $paths, true ) ) {
				/* translators: %d: attribute row number. */
				$errors[] = sprintf( __( 'Attribute %d: choose the element it belongs to from your field mappings (or the item element).', 'feedweaver' ), $n );
			}
			if ( ! Path_Validator::is_valid_attribute_name( $name, true ) ) {
				/* translators: %d: attribute row number. */
				$errors[] = sprintf( __( 'Attribute %d: the name must be letters, numbers, hyphens or underscores, start with a letter or underscore, and not start with "xml" (xml:lang is allowed).', 'feedweaver' ), $n );
			} else {
				$prefix = Path_Validator::prefix_of( $name );
				if ( null !== $prefix && 'xml' !== $prefix && ! in_array( $prefix, $prefixes, true ) ) {
					/* translators: 1: attribute row number, 2: prefix. */
					$errors[] = sprintf( __( 'Attribute %1$d: the namespace prefix "%2$s" is not declared under XML Namespaces.', 'feedweaver' ), $n, $prefix );
				}
				$key = ( null === $element ? '?' : $element ) . "\0" . $name;
				if ( isset( $seen[ $key ] ) ) {
					/* translators: 1: attribute row number, 2: attribute name. */
					$errors[] = sprintf( __( 'Attribute %1$d: "%2$s" is already set on the same element.', 'feedweaver' ), $n, $name );
				}
				$seen[ $key ] = true;
			}
			if ( 'static' === $type ) {
				if ( ! is_string( $value ) || strlen( $value ) > self::MAX_STATIC ) {
					/* translators: 1: attribute row number, 2: maximum length. */
					$errors[] = sprintf( __( 'Attribute %1$d: fixed text may be at most %2$d characters.', 'feedweaver' ), $n, self::MAX_STATIC );
				}
			} elseif ( 'source' === $type ) {
				if ( ! Source_Catalog::is_scalar_source( $value ) ) {
					/* translators: %d: attribute row number. */
					$errors[] = sprintf( __( 'Attribute %d: choose a WordPress field that holds a single value (not a list of terms).', 'feedweaver' ), $n );
				} elseif ( Source_Catalog::is_meta( $value ) ) {
					foreach ( Meta_Policy::check( (string) Source_Catalog::meta_key( $value ) ) as $reason ) {
						/* translators: 1: attribute row number, 2: reason. */
						$errors[] = sprintf( __( 'Attribute %1$d: %2$s', 'feedweaver' ), $n, $reason );
					}
				}
			} else {
				/* translators: %d: attribute row number. */
				$errors[] = sprintf( __( 'Attribute %d: choose fixed text or a WordPress field as the value.', 'feedweaver' ), $n );
			}
		}//end foreach
		return $errors;
	}

	/**
	 * Validates custom names for repeated (taxonomy) child elements.
	 *
	 * @param array    $repeat_names List of array{path:string,name:string}.
	 * @param array    $mappings     Mappings.
	 * @param string[] $prefixes     Declared prefixes.
	 * @return string[]
	 */
	public static function validate_repeat_names( array $repeat_names, array $mappings, array $prefixes ): array {
		if ( count( $repeat_names ) > self::MAX_REPEAT_NAMES ) {
			/* translators: %d: maximum. */
			return array( sprintf( __( 'Define at most %d repeated element names.', 'feedweaver' ), self::MAX_REPEAT_NAMES ) );
		}
		$taxonomy_paths = array();
		foreach ( $mappings as $mapping ) {
			if ( isset( $mapping['source'], $mapping['path'] ) && Source_Catalog::is_taxonomy( $mapping['source'] ) ) {
				$taxonomy_paths[] = trim( (string) $mapping['path'] );
			}
		}
		$errors = array();
		$seen   = array();
		foreach ( array_values( $repeat_names ) as $i => $row ) {
			$n    = $i + 1;
			$path = isset( $row['path'] ) && is_string( $row['path'] ) ? $row['path'] : '';
			$name = isset( $row['name'] ) ? $row['name'] : '';
			if ( ! in_array( $path, $taxonomy_paths, true ) ) {
				/* translators: %d: repeated element row number. */
				$errors[] = sprintf( __( 'Repeated element %d: choose one of your taxonomy fields.', 'feedweaver' ), $n );
			} elseif ( isset( $seen[ $path ] ) ) {
				/* translators: 1: repeated element row number, 2: path. */
				$errors[] = sprintf( __( 'Repeated element %1$d: "%2$s" already has a child element name.', 'feedweaver' ), $n, $path );
			}
			$seen[ $path ] = true;
			if ( ! Path_Validator::is_valid_name( $name, true ) ) {
				/* translators: %d: repeated element row number. */
				$errors[] = sprintf( __( 'Repeated element %d: the name must be letters, numbers, hyphens or underscores, start with a letter or underscore, and not start with "xml".', 'feedweaver' ), $n );
			} else {
				$prefix = Path_Validator::prefix_of( $name );
				if ( null !== $prefix && ! in_array( $prefix, $prefixes, true ) ) {
					/* translators: 1: repeated element row number, 2: prefix. */
					$errors[] = sprintf( __( 'Repeated element %1$d: the namespace prefix "%2$s" is not declared under XML Namespaces.', 'feedweaver' ), $n, $prefix );
				}
			}
		}//end foreach
		return $errors;
	}
}