memory-infrastructure-palace/code/websites/pokedex.online/tests/unit/composables/useFeatureFlags.test.js

/**
 * useFeatureFlags Composable Tests
 * Verifies feature flag state management, permissions, and overrides
 */

import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
import * as useAuthModule from '../../../src/composables/useAuth.js';
import { useFeatureFlags } from '../../../src/composables/useFeatureFlags.js';

// Mock useAuth module with default no-permissions user
vi.spyOn(useAuthModule, 'useAuth').mockReturnValue({
  user: { isAdmin: false, permissions: [] },
  token: null,
  hasPermission: vi.fn(() => false)
});

describe('useFeatureFlags', () => {
  beforeEach(() => {
    // Clear localStorage before each test
    localStorage.clear();
  });

  afterEach(() => {
    localStorage.clear();
  });

  describe('isEnabled', () => {
    it('returns flag default value when no override exists', () => {
      const { isEnabled } = useFeatureFlags();

      // ENABLE_CACHING defaults to true
      expect(isEnabled.value('enable-caching')).toBe(true);
      // DARK_MODE defaults to false
      expect(isEnabled.value('dark-mode')).toBe(false);
    });

    it('returns false for unknown flag name', () => {
      const { isEnabled } = useFeatureFlags();
      expect(isEnabled.value('nonexistent-flag')).toBe(false);
    });

    it('respects local override when set in same instance', () => {
      const { isEnabled, toggle } = useFeatureFlags();

      expect(isEnabled.value('dark-mode')).toBe(false);

      toggle('dark-mode');
      // Should be toggled in same instance
      expect(isEnabled.value('dark-mode')).toBe(true);
    });

    it('returns false for flag requiring permission without it', () => {
      const { isEnabled } = useFeatureFlags();

      // GAMEMASTER_DIFF_VIEWER requires 'gamemaster-advanced' permission
      expect(isEnabled.value('gamemaster-diff-viewer')).toBe(false);
    });
  });

  describe('toggle', () => {
    it('toggles flag override in development mode', () => {
      const { toggle, isEnabled } = useFeatureFlags();

      expect(isEnabled.value('dark-mode')).toBe(false);

      const result = toggle('dark-mode');
      expect(result).toBe(true);
      expect(isEnabled.value('dark-mode')).toBe(true);
    });

    it('persists override to localStorage', () => {
      const { toggle } = useFeatureFlags();

      toggle('dark-mode');

      const stored = localStorage.getItem('feature_flag_overrides');
      expect(stored).not.toBeNull();

      const overrides = JSON.parse(stored);
      expect(overrides['dark-mode']).toBe(true);
    });

    it('loads overrides from localStorage on init', () => {
      // Set override in storage first
      localStorage.setItem(
        'feature_flag_overrides',
        JSON.stringify({
          'dark-mode': true,
          'experimental-search': true
        })
      );

      const { isEnabled } = useFeatureFlags();

      expect(isEnabled.value('dark-mode')).toBe(true);
      expect(isEnabled.value('experimental-search')).toBe(true);
    });
  });

  describe('reset', () => {
    it('removes override for specific flag', () => {
      const { isEnabled, toggle, reset } = useFeatureFlags();

      toggle('dark-mode');
      expect(isEnabled.value('dark-mode')).toBe(true);

      reset('dark-mode');
      expect(isEnabled.value('dark-mode')).toBe(false);
    });

    it('returns to default after reset', () => {
      const { isEnabled, toggle, reset } = useFeatureFlags();

      // ENABLE_CACHING defaults to true
      const beforeToggle = isEnabled.value('enable-caching');
      toggle('enable-caching');
      expect(isEnabled.value('enable-caching')).not.toBe(beforeToggle);

      reset('enable-caching');
      expect(isEnabled.value('enable-caching')).toBe(beforeToggle);
    });
  });

  describe('resetAll', () => {
    it('clears all overrides', () => {
      const { isEnabled, toggle, resetAll } = useFeatureFlags();

      toggle('dark-mode');
      toggle('experimental-search');

      resetAll();

      // Should return to defaults
      expect(isEnabled.value('dark-mode')).toBe(false);
      expect(isEnabled.value('experimental-search')).toBe(false);
    });

    it('clears localStorage after reset', () => {
      const { toggle, resetAll } = useFeatureFlags();

      toggle('dark-mode');
      resetAll();

      const stored = localStorage.getItem('feature_flag_overrides');
      expect(stored).toBe('{}');
    });
  });

  describe('getFlags', () => {
    it('returns array of all flags with status', () => {
      const { getFlags } = useFeatureFlags();

      const flags = getFlags();

      expect(Array.isArray(flags)).toBe(true);
      expect(flags.length).toBeGreaterThan(0);

      const darkMode = flags.find(f => f.name === 'dark-mode');
      expect(darkMode).toBeDefined();
      expect(darkMode).toHaveProperty('isEnabled');
      expect(darkMode).toHaveProperty('hasOverride');
      expect(darkMode).toHaveProperty('requiresPermission');
    });

    it('marks flags with overrides', () => {
      const { getFlags, toggle } = useFeatureFlags();

      toggle('dark-mode');

      const flags = getFlags();
      const darkMode = flags.find(f => f.name === 'dark-mode');

      expect(darkMode.hasOverride).toBe(true);
      expect(darkMode.override).toBe(true);
    });

    it('indicates permission requirements for flags', () => {
      const { getFlags } = useFeatureFlags();

      const flags = getFlags();

      // Should have flags with and without permissions
      const withPerm = flags.find(f => f.requiresPermission);
      const withoutPerm = flags.find(f => !f.requiresPermission);

      expect(withPerm).toBeDefined();
      expect(withoutPerm).toBeDefined();
    });
  });

  describe('setBackendFlags', () => {
    it('sets flags from backend response', () => {
      const { isEnabled, setBackendFlags } = useFeatureFlags();

      expect(isEnabled.value('dark-mode')).toBe(false);

      setBackendFlags({
        'dark-mode': true,
        'experimental-search': true
      });

      expect(isEnabled.value('dark-mode')).toBe(true);
      expect(isEnabled.value('experimental-search')).toBe(true);
    });

    it('local overrides take precedence over backend flags', () => {
      const { isEnabled, toggle, setBackendFlags } = useFeatureFlags();

      toggle('dark-mode'); // Local override to true

      setBackendFlags({
        'dark-mode': false // Backend says false
      });

      // Local override should win
      expect(isEnabled.value('dark-mode')).toBe(true);
    });
  });
});