<?php
/**
 * Turns the attribute rules and a product's values into the marketplace attribute list, and reports what is missing.
 * Pure PHP: the caller supplies the product's values.
 *
 * @package Tidelist
 */

namespace Tidelist\Mapping;

use Tidelist\Support\Text;

/**
 * Attribute resolver.
 */
final class AttributeResolver {

	/**
	 * Resolves the attributes of a category for one product.
	 *
	 * @param array    $definitions Marketplace attribute definitions of the category (code, label, validation, values).
	 * @param array    $rules       Attribute code => AttributeRule.
	 * @param callable $values      callable( AttributeRule $rule ): string[] — the product's values for a WC_ATTRIBUTE or FIELD rule.
	 * @param array    $ask         Attribute code => value chosen for this product (for ASK rules).
	 * @param string[] $skip_codes  Attribute codes handled elsewhere (they are neither sent nor reported here).
	 * @param string   $channel_label Marketplace name used in the messages.
	 * @return array{attributes:array, errors:array, warnings:array}
	 */
	public static function resolve( array $definitions, array $rules, callable $values, array $ask = array(), array $skip_codes = array(), string $channel_label = '' ): array {
		$out = array(
			'attributes' => array(),
			'errors'     => array(),
			'warnings'   => array(),
		);
		foreach ( $definitions as $definition ) {
			$code = (string) ( $definition['code'] ?? '' );
			if ( '' === $code || in_array( $code, $skip_codes, true ) ) {
				continue;
			}
			$label    = (string) ( $definition['label'] ?? $code );
			$validate = (array) ( $definition['validation'] ?? array() );
			$required = ! empty( $validate['required'] );
			$multiple = ! empty( $validate['allow_multiple_values'] );
			$allowed  = (array) ( $definition['values'] ?? array() );
			$rule     = $rules[ $code ] ?? null;

			if ( null === $rule || AttributeRule::SKIP === $rule->type ) {
				if ( $required ) {
					$out['errors'][] = array(
						'code' => 'attribute_missing',
						'text' => sprintf( 'Required {channel} field "%s" has no source. Set it in the attribute mapping.', $label ),
						'args' => array( $label ),
					);
				}
				continue;
			}

			$raw = self::raw_values( $rule, $values, $ask, $code );
			if ( ! $raw ) {
				if ( $required ) {
					$out['errors'][] = array(
						'code' => 'attribute_missing',
						'text' => sprintf( 'Required {channel} field "%s" has no value for this product.', $label ),
						'args' => array( $label ),
					);
				}
				continue;
			}

			$mapped   = array();
			$unmapped = array();
			foreach ( $raw as $item ) {
				$value = self::map_value( $item, $rule, $allowed, $validate );
				if ( null === $value ) {
					$unmapped[] = $item;
				} else {
					$mapped[ $value ] = true;
				}
			}
			$mapped = array_map( 'strval', array_keys( $mapped ) );

			if ( ! $mapped ) {
				$text = sprintf( 'The value "%1$s" of "%2$s" is not in the {channel} list; map it in the attribute mapping.', implode( ', ', $unmapped ), $label );
				if ( $required ) {
					$out['errors'][] = array(
						'code' => 'attribute_unmapped',
						'text' => $text,
						'args' => array( $label, implode( ', ', $unmapped ) ),
					);
				} else {
					$out['warnings'][] = array(
						'code' => 'attribute_unmapped',
						'text' => $text,
						'args' => array( $label, implode( ', ', $unmapped ) ),
					);
				}
				continue;
			}
			if ( $unmapped ) {
				$out['warnings'][] = array(
					'code' => 'attribute_unmapped',
					'text' => sprintf( 'The value "%1$s" of "%2$s" is not in the {channel} list and was left out.', implode( ', ', $unmapped ), $label ),
					'args' => array( $label, implode( ', ', $unmapped ) ),
				);
			}
			if ( $multiple ) {
				$out['attributes'][] = array(
					'code'   => $code,
					'values' => $mapped,
				);
			} else {
				if ( count( $mapped ) > 1 ) {
					$out['warnings'][] = array(
						'code' => 'attribute_many',
						'text' => sprintf( '"%s" takes one value; the first was used.', $label ),
					);
				}
				$out['attributes'][] = array(
					'code'  => $code,
					'value' => $mapped[0],
				);
			}
		}
		if ( '' !== $channel_label ) {
			foreach ( array( 'errors', 'warnings' ) as $kind ) {
				foreach ( $out[ $kind ] as $i => $entry ) {
					$out[ $kind ][ $i ]['text'] = Text::channel( $entry['text'], $channel_label );
				}
			}
		}
		return $out;
	}

	/**
	 * The product's raw values for a rule.
	 *
	 * @param AttributeRule $rule   Rule.
	 * @param callable      $values Value callback.
	 * @param array         $ask    Per-product choices.
	 * @param string        $code   Attribute code.
	 * @return string[]
	 */
	private static function raw_values( AttributeRule $rule, callable $values, array $ask, string $code ): array {
		switch ( $rule->type ) {
			case AttributeRule::FIXED:
				$list = array( $rule->fixed );
				break;
			case AttributeRule::ASK:
				$list = isset( $ask[ $code ] ) ? (array) $ask[ $code ] : array();
				break;
			default:
				$list = (array) call_user_func( $values, $rule );
		}
		$out = array();
		foreach ( $list as $item ) {
			$item = trim( (string) $item );
			if ( '' !== $item ) {
				$out[] = $item;
			}
		}
		return array_values( array_unique( $out ) );
	}

	/**
	 * One shop value to a marketplace value, or null.
	 *
	 * @param string        $item     Shop value.
	 * @param AttributeRule $rule     Rule.
	 * @param array         $allowed  Allowed values.
	 * @param array         $validate Validation info of the attribute.
	 */
	private static function map_value( string $item, AttributeRule $rule, array $allowed, array $validate ): ?string {
		if ( ! $allowed ) {
			// Free input (a number or text).
			if ( ! empty( $validate['numeric'] ) ) {
				$number = str_replace( ',', '.', $item );
				if ( ! is_numeric( $number ) ) {
					return null;
				}
				$number = (float) $number;
				if ( ( isset( $validate['min'] ) && null !== $validate['min'] && $number < (float) $validate['min'] ) || ( isset( $validate['max'] ) && null !== $validate['max'] && $number > (float) $validate['max'] ) ) {
					return null;
				}
				return (string) $number;
			}
			return $item;
		}
		$key = Normalizer::key( $item );
		if ( isset( $rule->values[ $key ] ) ) {
			$code = $rule->values[ $key ];
			foreach ( $allowed as $value ) {
				if ( (string) ( $value['code'] ?? '' ) === $code ) {
					return $code;
				}
			}
			return null; // The saved choice is no longer offered by the marketplace.
		}
		foreach ( $allowed as $value ) {
			if ( (string) ( $value['code'] ?? '' ) === $item ) {
				return $item;
			}
		}
		return ValueSuggester::suggest( $item, $allowed );
	}
}