import {
  CURRENT_PROJECT_ID_KEY,
  PROGRESS_UPDATE_INTERVAL_MS,
  ROUTES,
  UPLOAD_ALLOWED_EXT,
  UPLOAD_CHUNK_SIZE_MB,
  UPLOAD_MAX_FILES,
  UPLOAD_MAX_MB,
} from "@config/config_frontend";
import { currentLanguageIndex, ui_locales } from "@ui/ui_template_locale";
import { createButton, createTag, showToast } from "@ui/ui_template_elements";
import { createGeneralLayout } from "@ui/ui_template_general_layout";
import { createWorkflowOverlays } from "@ui/ui_template_overlay";
import { createStepBar, WORKFLOW_STEP_ICONS } from "@ui/ui_template_workflow_layout";
import { fetchDashboardMe } from "../B01_Dashboard/B01_Dashboard_Api_Fetch";
import {
  checkWF1AnalysisStatus,
  createUploadSession,
  fetchUploadOverview,
  finalizeUploadSession,
  uploadFileChunk,
  type UploadedFileResult,
} from "./B03_FileInput_Api_Fetch";
import { navigateTo } from "../A00_Common/router";
import { workflowSteps } from "../A00_Common/b_page_scaffold";
import {
  fetchWorkflowState,
  goToWorkflowStage,
  WORKFLOW_STEP_ROUTES,
} from "../A00_Common/b_workflow_nav";
import {
  restoreB03ProjectState,
  saveB03UploadedFile,
  updateB03AnalysisState,
} from "./B03_FileInput_State";
import {
  createFileCardTemplate,
  formatBytes,
  formatEta,
  getExtension,
  initializeSlots,
  makeSessionKey,
  type FileSlot,
  type FileSlotState,
  type StoredUploadSession,
  type UploadStatus,
} from "./B03_FileInput_UI_Support";
import "./B03_FileInput_UI_Style.css";

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

export async function renderB03FileInput(root: HTMLElement): Promise<void> {
  const dashboardUser = await fetchDashboardMe();
  const completionRoute =
    dashboardUser.role === "SYSTEM_ADMIN" ? ROUTES.B04_PREPROCESS : ROUTES.B05_PROFILE;
  const slots = initializeSlots();
  const cardMap = new Map<FileSlot, HTMLElement>();
  const resultList = document.createElement("ul");
  resultList.className = "b03-file__results";
  let uploadButton: HTMLButtonElement;
  let resumeBanner: HTMLDivElement;
  let activeProjectId = localStorage.getItem(CURRENT_PROJECT_ID_KEY) ?? "";

  const subtitle = document.createElement("p");
  subtitle.className = "b03-file__subtitle";
  subtitle.textContent = L("B03_File_Subtitle");

  const fileInput = document.createElement("input");
  fileInput.type = "file";
  fileInput.multiple = true;
  fileInput.accept = UPLOAD_ALLOWED_EXT.join(",");
  fileInput.className = "b03-file__native-input";

  const dropzone = document.createElement("div");
  dropzone.className = "b03-file__dropzone";
  dropzone.tabIndex = 0;
  const dropzoneLabel = document.createElement("strong");
  dropzoneLabel.textContent = L("B03_File_Select_Label");
  const dropzoneHint = document.createElement("span");
  dropzoneHint.textContent = L("B03_File_Select_Hint");
  dropzone.append(dropzoneLabel, dropzoneHint, fileInput);

  const pageError = document.createElement("p");
  pageError.className = "b03-file__error";
  pageError.setAttribute("role", "alert");

  resumeBanner = document.createElement("div");
  resumeBanner.className = "b03-file__resume";

  // 재접속 현황(서버 정본) 표시 — 전체 완료 배지와 중단 세션 안내가 여기 붙는다.
  const overviewBanner = document.createElement("div");
  overviewBanner.className = "b03-file__overview";

  const template = createFileCardTemplate();

  function selectedStates(): FileSlotState[] {
    return Array.from(slots.values()).filter((state) => state.file);
  }

  function setCardState(slot: FileSlot, stateName: "empty" | "selected" | UploadStatus): void {
    const card = cardMap.get(slot);
    if (!card) return;
    card.classList.remove(
      "b03-file__card--empty",
      "b03-file__card--selected",
      "b03-file__card--uploading",
      "b03-file__card--completed",
      "b03-file__card--failed",
      "b03-file__card--error",
    );
    const cssState = stateName === "failed" ? "error" : stateName;
    card.classList.add(`b03-file__card--${cssState}`);

    const badgeContainer = card.querySelector<HTMLDivElement>(".b03-file__card-badge-container");
    if (badgeContainer) {
      badgeContainer.replaceChildren();
      if (stateName === "empty") {
        badgeContainer.append(createTag("미등록", "neutral"));
      } else if (stateName === "selected") {
        badgeContainer.append(createTag("대기중", "neutral"));
      } else if (stateName === "uploading") {
        badgeContainer.append(createTag("업로드중", "warning"));
      } else if (stateName === "completed") {
        badgeContainer.append(createTag("완료", "success"));
      } else if (stateName === "failed") {
        badgeContainer.append(createTag("오류", "danger"));
      }
    }
  }

  function updateUploadButton(): void {
    const validation = validateSlots();
    uploadButton.disabled = validation !== null;
    pageError.textContent = validation ?? "";
  }

  function renderSlot(slot: FileSlot): void {
    const state = slots.get(slot);
    const card = cardMap.get(slot);
    if (!state || !card) return;

    const fileName = card.querySelector<HTMLSpanElement>(".b03-file__file-name");
    const fileSize = card.querySelector<HTMLSpanElement>(".b03-file__file-size");
    const progress = card.querySelector<HTMLDivElement>(".b03-file__progress-bar");
    const progressBytes = card.querySelector<HTMLSpanElement>(".b03-file__progress-bytes");
    const progressSpeed = card.querySelector<HTMLSpanElement>(".b03-file__progress-speed");
    const progressEta = card.querySelector<HTMLSpanElement>(".b03-file__progress-eta");
    const error = card.querySelector<HTMLDivElement>(".b03-file__error-message");
    const remove = card.querySelector<HTMLButtonElement>(".b03-file__card-remove");

    const percent = state.file ? Math.min(100, (state.progressBytes / state.file.size) * 100) : 0;
    // 로컬 파일이 없어도 서버에 업로드된 파일이 있으면 그 정보(정본)를 보여준다.
    if (fileName) fileName.textContent = state.file?.name ?? state.serverUploaded?.name ?? "";
    if (fileSize) {
      fileSize.textContent = state.file
        ? formatBytes(state.file.size)
        : state.serverUploaded
          ? `${state.serverUploaded.sizeMb.toFixed(2)} MB`
          : "";
    }
    if (progress) progress.style.width = `${percent}%`;
    if (progressBytes) {
      progressBytes.textContent = `${L("B03_File_Progress_Bytes")}: ${formatBytes(
        state.progressBytes,
      )} / ${state.file ? formatBytes(state.file.size) : "-"}`;
    }
    if (progressSpeed) {
      progressSpeed.textContent = `${L("B03_File_Progress_Speed")}: ${state.speedMbs.toFixed(
        1,
      )} MB/s`;
    }
    if (progressEta) {
      progressEta.textContent = `${L("B03_File_Progress_Eta")}: ${formatEta(state.etaSeconds)}`;
    }
    if (error) error.textContent = state.error ?? "";
    if (remove) remove.hidden = !state.file;

    if (state.error) setCardState(slot, "failed");
    else if (!state.file) setCardState(slot, state.serverUploaded ? "completed" : "empty");
    else setCardState(slot, state.uploadStatus === "pending" ? "selected" : state.uploadStatus);
    updateUploadButton();
  }

  function showErrorMessage(slot: FileSlot, error: string): void {
    const state = slots.get(slot);
    if (!state) return;
    state.error = error;
    state.uploadStatus = "failed";
    renderSlot(slot);
  }

  function clearErrorMessage(slot: FileSlot): void {
    const state = slots.get(slot);
    if (!state) return;
    state.error = undefined;
    if (state.uploadStatus === "failed") state.uploadStatus = "pending";
    renderSlot(slot);
  }

  function validateFileForSlot(file: File, state: FileSlotState): string | null {
    const extension = getExtension(file.name);
    const maxBytes = UPLOAD_MAX_MB * 1024 * 1024;
    if (!state.extensions.includes(extension)) return L("B03_File_Error_SlotType");
    if (file.size === 0 || file.size > maxBytes) return L("B03_File_Error_Size");
    return null;
  }

  async function assignFileToSlot(file: File, targetSlot?: FileSlot): Promise<void> {
    const extension = getExtension(file.name);
    const state = targetSlot
      ? slots.get(targetSlot)
      : Array.from(slots.values()).find((candidate) => candidate.extensions.includes(extension));
    if (!state) {
      pageError.textContent = `${L("B03_File_Error_Extension")} ${file.name}`;
      return;
    }
    const validation = validateFileForSlot(file, state);
    if (validation) {
      showErrorMessage(state.slot, `${validation} ${file.name}`);
      return;
    }
    if (!targetSlot && state.file && state.file.name !== file.name) {
      showErrorMessage(state.slot, `${L("B03_File_Error_DuplicateSlot")} ${file.name}`);
      return;
    }
    // 서버에 이미 완료된 슬롯이면 교체 확인을 받는다(2026-08-04 사용자 지시). 이어올리기로
    // 같은 파일을 다시 고르는 경우는 업로드가 미완료라 serverUploaded가 없어 묻지 않는다.
    if (state.serverUploaded) {
      const accepted = await confirmReplaceUpload(L(state.labelKey), state.serverUploaded.name);
      if (!accepted) return;
    }

    state.file = file;
    state.uploadSessionId = undefined;
    state.uploadStatus = "pending";
    state.progressBytes = 0;
    state.speedMbs = 0;
    state.etaSeconds = null;
    state.error = undefined;
    renderSlot(state.slot);
  }

  function onFileSelected(files: readonly File[], targetSlot?: FileSlot): void {
    if (files.length === 0) return;
    // 이미 고른 슬롯을 다시 고르는 것은 "교체"라 총 개수가 늘지 않는다 — 그 슬롯을 빼고 센다.
    // (빼지 않으면 5개를 다 고른 뒤 하나만 바꾸려 할 때 개수 초과로 막힌다.)
    const occupied = selectedStates().filter((state) => state.slot !== targetSlot).length;
    if (occupied + files.length > UPLOAD_MAX_FILES) {
      pageError.textContent = L("B03_File_Error_Count");
      return;
    }
    pageError.textContent = "";
    void (async () => {
      for (const file of files) await assignFileToSlot(file, targetSlot);
      await detectPausedUploads();
    })();
  }

  function removeFile(slot: FileSlot): void {
    const state = slots.get(slot);
    if (!state) return;
    if (activeProjectId && state.file) {
      localStorage.removeItem(makeSessionKey(activeProjectId, state.file));
    }
    state.file = undefined;
    state.uploadSessionId = undefined;
    state.uploadStatus = "pending";
    state.progressBytes = 0;
    state.speedMbs = 0;
    state.etaSeconds = null;
    state.error = undefined;
    renderSlot(slot);
  }

  function validateSlots(): string | null {
    if (!activeProjectId) return L("B03_File_Error_Project");
    const selected = selectedStates();
    if (selected.length === 0) return L("B03_File_Error_Required");
    if (selected.length > UPLOAD_MAX_FILES) return L("B03_File_Error_Count");
    // 필수 슬롯은 로컬 선택이 없어도 **서버에 이미 올라간 파일**이 있으면 충족이다 —
    // 재접속 후 파일 하나만 교체 업로드하는 흐름을 막지 않는다(2026-08-04 사용자 지시).
    const missingRequired = Array.from(slots.values()).some(
      (state) => state.isRequired && !state.file && !state.serverUploaded,
    );
    if (missingRequired) return L("B03_File_Error_RequiredSlots");
    const lasState = slots.get("las_laz");
    if (!lasState?.file && !lasState?.serverUploaded) return L("B03_File_Error_Las");
    for (const state of selected) {
      if (state.error) return state.error;
      const validation = validateFileForSlot(state.file!, state);
      if (validation) return validation;
    }
    return null;
  }

  /**
   * 완료된 슬롯 재업로드 확인 모달 — 기존 파일·분석 결과가 교체된다는 경고에 사용자의
   * 명시적 확인을 받는다(2026-08-04 사용자 지시). 확인 시에만 resolve(true).
   */
  function confirmReplaceUpload(slotLabel: string, fileName: string): Promise<boolean> {
    return new Promise((resolve) => {
      const backdrop = document.createElement("div");
      backdrop.className = "b03-file__modal-backdrop";
      const modal = document.createElement("div");
      modal.className = "b03-file__modal";
      modal.setAttribute("role", "alertdialog");
      modal.setAttribute("aria-modal", "true");
      const title = document.createElement("strong");
      title.textContent = L("B03_File_Replace_Title");
      const message = document.createElement("p");
      message.textContent = `${slotLabel}: ${fileName}\n${L("B03_File_Replace_Message")}`;
      const actions = document.createElement("div");
      actions.className = "b03-file__modal-actions";
      const done = (accepted: boolean): void => {
        backdrop.remove();
        resolve(accepted);
      };
      const cancel = createButton({
        label: L("B03_File_Replace_Cancel"),
        variant: "ghost",
        onClick: () => done(false),
      });
      const accept = createButton({
        label: L("B03_File_Replace_Confirm"),
        variant: "filled",
        onClick: () => done(true),
      });
      actions.append(cancel, accept);
      modal.append(title, message, actions);
      backdrop.append(modal);
      backdrop.addEventListener("click", (event) => {
        if (event.target === backdrop) done(false);
      });
      document.body.append(backdrop);
      accept.focus();
    });
  }

  /**
   * 재접속 현황(서버 정본) 적용 — 업로드 완료 파일을 슬롯 카드에 표시하고, 중단된 청크
   * 세션은 파일 재선택 전에도 안내하며, 전체 완료면 완료 배지를 띄운다.
   * localStorage 기반 표시(restoreB03ProjectState)는 보조로 유지된다.
   */
  async function applyUploadOverview(): Promise<void> {
    if (!activeProjectId) return;
    overviewBanner.replaceChildren();
    overviewBanner.classList.remove("is-visible");
    try {
      const overview = await fetchUploadOverview(activeProjectId);
      // 확장자 → 슬롯 매핑으로 서버 파일을 카드에 얹는다(같은 슬롯이면 최신 것 우선 — 목록이
      // id 오름차순이므로 마지막 것이 남는다).
      for (const state of slots.values()) state.serverUploaded = undefined;
      for (const file of overview.files) {
        const extension = `.${file.file_type.toLowerCase()}`;
        const state = Array.from(slots.values()).find((candidate) =>
          candidate.extensions.includes(extension),
        );
        if (state) {
          state.serverUploaded = { name: file.original_filename, sizeMb: file.file_size_mb };
        }
      }
      for (const slot of slots.keys()) renderSlot(slot);

      const notes: HTMLElement[] = [];
      if (overview.required_complete && overview.analysis_complete) {
        const complete = document.createElement("p");
        complete.className = "b03-file__overview-complete";
        complete.textContent = L("B03_File_Overview_Complete");
        notes.push(complete);
      }
      for (const session of overview.pending_sessions) {
        const pending = document.createElement("p");
        pending.className = "b03-file__overview-pending";
        pending.textContent =
          `${session.original_filename} — ${session.progress_percent}% ` +
          L("B03_File_Overview_Pending");
        notes.push(pending);
      }
      if (notes.length) {
        overviewBanner.append(...notes);
        overviewBanner.classList.add("is-visible");
      }
    } catch {
      // 현황 조회 실패는 업로드 자체를 막지 않는다 — localStorage 보조 표시로만 동작.
    }
  }

  function createFileCard(state: FileSlotState): HTMLElement {
    const fragment = template.content.cloneNode(true) as DocumentFragment;
    const card = fragment.querySelector<HTMLElement>(".b03-file__card");
    if (!card) throw new Error("file-card-template is invalid");
    card.dataset.slotId = state.slot;
    card.querySelector(".b03-file__card-icon")!.textContent = state.icon;
    card.querySelector(".b03-file__card-label")!.textContent = L(state.labelKey);
    card.querySelector(".b03-file__card-ext")!.textContent = state.extensions.join(", ");
    const input = card.querySelector<HTMLInputElement>(".b03-file__slot-input")!;
    input.accept = state.extensions.join(",");
    const select = card.querySelector<HTMLButtonElement>(".b03-file__card-select")!;
    select.textContent = L("B03_File_Card_Select");
    select.addEventListener("click", () => input.click());
    input.addEventListener("change", () => {
      onFileSelected(input.files ? Array.from(input.files) : [], state.slot);
      input.value = "";
    });
    const remove = card.querySelector<HTMLButtonElement>(".b03-file__card-remove")!;
    remove.textContent = "×";
    remove.title = L("B03_File_Card_Remove");
    remove.setAttribute("aria-label", L("B03_File_Card_Remove"));
    remove.addEventListener("click", () => removeFile(state.slot));
    cardMap.set(state.slot, card);
    return card;
  }

  function createCardGroup(title: string, groupSlots: readonly FileSlot[]): HTMLElement {
    const group = document.createElement("section");
    group.className = "b03-file__group";
    if (title) {
      const groupTitle = document.createElement("h3");
      groupTitle.className = "b03-file__group-title";
      groupTitle.textContent = title;
      group.append(groupTitle);
    }
    const content = document.createElement("div");
    content.className = "b03-file__group-content";
    for (const slot of groupSlots) {
      const state = slots.get(slot);
      if (state) content.append(createFileCard(state));
    }
    group.append(content);
    return group;
  }

  function renderUploadResults(results: readonly UploadedFileResult[]): void {
    resultList.replaceChildren();
    for (const result of results) {
      const item = document.createElement("li");
      const filename = document.createElement("strong");
      filename.textContent = result.original_filename;
      const path = document.createElement("span");
      path.textContent = `${L("B03_File_Result_Path")}: ${result.relative_path}`;
      item.append(filename, path);
      resultList.append(item);
    }
  }

  async function detectPausedUploads(): Promise<void> {
    activeProjectId = localStorage.getItem(CURRENT_PROJECT_ID_KEY) ?? "";
    resumeBanner.replaceChildren();
    resumeBanner.classList.remove("is-visible");
    if (!activeProjectId) return;

    for (const state of selectedStates()) {
      const stored = localStorage.getItem(makeSessionKey(activeProjectId, state.file!));
      if (!stored) continue;
      const session = JSON.parse(stored) as StoredUploadSession;
      state.uploadSessionId = session.uploadSessionId;
      state.progressBytes = session.completedChunks * session.chunkSizeBytes;
      renderSlot(state.slot);
      const text = document.createElement("span");
      text.textContent = `${L("B03_File_Status_Detected")}: ${session.fileName}`;
      const resume = createButton({
        label: L("B03_File_Resume_Button"),
        variant: "ghost",
        onClick: () => void startChunkedUpload([state]),
      });
      const fresh = createButton({
        label: L("B03_File_New_Button"),
        variant: "ghost",
        onClick: () => {
          localStorage.removeItem(session.key);
          state.uploadSessionId = undefined;
          state.progressBytes = 0;
          renderSlot(state.slot);
          resumeBanner.replaceChildren();
          resumeBanner.classList.remove("is-visible");
        },
      });
      resumeBanner.append(text, resume, fresh);
      resumeBanner.classList.add("is-visible");
      break;
    }
  }

  async function uploadOneFile(
    projectId: string,
    state: FileSlotState,
    completeUpload: boolean,
  ): Promise<UploadedFileResult[]> {
    const file = state.file;
    if (!file) return [];
    clearErrorMessage(state.slot);
    state.uploadStatus = "uploading";
    renderSlot(state.slot);

    const chunkSizeBytes = UPLOAD_CHUNK_SIZE_MB * 1024 * 1024;
    const session =
      state.uploadSessionId ??
      (await createUploadSession(projectId, file, chunkSizeBytes)).upload_session_id;
    state.uploadSessionId = session;
    const totalChunks = Math.max(1, Math.ceil(file.size / chunkSizeBytes));
    const storageKey = makeSessionKey(projectId, file);
    const startedAt = performance.now();
    let lastPaintAt = 0;

    for (
      let chunkIndex = Math.floor(state.progressBytes / chunkSizeBytes);
      chunkIndex < totalChunks;
      chunkIndex += 1
    ) {
      const start = chunkIndex * chunkSizeBytes;
      const end = Math.min(file.size, start + chunkSizeBytes);
      const chunkStartedAt = performance.now();
      await uploadFileChunk(projectId, session, chunkIndex, file.slice(start, end));
      const elapsedSec = Math.max(0.001, (performance.now() - chunkStartedAt) / 1000);
      state.progressBytes = end;
      state.speedMbs = (end - start) / 1024 / 1024 / elapsedSec;
      state.etaSeconds =
        state.speedMbs > 0 ? (file.size - end) / 1024 / 1024 / state.speedMbs : null;

      const stored: StoredUploadSession = {
        key: storageKey,
        projectId,
        slot: state.slot,
        fileName: file.name,
        fileSize: file.size,
        uploadSessionId: session,
        chunkSizeBytes,
        totalChunks,
        completedChunks: chunkIndex + 1,
        updatedAt: Date.now(),
      };
      localStorage.setItem(storageKey, JSON.stringify(stored));

      const now = performance.now();
      if (now - lastPaintAt > PROGRESS_UPDATE_INTERVAL_MS || chunkIndex === totalChunks - 1) {
        lastPaintAt = now;
        renderSlot(state.slot);
      }
    }

    const response = await finalizeUploadSession(projectId, session, totalChunks, completeUpload);
    localStorage.removeItem(storageKey);
    saveB03UploadedFile(projectId, {
      slot: state.slot,
      fileName: file.name,
      fileSize: file.size,
    });
    state.progressBytes = file.size;
    state.speedMbs =
      file.size / 1024 / 1024 / Math.max(0.001, (performance.now() - startedAt) / 1000);
    state.etaSeconds = 0;
    state.uploadStatus = "completed";
    renderSlot(state.slot);
    return response.files;
  }

  async function pollWF1Analysis(projectId: string, maxAttempts = 360): Promise<boolean> {
    for (let attempt = 0; attempt < maxAttempts; attempt += 1) {
      try {
        const status = await checkWF1AnalysisStatus(projectId);
        updateB03AnalysisState(projectId, status.status, status.progress_percent);
        if (status.status === "completed") {
          return true;
        }
        if (
          status.current_stage === "awaiting_confirmation" &&
          status.message.includes("자동 확정 보류")
        ) {
          pageError.textContent = status.message;
          showToast(status.message, "warning");
          return false;
        }
      } catch {}
      await new Promise((resolve) => setTimeout(resolve, 5000));
    }
    return false;
  }

  async function startChunkedUpload(targetStates = selectedStates()): Promise<void> {
    activeProjectId = localStorage.getItem(CURRENT_PROJECT_ID_KEY) ?? "";
    const validation = validateSlots();
    if (validation) {
      pageError.textContent = validation;
      return;
    }

    pageError.textContent = "";
    const uploaded: UploadedFileResult[] = [];
    try {
      for (let index = 0; index < targetStates.length; index += 1) {
        const state = targetStates[index];
        uploaded.push(
          ...(await uploadOneFile(activeProjectId, state, index === targetStates.length - 1)),
        );
      }
      renderUploadResults(uploaded);
      showToast(L("B03_File_Upload_Success"), "success");

      showToast(L("B03_File_Analysis_InProgress"), "info");
      const analysisComplete = await pollWF1Analysis(activeProjectId);

      if (analysisComplete) {
        navigateTo(completionRoute);
      } else {
        showToast(L("B03_File_Analysis_StillRunning"), "warning");
      }
    } catch (error) {
      const failed = targetStates.find((state) => state.uploadStatus === "uploading");
      const detail = error instanceof Error ? error.message : L("B03_File_Upload_Failed");
      if (failed) showErrorMessage(failed.slot, detail);
      pageError.textContent = `${L("B03_File_Upload_Failed")} ${detail}`;
      showToast(L("B03_File_Upload_Failed"), "error");
    }
  }

  async function registerB03ServiceWorker(): Promise<void> {
    if (!("serviceWorker" in navigator)) {
      showToast(L("B03_File_ServiceWorker_Unavailable"), "warning");
      return;
    }
    try {
      const registration = await navigator.serviceWorker.register(
        new URL("./B03_FileInput_ServiceWorker.ts", import.meta.url),
        { type: "module" },
      );
      registration.active?.postMessage({ type: "B03_SW_PING" });
      showToast(L("B03_File_ServiceWorker_Ready"), "info");
    } catch {
      showToast(L("B03_File_ServiceWorker_Unavailable"), "warning");
    }
  }

  function onB03_File_Select_Change(): void {
    onFileSelected(fileInput.files ? Array.from(fileInput.files) : []);
    fileInput.value = "";
  }

  function onB03_File_Drop(event: DragEvent): void {
    event.preventDefault();
    dropzone.classList.remove("is-dragging");
    onFileSelected(event.dataTransfer?.files ? Array.from(event.dataTransfer.files) : []);
  }

  fileInput.addEventListener("change", onB03_File_Select_Change);
  dropzone.addEventListener("click", () => fileInput.click());
  dropzone.addEventListener("keydown", (event) => {
    if (event.key === "Enter" || event.key === " ") fileInput.click();
  });
  dropzone.addEventListener("dragover", (event) => {
    event.preventDefault();
    dropzone.classList.add("is-dragging");
  });
  dropzone.addEventListener("dragleave", () => dropzone.classList.remove("is-dragging"));
  dropzone.addEventListener("drop", onB03_File_Drop);

  uploadButton = createButton({
    label: L("B03_File_Upload_Button"),
    variant: "filled",
    onClick: () => void startChunkedUpload(),
    disabled: true,
  });

  const uploadControlPanel = document.createElement("div");
  uploadControlPanel.className = "b03-file__control-panel";
  uploadControlPanel.append(
    subtitle,
    overviewBanner,
    dropzone,
    resumeBanner,
    pageError,
    uploadButton,
    resultList,
  );

  const routeGroup = createCardGroup(L("B03_File_Group_Route"), ["csv"]);
  routeGroup.classList.add("b03-file__group--route");
  const filesGroup = createCardGroup(L("B03_File_Group_Terrain"), ["las_laz", "prj", "tfw", "tif"]);

  const cardsContainer = document.createElement("div");
  cardsContainer.className = "b03-file__control-panel b03-file__cards-container-panel";
  cardsContainer.append(routeGroup, filesGroup);

  const workflowState = activeProjectId
    ? await fetchWorkflowState(activeProjectId).catch(() => undefined)
    : undefined;
  const steps = workflowSteps();
  const progressContent = createStepBar(steps, 0, {
    stages: workflowState?.stages,
    currentStage: workflowState?.current_stage,
    routes: WORKFLOW_STEP_ROUTES,
    orientation: "vertical",
    icons: WORKFLOW_STEP_ICONS,
    onStepClick: (stepIndex) => {
      if (activeProjectId) {
        goToWorkflowStage(activeProjectId, WORKFLOW_STEP_ROUTES[stepIndex]);
      }
    },
  });
  const layout = createGeneralLayout({
    pageClass: "b03-file",
    content: [uploadControlPanel, cardsContainer],
  });
  layout.content.classList.add("b03-file__main-layout");
  const overlays = createWorkflowOverlays({
    title: L("B03_File_Title"),
    progressContent,
    showTitlePanel: false,
  });
  layout.root.append(overlays.root);
  root.replaceChildren(layout.root);

  for (const slot of slots.keys()) renderSlot(slot);
  void registerB03ServiceWorker();
  void applyUploadOverview();
  void detectPausedUploads();
  if (activeProjectId) {
    restoreB03ProjectState({
      projectId: activeProjectId,
      label: L("B03_File_Restore_State"),
      container: resumeBanner,
      poll: pollWF1Analysis,
      onComplete: () => navigateTo(completionRoute),
    });
  }
}