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

/**
 * 260917-jdd — `undici` wird gemockt, damit KEIN Test tatsaechlich ins Netz
 * geht: die produktive Datei ruft ab jetzt `undiciFetch` statt des globalen
 * `fetch` auf, mit einem Modul-Singleton-`Agent` als `dispatcher`. Die
 * Mock-Klasse zeichnet nur die uebergebenen `options` auf; `fetch` delegiert
 * ZUR LAUFZEIT (Pfeilfunktion, nicht beim Laden aufgeloest) an
 * `globalThis.fetch`, damit alle bestehenden `vi.stubGlobal('fetch', …)`-
 * Tests wortgleich gruen bleiben.
 */
vi.mock('undici', () => ({
  Agent: class Agent {
    constructor(public readonly options: unknown) {}
  },
  fetch: (...args: unknown[]) => (globalThis.fetch as any)(...args),
}));

import { Agent } from 'undici';
import {
  discardBody,
  IconDiscoveryService,
  isPublicHttpUrl,
  normalizeUrl,
  readTextCapped,
} from './icon-discovery.service';

function mockResponse(options: { contentType?: string; body?: ArrayBuffer }): Response {
  const body = options.body ?? new ArrayBuffer(10);
  return {
    ok: true,
    status: 200,
    headers: {
      get: (name: string) =>
        name.toLowerCase() === 'content-type' ? (options.contentType ?? 'image/png') : null,
    },
    arrayBuffer: async () => body,
  } as unknown as Response;
}

describe('isPublicHttpUrl', () => {
  afterEach(() => {
    vi.restoreAllMocks();
  });

  it('rejects private IPv4 addresses', async () => {
    await expect(isPublicHttpUrl(new URL('http://127.0.0.1/x'))).resolves.toBe(false);
    await expect(isPublicHttpUrl(new URL('http://10.0.0.5/x'))).resolves.toBe(false);
    await expect(isPublicHttpUrl(new URL('http://192.168.1.1/x'))).resolves.toBe(false);
    await expect(isPublicHttpUrl(new URL('http://169.254.1.1/x'))).resolves.toBe(false);
  });

  it('rejects blocked hostnames', async () => {
    await expect(isPublicHttpUrl(new URL('http://localhost/x'))).resolves.toBe(false);
    await expect(isPublicHttpUrl(new URL('http://foo.local/x'))).resolves.toBe(false);
    await expect(isPublicHttpUrl(new URL('http://0.0.0.0/x'))).resolves.toBe(false);
  });

  it('rejects non-http(s) protocols', async () => {
    await expect(isPublicHttpUrl(new URL('ftp://example.com/x'))).resolves.toBe(false);
  });

  it('accepts a public IPv4 address without DNS lookup', async () => {
    await expect(isPublicHttpUrl(new URL('http://8.8.8.8/x'))).resolves.toBe(true);
  });
});

describe('normalizeUrl', () => {
  it('prepends https:// to a scheme-less host', () => {
    expect(normalizeUrl('ctl.de')).toBe('https://ctl.de');
    expect(normalizeUrl('www.ctl.de/path')).toBe('https://www.ctl.de/path');
  });

  it('leaves an existing scheme untouched', () => {
    expect(normalizeUrl('http://ctl.de')).toBe('http://ctl.de');
    expect(normalizeUrl('https://ctl.de')).toBe('https://ctl.de');
  });

  it('trims surrounding whitespace', () => {
    expect(normalizeUrl('  ctl.de  ')).toBe('https://ctl.de');
  });

  it('returns empty string unchanged', () => {
    expect(normalizeUrl('   ')).toBe('');
  });
});

describe('IconDiscoveryService.discoverFavoriteIconUrl', () => {
  afterEach(() => {
    vi.restoreAllMocks();
    vi.unstubAllGlobals();
  });

  it('extracts the apple-touch-icon from page HTML', async () => {
    const html = `<html><head>
      <link rel="icon" href="https://ctl.de/fav-32.jpg" sizes="32x32" />
      <link rel="apple-touch-icon" href="https://ctl.de/apple-180.jpg" />
    </head></html>`;
    vi.stubGlobal(
      'fetch',
      vi.fn().mockResolvedValue({
        ok: true,
        status: 200,
        headers: {
          get: (n: string) =>
            n.toLowerCase() === 'content-type' ? 'text/html; charset=utf-8' : null,
        },
        text: async () => html,
      }),
    );

    const service = new IconDiscoveryService();
    // Public IP avoids a real DNS lookup in the SSRF guard.
    const icon = await service.discoverFavoriteIconUrl('http://8.8.8.8');

    expect(icon).toBe('https://ctl.de/apple-180.jpg');
  });

  it('normalizes a scheme-less URL so the fallback is absolute, not "/favicon.ico"', async () => {
    // fetch fails → discovery falls back. The fallback must be an absolute
    // https origin URL, not the broken relative path that produced the bug.
    vi.stubGlobal('fetch', vi.fn().mockRejectedValue(new Error('network')));

    const service = new IconDiscoveryService();
    const icon = await service.discoverFavoriteIconUrl('ctl.de');

    expect(icon).toBe('https://ctl.de/favicon.ico');
  });
});

describe('IconDiscoveryService.discoverFavoriteIconUrl — Seite mit Fehlerstatus (260929-lh3)', () => {
  afterEach(() => {
    vi.restoreAllMocks();
    vi.unstubAllGlobals();
  });

  function htmlResponse(status: number, html: string) {
    return {
      ok: status >= 200 && status < 300,
      status,
      headers: {
        get: (n: string) =>
          n.toLowerCase() === 'content-type' ? 'text/html; charset=utf-8' : null,
      },
      text: async () => html,
    };
  }

  it('Seite antwortet 400, traegt aber <link rel="SHORTCUT ICON"> (docuvita) -> dieser Verweis wird genutzt', async () => {
    const html =
      '<html><head><link rel="SHORTCUT ICON" type="image/png" href="/webclient/docuvita/resources/brandimage/favicon.ico" /></head></html>';
    vi.stubGlobal('fetch', vi.fn().mockResolvedValue(htmlResponse(400, html)));

    const icon = await new IconDiscoveryService().discoverFavoriteIconUrl(
      'http://8.8.8.8/server/services/web/',
    );

    expect(icon).toBe('http://8.8.8.8/webclient/docuvita/resources/brandimage/favicon.ico');
  });

  it('Fehlerseite ohne Symbol-Verweis, nur og:image -> Rueckfall <origin>/favicon.ico (og:image einer Fehlerseite zaehlt nicht)', async () => {
    const html =
      '<html><head><meta property="og:image" content="https://cdn.invalid/x.png"></head></html>';
    vi.stubGlobal('fetch', vi.fn().mockResolvedValue(htmlResponse(404, html)));

    const icon = await new IconDiscoveryService().discoverFavoriteIconUrl('http://8.8.8.8/x');

    expect(icon).toBe('http://8.8.8.8/favicon.ico');
  });

  it('fetchIconBytes bleibt streng: Fehlerstatus -> wirft (kein allowErrorStatus fuer Bilder)', async () => {
    vi.stubGlobal(
      'fetch',
      vi.fn().mockResolvedValue({ ...htmlResponse(404, ''), headers: { get: () => 'text/html' } }),
    );

    await expect(
      new IconDiscoveryService().fetchIconBytes('http://8.8.8.8/favicon.ico'),
    ).rejects.toThrow();
  });
});

describe('IconDiscoveryService.fetchIconBytes', () => {
  afterEach(() => {
    vi.restoreAllMocks();
    vi.unstubAllGlobals();
  });

  it('returns contentType and body for a valid image response', async () => {
    const body = new ArrayBuffer(100);
    vi.stubGlobal(
      'fetch',
      vi.fn().mockResolvedValue(mockResponse({ contentType: 'image/png', body })),
    );

    const service = new IconDiscoveryService();
    const result = await service.fetchIconBytes('http://8.8.8.8/favicon.ico');

    expect(result.contentType).toBe('image/png');
    expect(result.body).toBeInstanceOf(Buffer);
    expect(result.body.length).toBe(100);
  });

  it('rejects when Content-Type is not an image', async () => {
    vi.stubGlobal('fetch', vi.fn().mockResolvedValue(mockResponse({ contentType: 'text/html' })));

    const service = new IconDiscoveryService();

    await expect(service.fetchIconBytes('http://8.8.8.8/favicon.ico')).rejects.toThrow(
      /not an image/,
    );
  });

  it('rejects when the SSRF guard blocks the target', async () => {
    const fetchSpy = vi.fn();
    vi.stubGlobal('fetch', fetchSpy);

    const service = new IconDiscoveryService();

    await expect(service.fetchIconBytes('http://127.0.0.1/favicon.ico')).rejects.toThrow(
      /blocked or failed/,
    );
    expect(fetchSpy).not.toHaveBeenCalled();
  });

  it('rejects when the body exceeds the size cap', async () => {
    const oversized = new ArrayBuffer(1_000_001);
    vi.stubGlobal(
      'fetch',
      vi.fn().mockResolvedValue(mockResponse({ contentType: 'image/png', body: oversized })),
    );

    const service = new IconDiscoveryService();

    await expect(service.fetchIconBytes('http://8.8.8.8/favicon.ico')).rejects.toThrow(
      /size limit/,
    );
  });
});

describe('IconDiscoveryService.discoverFavoriteIconUrl (unchanged behaviour)', () => {
  afterEach(() => {
    vi.restoreAllMocks();
    vi.unstubAllGlobals();
  });

  it('falls back to <origin>/favicon.ico when the page cannot be fetched', async () => {
    vi.stubGlobal('fetch', vi.fn().mockRejectedValue(new Error('network error')));

    const service = new IconDiscoveryService();
    const result = await service.discoverFavoriteIconUrl('http://8.8.8.8/page');

    expect(result).toBe('http://8.8.8.8/favicon.ico');
  });

  it('still returns a URL string', async () => {
    vi.stubGlobal('fetch', vi.fn().mockResolvedValue(mockResponse({ contentType: 'text/html' })));

    const service = new IconDiscoveryService();
    const result = await service.discoverFavoriteIconUrl('http://8.8.8.8/page');

    expect(typeof result).toBe('string');
  });
});

describe('IconDiscoveryService — Dispatcher (260917-jdd)', () => {
  afterEach(() => {
    vi.restoreAllMocks();
    vi.unstubAllGlobals();
  });

  it('discoverFavoriteIconUrl uebergibt den tolerante-TLS-Agent als dispatcher und redirect: manual', async () => {
    const html = '<html><head><link rel="icon" href="https://ctl.de/fav.png" /></head></html>';
    const fetchSpy = vi.fn().mockResolvedValue({
      ok: true,
      status: 200,
      headers: {
        get: (n: string) =>
          n.toLowerCase() === 'content-type' ? 'text/html; charset=utf-8' : null,
      },
      text: async () => html,
    });
    vi.stubGlobal('fetch', fetchSpy);

    const service = new IconDiscoveryService();
    await service.discoverFavoriteIconUrl('http://8.8.8.8');

    const init = fetchSpy.mock.calls[0][1];
    expect(init.dispatcher).toBeInstanceOf(Agent);
    expect(init.dispatcher.options).toEqual({ connect: { rejectUnauthorized: false } });
    expect(init.redirect).toBe('manual');
  });

  it('fetchIconBytes uebergibt denselben tolerante-TLS-Agent als dispatcher und redirect: manual', async () => {
    const fetchSpy = vi.fn().mockResolvedValue(mockResponse({ contentType: 'image/png' }));
    vi.stubGlobal('fetch', fetchSpy);

    const service = new IconDiscoveryService();
    await service.fetchIconBytes('http://8.8.8.8/favicon.ico');

    const init = fetchSpy.mock.calls[0][1];
    expect(init.dispatcher).toBeInstanceOf(Agent);
    expect(init.dispatcher.options).toEqual({ connect: { rejectUnauthorized: false } });
    expect(init.redirect).toBe('manual');
  });

  it('Discovery und fetchIconBytes teilen DENSELBEN Agent (Modul-Singleton)', async () => {
    const html = '<html><head></head></html>';
    const fetchSpy = vi
      .fn()
      .mockResolvedValueOnce({
        ok: true,
        status: 200,
        headers: {
          get: (n: string) =>
            n.toLowerCase() === 'content-type' ? 'text/html; charset=utf-8' : null,
        },
        text: async () => html,
      })
      .mockResolvedValueOnce(mockResponse({ contentType: 'image/png' }));
    vi.stubGlobal('fetch', fetchSpy);

    const service = new IconDiscoveryService();
    await service.discoverFavoriteIconUrl('http://8.8.8.8');
    await service.fetchIconBytes('http://8.8.8.8/favicon.ico');

    const calls = fetchSpy.mock.calls;
    expect(calls[0][1].dispatcher).toBe(calls[1][1].dispatcher);
  });
});

describe('readTextCapped / discardBody — Groessendeckel beim Lesen (T-08-09)', () => {
  afterEach(() => {
    vi.restoreAllMocks();
    vi.unstubAllGlobals();
  });

  /** Stream aus `chunks` Stuecken je `chunkChars` ASCII-Zeichen; zaehlt gelesene Stuecke und Abbruch. */
  function countingStream(chunks: number, chunkChars: number) {
    const state = { pulled: 0, cancelled: false };
    const encoder = new TextEncoder();
    const body = new ReadableStream<Uint8Array>({
      pull(controller) {
        if (state.pulled >= chunks) {
          controller.close();
          return;
        }
        state.pulled += 1;
        controller.enqueue(encoder.encode('a'.repeat(chunkChars)));
      },
      cancel() {
        state.cancelled = true;
      },
    });
    return { body, state };
  }

  it('bricht den Stream nach der Grenze ab statt alles zu lesen', async () => {
    const { body, state } = countingStream(1000, 1000);
    const text = await readTextCapped({ body, text: async () => 'unbenutzt' } as never, 2500);

    expect(text).toHaveLength(2500);
    expect(state.pulled).toBeLessThan(10);
    expect(state.cancelled).toBe(true);
  });

  it('gibt nach der Zeitgrenze zurueck, was bis dahin da ist (tropfender Server)', async () => {
    let cancelled = false;
    const body = new ReadableStream<Uint8Array>({
      start(controller) {
        controller.enqueue(new TextEncoder().encode('<link rel="icon">'));
        // danach kommt nichts mehr, der Stream bleibt offen
      },
      cancel() {
        cancelled = true;
      },
    });

    const text = await readTextCapped({ body, text: async () => '' } as never, 200000, 50);

    expect(text).toBe('<link rel="icon">');
    expect(cancelled).toBe(true);
  });

  it('liest kurze Seiten vollstaendig, auch Mehrbyte-Zeichen ueber Chunk-Grenzen', async () => {
    const bytes = new TextEncoder().encode('<p>Grüße</p>');
    const body = new ReadableStream<Uint8Array>({
      start(controller) {
        // Das "ü" (2 Bytes) wird absichtlich zerteilt.
        controller.enqueue(bytes.slice(0, 5));
        controller.enqueue(bytes.slice(5));
        controller.close();
      },
    });

    const text = await readTextCapped({ body, text: async () => '' } as never, 200000);

    expect(text).toBe('<p>Grüße</p>');
  });

  it('ohne Stream: Rueckfall auf text() mit Deckel', async () => {
    const text = await readTextCapped(
      { body: null, text: async () => 'x'.repeat(50) } as never,
      10,
    );

    expect(text).toBe('x'.repeat(10));
  });

  it('discardBody bricht einen offenen Body ab und vertraegt fehlenden Body', () => {
    const { body, state } = countingStream(5, 10);
    discardBody({ body } as never);
    expect(state.cancelled).toBe(true);
    expect(() => discardBody({ body: null } as never)).not.toThrow();
  });

  it('Discovery: Fehlerstatus ohne HTML-Typ -> Body wird verworfen, Rueckfall favicon.ico', async () => {
    const { body, state } = countingStream(5, 10);
    vi.stubGlobal(
      'fetch',
      vi.fn().mockResolvedValue({
        ok: false,
        status: 500,
        headers: {
          get: (n: string) => (n.toLowerCase() === 'content-type' ? 'application/json' : null),
        },
        body,
      }),
    );

    const icon = await new IconDiscoveryService().discoverFavoriteIconUrl('http://8.8.8.8/x');

    expect(icon).toBe('http://8.8.8.8/favicon.ico');
    expect(state.cancelled).toBe(true);
  });

  it('Discovery: riesige HTML-Seite wird nur bis zur Grenze gelesen, Symbol am Anfang gefunden', async () => {
    const head = '<html><head><link rel="icon" href="/klein.png" /></head><body>';
    const encoder = new TextEncoder();
    const state = { pulled: 0, cancelled: false };
    const body = new ReadableStream<Uint8Array>({
      pull(controller) {
        state.pulled += 1;
        controller.enqueue(encoder.encode(state.pulled === 1 ? head : 'a'.repeat(64 * 1024)));
      },
      cancel() {
        state.cancelled = true;
      },
    });
    vi.stubGlobal(
      'fetch',
      vi.fn().mockResolvedValue({
        ok: true,
        status: 200,
        headers: { get: (n: string) => (n.toLowerCase() === 'content-type' ? 'text/html' : null) },
        body,
        text: async () => {
          throw new Error('text() darf bei vorhandenem Stream nicht laufen');
        },
      }),
    );

    const icon = await new IconDiscoveryService().discoverFavoriteIconUrl('http://8.8.8.8/');

    expect(icon).toBe('http://8.8.8.8/klein.png');
    expect(state.cancelled).toBe(true);
    // 200 000 Zeichen bei 64-KiB-Stuecken: hoechstens eine Handvoll gelesen.
    expect(state.pulled).toBeLessThan(10);
  });
});