import { render, screen } from '@testing-library/react';
import { describe, expect, it } from 'vitest';
import { Button } from './Button';

describe('Button', () => {
  describe('Rendering', () => {
    it('renders with default variant and size', () => {
      render(<Button>Click me</Button>);
      const button = screen.getByRole('button');
      expect(button).toBeInTheDocument();
      expect(button).toHaveTextContent('Click me');
    });

    it('renders as a button element', () => {
      render(<Button>Test</Button>);
      expect(screen.getByRole('button').tagName).toBe('BUTTON');
    });
  });

  describe('Variants', () => {
    it('applies default variant classes', () => {
      render(
        <Button variant="default" data-testid="button">
          Default
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('bg-primary');
      expect(button.className).toContain('text-primary-foreground');
    });

    it('applies destructive variant classes', () => {
      render(
        <Button variant="destructive" data-testid="button">
          Delete
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('bg-error');
      expect(button.className).toContain('text-error-foreground');
    });

    it('applies outline variant classes', () => {
      render(
        <Button variant="outline" data-testid="button">
          Outline
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('border');
      expect(button.className).toContain('bg-transparent');
    });

    it('applies secondary variant classes', () => {
      render(
        <Button variant="secondary" data-testid="button">
          Secondary
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('bg-secondary');
      expect(button.className).toContain('text-secondary-foreground');
    });

    it('applies ghost variant classes', () => {
      render(
        <Button variant="ghost" data-testid="button">
          Ghost
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('hover:bg-accent');
    });

    it('applies link variant classes', () => {
      render(
        <Button variant="link" data-testid="button">
          Link
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('text-primary');
      expect(button.className).toContain('underline-offset-4');
    });
  });

  describe('Sizes', () => {
    it('applies small size classes', () => {
      render(
        <Button size="sm" data-testid="button">
          Small
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('h-9');
      expect(button.className).toContain('px-3');
    });

    it('applies medium size classes (default)', () => {
      render(
        <Button size="md" data-testid="button">
          Medium
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('h-10');
      expect(button.className).toContain('px-4');
    });

    it('applies large size classes', () => {
      render(
        <Button size="lg" data-testid="button">
          Large
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('h-11');
      expect(button.className).toContain('px-8');
    });

    it('applies icon size classes', () => {
      render(<Button size="icon" data-testid="button" aria-label="Icon button" />);
      const button = screen.getByTestId('button');
      expect(button.className).toContain('h-10');
      expect(button.className).toContain('w-10');
    });
  });

  describe('Compound Variants', () => {
    it('applies compound variant for outline + small', () => {
      render(
        <Button variant="outline" size="sm" data-testid="button">
          Small Outline
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('border');
      expect(button.className).toContain('h-9');
    });

    it('applies compound variant for link variants (removes padding)', () => {
      render(
        <Button variant="link" size="md" data-testid="button">
          Link
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('px-0');
    });
  });

  describe('Loading State', () => {
    it('shows loading spinner when loading is true', () => {
      render(<Button loading>Loading</Button>);
      const button = screen.getByRole('button');

      // Should have loading indicator
      const spinner = button.querySelector('[aria-hidden="true"]');
      expect(spinner).toBeInTheDocument();
      expect(spinner?.className).toContain('animate-spin');
    });

    it('disables button when loading', () => {
      render(<Button loading>Loading</Button>);
      const button = screen.getByRole('button');
      expect(button).toBeDisabled();
      expect(button).toHaveAttribute('aria-busy', 'true');
    });

    it('applies cursor-wait class when loading', () => {
      render(
        <Button loading data-testid="button">
          Loading
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('cursor-wait');
    });

    it('still shows children text when loading', () => {
      render(<Button loading>Processing</Button>);
      expect(screen.getByText('Processing')).toBeInTheDocument();
    });
  });

  describe('Disabled State', () => {
    it('disables button when disabled prop is true', () => {
      render(<Button disabled>Disabled</Button>);
      const button = screen.getByRole('button');
      expect(button).toBeDisabled();
      expect(button).toHaveAttribute('aria-disabled', 'true');
    });

    it('applies disabled opacity class', () => {
      render(
        <Button disabled data-testid="button">
          Disabled
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('disabled:opacity-50');
      expect(button.className).toContain('disabled:pointer-events-none');
    });

    it('is disabled when both disabled and loading are true', () => {
      render(
        <Button disabled loading>
          Both
        </Button>
      );
      const button = screen.getByRole('button');
      expect(button).toBeDisabled();
    });
  });

  describe('Custom className', () => {
    it('merges custom className with variant classes', () => {
      render(
        <Button className="custom-class" data-testid="button">
          Custom
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button.className).toContain('custom-class');
      expect(button.className).toContain('bg-primary');
    });
  });

  describe('Ref Forwarding', () => {
    it('forwards ref to button element', () => {
      let ref: HTMLButtonElement | null = null;
      render(
        <Button
          ref={(el) => {
            ref = el;
          }}
        >
          Ref Test
        </Button>
      );
      expect(ref).toBeInstanceOf(HTMLButtonElement);
      expect(ref!.tagName).toBe('BUTTON');
    });
  });

  describe('HTML Attributes', () => {
    it('passes through HTML button attributes', () => {
      render(
        <Button type="submit" name="test-button" value="test-value" data-testid="button">
          Submit
        </Button>
      );
      const button = screen.getByTestId('button');
      expect(button).toHaveAttribute('type', 'submit');
      expect(button).toHaveAttribute('name', 'test-button');
      expect(button).toHaveAttribute('value', 'test-value');
    });

    it('supports onClick handler', () => {
      let clicked = false;
      render(
        <Button
          onClick={() => {
            clicked = true;
          }}
        >
          Click
        </Button>
      );
      const button = screen.getByRole('button');
      button.click();
      expect(clicked).toBe(true);
    });
  });

  describe('Accessibility', () => {
    it('has proper ARIA attributes for loading state', () => {
      render(<Button loading>Loading</Button>);
      const button = screen.getByRole('button');
      expect(button).toHaveAttribute('aria-busy', 'true');
      expect(button).toHaveAttribute('aria-disabled', 'true');
    });

    it('has proper ARIA attributes for disabled state', () => {
      render(<Button disabled>Disabled</Button>);
      const button = screen.getByRole('button');
      expect(button).toHaveAttribute('aria-disabled', 'true');
    });

    it('hides loading spinner from screen readers', () => {
      render(<Button loading>Loading</Button>);
      const button = screen.getByRole('button');
      const spinner = button.querySelector('[aria-hidden="true"]');
      expect(spinner).toHaveAttribute('aria-hidden', 'true');
    });

    it('supports aria-label for icon buttons', () => {
      render(
        <Button size="icon" aria-label="Close dialog">
          X
        </Button>
      );
      const button = screen.getByRole('button');
      expect(button).toHaveAccessibleName('Close dialog');
    });
  });

  describe('Base Classes', () => {
    it('always includes base classes', () => {
      render(<Button data-testid="button">Base</Button>);
      const button = screen.getByTestId('button');
      expect(button.className).toContain('inline-flex');
      expect(button.className).toContain('items-center');
      expect(button.className).toContain('justify-center');
      expect(button.className).toContain('font-medium');
      expect(button.className).toContain('rounded-md');
    });

    it('includes focus ring classes', () => {
      render(<Button data-testid="button">Focus</Button>);
      const button = screen.getByTestId('button');
      expect(button.className).toContain('focus-ring');
    });

    it('includes transition classes', () => {
      render(<Button data-testid="button">Transition</Button>);
      const button = screen.getByTestId('button');
      expect(button.className).toContain('transition-base');
    });
  });
});