/* =============================================================================
 * E05_StabReport_UI_Page.ts
 * E05 안정성평가 보고서(요구서 345 4-3 · 요구 347-5 · PLAN 534-3) — B05~B09 틀(group_workflow).
 *   GET /api/projects/{id}/stab/report → 작업본(없고 2D 결과가 있으면 서버가 처음 만듦) · 판 · stale.
 *   보기 = 내장 엑셀(시트 탭 · 그림 겹판 · 쪽 나눔 점선 · 늦게 불러옴).
 *   조작 = sessionStorage 캐시만(자동저장 없음) · [저장] = PUT {rev, book}(서버 재계산 · 판 다르면 409) ·
 *   [초기화] = POST …/reset · [보고서 갱신] = POST …/refresh(프로그램 몫 시트 · 그림만 다시).
 *   [엑셀] · [PDF] · [PDF 미리보기] = 화면 지금 책을 서버로(보기만이면 작업본 GET) · 저장 안 함.
 * ========================================================================== */

import "./E05_StabReport_UI_Style.css";
import { API_BASE_URL, CURRENT_PROJECT_ID_KEY, ROUTES } from "@config/config_frontend";
import {
  createButton,
  el,
  hideLoadingOverlay,
  showConfirmDialog,
  showLoadingOverlay,
  showToast,
} from "@ui/ui_template_elements";
import { t } from "@ui/ui_template_locale";
import { mountGroupStep } from "../A00_Common/group_workflow";
import type { SpreadsheetHandle } from "../A00_Common/spreadsheet/spreadsheet";
import type { Workbook } from "../A00_Common/spreadsheet/spreadsheet_types";

interface ReportMeta {
  fingerprint: string;
  built_at: string;
  figures: string[];
}

interface ReportResponse {
  book: Workbook | null;
  rev?: string | null;
  meta?: ReportMeta | null;
  stale?: boolean;
  has_initial?: boolean;
  editable?: boolean;
  reason?: string;
  overwritten?: string[];
}

interface CacheEntry {
  rev: string;
  book: Workbook;
}

const cacheKey = (projectId: string): string => `e05_report_cache:${projectId}`;

async function failure(response: Response): Promise<Error> {
  const body = (await response.json().catch(() => ({}))) as { detail?: unknown };
  return new Error(typeof body.detail === "string" ? body.detail : `HTTP ${response.status}`);
}

async function request(path: string, init?: RequestInit): Promise<ReportResponse> {
  const response = await fetch(`${API_BASE_URL}${path}`, {
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    ...init,
  });
  if (!response.ok) throw await failure(response);
  return (await response.json()) as ReportResponse;
}

function download(blob: Blob, name: string): void {
  const url = URL.createObjectURL(blob);
  const a = document.createElement("a");
  a.href = url;
  a.download = name;
  a.click();
  setTimeout(() => URL.revokeObjectURL(url), 1000);
}

export function renderE05StabReport(root: HTMLElement): void {
  const projectId = localStorage.getItem(CURRENT_PROJECT_ID_KEY);
  const main = el("div", { className: "e05-page" });
  const staleBar = el("div", { className: "e05-stale" });
  staleBar.hidden = true;
  const sheetHost = el("div", { className: "e05-sheet" });
  main.append(staleBar, sheetHost);
  const status = el("p", { className: "e05-status" });

  const button = (label: string, variant: "filled" | "ghost" | "danger-ghost", run: () => void) =>
    createButton({ label, variant, onClick: run });
  const saveButton = button(t("Common_Btn_Save"), "filled", () => void save());
  const resetButton = button(t("Common_Btn_Reset"), "danger-ghost", () => void reset());
  const refreshButton = button(t("E05_Btn_Refresh"), "ghost", () => void refresh());
  const xlsxButton = button(t("E05_Btn_Xlsx"), "ghost", () => void exportFile("xlsx"));
  const pdfButton = button(t("E05_Btn_Pdf"), "ghost", () => void exportFile("pdf"));
  const previewButton = button(t("E05_Btn_Preview"), "ghost", () => void preview());
  const staleButton = button(t("E05_Btn_Refresh"), "filled", () => void refresh());
  staleBar.append(el("span", { text: `${t("E05_Stale")} —` }), staleButton);
  const all = [saveButton, resetButton, refreshButton, xlsxButton, pdfButton, previewButton];
  for (const b of all) b.disabled = true; // 읽어 온 뒤 켬

  const exports = el("div", { className: "ui-sidebar-actions" });
  exports.append(xlsxButton, pdfButton, previewButton);
  const actions = el("div", { className: "ui-sidebar-actions" });
  actions.append(refreshButton, resetButton, saveButton);
  const panel = el("div", { className: "ui-sidebar-panel e05-panel" });
  panel.append(el("p", { className: "e05-hint", text: t("E05_Note") }), status, exports, actions);

  const frame = document.createElement("iframe");
  frame.className = "e05-preview__frame";
  frame.title = t("E05_Btn_Preview");
  const previewBox = el("div", { className: "e05-preview" });
  previewBox.hidden = true;
  let previewUrl: string | null = null;
  const closePreview = (): void => {
    previewBox.hidden = true;
    frame.removeAttribute("src");
    if (previewUrl) URL.revokeObjectURL(previewUrl);
    previewUrl = null;
  };
  const head = el("div", { className: "e05-preview__head" });
  head.append(button(t("Common_Btn_Close"), "ghost", closePreview));
  previewBox.append(head, frame);
  main.append(previewBox);

  mountGroupStep(root, ROUTES.E05_STAB_REPORT, { mainContent: main, leftPanel: panel });
  if (!projectId)
    return void sheetHost.append(el("p", { className: "e05-empty", text: t("E05_NoProject") }));

  let sheet: SpreadsheetHandle | null = null;
  let state: ReportResponse | null = null;
  let editable = false;
  let dirty = false;
  let busy = false;

  const paint = (): void => {
    const lines: string[] = [];
    if (!editable) lines.push(t("E05_ReadOnly"));
    if (busy) lines.push(t("E05_Working"));
    if (dirty) lines.push(t("E05_Unsaved"));
    if (state?.meta?.built_at)
      lines.push(`${t("E05_BuiltAt")} ${state.meta.built_at.replace("T", " ")}`);
    status.textContent = lines.join("\n");
    const ready = Boolean(state?.book) && !busy;
    saveButton.disabled = !ready || !editable || !dirty;
    resetButton.disabled = !ready || !editable || !state?.has_initial;
    refreshButton.disabled = staleButton.disabled = !ready || !editable;
    xlsxButton.disabled = pdfButton.disabled = previewButton.disabled = !ready;
    staleBar.hidden = !state?.stale || !editable;
  };

  const figureSrc = (key: string): string =>
    `${API_BASE_URL}/projects/${projectId}/stab/report/fig?key=${encodeURIComponent(key)}` +
    `&v=${encodeURIComponent(state?.meta?.built_at ?? "")}`;

  /** 서버 응답 받음 — keepCache 면 같은 판 캐시를 살림 */
  const adopt = async (body: ReportResponse, keepCache: boolean): Promise<void> => {
    state = body;
    if (body.editable !== undefined) editable = body.editable;
    if (!body.book) {
      sheet?.destroy();
      sheet = null;
      sheetHost.replaceChildren(el("p", { className: "e05-empty", text: body.reason ?? "" }));
      dirty = false;
      return paint();
    }
    let book = body.book;
    const raw = keepCache ? sessionStorage.getItem(cacheKey(projectId)) : null;
    const cached = raw ? (JSON.parse(raw) as CacheEntry) : null;
    if (cached && cached.rev === body.rev) book = cached.book;
    else sessionStorage.removeItem(cacheKey(projectId));
    dirty = Boolean(cached && cached.rev === body.rev);
    const { createSpreadsheet } = await import("../A00_Common/spreadsheet/spreadsheet");
    sheet?.destroy();
    sheetHost.replaceChildren();
    sheet = createSpreadsheet(sheetHost, book, {
      tabs: true,
      readOnly: !editable,
      figureSrc,
      onChange: (next) => {
        dirty = true;
        sessionStorage.setItem(
          cacheKey(projectId),
          JSON.stringify({ rev: state?.rev ?? "", book: next } satisfies CacheEntry),
        );
        paint();
      },
    });
    paint();
  };

  const run = async (task: () => Promise<void>, overlay = false): Promise<void> => {
    busy = true;
    paint();
    if (overlay) showLoadingOverlay();
    try {
      await task();
    } catch (error) {
      showToast(error instanceof Error ? error.message : t("Common_Status_Error"), "error");
    } finally {
      if (overlay) hideLoadingOverlay();
      busy = false;
      paint();
    }
  };

  const putBook = async (): Promise<void> => {
    if (!sheet || !state) return;
    const body = await request(`/projects/${projectId}/stab/report`, {
      method: "PUT",
      body: JSON.stringify({ rev: state.rev, book: sheet.getDoc() }),
    });
    sessionStorage.removeItem(cacheKey(projectId));
    state = { ...state, rev: body.rev, meta: body.meta, stale: body.stale };
    dirty = false;
  };

  async function save(): Promise<void> {
    if (!editable || !dirty) return;
    await run(async () => {
      await putBook();
      showToast(t("E05_Saved"), "success");
    }, true);
  }

  async function refresh(): Promise<void> {
    if (!editable || !state) return;
    if (
      dirty &&
      !(await showConfirmDialog(t("E05_SaveFirst"), t("Common_Btn_Save"), t("Common_Btn_Cancel")))
    )
      return;
    await run(async () => {
      if (dirty) await putBook();
      const body = await request(`/projects/${projectId}/stab/report/refresh`, {
        method: "POST",
        body: JSON.stringify({ rev: state?.rev }),
      });
      await adopt({ ...body, editable }, false);
      const over = body.overwritten ?? [];
      if (over.length) showToast(`${t("E05_Overwritten")} ${over.join(" · ")}`, "warning", 8000);
      else showToast(t("E05_Refreshed"), "success");
    });
  }

  async function reset(): Promise<void> {
    if (!editable) return;
    if (
      !(await showConfirmDialog(
        t("E05_ResetConfirm"),
        t("Common_Btn_Reset"),
        t("Common_Btn_Cancel"),
      ))
    )
      return;
    await run(async () => {
      const body = await request(`/projects/${projectId}/stab/report/reset`, { method: "POST" });
      await adopt({ ...body, editable }, false);
      showToast(t("E05_ResetDone"), "success");
    }, true);
  }

  /** 화면 지금 책(고칠 수 있으면) 또는 작업본(보기만) → 서버가 다시 풀어 만든 파일 */
  async function fetchFile(kind: "xlsx" | "pdf"): Promise<Blob> {
    const url = `${API_BASE_URL}/projects/${projectId}/stab/report/${kind}`;
    const init: RequestInit =
      editable && sheet
        ? {
            method: "POST",
            credentials: "include",
            headers: { "Content-Type": "application/json" },
            body: JSON.stringify({ book: sheet.getDoc() }),
          }
        : { credentials: "include" };
    const response = await fetch(url, init);
    if (!response.ok) throw await failure(response);
    return response.blob();
  }

  async function exportFile(kind: "xlsx" | "pdf"): Promise<void> {
    await run(async () => download(await fetchFile(kind), `안정성평가_보고서.${kind}`));
  }

  async function preview(): Promise<void> {
    await run(async () => {
      const blob = await fetchFile("pdf");
      closePreview();
      previewUrl = URL.createObjectURL(blob);
      frame.src = previewUrl;
      previewBox.hidden = false;
    });
  }

  void run(async () => {
    try {
      await adopt(await request(`/projects/${projectId}/stab/report`), true);
    } catch (error) {
      sheetHost.replaceChildren(
        el("p", {
          className: "e05-empty",
          text: error instanceof Error ? error.message : t("Common_Status_Error"),
        }),
      );
    }
  });
}