import {
  createInitialMeasurementMachine,
  transitionMeasurement,
} from '../measurement/measurementMachine';
import type {
  MeasurementEvent,
  MeasurementMachineSnapshot,
} from '../measurement/measurementTypes';
import {makeProcessingResult} from './syntheticMeasurements';

const send = (
  snapshot: MeasurementMachineSnapshot,
  ...events: readonly MeasurementEvent[]
): MeasurementMachineSnapshot =>
  events.reduce(transitionMeasurement, snapshot);

describe('measurement machine', () => {
  test('runs the complete camera-only lifecycle', () => {
    const result = makeProcessingResult();
    const snapshot = send(
      createInitialMeasurementMachine(),
      {type: 'START'},
      {type: 'CAMERA_PERMISSION_GRANTED'},
      {type: 'CAMERA_READY'},
      {type: 'CONTACT_CHANGED', contactState: 'valid'},
      {type: 'STABILIZATION_COMPLETE'},
      {type: 'ACQUISITION_COMPLETE'},
      {type: 'PROCESSING_SUCCEEDED', result},
    );

    expect(snapshot.value).toBe('completed');
    expect(snapshot.context.result).toEqual(result);
    expect(snapshot.context.attempt).toBe(1);
  });

  test('continues when the optional HealthKit request fails', () => {
    const snapshot = send(
      createInitialMeasurementMachine(),
      {type: 'START', requestHealthKit: true},
      {type: 'CAMERA_PERMISSION_GRANTED'},
    );
    expect(snapshot.value).toBe('requestingHealthPermission');

    const afterFailure = transitionMeasurement(snapshot, {
      type: 'HEALTH_PERMISSION_RESOLVED',
      status: 'requestFailed',
    });
    expect(afterFailure.value).toBe('preparingCamera');
    expect(afterFailure.context.healthPermission).toBe('requestFailed');
  });

  test('a rejected camera permission retry returns through idle before requesting again', () => {
    const denied = send(
      createInitialMeasurementMachine(),
      {type: 'START'},
      {type: 'CAMERA_PERMISSION_DENIED'},
    );
    expect(denied.value).toBe('error');

    const retrying = transitionMeasurement(denied, {type: 'RETRY'});
    expect(retrying.value).toBe('idle');
    expect(retrying.context.attempt).toBe(1);

    const requestingAgain = transitionMeasurement(retrying, {type: 'START'});
    expect(requestingAgain.value).toBe('requestingCameraPermission');
    expect(requestingAgain.context.attempt).toBe(2);
  });

  test.each(['waitingForFinger', 'measuring'] as const)(
    'routes a camera failure from %s to the global error state',
    activeState => {
      let active = send(
        createInitialMeasurementMachine(),
        {type: 'START'},
        {type: 'CAMERA_PERMISSION_GRANTED'},
        {type: 'CAMERA_READY'},
      );
      if (activeState === 'measuring') {
        active = send(
          active,
          {type: 'CONTACT_CHANGED', contactState: 'valid'},
          {type: 'STABILIZATION_COMPLETE'},
        );
      }

      const failed = transitionMeasurement(active, {
        type: 'FAIL',
        failure: {
          code: 'cameraRuntime',
          message: 'Camera runtime failure',
          recoverable: true,
        },
      });

      expect(failed.value).toBe('error');
      expect(failed.context.failure?.code).toBe('cameraRuntime');
    },
  );

  test('keeps stabilization and acquisition running when contact fluctuates', () => {
    const measuring = send(
      createInitialMeasurementMachine(),
      {type: 'START'},
      {type: 'CAMERA_PERMISSION_GRANTED'},
      {type: 'CAMERA_READY'},
      {type: 'CONTACT_CHANGED', contactState: 'valid'},
      {type: 'STABILIZATION_COMPLETE'},
    );
    expect(measuring.value).toBe('measuring');

    const waiting = transitionMeasurement(measuring, {
      type: 'CONTACT_CHANGED',
      contactState: 'unstable',
    });
    expect(waiting.value).toBe('measuring');

    const stillMeasuring = transitionMeasurement(waiting, {
      type: 'CONTACT_CHANGED',
      contactState: 'valid',
    });
    expect(stillMeasuring.value).toBe('measuring');
  });

  test('allows stabilization to complete even when the latest frame is unstable', () => {
    const stabilizing = send(
      createInitialMeasurementMachine(),
      {type: 'START'},
      {type: 'CAMERA_PERMISSION_GRANTED'},
      {type: 'CAMERA_READY'},
      {type: 'CONTACT_CHANGED', contactState: 'valid'},
      {type: 'CONTACT_CHANGED', contactState: 'unstable'},
    );
    expect(stabilizing.value).toBe('stabilizing');
    expect(
      transitionMeasurement(stabilizing, {type: 'STABILIZATION_COMPLETE'}).value,
    ).toBe('measuring');
  });

  test.each(['serious', 'critical'] as const)(
    'stops immediately for a %s thermal state',
    thermalState => {
      const measuring = send(
        createInitialMeasurementMachine(),
        {type: 'START'},
        {type: 'CAMERA_PERMISSION_GRANTED'},
        {type: 'CAMERA_READY'},
      );
      const stopped = transitionMeasurement(measuring, {
        type: 'THERMAL_STATE_CHANGED',
        thermalState,
      });

      expect(stopped.value).toBe('thermalStop');
      expect(stopped.context.failure?.code).toBe(
        thermalState === 'critical' ? 'thermalCritical' : 'thermalSerious',
      );
      expect(stopped.context.failure?.message).toMatch(/iPhone|chaud/);
    },
  );

  test('cannot reset past an unsafe thermal state', () => {
    const stopped = send(
      createInitialMeasurementMachine(),
      {type: 'START'},
      {type: 'CAMERA_PERMISSION_GRANTED'},
      {type: 'THERMAL_STATE_CHANGED', thermalState: 'serious'},
    );

    const reset = transitionMeasurement(stopped, {type: 'RESET'});
    expect(reset.value).toBe('thermalStop');

    const cooled = transitionMeasurement(reset, {
      type: 'THERMAL_STATE_CHANGED',
      thermalState: 'fair',
    });
    expect(transitionMeasurement(cooled, {type: 'RETRY'}).value).toBe(
      'preparingCamera',
    );
  });

  test('never completes an invalid native result', () => {
    const invalidResult = makeProcessingResult({
      valid: false,
      invalidReason: 'Signal insuffisant',
      quality: {
        ...makeProcessingResult().quality,
        score: 0.4,
        level: 'invalid',
      },
    });
    const snapshot = send(
      createInitialMeasurementMachine(),
      {type: 'START'},
      {type: 'CAMERA_PERMISSION_GRANTED'},
      {type: 'CAMERA_READY'},
      {type: 'CONTACT_CHANGED', contactState: 'valid'},
      {type: 'STABILIZATION_COMPLETE'},
      {type: 'ACQUISITION_COMPLETE'},
      {type: 'PROCESSING_SUCCEEDED', result: invalidResult},
    );

    expect(snapshot.value).toBe('invalid');
    expect(snapshot.context.result?.valid).toBe(false);
  });

  test('keeps a conservative BPM when PRV quality is poor', () => {
    const partialResult = makeProcessingResult({
      valid: true,
      bpm: {
        ...makeProcessingResult().bpm,
        bpm: 68,
      },
      quality: {
        ...makeProcessingResult().quality,
        score: 0.52,
        level: 'poor',
      },
      prv: {
        ...makeProcessingResult().prv,
        reliable: false,
      },
    });
    const snapshot = send(
      createInitialMeasurementMachine(),
      {type: 'START'},
      {type: 'CAMERA_PERMISSION_GRANTED'},
      {type: 'CAMERA_READY'},
      {type: 'CONTACT_CHANGED', contactState: 'valid'},
      {type: 'STABILIZATION_COMPLETE'},
      {type: 'ACQUISITION_COMPLETE'},
      {type: 'PROCESSING_SUCCEEDED', result: partialResult},
    );

    expect(snapshot.value).toBe('completed');
    expect(snapshot.context.result?.bpm.bpm).toBe(68);
    expect(snapshot.context.result?.prv.reliable).toBe(false);
  });
});