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

// Simple mock function for tests
function mockFn() {
  let callCount = 0;
  const fn = () => { callCount++; };
  
  Object.defineProperty(fn, 'toHaveBeenCalledTimes', {
    value: (expected: number) => {
      if (callCount !== expected) {
        throw new Error(`Expected ${expected} calls, got ${callCount}`);
      }
      return true;
    }
  });
  
  return fn;
}

// Mock HTML elements
class MockHTMLElement {
  public textContent: string = '';
  public className: string = '';
  public disabled: boolean = false;
  private eventListeners: { [key: string]: (() => void)[] } = {};

  addEventListener(event: string, handler: () => void) {
    if (!this.eventListeners[event]) {
      this.eventListeners[event] = [];
    }
    this.eventListeners[event].push(handler);
  }

  click() {
    const handlers = this.eventListeners['click'] || [];
    handlers.forEach(handler => handler());
  }
}

// Mock document.getElementById
const mockElements: { [id: string]: MockHTMLElement } = {};
const getElementByIdCalls: string[] = [];
(global as any).document = {
  getElementById: (id: string) => {
    getElementByIdCalls.push(id);
    return mockElements[id] || null;
  }
};

// Import after mocking
import { UIController } from "../../public/js/services/UIController.ts";

describe("UIController", () => {
  let uiController: UIController;
  let statusElement: MockHTMLElement;
  let subscribersElement: MockHTMLElement;
  let startButton: MockHTMLElement;
  let stopButton: MockHTMLElement;

  beforeEach(() => {
    // Reset mock elements
    statusElement = new MockHTMLElement();
    subscribersElement = new MockHTMLElement();
    startButton = new MockHTMLElement();
    stopButton = new MockHTMLElement();

    mockElements['status'] = statusElement;
    mockElements['subscribers'] = subscribersElement;
    mockElements['startBtn'] = startButton;
    mockElements['stopBtn'] = stopButton;
    
    // Clear call history
    getElementByIdCalls.length = 0;

    uiController = new UIController('status', 'subscribers', 'startBtn', 'stopBtn');
  });

  test("should initialize with all elements", () => {
    expect(getElementByIdCalls).toContain('status');
    expect(getElementByIdCalls).toContain('subscribers');
    expect(getElementByIdCalls).toContain('startBtn');
    expect(getElementByIdCalls).toContain('stopBtn');
  });

  test("should initialize with minimal elements", () => {
    getElementByIdCalls.length = 0; // Clear previous calls
    const minimalController = new UIController('status');
    expect(getElementByIdCalls).toContain('status');
  });

  test("should update status correctly", () => {
    uiController.updateStatus('Connected', 'connected');
    
    expect(statusElement.textContent).toBe('Connected');
    expect(statusElement.className).toBe('status connected');
  });

  test("should update subscribers count", () => {
    uiController.updateSubscribersCount(5);
    
    expect(subscribersElement.textContent).toBe('Subscribers: 5');
  });

  test("should handle missing subscribers element", () => {
    const controllerWithoutSubs = new UIController('status');
    
    expect(() => {
      controllerWithoutSubs.updateSubscribersCount(5);
    }).not.toThrow();
  });

  test("should set button states", () => {
    uiController.setButtonStates(false, true);
    
    expect(startButton.disabled).toBe(true);
    expect(stopButton.disabled).toBe(false);
    
    uiController.setButtonStates(true, false);
    
    expect(startButton.disabled).toBe(false);
    expect(stopButton.disabled).toBe(true);
  });

  test("should handle missing buttons", () => {
    const controllerWithoutButtons = new UIController('status');
    
    expect(() => {
      controllerWithoutButtons.setButtonStates(true, false);
    }).not.toThrow();
  });

  test("should add button click handlers", () => {
    const startHandler = mockFn();
    const stopHandler = mockFn();

    uiController.onButtonClick('startBtn', startHandler);
    uiController.onButtonClick('stopBtn', stopHandler);

    startButton.click();
    expect(startHandler.toHaveBeenCalledTimes(1)).toBe(true);

    stopButton.click();
    expect(stopHandler.toHaveBeenCalledTimes(1)).toBe(true);
  });

  test("should handle non-existent button click handlers", () => {
    const handler = mockFn();
    
    expect(() => {
      uiController.onButtonClick('nonExistentBtn', handler);
    }).not.toThrow();
  });

  test("should handle multiple clicks", () => {
    const handler = mockFn();
    uiController.onButtonClick('startBtn', handler);

    startButton.click();
    startButton.click();
    startButton.click();

    expect(handler.toHaveBeenCalledTimes(3)).toBe(true);
  });

  test("should support multiple handlers on same button", () => {
    const handler1 = mockFn();
    const handler2 = mockFn();

    uiController.onButtonClick('startBtn', handler1);
    uiController.onButtonClick('startBtn', handler2);

    startButton.click();

    expect(handler1.toHaveBeenCalledTimes(1)).toBe(true);
    expect(handler2.toHaveBeenCalledTimes(1)).toBe(true);
  });

  test("should update status with different classes", () => {
    uiController.updateStatus('Connecting...', 'waiting');
    expect(statusElement.className).toBe('status waiting');
    
    uiController.updateStatus('Connected', 'connected');
    expect(statusElement.className).toBe('status connected');
    
    uiController.updateStatus('Error occurred', 'error');
    expect(statusElement.className).toBe('status error');
  });

  test("should update subscribers count with zero", () => {
    uiController.updateSubscribersCount(0);
    expect(subscribersElement.textContent).toBe('Subscribers: 0');
  });

  test("should update subscribers count with large numbers", () => {
    uiController.updateSubscribersCount(1000);
    expect(subscribersElement.textContent).toBe('Subscribers: 1000');
  });
});