export default class LanguageManager {
	constructor() {
		this.availableLanguages = ['en', 'fr'];

		this.currentLang = 'en'
		this.chosenLang = localStorage.getItem('preferedLanguage') || this.currentLang;
		if (this.chosenLang !== this.currentLang && this.availableLanguages.includes(this.chosenLang)) {
			this.translatePage();
		}
	}

	async translatePage() {
		if (this.currentLang === this.chosenLang)
			return;

		let dictUrl = `${location.origin}/static/js/lang/${this.chosenLang}.json`;
		let translation = await fetch(dictUrl).then(response => {
			if (response.status !== 200)
				return null;
			return response.json();
		});
		if (!translation) {
			console.log(`No translation found for language ${this.chosenLang}`);
			return 1;
		}
		document.querySelectorAll('[data-i18n]').forEach(el => {
			let key = el.getAttribute('data-i18n');
			el.innerHTML = translation[key];
		})

		this.currentLang = this.chosenLang;
		return 0;
	}

	async changeLanguage(lang) {
		if (lang === this.currentLang || !this.availableLanguages.includes(lang))
			return;

		this.chosenLang = lang;
		if (await this.translatePage() !== 0)
			return;

		localStorage.setItem('preferedLanguage', lang);
	}
}