import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
import { writeFileSync, mkdirSync, rmSync, existsSync } from 'fs';
import { resolve } from 'path';
import { loadConfig, findConfigFile } from '../src/config';

const TMP = resolve(__dirname, 'tmp-config');

function clean() {
  try {
    rmSync(TMP, { recursive: true, force: true });
  } catch {}
}

describe('config', () => {
  beforeEach(() => {
    clean();
    mkdirSync(TMP, { recursive: true });
  });

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

  it('finds .codegov.yml', () => {
    writeFileSync(resolve(TMP, '.codegov.yml'), 'enabled: true\n');
    expect(findConfigFile(TMP)).toBe(resolve(TMP, '.codegov.yml'));
  });

  it('finds .codegov.json', () => {
    writeFileSync(resolve(TMP, '.codegov.json'), '{"enabled":true}');
    expect(findConfigFile(TMP)).toBe(resolve(TMP, '.codegov.json'));
  });

  it('returns null when no config exists', () => {
    expect(findConfigFile(TMP)).toBeNull();
  });

  it('loads JSON config', () => {
    writeFileSync(resolve(TMP, '.codegov.json'), JSON.stringify({ enabled: true, gates: { rfc: { required: false } } }));
    const { config, usingDefaults } = loadConfig(undefined, TMP);
    expect(config.enabled).toBe(true);
    expect(config.gates.rfc?.required).toBe(false);
    expect(usingDefaults).toBe(false);
  });

  it('loads YAML config', () => {
    writeFileSync(resolve(TMP, '.codegov.yml'), 'enabled: true\ngates:\n  disclosure:\n    required: false\n');
    const { config, usingDefaults } = loadConfig(undefined, TMP);
    expect(config.enabled).toBe(true);
    expect(config.gates.disclosure?.required).toBe(false);
    expect(usingDefaults).toBe(false);
  });

  it('uses defaults when no config exists', () => {
    const { config, usingDefaults } = loadConfig(undefined, TMP);
    expect(config.enabled).toBe(true);
    expect(config.gates.disclosure?.required).toBe(true);
    expect(usingDefaults).toBe(true);
  });

  it('merges partial config with defaults', () => {
    writeFileSync(resolve(TMP, '.codegov.json'), JSON.stringify({ enabled: false }));
    const { config } = loadConfig(undefined, TMP);
    expect(config.enabled).toBe(false);
    expect(config.gates.checklist?.required).toBe(true);
  });

  it('throws on missing explicit config path', () => {
    expect(() => loadConfig('/nonexistent/.codegov.yml', TMP)).toThrow('Config file not found');
  });

  it('throws on invalid config', () => {
    writeFileSync(resolve(TMP, '.codegov.json'), 'not-json');
    expect(() => loadConfig(undefined, TMP)).toThrow();
  });
});