/* =============================================================================
 * M02_MasterTemplete_UI_Main.ts
 * 마스터 템플릿 메인 칸 — 양식 한 개를 읽어 표·도면 편집 부품에 붙임(계약 `6_계약.md` 화면 부품).
 * 부품 파일이 없거나 못 읽어도 페이지는 뜸 — 빈 자리 글.
 * ========================================================================== */

import { createButton, el, showToast } from "@ui/ui_template_elements";
import { t as L } from "@ui/ui_template_locale";
import {
  readFilled,
  readTemplate,
  saveTemplate,
  StaleError,
  type Kind,
  type Layer,
} from "./M02_MasterTemplete_Api_Fetch";

export interface Selection {
  layer: Layer;
  projectId: string | null;
  kind: Kind;
  name: string;
}

interface EditorHandle {
  getDoc: () => unknown;
  destroy: () => void;
}

type Mods = Record<string, () => Promise<unknown>>;
// 표 부품(sub3) · 도면 부품(sub2) — 파일 이름은 각 창이 정함 → 폴더를 훑어 내보낸 이름으로 찾음
const SHEET_MODS: Mods = import.meta.glob("../ui_template/sheet/*.ts");
const DRAWING_MODS: Mods = import.meta.glob("./M02_MasterTemplete_Drawing*.ts");

async function findExport<T>(mods: Mods, name: string): Promise<T | null> {
  for (const load of Object.values(mods)) {
    try {
      const mod = (await load()) as Record<string, unknown>;
      if (typeof mod[name] === "function") return mod[name] as T;
    } catch {
      // 못 읽는 파일은 건너뜀 — 페이지는 뜸
    }
  }
  return null;
}

export interface MainHandle {
  root: HTMLElement;
  open: (sel: Selection | null) => Promise<void>;
  current: () => Selection | null;
}

/** 이 층에서 고칠 수 있나 — 시스템은 관리자만 · 회사는 여기서 못 고침(공식으로 저장으로만) */
export function canEdit(layer: Layer, isAdmin: boolean): boolean {
  return layer === "project" || layer === "personal" || (layer === "system" && isAdmin);
}

export function createMain(isAdmin: boolean): MainHandle {
  const title = el("h2", { className: "m02-main__title", text: L("M02_PickTemplate") });
  const reload = createButton({ label: L("M02_Reload"), variant: "ghost" });
  const save = createButton({ label: L("M02_Save"), variant: "filled" });
  const notice = el("div", { className: "m02-main__notice", attrs: { hidden: "" } });
  const host = el("div", { className: "m02-main__host" });
  const root = el("div", {
    className: "m02-main",
    children: [
      el("div", { className: "m02-main__head", children: [title, reload, save] }),
      notice,
      host,
    ],
  });

  let sel: Selection | null = null;
  let version = "";
  let loaded: unknown = null;
  let editor: EditorHandle | null = null;
  let seq = 0;

  const showNotice = (nodes: (HTMLElement | string)[]): void => {
    notice.replaceChildren(...nodes);
    notice.hidden = nodes.length === 0;
  };
  const empty = (text: string): void => {
    host.replaceChildren(el("p", { className: "m02-main__empty", text }));
  };
  const bar = (): void => {
    reload.hidden = !sel;
    save.hidden = !sel || !canEdit(sel.layer, isAdmin);
  };

  const drop = (): void => {
    editor?.destroy();
    editor = null;
  };

  async function mount(doc: unknown, at: Selection): Promise<void> {
    const readOnly = !canEdit(at.layer, isAdmin);
    host.replaceChildren();
    if (at.kind === "table") {
      const create = await findExport<(h: HTMLElement, d: unknown, o: object) => EditorHandle>(
        SHEET_MODS,
        "createSheet",
      );
      if (create) {
        editor = create(host, doc, { mode: at.layer === "project" ? "project" : "master" });
        return;
      }
      return empty(L("M02_NoSheet"));
    }
    const mountDrawing = await findExport<(h: HTMLElement, d: unknown, o: object) => EditorHandle>(
      DRAWING_MODS,
      "mountDrawingTemplate",
    );
    if (mountDrawing) {
      editor = mountDrawing(host, doc, { onSave: () => void doSave(), readOnly });
      return;
    }
    empty(L("M02_NoDrawing"));
  }

  async function open(next: Selection | null): Promise<void> {
    const mine = ++seq;
    drop();
    showNotice([]);
    sel = next;
    bar();
    if (!next) {
      title.textContent = L("M02_PickTemplate");
      return empty("");
    }
    title.textContent = next.name;
    try {
      const got = await readTemplate(next.layer, next.kind, next.name, next.projectId);
      if (mine !== seq) return;
      version = got.판 ?? "";
      loaded = got.문서;
      // 프로젝트 층 표 — 작업본 판은 그대로 두고 보이는 문서만 설계값으로 채움(서버가 채움 · 저장 안 함)
      const shown =
        next.layer === "project" && next.kind === "table" && next.projectId
          ? await readFilled(next.projectId, next.name).then(
              (f) => f.문서,
              () => got.문서,
            )
          : got.문서;
      if (mine !== seq) return;
      await mount(shown, next);
    } catch (error) {
      if (mine !== seq) return;
      empty("");
      const why = error instanceof Error ? error.message : "";
      showToast(L("M02_LoadFailed").replace("{value}", why), "error");
    }
  }

  async function doSave(): Promise<void> {
    if (!sel) return;
    const at = sel;
    try {
      const doc = editor ? editor.getDoc() : loaded;
      const info = await saveTemplate(at.layer, at.kind, at.name, at.projectId, version, doc);
      version = info.판;
      loaded = doc;
      showNotice([]);
      showToast(L("M02_Saved"), "success");
    } catch (error) {
      if (error instanceof StaleError) {
        const again = createButton({ label: L("M02_Reload"), variant: "ghost" });
        again.addEventListener("click", () => void open(at));
        showNotice([L("M02_Stale"), again]);
        return;
      }
      const why = error instanceof Error ? error.message : "";
      showToast(L("M02_SaveFailed").replace("{value}", why), "error");
    }
  }

  save.addEventListener("click", () => void doSave());
  reload.addEventListener("click", () => sel && void open(sel));
  bar();
  empty("");
  return { root, open, current: () => sel };
}