<?php
namespace Extendiment\Checkoutline;

defined( 'ABSPATH' ) || exit;

/**
 * WooCommerce's own address fields: a new label, and shown as optional, required or hidden.
 *
 * Company, address line 2 and phone use WooCommerce's settings for them (the options
 * woocommerce_checkout_{company|address_2|phone}_field, which both checkouts read). The other
 * fields change through WooCommerce's address locale, which the Checkout block, the classic
 * checkout (also when the country changes) and My Account's address forms all follow; countries
 * where WooCommerce hides a field (no postcode in some countries) keep it hidden. Stored in the
 * option checkoutline_core: field => [ label, mode ].
 */
class CoreFields {

	const OPTION = 'checkoutline_core';
	const OWN    = array( 'company', 'address_2', 'phone' );

	public function register(): void {
		add_filter( 'woocommerce_get_country_locale', array( $this, 'locale' ), 99 );
		add_filter( 'woocommerce_get_country_locale_default', array( $this, 'apply' ), 99 );
		add_filter( 'woocommerce_billing_fields', array( $this, 'billing' ), 99 );
		add_filter( 'woocommerce_shipping_fields', array( $this, 'shipping' ), 99 );
	}

	/** The fields that can change, with WooCommerce's labels. */
	public static function fields(): array {
		return array(
			'first_name' => __( 'First name', 'checkoutline' ),
			'last_name'  => __( 'Last name', 'checkoutline' ),
			'company'    => __( 'Company', 'checkoutline' ),
			'address_1'  => __( 'Address', 'checkoutline' ),
			'address_2'  => __( 'Address line 2', 'checkoutline' ),
			'city'       => __( 'City', 'checkoutline' ),
			'state'      => __( 'State / County', 'checkoutline' ),
			'postcode'   => __( 'Postcode / ZIP', 'checkoutline' ),
			'phone'      => __( 'Phone', 'checkoutline' ),
		);
	}

	/** Modes: '' (as WooCommerce has it, by country), required, optional, hidden. */
	public static function modes( string $field ): array {
		$modes = array(
			'optional' => __( 'Optional', 'checkoutline' ),
			'required' => __( 'Required', 'checkoutline' ),
			'hidden'   => __( 'Hidden', 'checkoutline' ),
		);
		return in_array( $field, self::OWN, true ) ? $modes : array( '' => __( 'As WooCommerce has it', 'checkoutline' ) ) + $modes;
	}

	/** @return array<string, array{label: string, mode: string}> */
	public static function all(): array {
		$saved = (array) get_option( self::OPTION, array() );
		$out   = array();
		foreach ( array_keys( self::fields() ) as $field ) {
			$row           = (array) ( $saved[ $field ] ?? array() );
			$mode          = (string) ( $row['mode'] ?? '' );
			$out[ $field ] = array(
				'label' => sanitize_text_field( (string) ( $row['label'] ?? '' ) ),
				'mode'  => in_array( $field, self::OWN, true ) ? self::own_mode( $field ) : ( array_key_exists( $mode, self::modes( $field ) ) ? $mode : '' ),
			);
		}
		return $out;
	}

	/** WooCommerce's setting for company, address line 2 or phone. */
	public static function own_mode( string $field ): string {
		$defaults = array( // WooCommerce's own (CartCheckoutUtils).
			'company'   => 'hidden',
			'address_2' => 'optional',
			'phone'     => 'optional',
		);
		$value    = (string) get_option( 'woocommerce_checkout_' . $field . '_field', $defaults[ $field ] );
		return in_array( $value, array( 'optional', 'required', 'hidden' ), true ) ? $value : $defaults[ $field ];
	}

	/** @param array<string, array{label?: string, mode?: string}> $rows */
	public static function save( array $rows ): void {
		$clean = array();
		foreach ( array_keys( self::fields() ) as $field ) {
			$row   = (array) ( $rows[ $field ] ?? array() );
			$label = sanitize_text_field( (string) ( $row['label'] ?? '' ) );
			$mode  = (string) ( $row['mode'] ?? '' );
			if ( in_array( $field, self::OWN, true ) ) {
				if ( array_key_exists( $mode, self::modes( $field ) ) ) {
					update_option( 'woocommerce_checkout_' . $field . '_field', $mode );
				}
				$mode = '';
			} elseif ( ! array_key_exists( $mode, self::modes( $field ) ) ) {
				$mode = '';
			}
			if ( '' !== $label || '' !== $mode ) {
				$clean[ $field ] = array(
					'label' => $label,
					'mode'  => $mode,
				);
			}
		}
		update_option( self::OPTION, $clean );
	}

	/**
	 * Applies the changes to one locale (a country's, or the default).
	 *
	 * @param array $locale Field => properties.
	 * @param bool  $partial A country's locale (only what differs from the default).
	 */
	public function apply( $locale, bool $partial = false ): array {
		$locale = (array) $locale;
		foreach ( self::all() as $field => $row ) {
			if ( '' === $row['label'] && '' === $row['mode'] ) {
				continue;
			}
			if ( $partial && ! isset( $locale[ $field ] ) && '' === $row['label'] && 'hidden' !== $row['mode'] ) {
				continue; // A country without its own rule for this field follows the default.
			}
			$props = (array) ( $locale[ $field ] ?? array() );
			if ( '' !== $row['label'] ) {
				$props['label'] = $row['label'];
			}
			if ( 'hidden' === $row['mode'] ) {
				$props['hidden']   = true;
				$props['required'] = false;
			} elseif ( '' !== $row['mode'] && empty( $props['hidden'] ) ) {
				$props['required'] = 'required' === $row['mode'];
			}
			$locale[ $field ] = $props;
		}
		return $locale;
	}

	/** @param array $locales Country => locale. */
	public function locale( $locales ): array {
		$locales = (array) $locales;
		foreach ( $locales as $country => $locale ) {
			$locales[ $country ] = $this->apply( $locale, true );
		}
		return $locales;
	}

	private static function address_fields( array $fields, string $group ): array {
		foreach ( self::all() as $field => $row ) {
			$key = $group . '_' . $field;
			if ( ! isset( $fields[ $key ] ) ) {
				continue;
			}
			if ( 'hidden' === $row['mode'] ) {
				unset( $fields[ $key ] );
				continue;
			}
			if ( '' !== $row['label'] ) {
				$fields[ $key ]['label'] = $row['label'];
			}
			if ( '' !== $row['mode'] && empty( $fields[ $key ]['hidden'] ) ) {
				$fields[ $key ]['required'] = 'required' === $row['mode'];
			}
		}
		return $fields;
	}

	/** Classic checkout and My Account's billing address. @param array $fields */
	public function billing( $fields ): array {
		return self::address_fields( (array) $fields, 'billing' );
	}

	/** @param array $fields */
	public function shipping( $fields ): array {
		return self::address_fields( (array) $fields, 'shipping' );
	}
}