Aislo/B07_DesignDetail/B07_DesignDetail_UI_Page.ts

/* =============================================================================
 * B07_DesignDetail_UI_Page.ts
 * 로그인 후 07: 4차 워크플로우 (상세 설계) — 독립형 2D CAD 임베드
 *
 * B07_DesignDetail/openwebcad를 프로젝트 소유 B07 CAD 앱으로 빌드하여
 * /b07-cad 경로로 서빙한다. 업무 도면은 추후 same-origin postMessage로
 * JSON만 전달하며 DXF/DWG 파싱은 이 브라우저 앱에서 수행하지 않는다.
 *
 * 레이아웃 (사용자 지시): 사이드 패널 빈 상태 유지 + 상세 영역 CAD 화면.
 * 제약 준수 (frontend.md §2 3단 레이아웃): createWorkflowLayout 재사용.
 * ========================================================================== */

import "./B07_DesignDetail_UI_Style.css";
import { attachCollapsible } from "@ui/ui_template_collapsible";
import { ui_locales, currentLanguageIndex } from "@ui/ui_template_locale";
import {
  createButton,
  hideLoadingOverlay,
  showLoadingOverlay,
  showToast,
} from "@ui/ui_template_elements";
import { createWorkflowLayout } from "@ui/ui_template_workflow_layout";
import { CURRENT_PROJECT_ID_KEY } from "@config/config_frontend";
import { workflowSteps } from "../A00_Common/b_page_scaffold";
import {
  fetchWorkflowState,
  goToWorkflowStage,
  WORKFLOW_STEP_ROUTES,
  type WorkflowState,
} from "../A00_Common/b_workflow_nav";
import {
  confirmDesignDrawing,
  fetchDesignDrawing,
  fetchDesignDrawingList,
  invalidateDesignDrawing,
  type CadDrawing,
  type CrossDesignInfo,
  type DesignDrawingItem,
  type DesignDrawingResponse,
  type QuantityTable,
} from "./B07_DesignDetail_Api_Fetch";
import { appendStructureEntities } from "./B07_DesignDetail_UI_Cad_Structures";

/** CAD 앱 수량 패널로 넘기는 설계 컨텍스트 (openwebcad DesignMeta와 동일 형식). */
interface DesignMeta {
  kind: "cover" | "cross" | "longitudinal" | "mass_haul" | "watershed";
  title: string;
  info: string;
  confirmed: boolean;
  quantityTable: QuantityTable | null;
  hasPrev: boolean;
  hasNext: boolean;
}

/** CAD 저장 응답 (도면 + 편집된 수량표). */
interface SaveResult {
  drawing: CadDrawing;
  quantityTable: QuantityTable | null;
}

/** B07 독립형 CAD 정적 경로 (main.py 마운트, dev는 vite proxy 위임) */
const B07_CAD_APP_URL = "/b07-cad/index.html";

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

const CAD_LOAD_MESSAGE = "aislo:b08:load-drawing";
const CAD_READY_MESSAGE = "aislo:b08:drawing-ready";
const CAD_LOADED_MESSAGE = "aislo:b08:drawing-loaded";
const CAD_ERROR_MESSAGE = "aislo:b08:drawing-error";
const CAD_CHANGED_MESSAGE = "aislo:b08:drawing-changed";
const CAD_SAVE_REQUEST_MESSAGE = "aislo:b08:save-request";
const CAD_SAVE_RESPONSE_MESSAGE = "aislo:b08:save-response";
const CAD_NAVIGATE_MESSAGE = "aislo:b08:navigate";
/** CAD 앱 알림 — 프로젝트 공용 토스트로 띄운다(2026-08-30 사용자 지시).
 *  CAD 안 react-toastify는 모양·자리가 달라 한 화면에 두 종류가 섞여 보였다. */
const CAD_TOAST_MESSAGE = "aislo:b08:toast";
const CAD_TOAST_ACTION_MESSAGE = "aislo:b08:toast-action";

/** 도면 구성 12분류 (2026-08-29 사용자 확정 순서). kind가 없으면 아직 만들지 않는 도면. */
const DRAWING_GROUPS: readonly { label: string; kind?: DesignDrawingItem["kind"] }[] = [
  { label: "표지", kind: "cover" },
  { label: "계획평면도(지형)" },
  { label: "계획평면도(노선배치도)" },
  { label: "계획평면도(배치도)" },
  { label: "계획평면도(라이다)" },
  { label: "종단면도", kind: "longitudinal" },
  { label: "표준 횡단면도" },
  { label: "횡단면도", kind: "cross" },
  { label: "토적도(유토곡선)", kind: "mass_haul" },
  { label: "유역도(배수 유역도)", kind: "watershed" },
  { label: "표준도" },
  { label: "용지도" },
];

/** B06 확정 산출물 기반 도면 목록 패널. */
function buildDrawingSidePanel(
  drawings: DesignDrawingItem[],
  onSelect: (drawing: DesignDrawingItem) => void,
  errorMessage?: string,
): HTMLDivElement {
  const panel = document.createElement("div");
  panel.className = "b07-drawing-list";
  const heading = document.createElement("div");
  heading.className = "b07-drawing-list__heading";
  const title = document.createElement("strong");
  title.textContent = "설계 도면";
  const count = document.createElement("span");
  count.textContent = `${drawings.length}건`;
  heading.append(title, count);
  panel.append(heading);

  if (errorMessage || drawings.length === 0) {
    const empty = document.createElement("p");
    empty.className = "b07-drawing-list__empty";
    empty.textContent = errorMessage ?? "확정된 종·횡단 도면이 없습니다.";
    panel.append(empty);
    return panel;
  }

  const drawingButton = (drawing: DesignDrawingItem, label: string): HTMLButtonElement => {
    const button = document.createElement("button");
    button.type = "button";
    button.className = "b07-drawing-button";
    button.dataset.drawingId = drawing.id;
    button.dataset.confirmed = String(drawing.confirmed);
    const name = document.createElement("span");
    name.className = "b07-drawing-button__name";
    name.textContent = label;
    button.append(name);
    button.addEventListener("click", () => onSelect(drawing));
    return button;
  };

  for (const group of DRAWING_GROUPS) {
    const items = group.kind ? drawings.filter((item) => item.kind === group.kind) : [];
    // 한 장짜리(와 아직 없는 도면)는 컨테이너 없이 버튼 하나로 둔다.
    if (items.length <= 1) {
      const [drawing] = items;
      const button = drawing
        ? drawingButton(drawing, group.label)
        : document.createElement("button");
      if (!drawing) {
        button.type = "button";
        button.className = "b07-drawing-button";
        button.disabled = true;
        button.title = "준비 중";
        const name = document.createElement("span");
        name.className = "b07-drawing-button__name";
        name.textContent = group.label;
        button.append(name);
      }
      button.dataset.pending = String(!drawing);
      panel.append(button);
      continue;
    }
    const section = document.createElement("section");
    // ui-sidebar-section: 사이드 컨테이너 공통 외곽선(B04~B06과 통일, 2026-08-06 사용자 지시).
    section.className = "b07-drawing-group ui-collapsible ui-sidebar-section";
    if (group.kind) section.dataset.kind = group.kind;
    const sectionTitle = document.createElement("h3");
    sectionTitle.className = "ui-collapsible__title";
    sectionTitle.textContent = `${group.label} ${items.length}`;
    section.append(sectionTitle);
    for (const drawing of items) {
      // 횡단면도는 장 단위(여러 측점)라 서버가 준 "N장 (구간)" 라벨을 그대로 쓴다.
      section.append(drawingButton(drawing, drawing.label));
    }
    panel.append(section);
  }
  attachCollapsible(panel);
  return panel;
}

const GROUND_TYPE_LABEL: Record<CrossDesignInfo["ground_type"], keyof typeof ui_locales> = {
  soil: "B06_Design_Ground_Soil",
  ripping_rock: "B06_Design_Ground_Ripping",
  blasting_rock: "B06_Design_Ground_Blasting",
};

/** 단면유형에서 절토측 표기를 유도한다. */
function cutSideLabel(mode: CrossDesignInfo["section_mode"]): string {
  if (mode === "left_cut") return L("B06_Design_Ditch_Left");
  if (mode === "right_cut") return L("B06_Design_Ditch_Right");
  if (mode === "both_cut") return L("B06_Design_Mode_BothCut");
  return L("B06_Design_Mode_BothFill");
}

/** 측구 규격 표시 문자열 (design 신구조: 형식별 ditch spec, F-2 호환). */
function ditchLabel(design: CrossDesignInfo): string {
  const ditch = design.ditch;
  if (!ditch || ditch.type === "none" || design.ditch_enabled === false) return "없음";
  if (ditch.type === "l_type")
    return `L형 ${ditch.width_m.toFixed(2)}×${ditch.depth_m.toFixed(2)}m`;
  return `${ditch.top_width_m.toFixed(2)}×${ditch.depth_m.toFixed(2)}m`;
}

function infoRow(label: string, value: string): HTMLElement {
  const row = document.createElement("div");
  row.className = "b07-info__row";
  const key = document.createElement("span");
  key.className = "b07-info__key";
  key.textContent = label;
  const val = document.createElement("span");
  val.className = "b07-info__val";
  val.textContent = value;
  row.append(key, val);
  return row;
}

/** 선택 횡단도의 지반정보/계획정보를 2분할로 렌더한다 (잠정치, B07 확정 시 재계산). */
function buildDesignInfoPanel(title: string, design: CrossDesignInfo | null): HTMLElement {
  const panel = document.createElement("div");
  panel.className = "b07-info";
  const heading = document.createElement("div");
  heading.className = "b07-info__heading";
  const stationName = document.createElement("strong");
  stationName.textContent = `${L("B07_Info_Station")} ${title}`;
  const confirmed = design?.status === "confirmed";
  const badge = document.createElement("span");
  badge.className = `b07-info__badge${confirmed ? " b07-info__badge--confirmed" : ""}`;
  badge.textContent = confirmed ? L("B07_Info_Confirmed") : L("B07_Info_Provisional");
  heading.append(stationName, badge);
  panel.append(heading);

  if (!design) {
    const empty = document.createElement("p");
    empty.className = "b07-info__empty";
    empty.textContent = L("B07_Info_NoDesign");
    panel.append(empty);
    return panel;
  }

  const ground = document.createElement("section");
  ground.className = "b07-info__block";
  const groundTitle = document.createElement("h4");
  groundTitle.textContent = L("B07_Info_Ground_Title");
  ground.append(
    groundTitle,
    infoRow(L("B07_Info_GroundType"), L(GROUND_TYPE_LABEL[design.ground_type])),
    infoRow(L("B07_Info_CutSide"), cutSideLabel(design.section_mode)),
    infoRow(
      L("B07_Info_DitchSide"),
      design.ditch_side === "left" ? L("B06_Design_Ditch_Left") : L("B06_Design_Ditch_Right"),
    ),
  );

  const plan = document.createElement("section");
  plan.className = "b07-info__block";
  const planTitle = document.createElement("h4");
  planTitle.textContent = L("B07_Info_Plan_Title");
  plan.append(
    planTitle,
    infoRow(L("B07_Info_DesignElevation"), `${design.design_elevation_m.toFixed(2)}m`),
    infoRow(L("B07_Info_CutSlope"), `1:${design.cut_slope_ratio}`),
    infoRow(L("B07_Info_FillSlope"), `1:${design.fill_slope_ratio}`),
    infoRow(L("B07_Info_RoadWidth"), `${design.roadbed_width_m.toFixed(2)}m`),
    infoRow(L("B07_Info_Ditch"), ditchLabel(design)),
    infoRow(L("B07_Info_CutArea"), `${design.cut_area_m2.toFixed(2)}㎡`),
    infoRow(L("B07_Info_FillArea"), `${design.fill_area_m2.toFixed(2)}㎡`),
  );

  panel.append(ground, plan);
  return panel;
}

/* -----------------------------------------------------------------------------
 * 페이지 진입점
 * -------------------------------------------------------------------------- */
export async function renderB07DesignDetail(root: HTMLElement): Promise<void> {
  const projectId = localStorage.getItem(CURRENT_PROJECT_ID_KEY);
  let workflowState: WorkflowState | undefined;
  let drawings: DesignDrawingItem[] = [];
  let drawingError: string | undefined;
  if (projectId) {
    const [workflowResult, drawingResult] = await Promise.allSettled([
      fetchWorkflowState(projectId),
      fetchDesignDrawingList(projectId),
    ]);
    if (workflowResult.status === "fulfilled") workflowState = workflowResult.value;
    if (drawingResult.status === "fulfilled") drawings = drawingResult.value.drawings;
    else
      drawingError =
        drawingResult.reason instanceof Error
          ? drawingResult.reason.message
          : "도면 목록을 불러오지 못했습니다.";
  }

  const cadHost = document.createElement("div");
  cadHost.className = "b07-cad-host";
  const frame = document.createElement("iframe");
  frame.className = "b07-cad-frame";
  frame.src = B07_CAD_APP_URL;
  frame.title = L("B07_Design_Title");
  const license = document.createElement("a");
  license.className = "b07-cad-license";
  license.href = "/b07-cad/THIRD_PARTY_LICENSES.txt";
  license.target = "_blank";
  license.rel = "noreferrer";
  license.textContent = "Drawing engine based on OpenWebCAD · MIT License";
  cadHost.append(frame, license);

  let cadReady = false;
  let pendingLoad: { drawing: CadDrawing; meta: DesignMeta } | undefined;
  let currentDrawing: DesignDrawingItem | undefined;
  let currentIndex = -1;
  let currentConfirmed = false;
  // 단계 완료 기준은 횡단도만 본다 (종단도 확정 여부는 다음 단계 진행과 무관).
  const isCross = (item: DesignDrawingItem): boolean => item.kind === "cross";
  let allDrawingsConfirmed =
    drawings.some(isCross) && drawings.filter(isCross).every((item) => item.confirmed);
  let resolveSave: ((payload: SaveResult) => void) | undefined;
  let drawingListEl: HTMLElement | undefined;
  const infoPanelHost = document.createElement("div");
  infoPanelHost.className = "b07-info-host";

  const updateInfoPanel = (drawing: DesignDrawingItem, response: DesignDrawingResponse): void => {
    if (drawing.kind !== "cross") {
      infoPanelHost.replaceChildren();
      return;
    }
    const title = drawing.label;
    infoPanelHost.replaceChildren(buildDesignInfoPanel(title, response.design ?? null));
  };

  const confirmButton = createButton({
    label: "현재 도면 확정",
    variant: "filled",
    onClick: () => void confirmCurrentDrawing(),
  });
  confirmButton.disabled = true;

  const findButton = (drawingId: string) =>
    drawingListEl?.querySelector<HTMLButtonElement>(
      `.b07-drawing-button[data-drawing-id="${drawingId}"]`,
    ) ?? undefined;

  const highlightActive = (drawingId: string) => {
    drawingListEl?.querySelectorAll<HTMLButtonElement>(".b07-drawing-button").forEach((item) => {
      item.dataset.active = String(item.dataset.drawingId === drawingId);
    });
  };

  const buildMeta = (
    drawing: DesignDrawingItem,
    response: DesignDrawingResponse,
    index: number,
  ): DesignMeta => ({
    kind: drawing.kind,
    title: drawing.label,
    info: drawing.kind === "cross" ? drawing.label : "",
    confirmed: response.confirmed,
    quantityTable: response.quantity_table ?? null,
    hasPrev: index > 0,
    hasNext: index < drawings.length - 1,
  });

  const sendLoad = (drawing: CadDrawing, meta: DesignMeta) => {
    pendingLoad = { drawing, meta };
    if (!cadReady) return;
    frame.contentWindow?.postMessage(
      { type: CAD_LOAD_MESSAGE, drawing, meta },
      window.location.origin,
    );
    pendingLoad = undefined;
  };

  /**
   * 도면 캐시 — 진입 직후 **목록의 모든 도면**을 배경에서 받아 둔다(2026-08-30 사용자 지시).
   *
   * 서버가 도면을 요청마다 새로 조립해(측점 설계선·장 배치·표) 클릭 한 번에 0.3~0.6초,
   * 구조물 얹기까지 더하면 0.8~1.0초가 걸렸다. 미리 받아 두면 클릭은 캐시에서 즉시 꺼낸다.
   * sessionStorage가 아니라 **모듈 메모리**에 둔다 — 유역도 한 장이 엔티티 1,581개라
   * 세션 저장 한도(5MB)를 넘길 위험이 있고, 새로고침이면 정본에서 다시 받는 편이 맞다.
   */
  const drawingCache = new Map<string, Promise<DesignDrawingResponse>>();

  /** 도면 하나를 받아 구조물까지 얹은 응답. 같은 id로 겹쳐 부르면 같은 Promise를 쓴다. */
  const requestDrawing = (drawing: DesignDrawingItem): Promise<DesignDrawingResponse> => {
    const cached = drawingCache.get(drawing.id);
    if (cached) return cached;
    const request = (async () => {
      const response = await fetchDesignDrawing(projectId as string, drawing.id);
      // 구조물(배수관·기슭막이·세월교·BOX·물넘이포장)은 B06 산식이 프론트에 있어
      // 여기서 얹는다. 확정본은 이미 구조물이 담겨 저장돼 있으므로 건드리지 않는다.
      if (drawing.kind === "cross" && !response.confirmed) {
        await appendStructureEntities(projectId as string, response.route_id, response.drawing);
      }
      return response;
    })().catch((error) => {
      drawingCache.delete(drawing.id); // 실패는 캐시에 남기지 않는다 — 다음 클릭에 다시 받는다.
      throw error;
    });
    drawingCache.set(drawing.id, request);
    return request;
  };

  /** 목록 전체를 순서대로 미리 받는다. 화면을 막지 않도록 한 번에 하나씩만 간다. */
  const prefetchAllDrawings = async (): Promise<void> => {
    if (!projectId) return;
    for (const item of drawings) {
      try {
        await requestDrawing(item);
      } catch {
        /* 한 장을 못 받아도 나머지는 계속 받는다 — 클릭 때 다시 시도한다. */
      }
    }
  };

  const loadDrawing = async (drawing: DesignDrawingItem, index: number) => {
    if (!projectId) return;
    highlightActive(drawing.id);
    const button = findButton(drawing.id);
    if (button) button.dataset.loading = "true";
    cadHost.dataset.loading = "true";
    try {
      const response = await requestDrawing(drawing);
      currentDrawing = drawing;
      currentIndex = index;
      currentConfirmed = response.confirmed;
      confirmButton.disabled = response.confirmed;
      updateInfoPanel(drawing, response);
      sendLoad(response.drawing, buildMeta(drawing, response, index));
    } catch (error) {
      cadHost.dataset.loading = "false";
      cadHost.dataset.error =
        error instanceof Error ? error.message : "CAD 도면을 불러오지 못했습니다.";
    } finally {
      if (button) button.dataset.loading = "false";
    }
  };

  const selectDrawing = (drawing: DesignDrawingItem) => {
    void loadDrawing(drawing, drawings.indexOf(drawing));
  };

  const navigateDrawing = (direction: "prev" | "next") => {
    if (currentIndex < 0) return;
    const target = direction === "prev" ? currentIndex - 1 : currentIndex + 1;
    if (target < 0 || target >= drawings.length) return;
    void loadDrawing(drawings[target], target);
  };

  const requestCadDrawing = (): Promise<SaveResult> =>
    new Promise((resolve, reject) => {
      resolveSave = resolve;
      frame.contentWindow?.postMessage({ type: CAD_SAVE_REQUEST_MESSAGE }, window.location.origin);
      window.setTimeout(() => {
        if (!resolveSave) return;
        resolveSave = undefined;
        reject(new Error("CAD 저장 응답 시간이 초과되었습니다."));
      }, 5000);
    });

  async function confirmCurrentDrawing(): Promise<void> {
    if (!projectId || !currentDrawing) return;
    showLoadingOverlay();
    try {
      const saved = await requestCadDrawing();
      const result = await confirmDesignDrawing(
        projectId,
        currentDrawing.id,
        saved.drawing,
        currentDrawing.kind === "cross" ? (saved.quantityTable ?? null) : null,
      );
      currentConfirmed = true;
      currentDrawing.confirmed = true;
      confirmButton.disabled = true;
      drawingCache.delete(currentDrawing.id); // 확정본은 서버 저장분이 정본이다.

      const button = findButton(currentDrawing.id);
      if (button) button.dataset.confirmed = "true";
      // 확정 시 재계산된 확정 단면적으로 지반/계획 정보 패널을 갱신한다.
      if (currentDrawing.kind === "cross") {
        infoPanelHost.replaceChildren(
          buildDesignInfoPanel(currentDrawing.label, result.design ?? null),
        );
      }
      showToast("현재 도면을 확정하고 저장했습니다.", "success");
      if (result.all_confirmed) {
        allDrawingsConfirmed = true;
        goToWorkflowStage(projectId, WORKFLOW_STEP_ROUTES[5]);
      }
    } catch (error) {
      showToast(
        error instanceof Error ? error.message : "현재 도면을 확정하지 못했습니다.",
        "error",
      );
    } finally {
      hideLoadingOverlay();
    }
  }

  const invalidateCurrentDrawing = async () => {
    if (!projectId || !currentDrawing) return;
    const wasConfirmed = currentConfirmed;
    drawingCache.delete(currentDrawing.id);
    currentConfirmed = false;
    allDrawingsConfirmed = false;
    currentDrawing.confirmed = false;
    confirmButton.disabled = false;
    const button = findButton(currentDrawing.id);
    if (button) button.dataset.confirmed = "false";
    if (wasConfirmed) {
      try {
        await invalidateDesignDrawing(projectId, currentDrawing.id);
      } catch (error) {
        showToast(
          error instanceof Error ? error.message : "도면 확정 상태를 되돌리지 못했습니다.",
          "error",
        );
      }
    }
  };

  window.addEventListener("message", (event: MessageEvent<unknown>) => {
    if (event.origin !== window.location.origin || event.source !== frame.contentWindow) return;
    const message = event.data as {
      type?: string;
      detail?: string;
      drawing?: CadDrawing;
      quantityTable?: QuantityTable | null;
      direction?: "prev" | "next";
      kind?: string;
      text?: string;
      actionId?: string;
      durationMs?: number;
    };
    if (message.type === CAD_TOAST_MESSAGE) {
      const kind = (["info", "success", "warning", "error"] as const).find(
        (item) => item === message.kind,
      );
      // autoClose:false로 온 안내(백업 되살리기)는 오래 띄운다 — 누를 시간을 준다.
      const duration = message.durationMs === 0 ? 15000 : (message.durationMs ?? 3000);
      const actionId = message.actionId;
      showToast(
        message.text ?? "",
        kind ?? "info",
        duration,
        actionId
          ? () =>
              frame.contentWindow?.postMessage(
                { type: CAD_TOAST_ACTION_MESSAGE, actionId },
                window.location.origin,
              )
          : undefined,
      );
    } else if (message.type === CAD_READY_MESSAGE) {
      cadReady = true;
      if (pendingLoad) sendLoad(pendingLoad.drawing, pendingLoad.meta);
    } else if (message.type === CAD_LOADED_MESSAGE) {
      cadHost.dataset.loading = "false";
    } else if (message.type === CAD_ERROR_MESSAGE) {
      cadHost.dataset.error = message.detail ?? "CAD 도면을 표시하지 못했습니다.";
    } else if (message.type === CAD_CHANGED_MESSAGE) {
      void invalidateCurrentDrawing();
    } else if (message.type === CAD_NAVIGATE_MESSAGE && message.direction) {
      navigateDrawing(message.direction);
    } else if (message.type === CAD_SAVE_RESPONSE_MESSAGE && message.drawing && resolveSave) {
      const resolve = resolveSave;
      resolveSave = undefined;
      resolve({ drawing: message.drawing, quantityTable: message.quantityTable ?? null });
    }
  });

  const drawingPanel = buildDrawingSidePanel(drawings, selectDrawing, drawingError);
  drawingListEl = drawingPanel;
  const confirmActions = document.createElement("div");
  // 하단 고정은 공용 ui-sidebar-actions로 통일 — 사이드 본문이 [스크롤 영역][액션 줄]로
  // 쪼개지고 액션 줄은 스크롤 밖에 남는다(2026-08-18 사용자 지시, B04~B07 공통).
  confirmActions.className = "b07-drawing-actions ui-sidebar-actions";
  confirmActions.append(confirmButton);

  drawingPanel.append(infoPanelHost, confirmActions);

  const layout = createWorkflowLayout({
    title: L("B07_Design_Title"),
    steps: workflowSteps(),
    activeStep: 4,
    leftPanel: drawingPanel,
    mainContent: cadHost,
    stages: workflowState?.stages,
    currentStage: workflowState?.current_stage,
    routes: WORKFLOW_STEP_ROUTES,
    onStepClick: (stepIndex) => {
      if (!projectId) return;
      if (stepIndex > 5 && !allDrawingsConfirmed) {
        showToast("모든 설계 도면을 확정한 뒤 다음 단계로 이동할 수 있습니다.", "warning");
        return;
      }
      goToWorkflowStage(projectId, WORKFLOW_STEP_ROUTES[stepIndex]);
    },
  });
  layout.root.classList.add("b07-design-layout");
  root.replaceChildren(layout.root);

  // 페이지 진입 시 첫 도면(종단도)을 자동 선택 — 빈 CAD 화면 방지.
  // CAD가 아직 준비 전이면 sendLoad가 pendingLoad로 대기했다가 ready 시 전송한다.
  if (drawings.length > 0) {
    void loadDrawing(drawings[0], 0).then(() => {
      // 첫 장을 띄운 뒤에 나머지를 받는다 — 진입 속도를 뺏지 않는다.
      void prefetchAllDrawings();
    });
  }
}