/* =============================================================================
 * B01_Dashboard_Api_Temp.ts
 * 임시 보관함(프로젝트 생성 전 업로드) API 클라이언트
 *
 * 백엔드 계약 (B03_FileInput_Router_Temp.py):
 *   POST   /api/temp-uploads                              묶음 생성
 *   GET    /api/temp-uploads                              내 보관함 목록
 *   DELETE /api/temp-uploads/{batch_id}                   묶음 삭제
 *   POST   /api/temp-uploads/{batch_id}/files             작은 파일 저장
 *   DELETE /api/temp-uploads/{batch_id}/files/{type}      파일 1건 삭제
 *   POST   /api/temp-uploads/{batch_id}/upload-sessions   청크 세션 생성
 *   POST   /api/temp-uploads/{batch_id}/chunks            청크 저장
 *   POST   /api/temp-uploads/{batch_id}/finalize          병합·완료
 *   GET    /api/temp-uploads/{batch_id}/upload-status/{s} 이어올리기 조회
 *   POST   /api/projects/{id}/temp-uploads/{batch_id}/attach  프로젝트로 이동
 * ========================================================================== */

import { API_BASE_URL } from "@config/config_frontend";

export interface TempBatchFile {
  file_type: string;
  original_filename: string;
  file_size_bytes: number;
  crs_epsg: number | null;
}

export interface TempBatchPendingSession {
  upload_session_id: string;
  original_filename: string;
  file_size_bytes: number;
  total_chunks: number;
  completed_chunks: number;
  progress_percent: number;
}

export interface TempBatchItem {
  batch_id: string;
  name: string;
  memo: string | null;
  status: string;
  files: TempBatchFile[];
  pending_sessions: TempBatchPendingSession[];
  total_size_bytes: number;
  required_complete: boolean;
  completed_at: string | null;
  expires_at: string | null;
  linked_project_id: string | null;
  created_at: string | null;
}

export interface TempBatchListResponse {
  status: string;
  batches: TempBatchItem[];
  retention_days: number;
}

async function requestJson<T>(path: string, init: RequestInit = {}): Promise<T> {
  const response = await fetch(`${API_BASE_URL}${path}`, {
    ...init,
    credentials: "include",
    headers:
      init.body instanceof FormData
        ? init.headers
        : {
            "Content-Type": "application/json",
            ...(init.headers ?? {}),
          },
  });
  const payload = await response.json().catch(() => ({}));
  if (!response.ok || payload.status === "error") {
    throw new Error(payload.message ?? `HTTP ${response.status}`);
  }
  return payload as T;
}

export async function createTempBatch(
  name: string,
  memo?: string,
): Promise<{ batch_id: string; name: string }> {
  return requestJson("/temp-uploads", {
    method: "POST",
    body: JSON.stringify({ name, memo: memo || null }),
  });
}

export async function fetchTempBatches(): Promise<TempBatchListResponse> {
  return requestJson("/temp-uploads", { method: "GET" });
}

export async function deleteTempBatch(batchId: string): Promise<void> {
  await requestJson(`/temp-uploads/${encodeURIComponent(batchId)}`, { method: "DELETE" });
}

/** 묶음 안 파일 1건 삭제 — 임시 저장소의 실제 파일도 함께 지워진다. */
export async function deleteTempBatchFile(batchId: string, fileType: string): Promise<void> {
  await requestJson(
    `/temp-uploads/${encodeURIComponent(batchId)}/files/${encodeURIComponent(fileType)}`,
    { method: "DELETE" },
  );
}

/** 작은 파일(csv·prj·tfw·tif)은 한 번에 보낸다. */
export async function uploadTempBatchFiles(
  batchId: string,
  files: readonly File[],
): Promise<{ required_complete: boolean }> {
  const form = new FormData();
  for (const file of files) form.append("files", file, file.name);
  return requestJson(`/temp-uploads/${encodeURIComponent(batchId)}/files`, {
    method: "POST",
    body: form,
  });
}

export async function createTempUploadSession(
  batchId: string,
  file: File,
  chunkSizeBytes: number,
): Promise<{ upload_session_id: string; total_chunks: number }> {
  return requestJson(`/temp-uploads/${encodeURIComponent(batchId)}/upload-sessions`, {
    method: "POST",
    body: JSON.stringify({
      original_filename: file.name,
      size_bytes: file.size,
      chunk_size_bytes: chunkSizeBytes,
    }),
  });
}

export async function uploadTempChunk(
  batchId: string,
  sessionId: string,
  chunkIndex: number,
  chunk: Blob,
): Promise<{ completed_chunks: number }> {
  const form = new FormData();
  form.append("session_id", sessionId);
  form.append("chunk_index", String(chunkIndex));
  form.append("chunk_data", chunk, `chunk_${chunkIndex}`);
  return requestJson(`/temp-uploads/${encodeURIComponent(batchId)}/chunks`, {
    method: "POST",
    body: form,
  });
}

export async function finalizeTempUpload(
  batchId: string,
  sessionId: string,
  totalChunks: number,
): Promise<{ required_complete: boolean }> {
  return requestJson(`/temp-uploads/${encodeURIComponent(batchId)}/finalize`, {
    method: "POST",
    body: JSON.stringify({
      session_id: sessionId,
      total_chunks: totalChunks,
      complete_upload: true,
    }),
  });
}

/** 이어올리기 — 이미 서버에 올라간 청크 번호. */
export async function fetchTempUploadStatus(
  batchId: string,
  sessionId: string,
): Promise<{ completed_chunk_indexes: number[]; total_chunks: number }> {
  return requestJson(
    `/temp-uploads/${encodeURIComponent(batchId)}/upload-status/${encodeURIComponent(sessionId)}`,
    { method: "GET" },
  );
}

export interface TempBatchAttachResponse {
  status: string;
  project_id: string;
  batch_id: string;
  moved_files: number;
  analysis_started: boolean;
}

/** 보관함 자료를 프로젝트 영구저장소로 옮기고 초기 분석을 시작한다. */
export async function attachTempBatch(
  projectId: string,
  batchId: string,
): Promise<TempBatchAttachResponse> {
  return requestJson(
    `/projects/${encodeURIComponent(projectId)}/temp-uploads/${encodeURIComponent(batchId)}/attach`,
    { method: "POST" },
  );
}