import { describe, it, expect, beforeEach, afterEach } from 'vitest';
import { mkdtempSync, rmSync, readFileSync, writeFileSync } from 'fs';
import { resolve } from 'path';
import { tmpdir } from 'os';
import { loadPreferences, savePreference } from './preferences.js';

describe('preferences', () => {
  let dataDir: string;

  beforeEach(() => {
    dataDir = mkdtempSync(resolve(tmpdir(), 'flynn-prefs-'));
  });

  afterEach(() => {
    rmSync(dataDir, { recursive: true, force: true });
  });

  it('returns empty object when file is missing', () => {
    expect(loadPreferences(dataDir)).toEqual({});
  });

  it('returns empty object when file is corrupt', () => {
    writeFileSync(resolve(dataDir, 'preferences.json'), 'not json!!!');
    expect(loadPreferences(dataDir)).toEqual({});
  });

  it('round-trips a saved preference', () => {
    savePreference(dataDir, 'modelTier', 'local');
    const prefs = loadPreferences(dataDir);
    expect(prefs.modelTier).toBe('local');
  });

  it('round-trips backend mode preference', () => {
    savePreference(dataDir, 'backendMode', 'force_native');
    const prefs = loadPreferences(dataDir);
    expect(prefs.backendMode).toBe('force_native');
  });

  it('merges preferences without overwriting other keys', () => {
    savePreference(dataDir, 'modelTier', 'fast');
    savePreference(dataDir, 'otherKey', 42);
    const raw = JSON.parse(readFileSync(resolve(dataDir, 'preferences.json'), 'utf-8'));
    expect(raw.modelTier).toBe('fast');
    expect(raw.otherKey).toBe(42);
  });

  it('creates parent directories if needed', () => {
    const nested = resolve(dataDir, 'sub', 'dir');
    savePreference(nested, 'modelTier', 'default');
    expect(loadPreferences(nested).modelTier).toBe('default');
  });

  it('ignores invalid backendMode values in stored preferences', () => {
    writeFileSync(
      resolve(dataDir, 'preferences.json'),
      JSON.stringify({ modelTier: 'default', backendMode: 'invalid-mode' }),
    );
    const prefs = loadPreferences(dataDir);
    expect(prefs.modelTier).toBe('default');
    expect(prefs.backendMode).toBeUndefined();
  });
});