<?php

namespace Kirby\Cms;

use Kirby\Toolkit\I18n;
use Kirby\Toolkit\Locale;
use Kirby\Toolkit\Str;

/**
 * AppTranslations
 *
 * @package   Kirby Cms
 * @author    Bastian Allgeier <bastian@getkirby.com>
 * @link      https://getkirby.com
 * @copyright Bastian Allgeier
 * @license   https://getkirby.com/license
 */
trait AppTranslations
{
    protected $translations;

    /**
     * Setup internationalization
     *
     * @return void
     */
    protected function i18n(): void
    {
        I18n::$load = function ($locale): array {
            $data = [];

            if ($translation = $this->translation($locale)) {
                $data = $translation->data();
            }

            // inject translations from the current language
            if (
                $this->multilang() === true &&
                $language = $this->languages()->find($locale)
            ) {
                $data = array_merge($data, $language->translations());
            }


            return $data;
        };

        // the actual locale is set using $app->setCurrentTranslation()
        I18n::$locale = function (): string {
            if ($this->multilang() === true) {
                return $this->defaultLanguage()->code();
            } else {
                return 'en';
            }
        };

        I18n::$fallback = function (): array {
            if ($this->multilang() === true) {
                // first try to fall back to the configured default language
                $defaultCode = $this->defaultLanguage()->code();
                $fallback = [$defaultCode];

                // if the default language is specified with a country code
                // (e.g. `en-us`), also try with just the language code
                if (preg_match('/^([a-z]{2})-[a-z]+$/i', $defaultCode, $matches) === 1) {
                    $fallback[] = $matches[1];
                }

                // fall back to the complete English translation
                // as a last resort
                $fallback[] = 'en';

                return $fallback;
            } else {
                return ['en'];
            }
        };

        I18n::$translations = [];

        // add slug rules based on config option
        if ($slugs = $this->option('slugs')) {
            // two ways that the option can be defined:
            // "slugs" => "de" or "slugs" => ["language" => "de"]
            if ($slugs = $slugs['language'] ?? $slugs ?? null) {
                Str::$language = Language::loadRules($slugs);
            }
        }
    }

    /**
     * Returns the language code that will be used
     * for the Panel if no user is logged in or if
     * no language is configured for the user
     *
     * @return string
     */
    public function panelLanguage(): string
    {
        if ($this->multilang() === true) {
            $defaultCode = $this->defaultLanguage()->code();

            // extract the language code from a language that
            // contains the country code (e.g. `en-us`)
            if (preg_match('/^([a-z]{2})-[a-z]+$/i', $defaultCode, $matches) === 1) {
                $defaultCode = $matches[1];
            }
        } else {
            $defaultCode = 'en';
        }

        return $this->option('panel.language', $defaultCode);
    }

    /**
     * Load and set the current language if it exists
     * Otherwise fall back to the default language
     *
     * @internal
     * @param string|null $languageCode
     * @return \Kirby\Cms\Language|null
     */
    public function setCurrentLanguage(string $languageCode = null)
    {
        if ($this->multilang() === false) {
            Locale::set($this->option('locale', 'en_US.utf-8'));
            return $this->language = null;
        }

        if ($language = $this->language($languageCode)) {
            $this->language = $language;
        } else {
            $this->language = $this->defaultLanguage();
        }

        if ($this->language) {
            Locale::set($this->language->locale());
        }

        // add language slug rules to Str class
        Str::$language = $this->language->rules();

        return $this->language;
    }

    /**
     * Set the current translation
     *
     * @internal
     * @param string|null $translationCode
     * @return void
     */
    public function setCurrentTranslation(string $translationCode = null): void
    {
        I18n::$locale = $translationCode ?? 'en';
    }

    /**
     * Set locale settings
     *
     * @deprecated 3.5.0 Use `\Kirby\Toolkit\Locale::set()` instead
     * @todo Remove in 3.7.0
     *
     * @param string|array $locale
     */
    public function setLocale($locale): void
    {
        // @codeCoverageIgnoreStart
        deprecated('`Kirby\Cms\App::setLocale()` has been deprecated and will be removed in 3.7.0. Use `Kirby\Toolkit\Locale::set()` instead');
        Locale::set($locale);
        // @codeCoverageIgnoreEnd
    }

    /**
     * Load a specific translation by locale
     *
     * @param string|null $locale Locale name or `null` for the current locale
     * @return \Kirby\Cms\Translation
     */
    public function translation(?string $locale = null)
    {
        $locale = $locale ?? I18n::locale();
        $locale = basename($locale);

        // prefer loading them from the translations collection
        if (is_a($this->translations, 'Kirby\Cms\Translations') === true) {
            if ($translation = $this->translations()->find($locale)) {
                return $translation;
            }
        }

        // get injected translation data from plugins etc.
        $inject = $this->extensions['translations'][$locale] ?? [];

        // inject current language translations
        if ($language = $this->language($locale)) {
            $inject = array_merge($inject, $language->translations());
        }

        // load from disk instead
        return Translation::load($locale, $this->root('i18n:translations') . '/' . $locale . '.json', $inject);
    }

    /**
     * Returns all available translations
     *
     * @return \Kirby\Cms\Translations
     */
    public function translations()
    {
        if (is_a($this->translations, 'Kirby\Cms\Translations') === true) {
            return $this->translations;
        }

        $translations = $this->extensions['translations'] ?? [];

        // injects languages translations
        if ($languages = $this->languages()) {
            foreach ($languages as $language) {
                $languageCode         = $language->code();
                $languageTranslations = $language->translations();

                // merges language translations with extensions translations
                if (empty($languageTranslations) === false) {
                    $translations[$languageCode] = array_merge(
                        $translations[$languageCode] ?? [],
                        $languageTranslations
                    );
                }
            }
        }

        $this->translations = Translations::load($this->root('i18n:translations'), $translations);

        return $this->translations;
    }
}
