/* =============================================================================
 * B09_Draft_Print_Page.ts
 * 인쇄 미리보기 페이지(PLAN 302-1 · 요구 192-3 · 초안) — 주소 #/b09-print(`…_Print_Route`).
 *   좌측 = 영역 셋(도면 · 수량산출 · 원가계산) 고르기 + 그 영역 쪽 목록(체크로 빼고 넣기 · 차례 그대로) +
 *          [PDF 내려받기] [엑셀 내려받기](도면 = PDF 만) + [B09 로 돌아가기]
 *   본문 = 고른 쪽들의 PDF 를 브라우저 PDF 보기로(보는 것 = 받는 것) · 만드는 동안 작은 표시(잠금 없음) ·
 *          실패 = 까닭 한 줄 · 체크를 바꾸면 다시 만듦(최신 요청만 채택)
 *   영역 = 다른 창 파일(`…_Print_Quantity` collectQuantitySheets · `…_Print_Cost` collectCostSheets ·
 *          `…_Print_Drawings` fetchDrawingList · fetchDrawingsPdf) — 없으면 「준비 중」
 *   표 영역 PDF · 엑셀 = 서버(`B09_Draft_Print_Router` table-pdf · table-xlsx) · 서버는 꼴만 바꿈
 * ========================================================================== */

import "@ui/ui_template_general_layout.css";
import "./B09_Draft_Print_Page.css";
import { API_BASE_URL, CURRENT_PROJECT_ID_KEY, ROUTES } from "@config/config_frontend";
import { attachCollapsible, createPanelCard } from "@ui/ui_template_collapsible";
import { createButton } from "@ui/ui_template_elements";
import { createWorkflowLayout } from "@ui/ui_template_workflow_layout";
import type { MountedPage } from "../../A00_Common/router";
import { navigateTo } from "../../A00_Common/router";
import { workflowSteps } from "../../A00_Common/b_page_scaffold";
import { goToWorkflowStage, WORKFLOW_STEP_ROUTES } from "../../A00_Common/b_workflow_nav";
import { inlineImages, pdfBody, xlsxBody } from "./B09_Draft_Print_Table";
import type {
  CollectSheets,
  DrawingItem,
  FetchDrawingList,
  FetchDrawingsPdf,
  PrintSheet,
} from "./B09_Draft_Print_Types";

type AreaId = "drawings" | "quantity" | "cost";

const AREAS: { id: AreaId; label: string; file: string }[] = [
  { id: "drawings", label: "도면", file: "./B09_Draft_Print_Drawings.ts" },
  { id: "quantity", label: "수량산출", file: "./B09_Draft_Print_Quantity.ts" },
  { id: "cost", label: "원가계산", file: "./B09_Draft_Print_Cost.ts" },
];

/** 영역 파일(다른 창 몫) — 없는 파일은 목록에 없음 = 「준비 중」 */
const MODS = import.meta.glob([
  "./B09_Draft_Print_Drawings.ts",
  "./B09_Draft_Print_Quantity.ts",
  "./B09_Draft_Print_Cost.ts",
]);

/** 영역 한 벌 — 쪽 목록 · 고른 쪽 PDF · 엑셀(도면 없음) */
interface Area {
  items: DrawingItem[];
  pdf: (ids: string[]) => Promise<Blob>;
  xlsx?: (ids: string[]) => Promise<Blob>;
  /** 그 PDF 곁 알림(도면 = 못 넣은 그림 수) */
  note?: (pdf: Blob) => string;
}

async function post(projectId: string, path: string, body: unknown): Promise<Blob> {
  const res = await fetch(`${API_BASE_URL}/projects/${projectId}/print/${path}`, {
    method: "POST",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(body),
  });
  if (!res.ok) {
    const detail = ((await res.json().catch(() => null)) as { detail?: unknown } | null)?.detail;
    throw new Error(typeof detail === "string" ? detail : `HTTP ${res.status}`);
  }
  return res.blob();
}

/** 표 영역 — 쪽 = PrintSheet · PDF · 엑셀 = 서버 꼴 바꿈 */
function tableArea(projectId: string, title: string, sheets: PrintSheet[]): Area {
  const pick = (ids: string[]) => ids.map((id) => sheets.find((s) => s.id === id)!);
  return {
    items: sheets.map(({ id, name }) => ({ id, name })),
    pdf: async (ids) => {
      const picked = await Promise.all(pick(ids).map(inlineImages));
      return post(projectId, "table-pdf", pdfBody(title, picked));
    },
    xlsx: (ids) => post(projectId, "table-xlsx", xlsxBody(title, pick(ids))),
  };
}

/** 영역 파일 읽기 — 없음 = null(준비 중) */
async function loadArea(projectId: string, id: AreaId): Promise<Area | null> {
  const def = AREAS.find((a) => a.id === id)!;
  const load = MODS[def.file];
  if (!load) return null;
  const mod = (await load()) as Record<string, unknown>;
  if (id === "drawings") {
    const list = mod.fetchDrawingList as FetchDrawingList | undefined;
    const pdf = mod.fetchDrawingsPdf as FetchDrawingsPdf | undefined;
    if (!list || !pdf) return null;
    const skipped = mod.skippedImagesOf as ((b: Blob) => Record<string, number>) | undefined;
    const note = (b: Blob) => {
      const n = Object.values(skipped?.(b) ?? {}).reduce((a, v) => a + v, 0);
      return n ? ` · 못 넣은 그림 ${n}개` : "";
    };
    return { items: await list(projectId), pdf: (ids) => pdf(projectId, ids), note };
  }
  const collect = mod[id === "quantity" ? "collectQuantitySheets" : "collectCostSheets"] as
    CollectSheets | undefined;
  return collect ? tableArea(projectId, def.label, await collect(projectId)) : null;
}

function save(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 renderB09Print(root: HTMLElement): MountedPage {
  const projectId = localStorage.getItem(CURRENT_PROJECT_ID_KEY);

  const status = document.createElement("p");
  status.className = "b09-print__status";
  status.dataset.b09PrintStatus = "";
  const frame = document.createElement("iframe");
  frame.className = "b09-print__frame";
  frame.title = "인쇄 미리보기";
  const body = document.createElement("div");
  body.className = "b09-print";
  body.append(status, frame);

  const areaCard = createPanelCard("영역");
  const areaRow = document.createElement("div");
  areaRow.className = "b09-print__areas";
  areaCard.append(areaRow);
  const sheetCard = createPanelCard("쪽 목록");
  const list = document.createElement("div");
  list.className = "b09-print__list";
  sheetCard.append(list);

  let area: Area | null = null;
  let areaId: AreaId = AREAS[0].id;
  let off = new Set<string>(); // 체크 뺀 쪽
  let seq = 0;
  let shown: { url: string; blob: Promise<Blob> } | null = null;
  let timer = 0;

  const label = () => AREAS.find((a) => a.id === areaId)!.label;
  const say = (text: string, error = false) => {
    status.textContent = text;
    status.classList.toggle("is-error", error);
  };
  const picked = () => (area?.items ?? []).map((it) => it.id).filter((id) => !off.has(id));
  const clearFrame = () => {
    if (shown?.url) URL.revokeObjectURL(shown.url);
    shown = null;
    frame.removeAttribute("src");
  };

  /** 고른 쪽 PDF 다시 만듦 — 최신 요청만 보임 · 내려받기는 같은 PDF */
  const rebuild = () => {
    const my = ++seq;
    const ids = picked();
    clearFrame();
    if (!area) return;
    if (!ids.length) return say("고른 쪽이 없습니다.");
    say(`${label()} PDF 만드는 중…`);
    const blob = area.pdf(ids);
    shown = { url: "", blob };
    blob.then(
      (b) => {
        if (my !== seq) return;
        shown!.url = URL.createObjectURL(b);
        frame.src = shown!.url;
        say(`${label()} · ${ids.length}장 묶음${area?.note?.(b) ?? ""}`);
      },
      (error: unknown) => my === seq && say(`PDF 를 못 만들었습니다 — ${errText(error)}`, true),
    );
  };
  const later = () => {
    clearTimeout(timer);
    timer = window.setTimeout(rebuild, 300);
  };

  const pdfBtn = createButton({
    label: "PDF 내려받기",
    onClick: () => {
      if (!shown) return;
      const name = `${label()}.pdf`;
      shown.blob.then(
        (b) => save(b, name),
        () => undefined,
      );
    },
  });
  pdfBtn.dataset.b09PrintPdf = "";
  const xlsxBtn = createButton({
    label: "엑셀 내려받기",
    variant: "ghost",
    onClick: () => {
      const ids = picked();
      if (!area?.xlsx || !ids.length) return;
      const name = `${label()}.xlsx`;
      say(`${label()} 엑셀 만드는 중…`);
      area.xlsx(ids).then(
        (b) => (save(b, name), say(`${label()} 엑셀을 내려받았습니다.`)),
        (error: unknown) => say(`엑셀을 못 만들었습니다 — ${errText(error)}`, true),
      );
    },
  });
  xlsxBtn.dataset.b09PrintXlsx = "";
  const back = createButton({
    label: "B09 로 돌아가기",
    variant: "ghost",
    onClick: () => navigateTo(ROUTES.B09_ESTIMATION),
  });

  const drawList = () => {
    list.replaceChildren(
      ...(area?.items ?? []).map((it) => {
        const row = document.createElement("label");
        row.className = "b09-print__item";
        const box = document.createElement("input");
        box.type = "checkbox";
        box.checked = !off.has(it.id);
        box.dataset.b09PrintItem = it.id;
        box.addEventListener("change", () => {
          if (box.checked) off.delete(it.id);
          else off.add(it.id);
          later();
        });
        const name = document.createElement("span");
        name.textContent = it.name;
        row.append(box, name);
        return row;
      }),
    );
  };

  const pickArea = (id: AreaId) => {
    areaId = id;
    area = null;
    off = new Set();
    const my = ++seq;
    clearFrame();
    areaRow.replaceChildren(
      ...AREAS.map((a) => {
        const b = createButton({
          label: a.label,
          size: "sm",
          variant: a.id === id ? "filled" : "ghost",
          onClick: () => a.id !== areaId && pickArea(a.id),
        });
        b.dataset.b09PrintArea = a.id;
        return b;
      }),
    );
    xlsxBtn.hidden = id === "drawings";
    drawList();
    if (!projectId) return say("현재 프로젝트가 없습니다.", true);
    say(`${label()} 쪽 목록 읽는 중…`);
    loadArea(projectId, id).then(
      (got) => {
        if (my !== seq) return;
        if (!got) return say(`${label()} — 준비 중`);
        area = got;
        drawList();
        if (!got.items.length) return say(`${label()} — 쪽이 없습니다.`);
        rebuild();
      },
      (error: unknown) =>
        my === seq && say(`${label()} 목록을 못 읽었습니다 — ${errText(error)}`, true),
    );
  };

  // 두 줄(302-5) — 위 = 내려받기 · 아래 = [?](도움말 줄) · 돌아가기 — 패널 폭 넘침 없음
  const files = document.createElement("div");
  files.className = "b09-print__row";
  files.append(pdfBtn, xlsxBtn);
  const nav = document.createElement("div");
  nav.className = "b09-print__row";
  nav.dataset.helpRow = "";
  nav.append(back);
  const actions = document.createElement("div");
  actions.className = "ui-sidebar-actions b09-print__actions";
  actions.append(files, nav);
  const left = document.createElement("div");
  left.className = "ui-sidebar-panel b09-print__panel";
  left.append(areaCard, sheetCard, actions);
  attachCollapsible(left);

  const layout = createWorkflowLayout({
    title: "인쇄 미리보기",
    steps: workflowSteps(),
    activeStep: 6,
    mainContent: body,
    leftPanel: left,
    routes: WORKFLOW_STEP_ROUTES,
    onStepClick: (stepIndex: number) => {
      if (projectId) goToWorkflowStage(projectId, WORKFLOW_STEP_ROUTES[stepIndex]);
    },
  });
  root.append(layout.root);
  pickArea(areaId);

  return {
    covers: () => false,
    show: () => undefined,
    dispose: () => {
      seq++;
      clearTimeout(timer);
      clearFrame();
    },
  };
}

const errText = (error: unknown): string =>
  error instanceof Error ? error.message : String(error);