/**
 * Unit tests for main.js: applyLangToUi (locale-to-DOM) and lang re-evaluation behaviour.
 */

import { describe, it, expect, beforeAll } from "vitest";

beforeAll(() => {
  document.body.innerHTML =
    '<div id="calendarSticky">' +
    '<button id="prevMonth"></button><h1 id="monthTitle"></h1><button id="nextMonth"></button>' +
    '<div class="weekdays">' +
    '<span></span><span></span><span></span><span></span><span></span><span></span><span></span>' +
    "</div></div>" +
    '<div id="dutyList"></div>' +
    '<div id="loading"><span class="loading__text"></span></div>' +
    '<div id="error"></div><div id="accessDenied"></div>';
});

import { applyLangToUi } from "./main.js";
import { state } from "./dom.js";

describe("applyLangToUi", () => {
  it("state.lang is set from getLang() at startup (getLang reads window.__DT_LANG; default en)", () => {
    expect(state.lang).toBe("en");
  });

  it("sets document title and loading text for en", () => {
    state.lang = "en";
    applyLangToUi();
    expect(document.title).toBe("Duty Calendar");
    const loadingText = document.querySelector(".loading__text");
    expect(loadingText && loadingText.textContent).toBe("Loading…");
  });

  it("sets document title and loading text for ru", () => {
    state.lang = "ru";
    applyLangToUi();
    expect(document.title).toBe("Календарь дежурств");
    const loadingText = document.querySelector(".loading__text");
    expect(loadingText && loadingText.textContent).toBe("Загрузка…");
  });

  it("sets documentElement.lang to state.lang", () => {
    state.lang = "en";
    applyLangToUi();
    expect(document.documentElement.lang).toBe("en");
    state.lang = "ru";
    applyLangToUi();
    expect(document.documentElement.lang).toBe("ru");
  });

  it("sets weekday labels and nav aria-labels for current lang", () => {
    state.lang = "en";
    applyLangToUi();
    const weekdays = document.querySelectorAll(".weekdays span");
    expect(weekdays.length).toBe(7);
    expect(weekdays[0].textContent).toBe("Mon");
    const prevBtn = document.getElementById("prevMonth");
    const nextBtn = document.getElementById("nextMonth");
    expect(prevBtn && prevBtn.getAttribute("aria-label")).toBe("Previous month");
    expect(nextBtn && nextBtn.getAttribute("aria-label")).toBe("Next month");

    state.lang = "ru";
    applyLangToUi();
    expect(weekdays[0].textContent).toBe("Пн");
    expect(prevBtn && prevBtn.getAttribute("aria-label")).toContain("Пред");
    expect(nextBtn && nextBtn.getAttribute("aria-label")).toContain("След");
  });
});