nexarch/web/dms-upload/lib/api.ts

// Duenner Client fuer DOC-03s Backend-Voraussetzung (dms/internal/uploadapi) —
// DOC-01 lieferte nur einen Go-Service ohne HTTP-Endpunkt, siehe DOC-03-PRUEFPROTOKOLL.md.

import { describeHttpError } from "@nexarch/shl";
import { apiFetch } from "./http";

export const CHUNK_SIZE_BYTES = 4 * 1024 * 1024;

function apiBase(): string {
  const base = process.env.NEXT_PUBLIC_UPLOAD_API_URL;
  if (!base) {
    throw new Error("NEXT_PUBLIC_UPLOAD_API_URL ist nicht gesetzt (Umgebungsvariable erforderlich)");
  }
  return base;
}

export interface StartUploadResult {
  sessionId: string;
}

export async function startUpload(filename: string, mimeType: string, totalSize: number): Promise<StartUploadResult> {
  const res = await apiFetch(`${apiBase()}/uploads`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ filename, mimeType, totalSize }),
  });
  if (!res.ok) {
    throw new Error(await extractErrorMessage(res));
  }
  return res.json();
}

export interface ChunkUploadResult {
  bytesReceived: number;
}

export async function uploadChunk(sessionId: string, offset: number, chunk: Blob): Promise<ChunkUploadResult> {
  const res = await apiFetch(`${apiBase()}/uploads/${encodeURIComponent(sessionId)}/chunk?offset=${offset}`, {
    method: "PUT",
    body: chunk,
  });
  if (!res.ok) {
    throw new Error(await extractErrorMessage(res));
  }
  return res.json();
}

export interface UploadStatus {
  sessionId: string;
  filename: string;
  totalSize: number;
  bytesReceived: number;
  status: string;
  documentId?: string;
}

export async function getUploadStatus(sessionId: string): Promise<UploadStatus> {
  const res = await apiFetch(`${apiBase()}/uploads/${encodeURIComponent(sessionId)}`);
  if (!res.ok) {
    throw new Error(await extractErrorMessage(res));
  }
  return res.json();
}

export interface CompleteUploadResult {
  documentId: string;
  revisionId: string;
}

export async function completeUpload(sessionId: string): Promise<CompleteUploadResult> {
  const res = await apiFetch(`${apiBase()}/uploads/${encodeURIComponent(sessionId)}/complete`, { method: "POST" });
  if (!res.ok) {
    throw new Error(await extractErrorMessage(res));
  }
  return res.json();
}

async function extractErrorMessage(res: Response): Promise<string> {
  if (res.status === 403 || res.status === 503) return describeHttpError(res.status);
  try {
    const text = await res.text();
    try {
      const message = JSON.parse(text)?.error?.message;
      if (typeof message === "string" && message) return message;
    } catch {
      // kein JSON: Klartext unverändert verwenden
    }
    return text || `Upload-API antwortete mit Status ${res.status}`;
  } catch {
    return `Upload-API antwortete mit Status ${res.status}`;
  }
}