import { test, expect, describe } from "bun:test";

// Mock WebSocket for testing SFU Demo Server functionality
class MockWebSocket {
  public readyState = WebSocket.OPEN;
  public url: string;
  public sentMessages: string[] = [];
  
  public onopen: (() => void) | null = null;
  public onclose: (() => void) | null = null;
  public onmessage: ((event: { data: string }) => void) | null = null;
  public onerror: ((error: any) => void) | null = null;

  constructor(url: string) {
    this.url = url;
    setTimeout(() => {
      if (this.onopen) {
        this.onopen();
      }
    }, 10);
  }

  send(data: string) {
    if (this.readyState === WebSocket.OPEN) {
      this.sentMessages.push(data);
    }
  }

  close() {
    this.readyState = WebSocket.CLOSED;
    if (this.onclose) {
      this.onclose();
    }
  }

  simulateMessage(data: any) {
    if (this.onmessage) {
      this.onmessage({ data: JSON.stringify(data) });
    }
  }

  getLastMessage() {
    if (this.sentMessages.length === 0) return null;
    return JSON.parse(this.sentMessages[this.sentMessages.length - 1]);
  }

  getAllMessages() {
    return this.sentMessages.map(msg => JSON.parse(msg));
  }
}

describe("SFU Demo Server Integration", () => {
  test("should simulate SFU publisher connection flow", () => {
    const publisherWs = new MockWebSocket("ws://localhost:3001?role=publisher");
    
    // Simulate server responses for publisher flow
    const messages: any[] = [];
    
    publisherWs.onmessage = (event) => {
      const message = JSON.parse(event.data);
      messages.push(message);
      
      // Simulate server responses
      if (message.type === 'join') {
        expect(message.data.role).toBe('publisher');
        expect(typeof message.data.clientId).toBe('string');
      }
    };

    // Simulate join message from server
    publisherWs.simulateMessage({
      type: 'join',
      data: { clientId: 'publisher-123', role: 'publisher' }
    });

    expect(messages).toHaveLength(1);
    expect(messages[0].type).toBe('join');
    expect(messages[0].data.role).toBe('publisher');
  });

  test("should simulate SFU subscriber connection flow", () => {
    const subscriberWs = new MockWebSocket("ws://localhost:3001?role=subscriber");
    
    const messages: any[] = [];
    
    subscriberWs.onmessage = (event) => {
      const message = JSON.parse(event.data);
      messages.push(message);
      
      if (message.type === 'join') {
        expect(message.data.role).toBe('subscriber');
        expect(typeof message.data.clientId).toBe('string');
      }
    };

    // Simulate join message from server
    subscriberWs.simulateMessage({
      type: 'join',
      data: { clientId: 'subscriber-123', role: 'subscriber' }
    });

    expect(messages).toHaveLength(1);
    expect(messages[0].type).toBe('join');
    expect(messages[0].data.role).toBe('subscriber');
  });

  test("should simulate SFU signaling message exchange", () => {
    const publisherWs = new MockWebSocket("ws://localhost:3001?role=publisher");
    const subscriberWs = new MockWebSocket("ws://localhost:3001?role=subscriber");
    
    const publisherMessages: any[] = [];
    const subscriberMessages: any[] = [];
    
    publisherWs.onmessage = (event) => {
      publisherMessages.push(JSON.parse(event.data));
    };
    
    subscriberWs.onmessage = (event) => {
      subscriberMessages.push(JSON.parse(event.data));
    };

    // Simulate SFU RTC capabilities exchange
    publisherWs.simulateMessage({
      type: 'routerRtpCapabilities',
      data: {
        rtpCapabilities: {
          codecs: [
            { mimeType: 'video/VP8', clockRate: 90000 },
            { mimeType: 'audio/opus', clockRate: 48000 }
          ]
        }
      }
    });

    // Simulate transport creation
    publisherWs.simulateMessage({
      type: 'webRtcTransportCreated',
      data: {
        id: 'transport-123',
        iceParameters: { usernameFragment: 'test' },
        iceCandidates: [],
        dtlsParameters: { fingerprints: [] }
      }
    });

    // Simulate producer created
    publisherWs.simulateMessage({
      type: 'produced',
      data: { producerId: 'producer-123' }
    });

    // Notify subscriber of new producer
    subscriberWs.simulateMessage({
      type: 'newProducer',
      data: { producerId: 'producer-123' }
    });

    // Simulate consumer created for subscriber
    subscriberWs.simulateMessage({
      type: 'consumed',
      data: {
        consumerId: 'consumer-123',
        producerId: 'producer-123',
        kind: 'video',
        rtpParameters: {}
      }
    });

    // Verify message flow
    expect(publisherMessages).toHaveLength(3);
    expect(publisherMessages[0].type).toBe('routerRtpCapabilities');
    expect(publisherMessages[1].type).toBe('webRtcTransportCreated');
    expect(publisherMessages[2].type).toBe('produced');

    expect(subscriberMessages).toHaveLength(2);
    expect(subscriberMessages[0].type).toBe('newProducer');
    expect(subscriberMessages[1].type).toBe('consumed');
    expect(subscriberMessages[1].data.producerId).toBe('producer-123');
  });

  test("should simulate SFU scaling advantages", () => {
    // Simulate 1 publisher and multiple subscribers
    const publisher = new MockWebSocket("ws://localhost:3001?role=publisher");
    const subscribers = [
      new MockWebSocket("ws://localhost:3001?role=subscriber"),
      new MockWebSocket("ws://localhost:3001?role=subscriber"),
      new MockWebSocket("ws://localhost:3001?role=subscriber"),
      new MockWebSocket("ws://localhost:3001?role=subscriber"),
      new MockWebSocket("ws://localhost:3001?role=subscriber")
    ];

    // In mesh architecture, publisher would need 5 connections
    // In SFU architecture, publisher needs only 1 connection to server
    
    const publisherConnections = 1; // SFU: constant regardless of subscribers
    const meshConnections = subscribers.length; // Mesh: scales with subscribers
    
    const bandwidthSaved = (meshConnections - publisherConnections) / meshConnections;
    
    expect(publisherConnections).toBe(1);
    expect(meshConnections).toBe(5);
    expect(bandwidthSaved).toBe(0.8); // 80% bandwidth saved for publisher
  });

  test("should simulate SFU adaptive bitrate", () => {
    const subscribers = [
      { quality: 'low', expectedBitrate: 800 },
      { quality: 'medium', expectedBitrate: 1500 },
      { quality: 'high', expectedBitrate: 2500 }
    ];

    // SFU can adapt bitrate per subscriber based on their capabilities
    subscribers.forEach(subscriber => {
      const ws = new MockWebSocket(`ws://localhost:3001?role=subscriber&quality=${subscriber.quality}`);
      const messages: any[] = [];
      
      ws.onmessage = (event) => {
        messages.push(JSON.parse(event.data));
      };
      
      ws.simulateMessage({
        type: 'consumed',
        data: {
          consumerId: 'consumer-' + subscriber.quality,
          bitrate: subscriber.expectedBitrate,
          quality: subscriber.quality
        }
      });

      expect(messages).toHaveLength(1);
      expect(messages[0].data.quality).toBe(subscriber.quality);
      expect(messages[0].data.bitrate).toBe(subscriber.expectedBitrate);
    });
  });

  test("should simulate SFU error handling", () => {
    const client = new MockWebSocket("ws://localhost:3001?role=subscriber");
    const messages: any[] = [];
    
    client.onmessage = (event) => {
      messages.push(JSON.parse(event.data));
    };

    // Simulate server error
    client.simulateMessage({
      type: 'error',
      data: { message: 'Producer not found' }
    });

    expect(messages).toHaveLength(1);
    expect(messages[0].type).toBe('error');
    expect(messages[0].data.message).toContain('Producer not found');
  });

  test("should simulate SFU statistics tracking", () => {
    // Mock server statistics
    const stats = {
      totalClients: 6,
      publishers: 1,
      subscribers: 5,
      streamsForwarded: 1,
      totalBandwidth: 8500, // 1 publisher (2500) + 5 subscribers (1200 each)
      uptime: 120
    };

    // Verify SFU efficiency metrics
    expect(stats.publishers).toBe(1);
    expect(stats.subscribers).toBe(5);
    expect(stats.streamsForwarded).toBe(1); // Server handles 1 stream, forwards to 5

    // Calculate bandwidth efficiency
    const publisherBandwidth = 2500;
    const meshTotalBandwidth = publisherBandwidth * stats.subscribers; // 12,500
    const sfuTotalBandwidth = stats.totalBandwidth; // 8,500
    const bandwidthSaved = (meshTotalBandwidth - sfuTotalBandwidth) / meshTotalBandwidth;

    expect(bandwidthSaved).toBeGreaterThan(0.3); // At least 30% bandwidth saved
  });

  test("should simulate SFU reconnection handling", () => {
    const client = new MockWebSocket("ws://localhost:3001?role=publisher");
    let reconnectAttempted = false;

    client.onclose = () => {
      reconnectAttempted = true;
    };

    // Simulate connection loss
    client.close();

    expect(reconnectAttempted).toBe(true);
    expect(client.readyState).toBe(WebSocket.CLOSED);

    // In a real SFU implementation, the client would reconnect
    // and the server would maintain stream state
    const reconnectedClient = new MockWebSocket("ws://localhost:3001?role=publisher");
    expect(reconnectedClient.readyState).toBe(WebSocket.OPEN);
  });

  test("should validate SFU message types", () => {
    const validSFUMessageTypes = [
      'join',
      'routerRtpCapabilities',
      'webRtcTransportCreated', 
      'webRtcTransportConnected',
      'produced',
      'consumed',
      'resumed',
      'paused',
      'newProducer',
      'producers',
      'error'
    ];

    validSFUMessageTypes.forEach(messageType => {
      expect(typeof messageType).toBe('string');
      expect(messageType.length).toBeGreaterThan(0);
    });

    // Test message structure
    const sampleMessage = {
      type: 'consumed',
      data: {
        consumerId: 'consumer-123',
        producerId: 'producer-123',
        kind: 'video'
      }
    };

    expect(sampleMessage.type).toBe('consumed');
    expect(sampleMessage.data.consumerId).toBe('consumer-123');
    expect(sampleMessage.data.producerId).toBe('producer-123');
    expect(sampleMessage.data.kind).toBe('video');
  });
});