import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
import { DEFAULT_CONFIG } from '../card/config';
import { renderCard, type CardAssets, type Ctx } from '../card/render';
import { applyTheme, currentTheme, initialTheme, initTheme, toggleTheme } from './theme';

const KEY = 'aircard.theme';
const html = document.documentElement;

function mockMatchMedia(prefersDark: boolean) {
  window.matchMedia = vi.fn((query: string) => ({
    matches: query === '(prefers-color-scheme: dark)' ? prefersDark : false,
    media: query,
    addEventListener: () => {},
    removeEventListener: () => {},
  })) as unknown as typeof window.matchMedia;
}

beforeEach(() => {
  localStorage.clear();
  html.removeAttribute('data-theme');
  document.head.innerHTML = '<meta name="theme-color" content="#0F1828" />';
  mockMatchMedia(true);
});

afterEach(() => {
  vi.restoreAllMocks();
});

describe('initialTheme', () => {
  it('ohne gespeicherten Wert gilt das System', () => {
    expect(initialTheme(null, true)).toBe('dark');
    expect(initialTheme(null, false)).toBe('light');
  });

  it('ein gespeicherter Wert schlägt das System', () => {
    expect(initialTheme('light', true)).toBe('light');
    expect(initialTheme('dark', false)).toBe('dark');
  });

  it('ein ungültiger Wert wird ignoriert (System)', () => {
    expect(initialTheme('blau', true)).toBe('dark');
    expect(initialTheme('blau', false)).toBe('light');
    expect(initialTheme('', false)).toBe('light');
    expect(initialTheme('LIGHT', true)).toBe('dark');
  });
});

describe('applyTheme', () => {
  it('setzt data-theme auf <html> und die Browserfarbe, speichert aber nichts', () => {
    applyTheme('light');
    expect(html.getAttribute('data-theme')).toBe('light');
    expect(document.querySelector('meta[name="theme-color"]')?.getAttribute('content')).toBe('#F4F6FB');
    applyTheme('dark');
    expect(html.getAttribute('data-theme')).toBe('dark');
    expect(document.querySelector('meta[name="theme-color"]')?.getAttribute('content')).toBe('#0F1828');
    expect(localStorage.getItem(KEY)).toBeNull();
  });

  it('kommt auch ohne theme-color-Tag klar', () => {
    document.head.innerHTML = '';
    expect(() => applyTheme('light')).not.toThrow();
    expect(html.getAttribute('data-theme')).toBe('light');
  });
});

describe('initTheme', () => {
  it('nimmt den gespeicherten Wert', () => {
    localStorage.setItem(KEY, 'light');
    expect(initTheme()).toBe('light');
    expect(html.getAttribute('data-theme')).toBe('light');
  });

  it('ohne gespeicherten Wert das System (dunkel bzw. hell)', () => {
    expect(initTheme()).toBe('dark');
    mockMatchMedia(false);
    expect(initTheme()).toBe('light');
  });

  it('wirft localStorage beim Lesen, gilt das System', () => {
    vi.spyOn(Storage.prototype, 'getItem').mockImplementation(() => {
      throw new DOMException('blockiert', 'SecurityError');
    });
    mockMatchMedia(false);
    expect(initTheme()).toBe('light');
    expect(html.getAttribute('data-theme')).toBe('light');
  });

  it('fehlt matchMedia, bleibt es dunkel', () => {
    window.matchMedia = undefined as unknown as typeof window.matchMedia;
    expect(initTheme()).toBe('dark');
  });
});

describe('toggleTheme', () => {
  it('wechselt zwischen dunkel und hell, setzt data-theme und speichert', () => {
    applyTheme('dark');
    expect(toggleTheme()).toBe('light');
    expect(html.getAttribute('data-theme')).toBe('light');
    expect(localStorage.getItem(KEY)).toBe('light');
    expect(toggleTheme()).toBe('dark');
    expect(html.getAttribute('data-theme')).toBe('dark');
    expect(localStorage.getItem(KEY)).toBe('dark');
  });

  it('ohne data-theme geht es vom Systemwert aus', () => {
    mockMatchMedia(false); // System hell → Wechsel auf dunkel
    expect(toggleTheme()).toBe('dark');
  });

  it('wirft localStorage beim Schreiben, gibt es keinen Fehler und der Wechsel gilt trotzdem', () => {
    vi.spyOn(Storage.prototype, 'setItem').mockImplementation(() => {
      throw new DOMException('voll', 'QuotaExceededError');
    });
    applyTheme('dark');
    expect(() => toggleTheme()).not.toThrow();
    expect(html.getAttribute('data-theme')).toBe('light');
    expect(currentTheme()).toBe('light');
  });
});

describe('Theme und Kartenausgabe', () => {
  // Umschalten verändert nur UI-Tokens: der Renderer liest weder data-theme noch CSS-Variablen.
  function drawLog(): string[] {
    const log: string[] = [];
    const state: Record<string, unknown> = {};
    const ctx = new Proxy(state, {
      get(target, prop: string) {
        if (prop in target) return target[prop];
        if (prop === 'measureText') return (text: string) => ({ width: text.length * 20 });
        if (prop === 'createLinearGradient') {
          return (...args: number[]) => {
            log.push(`gradient(${args.join(',')})`);
            return { addColorStop: (offset: number, color: string) => log.push(`stop(${offset},${color})`) };
          };
        }
        return (...args: unknown[]) => void log.push(`${prop}(${args.map((a) => (typeof a === 'object' ? 'obj' : String(a))).join(',')})`);
      },
      set(target, prop: string, value) {
        target[prop] = value;
        log.push(`${prop}=${String(value)}`);
        return true;
      },
    });
    const assets: CardAssets = {
      image: null,
      logo: { source: {} as CanvasImageSource, w: 200, h: 100 },
      brand: {} as CanvasImageSource,
    };
    renderCard(ctx as unknown as Ctx, { ...DEFAULT_CONFIG, template: 'classic' }, assets, () => log.push('strokePath'));
    return log;
  }

  it('hell und dunkel zeichnen dieselbe Karte', () => {
    applyTheme('dark');
    const dark = drawLog();
    applyTheme('light');
    const light = drawLog();
    expect(dark.length).toBeGreaterThan(10);
    expect(light).toEqual(dark);
    expect(dark.join('\n')).toContain('fillStyle=#1B2738');
  });
});