<?php
/**
 * Parameter schema.
 *
 * @package Recast\WCS
 */

namespace Recast\WCS\Operation;

defined( 'ABSPATH' ) || exit;

/**
 * A small, UI-renderable schema for operation parameters with validation.
 *
 * Field: {key, type, label, help?, required?, default?, options? [{value,label}], min?, max?, step?,
 *         show_if? {key, value}}.
 * Types: select, multiselect, number, integer, text, bool, date (Y-m-d), datetime (Y-m-d H:i),
 *        product_ids, variation_ids, int_list, product (one product or variation ID; the app
 *        offers a variation choice for variable products, and "every variation" when the field
 *        has any_variation).
 */
final class ParamSchema {

	/**
	 * Field definitions.
	 *
	 * @var array<int, array<string, mixed>>
	 */
	private $fields = array();

	/**
	 * Adds a field.
	 *
	 * @param array<string, mixed> $field Definition.
	 * @return ParamSchema
	 */
	public function add( array $field ) {
		$field          = wp_parse_args(
			$field,
			array(
				'type'     => 'text',
				'label'    => $field['key'],
				'help'     => '',
				'required' => false,
				'default'  => null,
			)
		);
		$this->fields[] = $field;
		return $this;
	}

	/**
	 * Field definitions.
	 *
	 * @return array<int, array<string, mixed>>
	 */
	public function fields() {
		return $this->fields;
	}

	/**
	 * REST form.
	 *
	 * @return array{fields: array<int, array<string, mixed>>}
	 */
	public function to_array() {
		return array( 'fields' => $this->fields );
	}

	/**
	 * Validates and normalises params. Unknown keys are dropped.
	 *
	 * @param array<string, mixed> $params Raw params.
	 * @return ValidationResult
	 */
	public function validate( array $params ) {
		$result = new ValidationResult();
		$clean  = array();
		foreach ( $this->fields as $field ) {
			$key = $field['key'];
			if ( ! empty( $field['show_if'] ) ) {
				$dep       = $field['show_if'];
				$dep_value = isset( $clean[ $dep['key'] ] ) ? $clean[ $dep['key'] ] : ( isset( $params[ $dep['key'] ] ) ? $params[ $dep['key'] ] : null );
				$wanted    = (array) $dep['value'];
				if ( ! in_array( $dep_value, $wanted, true ) && ! in_array( (string) $dep_value, array_map( 'strval', $wanted ), true ) ) {
					continue; // Field not applicable; skip validation and omit.
				}
			}
			$present = array_key_exists( $key, $params ) && null !== $params[ $key ] && '' !== $params[ $key ];
			if ( ! $present ) {
				if ( $field['required'] && null === $field['default'] ) {
					$result->add_error( $key, sprintf( /* translators: %s: field label */ __( '%s is required.', 'recast-subscriptions' ), $field['label'] ) );
				} elseif ( null !== $field['default'] ) {
					$clean[ $key ] = $field['default'];
				}
				continue;
			}
			$value         = $params[ $key ];
			$error         = null;
			$clean[ $key ] = $this->normalise( $field, $value, $error );
			if ( null !== $error ) {
				$result->add_error( $key, $error );
				unset( $clean[ $key ] );
			}
		}
		$result->set_params( $clean );
		return $result;
	}

	/**
	 * Normalises one value per its type.
	 *
	 * @param array<string, mixed> $field Field.
	 * @param mixed                $value Raw value.
	 * @param string|null          $error Error message (by reference).
	 * @return mixed
	 */
	private function normalise( array $field, $value, &$error ) {
		$label = $field['label'];
		switch ( $field['type'] ) {
			case 'select':
				$allowed = wp_list_pluck( isset( $field['options'] ) ? $field['options'] : array(), 'value' );
				if ( ! in_array( $value, $allowed, true ) && ! in_array( (string) $value, array_map( 'strval', $allowed ), true ) ) {
					/* translators: %s: field label */
					$error = sprintf( __( '%s has an invalid choice.', 'recast-subscriptions' ), $label );
					return null;
				}
				return is_numeric( $value ) && in_array( $value + 0, $allowed, true ) ? $value + 0 : (string) $value;
			case 'multiselect':
				$allowed = array_map( 'strval', wp_list_pluck( isset( $field['options'] ) ? $field['options'] : array(), 'value' ) );
				$values  = array_map( 'strval', (array) $value );
				foreach ( $values as $v ) {
					if ( ! in_array( $v, $allowed, true ) ) {
						/* translators: %s: field label */
						$error = sprintf( __( '%s has an invalid choice.', 'recast-subscriptions' ), $label );
						return null;
					}
				}
				return array_values( array_unique( $values ) );
			case 'number':
			case 'integer':
				if ( ! is_numeric( $value ) ) {
					/* translators: %s: field label */
					$error = sprintf( __( '%s must be a number.', 'recast-subscriptions' ), $label );
					return null;
				}
				$number = 'integer' === $field['type'] ? (int) $value : (float) $value;
				if ( isset( $field['min'] ) && $number < $field['min'] ) {
					/* translators: 1: field label, 2: minimum */
					$error = sprintf( __( '%1$s must be at least %2$s.', 'recast-subscriptions' ), $label, $field['min'] );
					return null;
				}
				if ( isset( $field['max'] ) && $number > $field['max'] ) {
					/* translators: 1: field label, 2: maximum */
					$error = sprintf( __( '%1$s must be at most %2$s.', 'recast-subscriptions' ), $label, $field['max'] );
					return null;
				}
				return $number;
			case 'bool':
				return in_array( $value, array( true, 1, '1', 'true', 'yes', 'on' ), true );
			case 'date':
				$dt = is_string( $value ) ? \DateTimeImmutable::createFromFormat( '!Y-m-d', $value ) : false;
				if ( ! $dt || $dt->format( 'Y-m-d' ) !== $value ) {
					/* translators: %s: field label */
					$error = sprintf( __( '%s must be a date (YYYY-MM-DD).', 'recast-subscriptions' ), $label );
					return null;
				}
				return $value;
			case 'datetime':
				$dt = is_string( $value ) ? \DateTimeImmutable::createFromFormat( 'Y-m-d H:i', $value ) : false;
				if ( ! $dt || $dt->format( 'Y-m-d H:i' ) !== $value ) {
					/* translators: %s: field label */
					$error = sprintf( __( '%s must be a date and time (YYYY-MM-DD HH:MM).', 'recast-subscriptions' ), $label );
					return null;
				}
				return $value;
			case 'product':
				if ( ! is_numeric( $value ) || (int) $value <= 0 ) {
					/* translators: %s: field label */
					$error = sprintf( __( '%s must be a product.', 'recast-subscriptions' ), $label );
					return null;
				}
				return (int) $value;
			case 'product_ids':
			case 'variation_ids':
			case 'int_list':
				$ids = array();
				foreach ( (array) $value as $id ) {
					if ( ! is_numeric( $id ) || (int) $id <= 0 ) {
						/* translators: %s: field label */
						$error = sprintf( __( '%s must contain positive IDs.', 'recast-subscriptions' ), $label );
						return null;
					}
					$ids[] = (int) $id;
				}
				$ids = array_values( array_unique( $ids ) );
				sort( $ids );
				return $ids;
			case 'text':
			default:
				if ( ! is_scalar( $value ) ) {
					/* translators: %s: field label */
					$error = sprintf( __( '%s must be text.', 'recast-subscriptions' ), $label );
					return null;
				}
				$text = sanitize_text_field( (string) $value );
				if ( isset( $field['pattern'] ) && ! preg_match( $field['pattern'], $text ) ) {
					/* translators: %s: field label */
					$error = sprintf( __( '%s has an invalid format.', 'recast-subscriptions' ), $label );
					return null;
				}
				return $text;
		}
	}
}