import { describe, it, expect, beforeEach, afterEach } from 'vitest';

// Types based on data-model.md
interface ContainerSize {
  width: number;
  height: number;
  devicePixelRatio: number;
}

interface Mood {
  hue: number; // 0-360
  intensity: number; // 0-1
  note?: string;
}

interface HabitEntry {
  id: string;
  type: 'positive' | 'negative';
  habitId: string;
  label: string;
  weight: number;
  timestamp: string; // ISO datetime
}

interface DayTile {
  date: string; // ISO date (YYYY-MM-DD)
  mood: Mood;
  entries: HabitEntry[];
  netScore: number;
}

interface Theme {
  palette: Record<string, string>;
  cssVariables: Record<string, string>;
}

interface RenderOptions {
  showLegend: boolean;
  pngScale: number;
}

// Expected renderer API interface
interface Renderer {
  renderGrid(
    container: HTMLElement,
    days: DayTile[],
    theme: Theme,
    options: RenderOptions
  ): Promise<void> | void;
}

describe('Renderer Contract', () => {
  let container: HTMLElement;
  let mockDays: DayTile[];
  let mockTheme: Theme;
  let mockOptions: RenderOptions;

  beforeEach(() => {
    // Create a test container
    container = document.createElement('div');
    container.style.width = '800px';
    container.style.height = '600px';
    document.body.appendChild(container);

    // Mock data following the data model
    mockDays = [
      {
        date: '2025-09-18',
        mood: {
          hue: 120, // Green
          intensity: 0.7,
          note: 'Good day'
        },
        entries: [
          {
            id: 'entry-1',
            type: 'positive',
            habitId: 'habit-1',
            label: 'Exercise',
            weight: 1,
            timestamp: '2025-09-18T08:00:00Z'
          },
          {
            id: 'entry-2',
            type: 'negative',
            habitId: 'habit-2',
            label: 'Junk food',
            weight: 1,
            timestamp: '2025-09-18T14:00:00Z'
          }
        ],
        netScore: 0 // 1 positive - 1 negative
      },
      {
        date: '2025-09-17',
        mood: {
          hue: 240, // Blue
          intensity: 0.5
        },
        entries: [
          {
            id: 'entry-3',
            type: 'positive',
            habitId: 'habit-3',
            label: 'Meditation',
            weight: 1,
            timestamp: '2025-09-17T07:00:00Z'
          }
        ],
        netScore: 1
      }
    ];

    mockTheme = {
      palette: {
        primary: '#3b82f6',
        secondary: '#8b5cf6',
        background: '#ffffff',
        text: '#1f2937'
      },
      cssVariables: {
        '--color-mood-base': '#ffffff',
        '--color-glow-intensity': '0.8',
        '--color-negative-overlay': '#ff000020'
      }
    };

    mockOptions = {
      showLegend: true,
      pngScale: 1.0
    };
  });

  afterEach(() => {
    document.body.removeChild(container);
  });

  it('should have renderGrid function available', async () => {
    // This test should fail until the renderer is implemented
    let renderer: Renderer;
    
    try {
      // Try to import the renderer module
      const rendererModule = await import('../../src/renderer.js');
      renderer = rendererModule;
    } catch (error) {
      expect.fail('Renderer module should exist at packages/viz/src/renderer.ts');
    }

    expect(renderer.renderGrid).toBeDefined();
    expect(typeof renderer.renderGrid).toBe('function');
  });

  it('should accept correct parameters for renderGrid', async () => {
    // This test should fail until the renderer is implemented
    let renderer: Renderer;
    
    try {
      const rendererModule = await import('../../src/renderer.js');
      renderer = rendererModule;
    } catch (error) {
      expect.fail('Renderer module should exist');
    }

    // Should not throw when called with correct parameters
    expect(() => {
      renderer.renderGrid(container, mockDays, mockTheme, mockOptions);
    }).not.toThrow();
  });

  it('should render Canvas element for tiles', async () => {
    let renderer: Renderer;
    
    try {
      const rendererModule = await import('../../src/renderer.js');
      renderer = rendererModule;
      
      await renderer.renderGrid(container, mockDays, mockTheme, mockOptions);
      
      // Should create a Canvas element for tile rendering
      const canvas = container.querySelector('canvas');
      expect(canvas).toBeTruthy();
      expect(canvas?.tagName).toBe('CANVAS');
    } catch (error) {
      expect.fail('Should render Canvas element for tiles');
    }
  });

  it('should render SVG element for glyphs and overlays', async () => {
    let renderer: Renderer;
    
    try {
      const rendererModule = await import('../../src/renderer.js');
      renderer = rendererModule;
      
      await renderer.renderGrid(container, mockDays, mockTheme, mockOptions);
      
      // Should create an SVG element for glyph overlays
      const svg = container.querySelector('svg');
      expect(svg).toBeTruthy();
      expect(svg?.tagName).toBe('SVG');
    } catch (error) {
      expect.fail('Should render SVG element for glyphs and overlays');
    }
  });

  it('should apply mood hue to tiles', async () => {
    let renderer: Renderer;
    
    try {
      const rendererModule = await import('../../src/renderer.js');
      renderer = rendererModule;
      
      await renderer.renderGrid(container, mockDays, mockTheme, mockOptions);
      
      // Canvas should be configured to use mood hues
      const canvas = container.querySelector('canvas') as HTMLCanvasElement;
      expect(canvas).toBeTruthy();
      
      // The canvas context should have been used for drawing
      // This is a basic check - actual hue application would be tested in integration tests
      const ctx = canvas.getContext('2d');
      expect(ctx).toBeTruthy();
    } catch (error) {
      expect.fail('Should apply mood hue to tiles');
    }
  });

  it('should render glyph counts for habit entries', async () => {
    let renderer: Renderer;
    
    try {
      const rendererModule = await import('../../src/renderer.js');
      renderer = rendererModule;
      
      await renderer.renderGrid(container, mockDays, mockTheme, mockOptions);
      
      // SVG should contain glyph elements
      const svg = container.querySelector('svg');
      expect(svg).toBeTruthy();
      
      // Should have glyph elements for positive (ticks) and negative (dots) entries
      // This is a structural test - actual glyph rendering would be tested visually
    } catch (error) {
      expect.fail('Should render glyph counts for habit entries');
    }
  });

  it('should support keyboard accessibility', async () => {
    let renderer: Renderer;
    
    try {
      const rendererModule = await import('../../src/renderer.js');
      renderer = rendererModule;
      
      await renderer.renderGrid(container, mockDays, mockTheme, mockOptions);
      
      // Should have focusable elements for keyboard navigation
      const focusableElements = container.querySelectorAll('[tabindex]');
      expect(focusableElements.length).toBeGreaterThan(0);
      
      // Should have ARIA labels for screen readers
      const ariaElements = container.querySelectorAll('[aria-label]');
      expect(ariaElements.length).toBeGreaterThan(0);
    } catch (error) {
      expect.fail('Should support keyboard accessibility');
    }
  });

  it('should handle empty days array', async () => {
    let renderer: Renderer;
    
    try {
      const rendererModule = await import('../../src/renderer.js');
      renderer = rendererModule;
      
      // Should not throw with empty days
      expect(() => {
        renderer.renderGrid(container, [], mockTheme, mockOptions);
      }).not.toThrow();
    } catch (error) {
      expect.fail('Should handle empty days array');
    }
  });

  it('should respect pngScale option for export', async () => {
    let renderer: Renderer;
    
    try {
      const rendererModule = await import('../../src/renderer.js');
      renderer = rendererModule;
      
      const exportOptions = { ...mockOptions, pngScale: 2.0 };
      
      // Should handle different pngScale values
      expect(() => {
        renderer.renderGrid(container, mockDays, mockTheme, exportOptions);
      }).not.toThrow();
    } catch (error) {
      expect.fail('Should respect pngScale option for export');
    }
  });

  it('should apply luminance curve based on netScore', async () => {
    let renderer: Renderer;
    
    try {
      const rendererModule = await import('../../src/renderer.js');
      renderer = rendererModule;
      
      // Test with days having different netScores
      const daysWithVariedScores: DayTile[] = [
        { ...mockDays[0], netScore: -2 }, // Should be dimmer
        { ...mockDays[1], netScore: 3 }   // Should be brighter
      ];
      
      await renderer.renderGrid(container, daysWithVariedScores, mockTheme, mockOptions);
      
      // Canvas should reflect luminance differences based on netScore
      const canvas = container.querySelector('canvas');
      expect(canvas).toBeTruthy();
    } catch (error) {
      expect.fail('Should apply luminance curve based on netScore');
    }
  });
});