frontend/src/hooks/__tests__/useSegmentation.test.tsx

import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
import { renderHook, waitFor, act } from "@testing-library/react";
import { server } from "../../mocks/server";
import { errorHandlers } from "../../mocks/handlers";
import { useSegmentation } from "../useSegmentation";

describe("useSegmentation", () => {
  beforeEach(() => {
    vi.useFakeTimers({ shouldAdvanceTime: true });
  });

  afterEach(() => {
    vi.useRealTimers();
  });

  it("starts with null result and not loading", () => {
    const { result } = renderHook(() => useSegmentation());

    expect(result.current.result).toBeNull();
    expect(result.current.isLoading).toBe(false);
    expect(result.current.error).toBeNull();
    expect(result.current.jobStatus).toBeNull();
  });

  it("sets loading state and job status during segmentation", async () => {
    const { result } = renderHook(() => useSegmentation());

    act(() => {
      result.current.runSegmentation("sub-stroke0001");
    });

    expect(result.current.isLoading).toBe(true);

    // Wait for job to be created
    await waitFor(() => {
      expect(result.current.jobId).toBeDefined();
    });

    expect(result.current.jobStatus).toBeDefined();
  });

  it("returns result on job completion", async () => {
    const { result } = renderHook(() => useSegmentation());

    act(() => {
      result.current.runSegmentation("sub-stroke0001");
    });

    // Wait for job creation
    await waitFor(() => {
      expect(result.current.jobId).toBeDefined();
    });

    // Advance time to allow job to complete (mock jobs complete in ~3s)
    await act(async () => {
      await vi.advanceTimersByTimeAsync(5000);
    });

    await waitFor(() => {
      expect(result.current.isLoading).toBe(false);
      expect(result.current.result).not.toBeNull();
    });

    expect(result.current.result?.metrics.caseId).toBe("sub-stroke0001");
    expect(result.current.result?.metrics.diceScore).toBe(0.847);
    expect(result.current.result?.dwiUrl).toContain("dwi.nii.gz");
  });

  it("shows progress updates during job execution", async () => {
    const { result } = renderHook(() => useSegmentation());

    act(() => {
      result.current.runSegmentation("sub-stroke0001");
    });

    // Wait for job to start
    await waitFor(() => {
      expect(result.current.jobId).toBeDefined();
    });

    // Progress should be tracked
    expect(result.current.progress).toBeGreaterThanOrEqual(0);
    expect(result.current.progressMessage).toBeDefined();
  });

  it("sets error on job creation failure", async () => {
    server.use(errorHandlers.segmentCreateError);

    const { result } = renderHook(() => useSegmentation());

    act(() => {
      result.current.runSegmentation("sub-stroke0001");
    });

    await waitFor(() => {
      expect(result.current.isLoading).toBe(false);
    });

    expect(result.current.error).toMatch(/failed to create job/i);
    expect(result.current.result).toBeNull();
  });

  it("clears previous error on new request", async () => {
    server.use(errorHandlers.segmentCreateError);
    const { result } = renderHook(() => useSegmentation());

    // First request fails
    act(() => {
      result.current.runSegmentation("sub-stroke0001");
    });

    await waitFor(() => {
      expect(result.current.error).not.toBeNull();
    });

    // Reset to success handler
    server.resetHandlers();

    // Second request should clear error
    act(() => {
      result.current.runSegmentation("sub-stroke0001");
    });

    expect(result.current.error).toBeNull();
    expect(result.current.isLoading).toBe(true);
  });

  it("can cancel a running job", async () => {
    const { result } = renderHook(() => useSegmentation());

    act(() => {
      result.current.runSegmentation("sub-stroke0001");
    });

    await waitFor(() => {
      expect(result.current.isLoading).toBe(true);
    });

    // Cancel the job
    act(() => {
      result.current.cancelJob();
    });

    expect(result.current.isLoading).toBe(false);
    expect(result.current.jobStatus).toBeNull();
  });

  it("cleans up polling on unmount", async () => {
    const { result, unmount } = renderHook(() => useSegmentation());

    act(() => {
      result.current.runSegmentation("sub-stroke0001");
    });

    await waitFor(() => {
      expect(result.current.isLoading).toBe(true);
    });

    // Unmount should not throw
    unmount();
  });
});