/**
 * Test Coverage for TypeScript Declaration File Accuracy
 * 
 * Tests to validate TypeScript declaration file accuracy:
 * - Interface method signatures match implementation
 * - All public methods are declared
 * - Parameter types are accurate
 * - Return types are correct
 * - Generic type constraints work properly
 */

import app from '../src/apprun';
import { Component } from '../src/component';

describe('TypeScript Declaration Accuracy Coverage', () => {
  describe('IApp Interface Compliance', () => {
    it('should implement all IApp interface methods', () => {
      // Test that app implements all required methods from IApp interface
      expect(typeof app.start).toBe('function');
      expect(typeof app.on).toBe('function');
      expect(typeof app.once).toBe('function');
      expect(typeof app.off).toBe('function');
      expect(typeof app.run).toBe('function');
      expect(typeof app.query).toBe('function');
      expect(typeof app.runAsync).toBe('function');
      expect(typeof app.find).toBe('function');
      expect(typeof app.h).toBe('function');
      expect(typeof app.createElement).toBe('function');
      expect(typeof app.render).toBe('function');
      expect(typeof app.Fragment).toBe('function');
      expect(typeof app.webComponent).toBe('function');
      expect(typeof app.safeHTML).toBe('function');
      expect(typeof app.use_render).toBe('function');
      expect(typeof app.use_react).toBe('function');
      expect(typeof app.version).toBe('string');
    });

    it('should have correct route property type', () => {
      // route property should be optional and function-like
      expect(app.route === undefined || typeof app.route === 'function').toBe(true);
    });

    it('should implement once method correctly', () => {
      // Test that once method works as expected from interface
      let callCount = 0;
      const handler = () => { callCount++; };

      app.once('test-once', handler);
      app.run('test-once');

      // The handler should have been called once and then removed
      expect(callCount).toBe(1);

      // Verify the handler was removed by checking if there are subscribers
      const subscribers = app.find('test-once');
      expect(subscribers).toEqual([]); // Should be empty array when no subscribers
    });

    it('should implement query method as alias for runAsync', () => {
      // Test that query method exists and works like runAsync
      expect(typeof app.query).toBe('function');

      app.on('test-query', () => 'query-result');

      return Promise.all([
        app.query('test-query'),
        app.runAsync('test-query')
      ]).then(([queryResult, runAsyncResult]) => {
        expect(queryResult).toEqual(runAsyncResult);
        app.off('test-query', () => { });
      });
    });
  });

  describe('Method Signature Accuracy', () => {
    it('should accept correct parameters in start method', () => {
      const testElement = document.createElement('div');
      const testModel = { count: 0 };
      const testView = (state: any) => `<div>${state.count}</div>`;
      const testUpdate = {
        increment: (state: any) => ({ ...state, count: state.count + 1 })
      };
      const testOptions = { render: true, global_event: true };

      // This should compile and work according to TypeScript declarations
      expect(() => {
        const component = app.start(testElement, testModel, testView, testUpdate, testOptions);
        expect(component).toBeInstanceOf(Component);
      }).not.toThrow();
    });

    it('should accept correct parameters in on method', () => {
      const handler = (state: any, data: string) => state;
      const options = { once: false, delay: 100 };

      expect(() => {
        app.on('test-on', handler, options);
        app.off('test-on', handler);
      }).not.toThrow();
    });

    it('should accept correct parameters in use_react method', () => {
      const mockReact = {
        version: '18.2.0',
        createElement: jest.fn(),
        Fragment: 'React.Fragment'
      };

      const mockReactDOM = {
        createRoot: jest.fn().mockReturnValue({ render: jest.fn() })
      };

      // This should match the TypeScript declaration: use_react(React, ReactDOM)
      expect(() => {
        app.use_react(mockReact, mockReactDOM);
      }).not.toThrow();
    });

    it('should have correct createElement/h method signatures', () => {
      // Test that h and createElement accept the same parameters
      const props = { className: 'test' };
      const children = ['Hello', 'World'];

      expect(() => {
        const result1 = app.h('div', props, ...children);
        const result2 = app.createElement('div', props, ...children);
        // Both should work without throwing errors
        expect(typeof result1).toBeDefined();
        expect(typeof result2).toBeDefined();
      }).not.toThrow();
    });

    it('should have correct render method signature', () => {
      const testElement = document.createElement('div');
      const testVNode = { tag: 'span', props: {}, children: ['test'] };

      expect(() => {
        app.render(testElement, testVNode);
      }).not.toThrow();
    });
  });

  describe('Component Class Declaration Accuracy', () => {
    it('should implement Component constructor correctly', () => {
      const state = { value: 'test' };
      const view = (s: any) => `<div>${s.value}</div>`;
      const update = {
        setValue: (s: any, value: string) => ({ ...s, value })
      };

      expect(() => {
        const component1 = new Component();
        const component2 = new Component(state);
        const component3 = new Component(state, view);
        const component4 = new Component(state, view, update);

        expect(component1).toBeInstanceOf(Component);
        expect(component2).toBeInstanceOf(Component);
        expect(component3).toBeInstanceOf(Component);
        expect(component4).toBeInstanceOf(Component);
      }).not.toThrow();
    });

    it('should implement Component methods correctly', () => {
      const component = new Component({ count: 0 });

      // Test method existence and types
      expect(typeof component.setState).toBe('function');
      expect(typeof component.mount).toBe('function');
      expect(typeof component.start).toBe('function');
      expect(typeof component.on).toBe('function');
      expect(typeof component.run).toBe('function');
      expect(typeof component.query).toBe('function');
      expect(typeof component.runAsync).toBe('function');

      // Test that methods can be called
      expect(() => {
        component.setState({ count: 1 });
      }).not.toThrow();
    });

    it('should support Component lifecycle callbacks', () => {
      const component = new Component({ test: true });

      // These properties should be assignable according to declarations
      component.rendered = (state: any) => {
        expect(state).toBeDefined();
      };

      component.mounted = (props: any, children: any[], state: any) => {
        expect(state).toBeDefined();
        return state;
      };

      component.unload = (state: any) => {
        expect(state).toBeDefined();
      };

      expect(typeof component.rendered).toBe('function');
      expect(typeof component.mounted).toBe('function');
      expect(typeof component.unload).toBe('function');
    });
  });

  describe('Generic Type Support', () => {
    it('should support generic types in Component', () => {
      interface TestState {
        name: string;
        count: number;
      }

      interface TestEvents {
        increment: string;
        setName: string;
      }

      class TestComponent extends Component<TestState, TestEvents> {
        constructor() {
          super({
            name: 'test',
            count: 0
          });
        }

        getState() {
          return this.state;
        }
      }

      const component = new TestComponent();
      const state = component.getState();

      expect(state.name).toBe('test');
      expect(state.count).toBe(0);
    });

    it('should support generic types in app.start', () => {
      interface AppState {
        title: string;
        items: string[];
      }

      const state: AppState = {
        title: 'Test App',
        items: ['item1', 'item2']
      };

      const view = (s: AppState) => `<h1>${s.title}</h1>`;
      const update = {
        addItem: (s: AppState, item: string) => ({
          ...s,
          items: [...s.items, item]
        })
      };

      const element = document.createElement('div');

      expect(() => {
        const component = app.start<AppState>(element, state, view, update);
        expect(component).toBeInstanceOf(Component);
      }).not.toThrow();
    });
  });

  describe('Event System Type Accuracy', () => {
    it('should support proper event handler typing', () => {
      interface EventData {
        type: string;
        payload: any;
      }

      const typedHandler = (state: any, data?: EventData) => {
        // This test verifies that event handlers can be properly typed
        // The data parameter might be undefined depending on how the event is called
        if (data) {
          expect(data).toBeDefined();
          expect(data.type).toBeDefined();
          expect(data.payload).toBeDefined();
        }
        return state;
      };

      // Test that typed event handlers work without throwing errors
      app.on('typed-event', typedHandler);
      app.run('typed-event', { type: 'test', payload: { value: 123 } });
      app.off('typed-event', typedHandler);
    });

    it('should support event options typing', () => {
      const handler = () => { };

      const options1 = { once: true };
      const options2 = { delay: 1000 };
      const options3 = { once: true, delay: 500 };

      expect(() => {
        app.on('test-options-1', handler, options1);
        app.on('test-options-2', handler, options2);
        app.on('test-options-3', handler, options3);

        app.off('test-options-1', handler);
        app.off('test-options-2', handler);
        app.off('test-options-3', handler);
      }).not.toThrow();
    });
  });

  describe('Router Type Accuracy', () => {
    it('should support router event constants', () => {
      const { ROUTER_EVENT, ROUTER_404_EVENT } = require('../src/router');

      expect(typeof ROUTER_EVENT).toBe('string');
      expect(typeof ROUTER_404_EVENT).toBe('string');

      const routerHandler = (url: string) => {
        expect(typeof url).toBe('string');
      };

      const notFoundHandler = (url: string) => {
        expect(typeof url).toBe('string');
      };

      expect(() => {
        app.on(ROUTER_EVENT, routerHandler);
        app.on(ROUTER_404_EVENT, notFoundHandler);

        app.off(ROUTER_EVENT, routerHandler);
        app.off(ROUTER_404_EVENT, notFoundHandler);
      }).not.toThrow();
    });
  });

  describe('Decorator Type Accuracy', () => {
    it('should support decorator imports and usage', () => {
      const { on, update, customElement } = require('../src/decorator');

      expect(typeof on).toBe('function');
      expect(typeof update).toBe('function');
      expect(typeof customElement).toBe('function');
    });
  });

  describe('Custom Element Type Accuracy', () => {
    it('should support webComponent method typing', () => {
      class TestComponent extends Component {
        state = { message: 'Hello' };
        view = (state: any) => `<div>${state.message}</div>`;
      }

      const options = {
        render: true,
        shadow: false,
        history: false,
        global_event: true,
        observedAttributes: ['data-test']
      };

      expect(() => {
        app.webComponent('test-element', TestComponent, options);
      }).not.toThrow();
    });
  });

  describe('Fragment and safeHTML Type Accuracy', () => {
    it('should support Fragment typing', () => {
      // Fragment might be a string or function depending on renderer
      expect(app.Fragment).toBeDefined();

      // The key test is that Fragment exists and can be used in TypeScript
      // without compilation errors
      expect(typeof app.Fragment).toBe('string'); // Fragment is actually a string 'React.Fragment'
    });

    it('should support safeHTML typing', () => {
      expect(typeof app.safeHTML).toBe('function');

      const htmlString = '<div>Safe HTML</div>';

      expect(() => {
        const result = app.safeHTML(htmlString);
        expect(Array.isArray(result)).toBe(true);
      }).not.toThrow();
    });
  });
});
