export const API_BASE = import.meta.env.VITE_API_BASE ?? "http://localhost:8000";

// ---------------------------------------------------------------------------
// Types
// ---------------------------------------------------------------------------

export interface StepSummary {
  step_number:        number;
  status:             "pending" | "processing" | "completed" | "failed";
  original_image_url: string | null;
  result_image_url:   string | null;
  error_message:      string | null;
}

// ---------------------------------------------------------------------------
// Upload
// ---------------------------------------------------------------------------

/**
 * Upload an image file to the backend.
 * POSTs as multipart/form-data; backend applies EXIF rotation, saves step 0,
 * and returns the job_id.
 */
export async function uploadImage(file: File): Promise<{ job_id: string }> {
  const formData = new FormData();
  formData.append("file", file);

  const response = await fetch(`${API_BASE}/upload`, {
    method: "POST",
    body:   formData,
  });

  if (!response.ok) {
    let detail = `HTTP ${response.status}`;
    try {
      const json = await response.json();
      if (json?.detail) detail = json.detail;
    } catch { /* ignore */ }
    throw new Error(detail);
  }

  return response.json() as Promise<{ job_id: string }>;
}

// ---------------------------------------------------------------------------
// Generate
// ---------------------------------------------------------------------------

/**
 * POST /generate — send the mask JSON to the backend and start inpainting.
 *
 * The backend creates a new step (truncating any forward history if needed),
 * starts inference in a BackgroundTask, and returns immediately.
 */
export async function generateMask(
  jobId:      string,
  maskJson:   object,
  maskSource: "manual" | "ocr" | "mixed" = "manual",
): Promise<{ job_id: string; step_number: number; status: string }> {
  const response = await fetch(`${API_BASE}/generate`, {
    method:  "POST",
    headers: { "Content-Type": "application/json" },
    body:    JSON.stringify({
      job_id:      jobId,
      mask_source: maskSource,
      mask_json:   maskJson,
    }),
  });

  if (!response.ok) {
    let detail = `HTTP ${response.status}`;
    try {
      const json = await response.json();
      if (json?.detail) detail = json.detail;
    } catch { /* ignore */ }
    throw new Error(detail);
  }

  return response.json() as Promise<{ job_id: string; step_number: number; status: string }>;
}

// ---------------------------------------------------------------------------
// Result polling
// ---------------------------------------------------------------------------

/**
 * GET /result/{job_id} — poll current job state.
 *
 * Returns top-level `status` / `error_message` for the current step
 * (backward-compatible with the polling hook), plus the full `steps[]` array
 * and `current_step` for the multi-step history navigator.
 */
export async function getJobResult(jobId: string): Promise<{
  job_id:             string;
  current_step:       number;
  status:             "pending" | "processing" | "completed" | "failed";
  result_image_url:   string | null;
  original_image_url: string | null;
  error_message:      string | null;
  steps:              StepSummary[];
}> {
  const response = await fetch(`${API_BASE}/result/${jobId}`);
  if (!response.ok) throw new Error(`HTTP ${response.status}`);
  return response.json();
}

// ---------------------------------------------------------------------------
// Step navigation
// ---------------------------------------------------------------------------

/**
 * POST /jobs/{job_id}/goto-step — set job.current_step to stepNumber.
 *
 * Only completed steps may be navigated to.  Truncation of forward history
 * happens lazily on the next POST /generate call.
 */
export async function goToStep(
  jobId:      string,
  stepNumber: number,
): Promise<{ job_id: string; current_step: number }> {
  const response = await fetch(`${API_BASE}/jobs/${jobId}/goto-step`, {
    method:  "POST",
    headers: { "Content-Type": "application/json" },
    body:    JSON.stringify({ step_number: stepNumber }),
  });

  if (!response.ok) {
    let detail = `HTTP ${response.status}`;
    try {
      const json = await response.json();
      if (json?.detail) detail = json.detail;
    } catch { /* ignore */ }
    throw new Error(detail);
  }

  return response.json() as Promise<{ job_id: string; current_step: number }>;
}