/* =============================================================================
 * A01_Home_UI_Page.ts
 * 로그인 전 01: 홈 (소개 히어로 + 최신 소식 + 주요 기능)
 *
 * 제약 준수:
 *   - 모든 문구는 ui_template_locale.ts 참조 (하드코딩 금지).
 *   - 색상/간격은 A01_Home_UI_Style.css + theme.css 변수만 사용.
 *   - 공통 컴포넌트(createButton/createCard/createTag) 우선 사용.
 *   - 이벤트 핸들러는 on[페이지]_[기능]_[액션] 명명.
 * ========================================================================== */

import { ui_locales, currentLanguageIndex } from "@ui/ui_template_locale";
import { createButton, createCard, createTag } from "@ui/ui_template_elements";
import { navigateTo } from "../A00_Common/router";
import { ROUTES } from "@config/config_frontend";
import "./A01_Home_UI_Style.css";

/** locale 헬퍼 */
function L(key: keyof typeof ui_locales): string {
  return ui_locales[key][currentLanguageIndex];
}

/* -----------------------------------------------------------------------------
 * Mock 데이터 (백엔드 연결 전) — 나중에 GET /api/a01/news로 교체
 * -------------------------------------------------------------------------- */
interface NewsItem {
  id: number;
  title: string;
  date: string;
}

const MOCK_NEWS: NewsItem[] = [
  { id: 1, title: "v0.1 프론트엔드 프로토타입 공개", date: "2026-07-05" },
  { id: 2, title: "3D 지형 뷰어 Three.js 엔진 확정", date: "2026-07-04" },
  { id: 3, title: "임도 설계 워크플로우 6단계 정의 완료", date: "2026-07-01" },
];

/* -----------------------------------------------------------------------------
 * 이벤트 핸들러
 * -------------------------------------------------------------------------- */
function onA01_Home_GetStarted_Click(): void {
  navigateTo(ROUTES.A07_REGISTER);
}

function onA01_Home_Explore_Click(): void {
  navigateTo(ROUTES.A02_PROG_DETAIL);
}

/* -----------------------------------------------------------------------------
 * 섹션 빌더
 * -------------------------------------------------------------------------- */
function buildHero(): HTMLElement {
  const hero = document.createElement("section");
  hero.className = "a01-hero";

  const inner = document.createElement("div");
  inner.className = "a01-hero__inner";

  const title = document.createElement("h1");
  title.className = "a01-hero__title";
  title.textContent = L("A01_Home_Title");

  const subtitle = document.createElement("p");
  subtitle.className = "a01-hero__subtitle";
  subtitle.textContent = L("A01_Home_Hero_Subtitle");

  const ctas = document.createElement("div");
  ctas.className = "a01-hero__ctas";
  ctas.append(
    createButton({
      label: L("A01_Home_Hero_CtaPrimary"),
      variant: "filled",
      onClick: onA01_Home_GetStarted_Click,
    }),
    createButton({
      label: L("A01_Home_Hero_CtaSecondary"),
      variant: "ghost",
      onClick: onA01_Home_Explore_Click,
    }),
  );

  inner.append(title, subtitle, ctas);
  hero.append(inner);
  return hero;
}

function buildNews(): HTMLElement {
  const section = document.createElement("section");
  section.className = "a01-section";

  const heading = document.createElement("h2");
  heading.className = "a01-section__title";
  heading.textContent = L("A01_Home_News_SectionTitle");

  const list = document.createElement("div");
  list.className = "a01-news-list";

  for (const item of MOCK_NEWS) {
    const row = document.createElement("div");
    row.className = "a01-news-row";

    const tag = createTag(L("A01_Home_News_Tag"), "accent");
    const titleEl = document.createElement("span");
    titleEl.className = "a01-news-row__title";
    titleEl.textContent = item.title;
    const dateEl = document.createElement("span");
    dateEl.className = "a01-news-row__date";
    dateEl.textContent = item.date;

    row.append(tag, titleEl, dateEl);
    list.append(row);
  }

  section.append(heading, list);
  return section;
}

function buildFeatures(): HTMLElement {
  const section = document.createElement("section");
  section.className = "a01-section";

  const heading = document.createElement("h2");
  heading.className = "a01-section__title";
  heading.textContent = L("A01_Home_Features_SectionTitle");

  const grid = document.createElement("div");
  grid.className = "a01-feature-grid";

  const features: [keyof typeof ui_locales, keyof typeof ui_locales][] = [
    ["A01_Home_Feature1_Title", "A01_Home_Feature1_Desc"],
    ["A01_Home_Feature2_Title", "A01_Home_Feature2_Desc"],
    ["A01_Home_Feature3_Title", "A01_Home_Feature3_Desc"],
  ];

  for (const [titleKey, descKey] of features) {
    const desc = document.createElement("p");
    desc.className = "a01-feature__desc";
    desc.textContent = L(descKey);
    const card = createCard({ title: L(titleKey), body: [desc] });
    card.classList.add("a01-feature-card");
    grid.append(card);
  }

  section.append(heading, grid);
  return section;
}

/* -----------------------------------------------------------------------------
 * 페이지 진입점
 * -------------------------------------------------------------------------- */
export function renderA01Home(root: HTMLElement): void {
  const page = document.createElement("div");
  page.className = "a01-home";
  page.append(buildHero(), buildNews(), buildFeatures());
  root.append(page);
}