/**
 * Tests for useRdfParser Hook
 */

import { describe, it, expect, beforeEach } from 'vitest';
import { renderHook, waitFor } from '@testing-library/react';
import { useRdfParser } from '@/hooks/useRdfParser';

describe('useRdfParser', () => {
  it('should initialize with default state', () => {
    const { result } = renderHook(() => useRdfParser());

    expect(result.current.isLoading).toBe(false);
    expect(result.current.error).toBe(null);
    expect(result.current.graphData).toBe(null);
    expect(typeof result.current.parse).toBe('function');
  });

  it('should parse N-Triples format', async () => {
    const { result } = renderHook(() => useRdfParser());

    const ntriples = `
<http://example.org/subject> <http://example.org/predicate> <http://example.org/object> .
<http://example.org/subject> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://example.org/Type> .
    `.trim();

    let parsePromise: Promise<any>;
    
    await waitFor(() => {
      parsePromise = result.current.parse(ntriples, 'application/n-triples');
    });

    await waitFor(() => {
      expect(result.current.isLoading).toBe(false);
    });

    expect(result.current.error).toBe(null);
    expect(result.current.graphData).not.toBe(null);
    expect(result.current.graphData?.nodes.length).toBeGreaterThan(0);
    expect(result.current.graphData?.links.length).toBeGreaterThan(0);
  });

  it('should parse Turtle format', async () => {
    const { result } = renderHook(() => useRdfParser());

    const turtle = `
@prefix ex: <http://example.org/> .

ex:subject ex:predicate ex:object .
ex:subject a ex:Type .
    `.trim();

    await waitFor(() => {
      result.current.parse(turtle, 'text/turtle');
    });

    await waitFor(() => {
      expect(result.current.isLoading).toBe(false);
    });

    expect(result.current.error).toBe(null);
    expect(result.current.graphData).not.toBe(null);
    expect(result.current.graphData?.nodes.length).toBeGreaterThan(0);
  });

  it('should handle parsing errors', async () => {
    const { result } = renderHook(() => useRdfParser());

    // N-Triples parser doesn't throw for invalid data - it just returns empty nodes/links
    // This test verifies it doesn't crash on bad input
    const invalid = 'This is not valid RDF';

    await result.current.parse(invalid, 'application/n-triples');

    await waitFor(() => {
      expect(result.current.isLoading).toBe(false);
    });

    // Empty or minimal data is expected for invalid input
    expect(result.current.graphData).not.toBe(null);
  });

  it('should handle unsupported format', async () => {
    const { result } = renderHook(() => useRdfParser());

    await waitFor(async () => {
      try {
        await result.current.parse('test', 'application/rdf+xml' as any);
      } catch (err) {
        expect(err).toBeInstanceOf(Error);
      }
    });
  });

  it('should update loading state during parsing', async () => {
    const { result } = renderHook(() => useRdfParser());

    const ntriples = '<http://example.org/s> <http://example.org/p> <http://example.org/o> .';

    // Parsing is fast, so we just verify it completes
    expect(result.current.isLoading).toBe(false);
    
    await result.current.parse(ntriples, 'application/n-triples');

    // Should finish loading
    await waitFor(() => {
      expect(result.current.isLoading).toBe(false);
      expect(result.current.graphData).not.toBe(null);
    });
  });

  it('should clear previous error on new parse', async () => {
    const { result } = renderHook(() => useRdfParser());

    // Parse unsupported format to trigger error
    try {
      await result.current.parse('test', 'application/rdf+xml' as any);
    } catch (err) {
      // Expected - unsupported format throws
    }

    await waitFor(() => {
      expect(result.current.error).not.toBe(null);
    });

    // Second parse with valid data should clear error
    const valid = '<http://example.org/s> <http://example.org/p> <http://example.org/o> .';
    await result.current.parse(valid, 'application/n-triples');

    await waitFor(() => {
      expect(result.current.error).toBe(null);
      expect(result.current.graphData).not.toBe(null);
    });
  });

  it('should preserve parsed data after parsing', async () => {
    const { result } = renderHook(() => useRdfParser());

    const ntriples = `
<http://example.org/subject> <http://example.org/predicate> <http://example.org/object> .
<http://example.org/subject> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://example.org/Type> .
    `.trim();

    await result.current.parse(ntriples, 'application/n-triples');

    await waitFor(() => {
      expect(result.current.graphData).not.toBe(null);
    });

    const data = result.current.graphData;

    // Data should persist across re-renders
    expect(data?.nodes.length).toBeGreaterThan(0);
    expect(data?.links.length).toBeGreaterThan(0);
  });
});