/**
 * Tests for ModalManager
 * Covers the three bugs fixed in modal refactor:
 *   1. open() animation: reflow between hidden removal and open class add
 *   2. close() cleanup: 'hidden' class restored after transition
 *   3. State management: isOpen() accuracy
 */

const { ModalManager } = require('../src/utils/ModalManager');

function createModalElement(id = 'test-modal') {
  const modal = document.createElement('div');
  modal.id = id;
  modal.className = 'modal hidden';
  modal.setAttribute('role', 'dialog');
  modal.setAttribute('aria-modal', 'true');

  const backdrop = document.createElement('div');
  backdrop.className = 'modal-backdrop';
  backdrop.setAttribute('data-close', '');

  const content = document.createElement('div');
  content.className = 'modal-content';

  const header = document.createElement('div');
  header.className = 'modal-header';

  const closeBtn = document.createElement('button');
  closeBtn.className = 'modal-close';
  closeBtn.setAttribute('aria-label', 'Close');

  const body = document.createElement('div');
  body.className = 'modal-body';

  const input = document.createElement('input');
  input.type = 'text';

  body.appendChild(input);
  header.appendChild(closeBtn);
  content.appendChild(header);
  content.appendChild(body);
  modal.appendChild(backdrop);
  modal.appendChild(content);
  document.body.appendChild(modal);

  return modal;
}

describe('ModalManager', () => {
  let modal;
  let manager;

  beforeEach(() => {
    modal = createModalElement();
    manager = new ModalManager(modal);
  });

  afterEach(() => {
    manager.destroy();
    while (document.body.firstChild) {
      document.body.removeChild(document.body.firstChild);
    }
    document.body.style.overflow = '';
  });

  // =========================================================
  // open()
  // =========================================================

  describe('open()', () => {
    test('removes hidden class and adds open class', () => {
      expect(modal.classList.contains('hidden')).toBe(true);
      expect(modal.classList.contains('open')).toBe(false);

      manager.open();

      expect(modal.classList.contains('hidden')).toBe(false);
      expect(modal.classList.contains('open')).toBe(true);
    });

    test('sets isOpen to true', () => {
      expect(manager.isOpen()).toBe(false);
      manager.open();
      expect(manager.isOpen()).toBe(true);
    });

    test('prevents body scroll', () => {
      manager.open();
      expect(document.body.style.overflow).toBe('hidden');
    });

    test('does not open again if already open', () => {
      manager.open();
      manager.open(); // second call should be no-op
      expect(manager.isOpen()).toBe(true);
    });

    test('calls onOpen callback', () => {
      const onOpen = jest.fn();
      manager.destroy();
      manager = new ModalManager(modal, { onOpen });
      manager.open();
      expect(onOpen).toHaveBeenCalledTimes(1);
    });

    test('dispatches modal:open custom event', () => {
      const handler = jest.fn();
      modal.addEventListener('modal:open', handler);
      manager.open();
      expect(handler).toHaveBeenCalledTimes(1);
    });
  });

  // =========================================================
  // close()
  // =========================================================

  describe('close()', () => {
    beforeEach(() => {
      manager.open();
    });

    test('removes open class', () => {
      expect(modal.classList.contains('open')).toBe(true);
      manager.close();
      expect(modal.classList.contains('open')).toBe(false);
    });

    test('sets isOpen to false immediately', () => {
      manager.close();
      expect(manager.isOpen()).toBe(false);
    });

    test('restores body scroll when no modals remain open', () => {
      manager.close();
      expect(document.body.style.overflow).toBe('');
    });

    test('adds hidden class after transitionend event fires', () => {
      manager.close();

      // Immediately after close(): hidden should NOT yet be added —
      // the close animation is still in progress.
      // (This is the bug that existed before the fix.)
      expect(modal.classList.contains('hidden')).toBe(false);

      // Simulate the CSS transition completing
      const event = new Event('transitionend');
      Object.defineProperty(event, 'target', { value: modal, writable: false });
      modal.dispatchEvent(event);

      expect(modal.classList.contains('hidden')).toBe(true);
    });

    test('adds hidden class via 250ms timeout fallback when transitionend never fires', () => {
      jest.useFakeTimers();

      manager.close();
      expect(modal.classList.contains('hidden')).toBe(false);

      // Advance past the fallback timeout (250ms)
      jest.advanceTimersByTime(300);

      expect(modal.classList.contains('hidden')).toBe(true);

      jest.useRealTimers();
    });

    test('does not add hidden class if modal is reopened before timeout fires', () => {
      jest.useFakeTimers();

      manager.close();
      jest.advanceTimersByTime(100); // halfway through timeout

      // Re-open the modal before the timeout fires
      manager.open();

      jest.advanceTimersByTime(200); // past original timeout expiry

      // Modal was reopened, so hidden must NOT have been added
      expect(modal.classList.contains('hidden')).toBe(false);
      expect(modal.classList.contains('open')).toBe(true);

      jest.useRealTimers();
    });

    test('calls onClose callback', () => {
      const onClose = jest.fn();
      manager.destroy();
      manager = new ModalManager(modal, { onClose });
      manager.open();
      manager.close();
      expect(onClose).toHaveBeenCalledTimes(1);
    });

    test('dispatches modal:close custom event', () => {
      const handler = jest.fn();
      modal.addEventListener('modal:close', handler);
      manager.close();
      expect(handler).toHaveBeenCalledTimes(1);
    });

    test('is a no-op when modal is already closed', () => {
      manager.close(); // close from open
      const onClose = jest.fn();
      manager.destroy();
      manager = new ModalManager(modal, { onClose });
      manager.close(); // call close on an already-closed modal
      expect(onClose).not.toHaveBeenCalled();
    });
  });

  // =========================================================
  // Keyboard interaction
  // =========================================================

  describe('keyboard shortcuts', () => {
    test('Escape key closes an open modal', () => {
      manager.open();
      document.dispatchEvent(new KeyboardEvent('keydown', { key: 'Escape', bubbles: true }));
      expect(manager.isOpen()).toBe(false);
    });

    test('Escape key does nothing when modal is already closed', () => {
      expect(() => {
        document.dispatchEvent(new KeyboardEvent('keydown', { key: 'Escape', bubbles: true }));
      }).not.toThrow();
    });

    test('closeOnEscape: false prevents Escape from closing', () => {
      manager.destroy();
      manager = new ModalManager(modal, { closeOnEscape: false });
      manager.open();
      document.dispatchEvent(new KeyboardEvent('keydown', { key: 'Escape', bubbles: true }));
      expect(manager.isOpen()).toBe(true);
    });
  });

  // =========================================================
  // Close triggers
  // =========================================================

  describe('close triggers', () => {
    test('clicking the × close button closes the modal', () => {
      manager.open();
      modal.querySelector('.modal-close').click();
      expect(manager.isOpen()).toBe(false);
    });

    test('clicking backdrop (data-close) closes the modal', () => {
      manager.open();
      modal.querySelector('.modal-backdrop').click();
      expect(manager.isOpen()).toBe(false);
    });

    test('closeOnBackdrop: false prevents backdrop from closing', () => {
      manager.destroy();
      manager = new ModalManager(modal, { closeOnBackdrop: false });
      manager.open();
      modal.querySelector('.modal-backdrop').click();
      expect(manager.isOpen()).toBe(true);
    });
  });

  // =========================================================
  // destroy()
  // =========================================================

  describe('destroy()', () => {
    test('closes modal if open', () => {
      manager.open();
      manager.destroy();
      expect(manager.isOpen()).toBe(false);
    });

    test('does not throw when destroying a closed modal', () => {
      expect(() => manager.destroy()).not.toThrow();
    });
  });
});