import React from 'react';
import {AppState} from 'react-native';
import ReactTestRenderer from 'react-test-renderer';
import {
  haptikaPPG,
  type PPGFrameUpdate,
} from 'react-native-haptika-ppg';

import {
  usePPGMeasurement,
  type PPGMeasurementController,
} from '../measurement/usePPGMeasurement';

jest.mock('react-native-haptika-ppg', () => ({
  haptikaPPG: {
    startMeasurement: jest.fn(),
    processFrame: jest.fn(),
    finishMeasurement: jest.fn(),
    cancelMeasurement: jest.fn(),
    getThermalState: jest.fn(() => 'nominal'),
  },
  haptikaHealthKit: {
    isAvailable: jest.fn(() => false),
    requestReadAuthorization: jest.fn(async () => false),
  },
}));

const nativePPG = haptikaPPG as jest.Mocked<typeof haptikaPPG>;
let controller: PPGMeasurementController;
let renderer: ReactTestRenderer.ReactTestRenderer | null = null;
let memoryWarningHandler: (() => void) | null = null;

function Harness(): null {
  controller = usePPGMeasurement();
  return null;
}

const frameUpdate = (
  thermalState: PPGFrameUpdate['thermalState'],
  overrides: Partial<PPGFrameUpdate> = {},
): PPGFrameUpdate => ({
  timestampSeconds: 1,
  contactState: 'absent',
  contactConfidence: 0,
  signalLevel: 0,
  saturationRatio: 0,
  motionArtifactScore: 0,
  collectedSampleCount: 0,
  usableDurationSeconds: 0,
  droppedFrameCount: 0,
  thermalState,
  waveformValue: 0,
  beatSequence: 0,
  acceptedBeats: [],
  ...overrides,
});

async function startCamera(): Promise<void> {
  await ReactTestRenderer.act(async () => {
    await controller.start({
      includeHealthKitContext: false,
      sensitiveContact: true,
      requestCameraPermission: async () => true,
    });
  });
  ReactTestRenderer.act(() => controller.onCameraStarted());
}

describe('usePPGMeasurement safety coordination', () => {
  beforeEach(async () => {
    jest.clearAllMocks();
    memoryWarningHandler = null;
    jest.spyOn(AppState, 'addEventListener').mockImplementation(
      ((eventType: string, listener: () => void) => {
        if (eventType === 'memoryWarning') memoryWarningHandler = listener;
        return {remove: jest.fn()};
      }) as unknown as typeof AppState.addEventListener,
    );
    nativePPG.getThermalState.mockReturnValue('nominal');
    await ReactTestRenderer.act(async () => {
      renderer = ReactTestRenderer.create(<Harness />);
    });
  });

  afterEach(() => {
    if (renderer !== null) {
      ReactTestRenderer.act(() => renderer?.unmount());
      renderer = null;
    }
    jest.restoreAllMocks();
  });

  test('cancels the native session synchronously before publishing a camera failure', async () => {
    await startCamera();
    expect(nativePPG.startMeasurement).toHaveBeenCalledWith(
      expect.objectContaining({minimumContactConfidence: 0.45}),
    );
    expect(controller.snapshot.value).toBe('stabilizing');

    ReactTestRenderer.act(() => {
      controller.onCameraError({
        code: 'cameraRuntime',
        message: 'Frame processing failed',
      });
      expect(nativePPG.cancelMeasurement).toHaveBeenCalledTimes(1);
    });

    expect(controller.snapshot.value).toBe('error');
    expect(controller.snapshot.context.failure?.code).toBe('cameraRuntime');
  });

  test('re-reads native thermal state before leaving thermalStop', async () => {
    await startCamera();
    ReactTestRenderer.act(() => controller.onFrameUpdate(frameUpdate('serious')));
    expect(controller.snapshot.value).toBe('thermalStop');

    nativePPG.getThermalState.mockReturnValueOnce('serious');
    ReactTestRenderer.act(() => controller.retry());
    expect(controller.snapshot.value).toBe('thermalStop');

    nativePPG.getThermalState.mockReturnValueOnce('fair');
    ReactTestRenderer.act(() => controller.retry());
    expect(controller.snapshot.value).toBe('preparingCamera');
    expect(nativePPG.getThermalState).toHaveBeenCalledTimes(2);
  });

  test('pauses useful progress without stopping capture when contact is unusable', async () => {
    await startCamera();

    ReactTestRenderer.act(() =>
      controller.onFrameUpdate(
        frameUpdate('nominal', {
          timestampSeconds: 10,
          contactState: 'valid',
          contactConfidence: 0.95,
          usableDurationSeconds: 0,
        }),
      ),
    );
    expect(controller.snapshot.value).toBe('stabilizing');

    ReactTestRenderer.act(() =>
      controller.onFrameUpdate(
        frameUpdate('nominal', {
          timestampSeconds: 12,
          contactState: 'unstable',
          contactConfidence: 0.15,
          usableDurationSeconds: 0,
          motionArtifactScore: 1,
        }),
      ),
    );
    expect(controller.snapshot.value).toBe('stabilizing');
    expect(controller.phaseProgress).toBe(0);

    ReactTestRenderer.act(() =>
      controller.onFrameUpdate(
        frameUpdate('nominal', {
          timestampSeconds: 15.1,
          contactState: 'absent',
          usableDurationSeconds: 0,
        }),
      ),
    );
    expect(controller.snapshot.value).toBe('stabilizing');

    ReactTestRenderer.act(() => {
      for (let timestamp = 16; timestamp <= 21.5; timestamp += 0.5) {
        controller.onFrameUpdate(
          frameUpdate('nominal', {
            timestampSeconds: timestamp,
            contactState: 'valid',
            contactConfidence: 0.9,
          }),
        );
      }
    });
    expect(controller.snapshot.value).toBe('measuring');

    ReactTestRenderer.act(() =>
      controller.onFrameUpdate(
        frameUpdate('nominal', {
          timestampSeconds: 32.1,
          contactState: 'overexposed',
          contactConfidence: 0.05,
          usableDurationSeconds: 0,
          saturationRatio: 1,
        }),
      ),
    );
    const firstAcquisitionProgress = controller.phaseProgress;
    expect(firstAcquisitionProgress).toBe(0);
    expect(controller.snapshot.value).toBe('measuring');

    ReactTestRenderer.act(() =>
      controller.onFrameUpdate(
        frameUpdate('nominal', {
          timestampSeconds: 54.1,
          contactState: 'tooMuchPressure',
          contactConfidence: 0.1,
          usableDurationSeconds: 0,
        }),
      ),
    );

    expect(controller.snapshot.value).toBe('measuring');
    expect(controller.phaseProgress).toBe(firstAcquisitionProgress);
    expect(nativePPG.cancelMeasurement).not.toHaveBeenCalled();
  });

  test('finishes after fifty detected beats and the minimum acquisition time', async () => {
    nativePPG.finishMeasurement.mockImplementationOnce(() => {
      throw new Error('synthetic processing stop');
    });
    await startCamera();
    ReactTestRenderer.act(() => {
      for (let timestamp = 10; timestamp <= 15.5; timestamp += 0.5) {
        controller.onFrameUpdate(
          frameUpdate('nominal', {
            timestampSeconds: timestamp,
            contactState: 'valid',
            contactConfidence: 0.95,
            beatSequence: 4,
            usableDurationSeconds: timestamp - 10,
          }),
        );
      }
    });
    expect(controller.snapshot.value).toBe('measuring');

    ReactTestRenderer.act(() =>
      controller.onFrameUpdate(
        frameUpdate('nominal', {
          timestampSeconds: 60.7,
          contactState: 'unstable',
          beatSequence: 49,
          usableDurationSeconds: 50.7,
          collectedSampleCount: 1_500,
        }),
      ),
    );

    expect(controller.phaseProgress).toBe(1);
    expect(nativePPG.finishMeasurement).toHaveBeenCalledTimes(1);
    expect(controller.snapshot.value).not.toBe('measuring');
  });

  test('stops and releases the native camera session on memory pressure', async () => {
    await startCamera();
    expect(controller.snapshot.value).toBe('stabilizing');
    expect(memoryWarningHandler).not.toBeNull();

    ReactTestRenderer.act(() => memoryWarningHandler?.());

    expect(nativePPG.cancelMeasurement).toHaveBeenCalledTimes(1);
    expect(controller.snapshot.value).toBe('error');
    expect(controller.snapshot.context.failure?.code).toBe('memoryPressure');
  });
});