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

interface JobStatus {
  status: "processing" | "done" | "failed" | "timeout";
  progress?: number;
  stage?: string;
  eta_seconds?: number;
  filename?: string;
  mask_count?: number;
  message?: string;
}

async function pollJob(
  jobId: string,
  onProgress: (progress: number, message: string) => void,
  intervalMs = 2000,
): Promise<{ filename: string; mask_count: number }> {
  while (true) {
    const res = await fetch(`${API_BASE}/seg/jobs/${jobId}`);
    if (!res.ok) throw new Error(`Error al consultar el job: ${res.status}`);
    const job: JobStatus = await res.json();

    if (job.status === "done" && job.filename && job.mask_count != null) {
      return { filename: job.filename, mask_count: job.mask_count };
    }
    if (job.status === "failed" || job.status === "timeout") {
      throw new Error(job.message ?? "La segmentación falló");
    }

    onProgress(job.progress ?? 0, job.message ?? "Procesando...");
    await new Promise((r) => setTimeout(r, intervalMs));
  }
}

export function useSegmentUpload() {
  const [isUploading, setIsUploading] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const uploadAndSegment = useCallback(
    async (
      file: File,
      onProgress: (progress: number, message: string) => void,
    ): Promise<{ filename: string; maskCount: number }> => {
      setIsUploading(true);
      setError(null);

      try {
        const form = new FormData();
        form.append("file", file);

        onProgress(2, "Subiendo imagen...");
        const res = await fetch(`${API_BASE}/seg/upload_async`, {
          method: "POST",
          body: form,
        });

        if (!res.ok) {
          const text = await res.text();
          throw new Error(text || `Error al subir imagen: ${res.status}`);
        }

        const { job_id } = await res.json();
        onProgress(10, "Imagen recibida. Iniciando segmentación...");

        const result = await pollJob(job_id, onProgress);
        return { filename: result.filename, maskCount: result.mask_count };
      } catch (err) {
        const message =
          err instanceof Error ? err.message : "Error en la segmentación";
        setError(message);
        throw new Error(message);
      } finally {
        setIsUploading(false);
      }
    },
    [],
  );

  return { uploadAndSegment, isUploading, error };
}