<?php
/**
 * Input checks. The limits and the messages mirror src/engine/validation.ts: the page checks first,
 * the server checks again because it never trusts the page.
 *
 * @package LotCost
 */

namespace LotCost;

defined( 'ABSPATH' ) || exit;

/**
 * Validates what the merchant may save. Every method returns
 * array( 'ok' => true, 'value' => array ) or array( 'ok' => false, 'errors' => array( field => message ) ).
 */
final class Validator {

	const NAME_MAX    = 80;
	const SOURCE_MAX  = 80;
	const TITLE_MAX   = 255;
	const MAX_CENTS   = 2000000000;
	const MAX_UNITS   = 100000;
	const MAX_PIECES  = 500;
	const WOO_ID      = '/^[1-9][0-9]{0,18}$/';
	const METHODS     = array( 'equal', 'price', 'manual' );

	/**
	 * Whether the value is a whole number inside the range (JSON may hand us 1500.0).
	 *
	 * @param mixed $value Value to check.
	 * @param float $min   Smallest allowed.
	 * @param float $max   Largest allowed.
	 */
	public static function is_int_in( $value, $min, $max ): bool {
		if ( is_float( $value ) ) {
			if ( floor( $value ) !== $value ) {
				return false;
			}
			$value = (int) $value;
		}
		return is_int( $value ) && $value >= $min && $value <= $max;
	}

	/**
	 * Trim and collapse white space.
	 *
	 * @param mixed $text Text to clean.
	 */
	public static function clean( $text ): string {
		if ( ! is_string( $text ) ) {
			return '';
		}
		return trim( (string) preg_replace( '/\s+/u', ' ', $text ) );
	}

	/**
	 * Length in characters.
	 *
	 * @param string $text Text to measure.
	 */
	private static function length( string $text ): int {
		return function_exists( 'mb_strlen' ) ? mb_strlen( $text ) : strlen( $text );
	}

	/**
	 * Whether the text is a real calendar day like 2026-10-14.
	 *
	 * @param string $text Text to check.
	 */
	public static function is_calendar_date( string $text ): bool {
		if ( ! preg_match( '/^(\d{4})-(\d{2})-(\d{2})$/', $text, $match ) ) {
			return false;
		}
		return checkdate( (int) $match[2], (int) $match[3], (int) $match[1] );
	}

	/**
	 * Check a lot, pieces included. Whether the products exist is checked by the Lots store.
	 *
	 * @param mixed $input Decoded JSON.
	 */
	public static function lot( $input ): array {
		$input        = is_array( $input ) ? $input : array();
		$errors       = array();
		$name         = self::clean( $input['name'] ?? '' );
		$source       = self::clean( $input['source'] ?? '' );
		$purchased_at = isset( $input['purchasedAt'] ) && is_string( $input['purchasedAt'] ) ? trim( $input['purchasedAt'] ) : '';
		$method       = $input['method'] ?? null;

		if ( '' === $name ) {
			$errors['name'] = __( 'Enter a name for the lot.', 'lotcost' );
		} elseif ( self::length( $name ) > self::NAME_MAX ) {
			/* translators: %d: maximum number of characters */
			$errors['name'] = sprintf( __( 'Use at most %d characters.', 'lotcost' ), self::NAME_MAX );
		}
		if ( self::length( $source ) > self::SOURCE_MAX ) {
			/* translators: %d: maximum number of characters */
			$errors['source'] = sprintf( __( 'Use at most %d characters.', 'lotcost' ), self::SOURCE_MAX );
		}
		if ( '' !== $purchased_at && ! self::is_calendar_date( $purchased_at ) ) {
			$errors['purchasedAt'] = __( 'Enter a date like 2026-10-14, or leave it empty.', 'lotcost' );
		}
		if ( ! self::is_int_in( $input['itemsCents'] ?? null, 0, self::MAX_CENTS ) ) {
			$errors['itemsCents'] = __( 'Enter the price you paid for the lot (0 or more).', 'lotcost' );
		}
		if ( ! self::is_int_in( $input['shippingCents'] ?? null, 0, self::MAX_CENTS ) ) {
			$errors['shippingCents'] = __( 'Enter the shipping cost (0 or more).', 'lotcost' );
		}
		if ( ! self::is_int_in( $input['otherCents'] ?? null, 0, self::MAX_CENTS ) ) {
			$errors['otherCents'] = __( 'Enter the other costs (0 or more).', 'lotcost' );
		}
		if ( ! is_string( $method ) || ! in_array( $method, self::METHODS, true ) ) {
			$errors['method'] = __( 'Choose how the cost is shared.', 'lotcost' );
		}

		$pieces = array();
		$raw    = $input['pieces'] ?? null;
		if ( ! is_array( $raw ) ) {
			$errors['pieces'] = __( 'The lot has no list of pieces.', 'lotcost' );
		} elseif ( count( $raw ) > self::MAX_PIECES ) {
			/* translators: %d: maximum number of pieces */
			$errors['pieces'] = sprintf( __( 'A lot can have at most %d pieces.', 'lotcost' ), self::MAX_PIECES );
		} else {
			$seen = array();
			foreach ( $raw as $piece ) {
				$piece      = is_array( $piece ) ? $piece : array();
				$title      = self::clean( $piece['title'] ?? '' );
				$product_id = $piece['productId'] ?? null;
				$variant_id = $piece['variantId'] ?? null;
				$pinned     = $piece['pinnedCents'] ?? null;
				$manual     = $piece['manualCents'] ?? null;
				$problem    = null;
				if ( ! is_string( $product_id ) || ! preg_match( self::WOO_ID, $product_id ) || ! is_string( $variant_id ) || ! preg_match( self::WOO_ID, $variant_id ) ) {
					$problem = __( 'This is not a product of your store.', 'lotcost' );
				} elseif ( '' === $title ) {
					$problem = __( 'The product has no title.', 'lotcost' );
				} elseif ( self::length( $title ) > self::TITLE_MAX ) {
					/* translators: %d: maximum number of characters */
					$problem = sprintf( __( 'Use at most %d characters for the title.', 'lotcost' ), self::TITLE_MAX );
				} elseif ( ! self::is_int_in( $piece['units'] ?? null, 1, self::MAX_UNITS ) ) {
					/* translators: %d: maximum number of units */
					$problem = sprintf( __( 'Enter a whole number of units (1 to %d).', 'lotcost' ), self::MAX_UNITS );
				} elseif ( null !== $pinned && ! self::is_int_in( $pinned, 0, self::MAX_CENTS ) ) {
					$problem = __( 'Enter a fixed cost of 0 or more.', 'lotcost' );
				} elseif ( null !== $manual && ! self::is_int_in( $manual, 0, self::MAX_CENTS ) ) {
					$problem = __( 'Enter a cost of 0 or more.', 'lotcost' );
				} elseif ( isset( $seen[ $variant_id ] ) ) {
					$problem = __( 'This piece is in the lot twice.', 'lotcost' );
				}
				if ( null !== $problem ) {
					$errors['pieces'] = '' !== $title ? $title . ': ' . $problem : $problem;
					break;
				}
				$seen[ $variant_id ] = true;
				$pieces[]            = array(
					'productId'   => $product_id,
					'variantId'   => $variant_id,
					'title'       => $title,
					'units'       => (int) $piece['units'],
					'pinnedCents' => null === $pinned ? null : (int) $pinned,
					'manualCents' => null === $manual ? null : (int) $manual,
				);
			}
		}

		if ( $errors ) {
			return array(
				'ok'     => false,
				'errors' => $errors,
			);
		}
		return array(
			'ok'    => true,
			'value' => array(
				'name'          => $name,
				'source'        => $source,
				'purchasedAt'   => $purchased_at,
				'itemsCents'    => (int) $input['itemsCents'],
				'shippingCents' => (int) $input['shippingCents'],
				'otherCents'    => (int) $input['otherCents'],
				'method'        => $method,
				'confirmed'     => isset( $input['confirmed'] ) && true === $input['confirmed'],
				'pieces'        => $pieces,
			),
		);
	}

	/**
	 * Check the settings.
	 *
	 * @param mixed $input Decoded JSON.
	 */
	public static function settings( $input ): array {
		$input  = is_array( $input ) ? $input : array();
		$delete = $input['deleteDataOnUninstall'] ?? false;
		if ( ! is_bool( $delete ) ) {
			return array(
				'ok'     => false,
				'errors' => array( 'deleteDataOnUninstall' => __( 'Choose yes or no.', 'lotcost' ) ),
			);
		}
		return array(
			'ok'    => true,
			'value' => array( 'deleteDataOnUninstall' => $delete ),
		);
	}
}