/**
 * Tests for BLE Connection State Machine
 */

import { MockBLEManager } from '../MockBLEManager';
import { BLEConnectionState, BLEConnectionEvent } from '../types';

describe('BLE Connection State Machine', () => {
  let manager: MockBLEManager;

  beforeEach(() => {
    manager = new MockBLEManager();
  });

  afterEach(async () => {
    await manager.cleanup();
  });

  describe('State Transitions', () => {
    it('should start in DISCONNECTED state', () => {
      const state = manager.getConnectionState('test-device');
      expect(state).toBe(BLEConnectionState.DISCONNECTED);
    });

    it('should transition through states during connection', async () => {
      const states: BLEConnectionState[] = [];
      const listener = (deviceId: string, event: BLEConnectionEvent, data?: any) => {
        if (event === 'state_changed') {
          states.push(data.state);
        }
      };

      manager.addEventListener(listener);

      await manager.connectDevice('test-device');

      // Should go through: CONNECTING -> CONNECTED -> DISCOVERING -> READY
      expect(states).toContain(BLEConnectionState.CONNECTING);
      expect(states).toContain(BLEConnectionState.CONNECTED);
      expect(states).toContain(BLEConnectionState.DISCOVERING);
      expect(states).toContain(BLEConnectionState.READY);

      // Final state should be READY
      expect(manager.getConnectionState('test-device')).toBe(BLEConnectionState.READY);
    });

    it('should transition to DISCONNECTING then DISCONNECTED on disconnect', async () => {
      const states: BLEConnectionState[] = [];
      const listener = (deviceId: string, event: BLEConnectionEvent, data?: any) => {
        if (event === 'state_changed') {
          states.push(data.state);
        }
      };

      manager.addEventListener(listener);

      await manager.connectDevice('test-device');
      states.length = 0; // Clear connection states

      await manager.disconnectDevice('test-device');

      expect(states).toContain(BLEConnectionState.DISCONNECTING);
      expect(states).toContain(BLEConnectionState.DISCONNECTED);
      expect(manager.getConnectionState('test-device')).toBe(BLEConnectionState.DISCONNECTED);
    });
  });

  describe('Event Emission', () => {
    it('should emit ready event when connection completes', async () => {
      let readyEmitted = false;
      const listener = (deviceId: string, event: BLEConnectionEvent) => {
        if (event === 'ready') {
          readyEmitted = true;
        }
      };

      manager.addEventListener(listener);
      await manager.connectDevice('test-device');

      expect(readyEmitted).toBe(true);
    });

    it('should emit disconnected event on disconnect', async () => {
      let disconnectedEmitted = false;
      const listener = (deviceId: string, event: BLEConnectionEvent) => {
        if (event === 'disconnected') {
          disconnectedEmitted = true;
        }
      };

      manager.addEventListener(listener);
      await manager.connectDevice('test-device');
      await manager.disconnectDevice('test-device');

      expect(disconnectedEmitted).toBe(true);
    });

    it('should emit state_changed event on each state transition', async () => {
      let stateChangedCount = 0;
      const listener = (deviceId: string, event: BLEConnectionEvent) => {
        if (event === 'state_changed') {
          stateChangedCount++;
        }
      };

      manager.addEventListener(listener);
      await manager.connectDevice('test-device');

      // Should have multiple state changes during connection
      expect(stateChangedCount).toBeGreaterThanOrEqual(4);
    });
  });

  describe('Multiple Devices', () => {
    it('should track state for multiple devices independently', async () => {
      await manager.connectDevice('device-1');
      await manager.connectDevice('device-2');

      expect(manager.getConnectionState('device-1')).toBe(BLEConnectionState.READY);
      expect(manager.getConnectionState('device-2')).toBe(BLEConnectionState.READY);

      await manager.disconnectDevice('device-1');

      expect(manager.getConnectionState('device-1')).toBe(BLEConnectionState.DISCONNECTED);
      expect(manager.getConnectionState('device-2')).toBe(BLEConnectionState.READY);
    });

    it('should emit events with correct deviceId', async () => {
      const events: Array<{ deviceId: string; event: BLEConnectionEvent }> = [];
      const listener = (deviceId: string, event: BLEConnectionEvent) => {
        events.push({ deviceId, event });
      };

      manager.addEventListener(listener);

      await manager.connectDevice('device-1');
      await manager.connectDevice('device-2');

      const device1Events = events.filter(e => e.deviceId === 'device-1');
      const device2Events = events.filter(e => e.deviceId === 'device-2');

      expect(device1Events.length).toBeGreaterThan(0);
      expect(device2Events.length).toBeGreaterThan(0);
    });
  });

  describe('Connection Info', () => {
    it('should store connection metadata', async () => {
      await manager.connectDevice('test-device');

      const connections = manager.getAllConnections();
      const deviceConnection = connections.get('test-device');

      expect(deviceConnection).toBeDefined();
      expect(deviceConnection?.deviceId).toBe('test-device');
      expect(deviceConnection?.state).toBe(BLEConnectionState.READY);
      expect(deviceConnection?.connectedAt).toBeDefined();
      expect(deviceConnection?.lastActivity).toBeDefined();
    });

    it('should update lastActivity on state changes', async () => {
      await manager.connectDevice('test-device');

      const connections1 = manager.getAllConnections();
      const firstActivity = connections1.get('test-device')?.lastActivity;

      // Wait a bit and disconnect
      await new Promise(resolve => setTimeout(resolve, 100));
      await manager.disconnectDevice('test-device');

      const connections2 = manager.getAllConnections();
      const secondActivity = connections2.get('test-device')?.lastActivity;

      expect(secondActivity).toBeGreaterThan(firstActivity!);
    });
  });

  describe('Event Listeners', () => {
    it('should add and remove listeners', () => {
      const listener1 = jest.fn();
      const listener2 = jest.fn();

      manager.addEventListener(listener1);
      manager.addEventListener(listener2);
      manager.removeEventListener(listener1);

      // Trigger an event
      manager.connectDevice('test-device');

      // listener2 should be called, listener1 should not
      expect(listener2).toHaveBeenCalled();
      // Note: In real implementation, this would work, but here we need to wait
    });

    it('should not add duplicate listeners', async () => {
      let callCount = 0;
      const listener = () => {
        callCount++;
      };

      manager.addEventListener(listener);
      manager.addEventListener(listener); // Try to add again

      await manager.connectDevice('test-device');

      // Each event should only increment once
      // (multiple state changes will still cause multiple calls)
      const expectedCalls = 4; // CONNECTING, CONNECTED, DISCOVERING, READY
      expect(callCount).toBeLessThan(expectedCalls * 2); // Not doubled
    });

    it('should handle listener errors gracefully', async () => {
      const errorListener = () => {
        throw new Error('Listener error');
      };
      const goodListener = jest.fn();

      manager.addEventListener(errorListener);
      manager.addEventListener(goodListener);

      await manager.connectDevice('test-device');

      // Good listener should still be called despite error listener
      expect(goodListener).toHaveBeenCalled();
    });
  });

  describe('Cleanup', () => {
    it('should disconnect all devices on cleanup', async () => {
      await manager.connectDevice('device-1');
      await manager.connectDevice('device-2');
      await manager.connectDevice('device-3');

      expect(manager.getConnectionState('device-1')).toBe(BLEConnectionState.READY);
      expect(manager.getConnectionState('device-2')).toBe(BLEConnectionState.READY);
      expect(manager.getConnectionState('device-3')).toBe(BLEConnectionState.READY);

      await manager.cleanup();

      expect(manager.getConnectionState('device-1')).toBe(BLEConnectionState.DISCONNECTED);
      expect(manager.getConnectionState('device-2')).toBe(BLEConnectionState.DISCONNECTED);
      expect(manager.getConnectionState('device-3')).toBe(BLEConnectionState.DISCONNECTED);
    });

    it('should clear all connection states on cleanup', async () => {
      await manager.connectDevice('device-1');
      await manager.connectDevice('device-2');

      let connections = manager.getAllConnections();
      expect(connections.size).toBeGreaterThan(0);

      await manager.cleanup();

      connections = manager.getAllConnections();
      expect(connections.size).toBe(0);
    });

    it('should clear all event listeners on cleanup', async () => {
      const listener = jest.fn();
      manager.addEventListener(listener);

      await manager.cleanup();

      // Try to trigger events
      await manager.connectDevice('test-device');

      // Listener should not be called after cleanup
      // (Will be called during cleanup disconnect, but not after)
      const callsBeforeCleanup = listener.mock.calls.length;
      await manager.connectDevice('another-device');
      expect(listener.mock.calls.length).toBe(callsBeforeCleanup);
    });
  });

  describe('Edge Cases', () => {
    it('should handle disconnect of non-connected device', async () => {
      // Should not throw
      await expect(manager.disconnectDevice('non-existent')).resolves.not.toThrow();

      expect(manager.getConnectionState('non-existent')).toBe(BLEConnectionState.DISCONNECTED);
    });

    it('should handle reconnection to same device', async () => {
      await manager.connectDevice('test-device');
      await manager.disconnectDevice('test-device');
      await manager.connectDevice('test-device');

      expect(manager.getConnectionState('test-device')).toBe(BLEConnectionState.READY);
    });

    it('should preserve connection info across state changes', async () => {
      await manager.connectDevice('test-device');

      const connections1 = manager.getAllConnections();
      const connectedAt = connections1.get('test-device')?.connectedAt;

      // Trigger state change without disconnecting
      // (In real implementation, this would be a command send)
      await manager.sendCommand('test-device', 'test');

      const connections2 = manager.getAllConnections();
      const stillConnectedAt = connections2.get('test-device')?.connectedAt;

      expect(stillConnectedAt).toBe(connectedAt);
    });
  });
});