silo/web/src/hooks/useFileUpload.ts

import { useState, useCallback } from "react";
import { post } from "../api/client";

export interface PendingAttachment {
  file: File;
  objectKey: string;
  uploadProgress: number;
  uploadStatus: "pending" | "uploading" | "complete" | "error";
  error?: string;
}

interface PresignResponse {
  object_key: string;
  upload_url: string;
  expires_at: string;
}

export function useFileUpload() {
  const [uploading, setUploading] = useState(false);

  const upload = useCallback(
    (
      file: File,
      onProgress?: (progress: number) => void,
    ): Promise<PendingAttachment> => {
      setUploading(true);

      return (async () => {
        try {
          // Get presigned URL.
          const presign = await post<PresignResponse>(
            "/api/uploads/presign",
            {
              filename: file.name,
              content_type: file.type || "application/octet-stream",
              size: file.size,
            },
          );

          // Upload via XMLHttpRequest for progress events.
          await new Promise<void>((resolve, reject) => {
            const xhr = new XMLHttpRequest();
            xhr.open("PUT", presign.upload_url);
            xhr.setRequestHeader(
              "Content-Type",
              file.type || "application/octet-stream",
            );

            xhr.upload.onprogress = (e) => {
              if (e.lengthComputable) {
                onProgress?.(Math.round((e.loaded / e.total) * 100));
              }
            };

            xhr.onload = () => {
              if (xhr.status >= 200 && xhr.status < 300) resolve();
              else reject(new Error(`Upload failed: HTTP ${xhr.status}`));
            };

            xhr.onerror = () => reject(new Error("Upload failed"));
            xhr.send(file);
          });

          return {
            file,
            objectKey: presign.object_key,
            uploadProgress: 100,
            uploadStatus: "complete" as const,
          };
        } catch (e) {
          return {
            file,
            objectKey: "",
            uploadProgress: 0,
            uploadStatus: "error" as const,
            error: e instanceof Error ? e.message : "Upload failed",
          };
        } finally {
          setUploading(false);
        }
      })();
    },
    [],
  );

  return { upload, uploading };
}