<?php
namespace Admirly\Wp;

use Admirly\Domain\Lang;
use Admirly\Plugin;

/**
 * WPML / Polylang integration: translatable setting texts and field labels, review language, page mapping.
 */
final class Multilingual {
	public const CONTEXT = 'Admirly';
	/** Setting keys whose values are translatable. */
	public const KEYS = [ 'form_title', 'thanks_text' ];

	public function register(): void {
		add_action( 'init', [ $this, 'registerStringsFromOptions' ], 20 );
		add_action( 'update_option_' . Plugin::OPTION, [ $this, 'registerStringsFromOptions' ], 10, 0 );
		add_filter( 'pll_get_post_types', [ $this, 'excludeFromPolylang' ] );
	}

	public static function active(): bool {
		return defined( 'ICL_SITEPRESS_VERSION' ) || function_exists( 'pll_current_language' );
	}

	/** Current language code ("tr", "en"); site locale when no multilingual plugin is active. */
	public static function current(): string {
		if ( function_exists( 'pll_current_language' ) ) {
			$l = Lang::normalize( (string) pll_current_language( 'slug' ) );
			if ( $l !== '' ) {
				return $l;
			}
		}
		if ( defined( 'ICL_SITEPRESS_VERSION' ) ) {
			$l = Lang::normalize( (string) apply_filters( 'wpml_current_language', '' ) );
			if ( $l !== '' ) {
				return $l;
			}
		}
		return Lang::normalize( (string) get_locale() );
	}

	/** Field groups whose item labels are translatable; extensions add their own lists. @return string[] */
	private static function groups(): array {
		/** @param string[] $groups Keys of list-type field groups in the field definitions. */
		return (array) apply_filters( 'admirly_translatable_groups', [ 'roles' ] );
	}

	/** Registers option texts and field labels with WPML String Translation / Polylang. @param array<string,mixed> $opts */
	public static function registerStrings( array $opts ): void {
		if ( ! self::active() ) {
			return;
		}
		$strings = [];
		foreach ( self::KEYS as $k ) {
			$strings[ $k ] = (string) ( $opts[ $k ] ?? '' );
		}
		$raw                  = (array) Plugin::opt( 'fields', [] );
		$f                    = (array) apply_filters( 'admirly_fields', \Admirly\Domain\FieldConfig::normalize( $raw ), $raw ); // untranslated source labels
		$strings['sub.label'] = $f['sub']['label'];
		foreach ( self::groups() as $group ) {
			foreach ( (array) ( $f[ $group ] ?? [] ) as $it ) {
				$strings[ $group . '.' . $it['slug'] ] = $it['label'];
			}
		}
		foreach ( $f['sub']['options'] as $it ) {
			$strings[ 'sub.' . $it['slug'] ] = $it['label'];
		}
		foreach ( $strings as $name => $value ) {
			if ( $value === '' ) {
				continue;
			}
			if ( function_exists( 'pll_register_string' ) ) {
				pll_register_string( $name, $value, self::CONTEXT );
			}
			do_action( 'wpml_register_single_string', self::CONTEXT, $name, $value );
		}
	}

	public function registerStringsFromOptions(): void {
		self::registerStrings( Settings::all() );
	}

	/** Translated value for the current language (unchanged when no multilingual plugin is active). */
	public static function translate( string $name, string $value ): string {
		if ( $value === '' || ! self::active() ) {
			return $value;
		}
		if ( function_exists( 'pll__' ) ) {
			return (string) pll__( $value );
		}
		return (string) apply_filters( 'wpml_translate_single_string', $value, self::CONTEXT, $name );
	}

	/** Translated page id for the current language (falls back to the original). */
	public static function pageId( int $id ): int {
		if ( $id <= 0 || ! self::active() ) {
			return max( 0, $id );
		}
		if ( function_exists( 'pll_get_post' ) ) {
			$t = pll_get_post( $id );
			return $t ? (int) $t : $id;
		}
		return (int) apply_filters( 'wpml_object_id', $id, 'page', true );
	}

	/** Field config with labels translated for the current language. @param array<string,mixed> $f */
	public static function translateFields( array $f ): array {
		if ( ! self::active() ) {
			return $f;
		}
		$f['sub']['label'] = self::translate( 'sub.label', $f['sub']['label'] );
		foreach ( self::groups() as $g ) {
			foreach ( (array) ( $f[ $g ] ?? [] ) as $i => $it ) {
				$f[ $g ][ $i ]['label'] = self::translate( $g . '.' . $it['slug'], $it['label'] );
			}
		}
		foreach ( $f['sub']['options'] as $i => $it ) {
			$f['sub']['options'][ $i ]['label'] = self::translate( 'sub.' . $it['slug'], $it['label'] );
		}
		return $f;
	}

	/** Reviews are not translated as posts; language lives in meta. @param array<string,string> $types */
	public function excludeFromPolylang( array $types ): array {
		unset( $types[ Plugin::CPT ] );
		return $types;
	}
}