import { describe, it, expect } from 'vitest';
import { Formatter } from './formatter.js';
import { TerminalFormatter } from './terminal.formatter.js';
import { JsonFormatter } from './json.formatter.js';
import type { FeedItem } from '../../interfaces/feed.types.js';

describe('Formatter', () => {
  const formatter = new Formatter();

  const createMockItem = (id: string, overrides: Partial<FeedItem> = {}): FeedItem => ({
    id,
    source: 'https://example.com/feed',
    title: 'Test Article',
    url: 'https://example.com/article/1',
    publishedAt: new Date('2026-05-05T10:30:00Z'),
    content: undefined,
    summary: undefined,
    ...overrides
  });

  describe('format with terminal format', () => {
    it('should format empty array', async () => {
      const result = await formatter.format([], 'terminal');
      expect(result).toContain('No items to display');
    });

    it('should format single item', async () => {
      const item = createMockItem('item-1', {
        title: 'My Article',
        source: 'https://myblog.com/feed'
      });
      const result = await formatter.format([item], 'terminal');
      expect(result).toContain('1.');
      expect(result).toContain('My Article');
      expect(result).toContain('https://myblog.com/feed');
      expect(result).toContain('https://example.com/article/1');
    });

    it('should format multiple items', async () => {
      const items = [
        createMockItem('item-1', { title: 'Article 1' }),
        createMockItem('item-2', { title: 'Article 2' })
      ];
      const result = await formatter.format(items, 'terminal');
      expect(result).toContain('Found 2 items');
      expect(result).toContain('1.');
      expect(result).toContain('2.');
      expect(result).toContain('Article 1');
      expect(result).toContain('Article 2');
    });

    it('should include summary when present', async () => {
      const item = createMockItem('item-1', {
        summary: 'This is a test summary that might be truncated'
      });
      const result = await formatter.format([item], 'terminal');
      expect(result).toContain('This is a test summary');
    });
  });

  describe('format with json format', () => {
    it('should format empty array', async () => {
      const result = await formatter.format([], 'json');
      expect(JSON.parse(result)).toEqual([]);
    });

    it('should format single item', async () => {
      const item = createMockItem('item-1', {
        title: 'My Article'
      });
      const result = await formatter.format([item], 'json');
      const parsed = JSON.parse(result);
      expect(parsed).toHaveLength(1);
      expect(parsed[0].id).toBe('item-1');
      expect(parsed[0].title).toBe('My Article');
      expect(parsed[0].publishedAt).toBe('2026-05-05T10:30:00.000Z');
    });

    it('should format multiple items', async () => {
      const items = [
        createMockItem('item-1', { title: 'Article 1' }),
        createMockItem('item-2', { title: 'Article 2' })
      ];
      const result = await formatter.format(items, 'json');
      const parsed = JSON.parse(result);
      expect(parsed).toHaveLength(2);
      expect(parsed[0].title).toBe('Article 1');
      expect(parsed[1].title).toBe('Article 2');
    });

    it('should include optional content when present', async () => {
      const item = createMockItem('item-1', {
        content: 'Full article content here'
      });
      const result = await formatter.format([item], 'json');
      const parsed = JSON.parse(result);
      expect(parsed[0].content).toBe('Full article content here');
    });

    it('should include optional summary when present', async () => {
      const item = createMockItem('item-1', {
        summary: 'Article summary'
      });
      const result = await formatter.format([item], 'json');
      const parsed = JSON.parse(result);
      expect(parsed[0].summary).toBe('Article summary');
    });

    it('should not include undefined fields', async () => {
      const item = createMockItem('item-1');
      const result = await formatter.format([item], 'json');
      const parsed = JSON.parse(result);
      expect(parsed[0]).not.toHaveProperty('content');
      expect(parsed[0]).not.toHaveProperty('summary');
    });

    it('should use ISO 8601 date format', async () => {
      const item = createMockItem('item-1', {
        publishedAt: new Date('2026-12-25T15:30:45.123Z')
      });
      const result = await formatter.format([item], 'json');
      const parsed = JSON.parse(result);
      expect(parsed[0].publishedAt).toBe('2026-12-25T15:30:45.123Z');
    });
  });

  describe('error handling', () => {
    it('should throw FormatterError for HTML format', async () => {
      await expect(formatter.format([], 'html')).rejects.toMatchObject({
        code: 'UNKNOWN',
        message: 'HTML format not implemented'
      });
    });

    it('should throw FormatterError for unknown format', async () => {
      await expect(formatter.format([], 'unknown-format' as any)).rejects.toMatchObject({
        code: 'SERIALIZE_ERROR'
      });
    });
  });
});

describe('TerminalFormatter', () => {
  const terminalFormatter = new TerminalFormatter();

  it('should truncate long summary text', () => {
    const longSummary = 'a'.repeat(100);
    const item: FeedItem = {
      id: 'item-1',
      source: 'https://example.com',
      title: 'Test',
      url: 'https://example.com/article',
      publishedAt: new Date(),
      summary: longSummary
    };
    const result = terminalFormatter.format([item]);
    expect(result).toContain('...');
    expect(result).not.toContain(longSummary);
  });

  it('should format date in readable format', () => {
    const item: FeedItem = {
      id: 'item-1',
      source: 'https://example.com',
      title: 'Test',
      url: 'https://example.com/article',
      publishedAt: new Date('2026-05-05T10:30:00Z')
    };
    const result = terminalFormatter.format([item]);
    expect(result).toContain('May');
    expect(result).toContain('2026');
  });
});

describe('JsonFormatter', () => {
  const jsonFormatter = new JsonFormatter();

  it('should produce valid JSON', () => {
    const items: FeedItem[] = [
      {
        id: 'test-1',
        source: 'https://example.com',
        title: 'Test Article',
        url: 'https://example.com/1',
        publishedAt: new Date()
      }
    ];
    const result = jsonFormatter.format(items);
    expect(() => JSON.parse(result)).not.toThrow();
  });

  it('should convert Date to ISO string', () => {
    const date = new Date('2026-01-15T08:00:00Z');
    const items: FeedItem[] = [
      {
        id: 'test-1',
        source: 'https://example.com',
        title: 'Test',
        url: 'https://example.com/1',
        publishedAt: date
      }
    ];
    const result = jsonFormatter.format(items);
    const parsed = JSON.parse(result);
    expect(parsed[0].publishedAt).toBe('2026-01-15T08:00:00.000Z');
  });
});