<?php

namespace Glovario\Locale;

defined( 'ABSPATH' ) || exit;

final class LocaleSwitcher {
	private $manager;
	private $catalog;
	private $global_rendered = false;

	public function __construct( StandaloneLocale $manager, LocaleCatalog $catalog ) {
		$this->manager = $manager;
		$this->catalog = $catalog;
	}

	public function register() {
		add_shortcode( 'glvr_locale_switcher', array( $this, 'shortcode' ) );
		add_action( 'init', array( $this, 'register_block' ) );
		add_action( 'wp_enqueue_scripts', array( $this, 'enqueue_style' ) );
		add_action( 'wp_body_open', array( $this, 'render_global' ), 20 );
		add_action( 'wp_footer', array( $this, 'render_global' ), 1 );
		add_filter( 'body_class', array( $this, 'body_classes' ) );
	}

	public function register_block() {
		wp_register_style( 'glovario-locale-switcher', GLOVARIO_URL . 'assets/locale-switcher.css', array(), GLOVARIO_VERSION );
		register_block_type(
			GLOVARIO_PATH . 'blocks/locale-switcher',
			array( 'render_callback' => array( $this, 'render' ) )
		);
	}

	/**
	 * Loads the stylesheet in the head only for the site-wide flag, which is
	 * printed at the top of every page. The block and the shortcode enqueue it
	 * themselves when they render, so other pages load no Glovario asset.
	 */
	public function enqueue_style() {
		if ( $this->manager->global_switcher_enabled() && $this->manager->standalone_available() ) {
			wp_enqueue_style( 'glovario-locale-switcher' );
		}
	}

	public function body_classes( $classes ) {
		if ( $this->manager->global_switcher_enabled() && $this->manager->standalone_available() ) {
			$classes[] = 'glovario-global-locale-switcher-enabled';
		}
		return $classes;
	}

	public function shortcode( $attributes ) {
		$attributes = shortcode_atts(
			array(
				'show_codes' => 'false',
			),
			$attributes,
			'glvr_locale_switcher'
		);
		return $this->render( array( 'showCodes' => 'true' === strtolower( (string) $attributes['show_codes'] ) ) );
	}

	public function render( $attributes = array() ) {
		if ( ! $this->manager->standalone_available() ) {
			return current_user_can( 'manage_options' ) && ( is_admin() || $this->is_rest_request() ) ? '<p class="glovario-locale-switcher-notice">' . /* translators: Glovario is the product name; do not translate it. */ esc_html__( 'Enable Standalone Glovario selector mode under Locale Settings to display this switcher.', 'glovario' ) . '</p>' : '';
		}
		wp_enqueue_style( 'glovario-locale-switcher' );
		$show_codes = ! empty( $attributes['showCodes'] );
		/**
		 * Short-circuits the inline switcher markup.
		 *
		 * @param string|null    $markup     Null to render the default and the second language.
		 * @param bool           $show_codes Whether locale codes follow the names.
		 * @param LocaleSwitcher $switcher   This switcher, for its link helpers.
		 */
		$markup = apply_filters( 'glovario_locale_switcher_markup', null, $show_codes, $this );
		if ( is_string( $markup ) ) {
			return wp_kses( $markup, self::allowed_html() );
		}
		$settings = $this->manager->settings();
		$links    = $this->link_markup( $settings['default_locale'], 'inline', $show_codes );
		if ( '' !== $settings['second_locale'] ) {
			$links .= $this->link_markup( $settings['second_locale'], 'inline', $show_codes );
		}
		return $this->inline_container( $links );
	}

	/**
	 * One language link, shared by the inline and site-wide switchers.
	 *
	 * @param string $locale     Locale code.
	 * @param string $variant    'inline' or 'global'.
	 * @param bool   $show_codes Whether the locale code follows the name.
	 * @return string Escaped markup.
	 */
	public function link_markup( $locale, $variant, $show_codes = false ) {
		$active = $this->active_locale();
		$name   = $this->catalog->name( $locale );
		$label  = $show_codes ? $name . ' (' . $locale . ')' : $name;
		$global = 'global' === $variant;
		return sprintf(
			'<a class="%1$s%2$s" href="%3$s" lang="%4$s" hreflang="%4$s"%5$s>%6$s<span%7$s>%8$s</span></a>',
			$global ? 'glovario-global-locale-switcher__option' : 'glovario-locale-switcher__link',
			$locale === $active ? ' is-active' : '',
			esc_url( add_query_arg( StandaloneLocale::QUERY, $locale, $this->current_url() ) ),
			esc_attr( str_replace( '_', '-', $locale ) ),
			$locale === $active ? ' aria-current="true"' : '',
			$this->flag_markup( $locale, $global ? 'glovario-global-locale-switcher__flag' : 'glovario-locale-switcher__flag' ),
			$global ? '' : ' class="glovario-locale-switcher__label"',
			esc_html( $label )
		);
	}

	/**
	 * Wrap language links in the inline switcher container.
	 *
	 * @param string $links Escaped link markup.
	 * @return string
	 */
	public function inline_container( $links ) {
		return sprintf(
			'<nav class="glovario-locale-switcher" aria-label="%1$s">%2$s</nav>',
			esc_attr__( 'Language', 'glovario' ),
			$links
		);
	}

	public function render_global() {
		if ( $this->global_rendered || ! $this->manager->global_switcher_enabled() || ! $this->manager->standalone_available() ) {
			return;
		}
		$this->global_rendered = true;
		echo $this->global_markup(); // phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- Markup is assembled exclusively from escaped values below.
	}

	public function global_markup() {
		if ( ! $this->manager->global_switcher_enabled() || ! $this->manager->standalone_available() ) {
			return '';
		}

		wp_enqueue_style( 'glovario-locale-switcher' );
		/**
		 * Short-circuits the language links of the site-wide switcher.
		 *
		 * @param string|null    $links    Null to list the default and the second language.
		 * @param LocaleSwitcher $switcher This switcher, for its link helpers.
		 */
		$links = apply_filters( 'glovario_global_locale_switcher_links', null, $this );
		if ( is_string( $links ) ) {
			$links = wp_kses( $links, self::allowed_html() );
		} else {
			$settings = $this->manager->settings();
			$links    = $this->link_markup( $settings['default_locale'], 'global' );
			if ( '' !== $settings['second_locale'] ) {
				$links .= $this->link_markup( $settings['second_locale'], 'global' );
			}
		}
		$active = $this->active_locale();

		/* translators: %s: current language name. */
		$summary = sprintf( __( 'Choose language. Current language: %s.', 'glovario' ), $this->catalog->name( $active ) );
		return sprintf(
			'<div class="glovario-global-locale-switcher" data-glovario-global-locale-switcher><details><summary aria-label="%1$s" title="%2$s">%3$s<span class="screen-reader-text">%1$s</span></summary><nav class="glovario-global-locale-switcher__menu" aria-label="%4$s">%5$s</nav></details></div>',
			esc_attr( $summary ),
			esc_attr__( 'Choose language', 'glovario' ),
			$this->flag_markup( $active, 'glovario-global-locale-switcher__flag' ),
			esc_attr__( 'Available languages', 'glovario' ),
			$links
		);
	}

	/**
	 * Tags and attributes the switchers print, for markup that filters return.
	 *
	 * @return array Allowed HTML for wp_kses().
	 */
	public static function allowed_html() {
		$common = array(
			'class'        => true,
			'id'           => true,
			'lang'         => true,
			'title'        => true,
			'aria-label'   => true,
			'aria-hidden'  => true,
			'aria-current' => true,
		);
		return array(
			'nav'  => $common,
			'ul'   => $common,
			'li'   => $common,
			'span' => $common,
			'a'    => array_merge(
				$common,
				array(
					'href'     => true,
					'hreflang' => true,
				)
			),
			'img'  => array_merge(
				$common,
				array(
					'src'    => true,
					'alt'    => true,
					'width'  => true,
					'height' => true,
				)
			),
		);
	}

	private function current_url() {
		return remove_query_arg( array( StandaloneLocale::QUERY, LocaleManager::PREVIEW_QUERY, '_glovario_locale_nonce' ), StandaloneLocale::request_path() );
	}

	private function active_locale() {
		return apply_filters( 'glovario_current_locale', determine_locale(), array( 'source' => 'locale_switcher' ) );
	}

	private function flag_markup( $locale, $class_name ) {
		$flag = $this->flag_for_locale( $locale );
		if ( $flag ) {
			return '<span class="' . esc_attr( $class_name ) . '" aria-hidden="true">' . esc_html( $flag ) . '</span>';
		}
		$parts = preg_split( '/[_-]/', sanitize_locale_name( $locale ) );
		$code  = strtoupper( substr( (string) ( $parts[0] ?? $locale ), 0, 2 ) );
		return '<span class="' . esc_attr( $class_name . ' ' . $class_name . '--code' ) . '" aria-hidden="true">' . esc_html( $code ) . '</span>';
	}

	private function flag_for_locale( $locale ) {
		$parts  = preg_split( '/[_-]/', sanitize_locale_name( $locale ) );
		$region = '';
		foreach ( array_slice( $parts, 1 ) as $part ) {
			if ( preg_match( '/^[A-Za-z]{2}$/', $part ) ) {
				$region = strtoupper( $part );
				break;
			}
		}
		if ( in_array( $region, array( 'UN', 'XA', 'XB', 'ZZ' ), true ) ) {
			$region = '';
		}
		if ( ! $region ) {
			$defaults = array(
				'af' => 'ZA',
				'am' => 'ET',
				'ar' => 'SA',
				'az' => 'AZ',
				'bel' => 'BY',
				'bg' => 'BG',
				'bn' => 'BD',
				'bs' => 'BA',
				'ca' => 'ES',
				'ceb' => 'PH',
				'cs' => 'CZ',
				'cy' => 'GB',
				'da' => 'DK',
				'de' => 'DE',
				'el' => 'GR',
				'en' => 'US',
				'es' => 'ES',
				'et' => 'EE',
				'eu' => 'ES',
				'fa' => 'IR',
				'fi' => 'FI',
				'fil' => 'PH',
				'fr' => 'FR',
				'gd' => 'GB',
				'gl' => 'ES',
				'gu' => 'IN',
				'he' => 'IL',
				'hi' => 'IN',
				'hr' => 'HR',
				'hu' => 'HU',
				'hy' => 'AM',
				'id' => 'ID',
				'is' => 'IS',
				'it' => 'IT',
				'ja' => 'JP',
				'jv' => 'ID',
				'ka' => 'GE',
				'kk' => 'KZ',
				'km' => 'KH',
				'kn' => 'IN',
				'ko' => 'KR',
				'lo' => 'LA',
				'lt' => 'LT',
				'lv' => 'LV',
				'mk' => 'MK',
				'ml' => 'IN',
				'mn' => 'MN',
				'mr' => 'IN',
				'ms' => 'MY',
				'my' => 'MM',
				'nb' => 'NO',
				'ne' => 'NP',
				'nl' => 'NL',
				'nn' => 'NO',
				'pa' => 'IN',
				'pl' => 'PL',
				'ps' => 'AF',
				'pt' => 'PT',
				'ro' => 'RO',
				'ru' => 'RU',
				'si' => 'LK',
				'sk' => 'SK',
				'sl' => 'SI',
				'sq' => 'AL',
				'sr' => 'RS',
				'sv' => 'SE',
				'sw' => 'TZ',
				'ta' => 'IN',
				'te' => 'IN',
				'th' => 'TH',
				'tl' => 'PH',
				'tr' => 'TR',
				'tt' => 'RU',
				'ug' => 'CN',
				'uk' => 'UA',
				'ur' => 'PK',
				'uz' => 'UZ',
				'vi' => 'VN',
				'zh' => 'CN',
				'yor' => 'NG',
			);
			$region = $defaults[ strtolower( (string) ( $parts[0] ?? '' ) ) ] ?? '';
		}
		if ( ! preg_match( '/^[A-Z]{2}$/', $region ) ) {
			return '';
		}

		$entities = '';
		foreach ( str_split( $region ) as $letter ) {
			$entities .= '&#' . ( 127397 + ord( $letter ) ) . ';';
		}
		return html_entity_decode( $entities, ENT_NOQUOTES, 'UTF-8' );
	}

	private function is_rest_request() {
		return defined( 'REST_REQUEST' ) && REST_REQUEST;
	}
}