/**
 * UI State Persistence Tests
 * 
 * Tests for localStorage utilities and UIStateContext
 */

import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
import {
  loadUIState,
  saveUIState,
  updateUIState,
  clearUIState,
  addRecentFile,
  addRecentQuery,
  clearRecentFiles,
  clearRecentQueries,
  exportUIState,
  importUIState,
  DEFAULT_UI_STATE,
  UIState,
} from '../../src/lib/storage/ui-state';

describe('UI State localStorage Utilities', () => {
  beforeEach(() => {
    localStorage.clear();
  });

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

  describe('loadUIState', () => {
    it('should return default state when localStorage is empty', () => {
      const state = loadUIState();
      expect(state).toEqual(DEFAULT_UI_STATE);
    });

    it('should load saved state from localStorage', () => {
      const customState: UIState = {
        ...DEFAULT_UI_STATE,
        theme: 'dark',
        visualization: {
          ...DEFAULT_UI_STATE.visualization,
          layout: 'hierarchical',
          nodeSize: 12,
        },
      };

      localStorage.setItem('rdf-visualizer:ui-state', JSON.stringify(customState));
      
      const loaded = loadUIState();
      expect(loaded.theme).toBe('dark');
      expect(loaded.visualization.layout).toBe('hierarchical');
      expect(loaded.visualization.nodeSize).toBe(12);
    });

    it('should return default state on parse error', () => {
      localStorage.setItem('rdf-visualizer:ui-state', 'invalid json');
      
      const state = loadUIState();
      expect(state).toEqual(DEFAULT_UI_STATE);
    });

    it('should migrate old version to current version', () => {
      const oldState = {
        ...DEFAULT_UI_STATE,
        version: 0, // Old version
        theme: 'dark',
      };

      localStorage.setItem('rdf-visualizer:ui-state', JSON.stringify(oldState));
      
      const loaded = loadUIState();
      expect(loaded.version).toBe(1); // Current version
      expect(loaded.theme).toBe('dark'); // Preserved data
    });
  });

  describe('saveUIState', () => {
    it('should save state to localStorage', () => {
      const state: UIState = {
        ...DEFAULT_UI_STATE,
        theme: 'dark',
      };

      const success = saveUIState(state);
      expect(success).toBe(true);

      const stored = localStorage.getItem('rdf-visualizer:ui-state');
      expect(stored).toBeTruthy();
      
      const parsed = JSON.parse(stored!);
      expect(parsed.theme).toBe('dark');
    });

    it('should update last-updated timestamp', () => {
      const state = { ...DEFAULT_UI_STATE };
      saveUIState(state);

      const timestamp = localStorage.getItem('rdf-visualizer:last-updated');
      expect(timestamp).toBeTruthy();
      expect(parseInt(timestamp!)).toBeGreaterThan(0);
    });
  });

  describe('updateUIState', () => {
    it('should update partial state', () => {
      // Save initial state
      saveUIState(DEFAULT_UI_STATE);

      // Update theme only
      const success = updateUIState({ theme: 'dark' });
      expect(success).toBe(true);

      // Verify update
      const loaded = loadUIState();
      expect(loaded.theme).toBe('dark');
      expect(loaded.visualization).toEqual(DEFAULT_UI_STATE.visualization); // Unchanged
    });

    it('should deep merge nested objects', () => {
      saveUIState(DEFAULT_UI_STATE);

      // Update only visualization.nodeSize
      updateUIState({
        visualization: {
          ...DEFAULT_UI_STATE.visualization,
          nodeSize: 15,
        },
      });

      const loaded = loadUIState();
      expect(loaded.visualization.nodeSize).toBe(15);
      expect(loaded.visualization.layout).toBe(DEFAULT_UI_STATE.visualization.layout); // Unchanged
    });
  });

  describe('clearUIState', () => {
    it('should remove state from localStorage', () => {
      saveUIState(DEFAULT_UI_STATE);
      expect(localStorage.getItem('rdf-visualizer:ui-state')).toBeTruthy();

      const success = clearUIState();
      expect(success).toBe(true);
      expect(localStorage.getItem('rdf-visualizer:ui-state')).toBeNull();
    });

    it('should remove last-updated timestamp', () => {
      saveUIState(DEFAULT_UI_STATE);
      expect(localStorage.getItem('rdf-visualizer:last-updated')).toBeTruthy();

      clearUIState();
      expect(localStorage.getItem('rdf-visualizer:last-updated')).toBeNull();
    });
  });

  describe('addRecentFile', () => {
    it('should add file to recent files', () => {
      const file = {
        id: 'file-1',
        name: 'test.ttl',
        format: 'turtle',
      };

      addRecentFile(file);
      
      const state = loadUIState();
      expect(state.recentFiles).toHaveLength(1);
      expect(state.recentFiles[0].id).toBe('file-1');
      expect(state.recentFiles[0].name).toBe('test.ttl');
      expect(state.recentFiles[0].timestamp).toBeGreaterThan(0);
    });

    it('should add file to front of list', () => {
      addRecentFile({ id: 'file-1', name: 'first.ttl', format: 'turtle' });
      addRecentFile({ id: 'file-2', name: 'second.ttl', format: 'turtle' });
      
      const state = loadUIState();
      expect(state.recentFiles[0].id).toBe('file-2'); // Most recent first
      expect(state.recentFiles[1].id).toBe('file-1');
    });

    it('should remove duplicate files', () => {
      addRecentFile({ id: 'file-1', name: 'test.ttl', format: 'turtle' });
      addRecentFile({ id: 'file-2', name: 'other.ttl', format: 'turtle' });
      addRecentFile({ id: 'file-1', name: 'test.ttl', format: 'turtle' }); // Duplicate
      
      const state = loadUIState();
      expect(state.recentFiles).toHaveLength(2);
      expect(state.recentFiles[0].id).toBe('file-1'); // Moved to front
    });

    it('should limit to 10 recent files', () => {
      // Add 15 files
      for (let i = 0; i < 15; i++) {
        addRecentFile({ id: `file-${i}`, name: `file${i}.ttl`, format: 'turtle' });
      }
      
      const state = loadUIState();
      expect(state.recentFiles).toHaveLength(10); // Max 10
      expect(state.recentFiles[0].id).toBe('file-14'); // Most recent
      expect(state.recentFiles[9].id).toBe('file-5'); // 10th most recent
    });
  });

  describe('addRecentQuery', () => {
    it('should add query to recent queries', () => {
      addRecentQuery('SELECT * WHERE { ?s ?p ?o }');
      
      const state = loadUIState();
      expect(state.recentQueries).toHaveLength(1);
      expect(state.recentQueries[0].query).toBe('SELECT * WHERE { ?s ?p ?o }');
    });

    it('should remove duplicate queries', () => {
      addRecentQuery('SELECT * WHERE { ?s ?p ?o }');
      addRecentQuery('SELECT ?s WHERE { ?s a ?type }');
      addRecentQuery('SELECT * WHERE { ?s ?p ?o }'); // Duplicate
      
      const state = loadUIState();
      expect(state.recentQueries).toHaveLength(2);
      expect(state.recentQueries[0].query).toBe('SELECT * WHERE { ?s ?p ?o }'); // Moved to front
    });

    it('should limit to 20 recent queries', () => {
      for (let i = 0; i < 25; i++) {
        addRecentQuery(`SELECT * WHERE { ?s ?p ?o${i} }`);
      }
      
      const state = loadUIState();
      expect(state.recentQueries).toHaveLength(20); // Max 20
    });
  });

  describe('clearRecentFiles', () => {
    it('should clear recent files', () => {
      addRecentFile({ id: 'file-1', name: 'test.ttl', format: 'turtle' });
      addRecentFile({ id: 'file-2', name: 'other.ttl', format: 'turtle' });
      
      clearRecentFiles();
      
      const state = loadUIState();
      expect(state.recentFiles).toHaveLength(0);
    });
  });

  describe('clearRecentQueries', () => {
    it('should clear recent queries', () => {
      addRecentQuery('SELECT * WHERE { ?s ?p ?o }');
      addRecentQuery('SELECT ?s WHERE { ?s a ?type }');
      
      clearRecentQueries();
      
      const state = loadUIState();
      expect(state.recentQueries).toHaveLength(0);
    });
  });

  describe('exportUIState', () => {
    it('should export state as JSON string', () => {
      saveUIState({ ...DEFAULT_UI_STATE, theme: 'dark' });
      
      const json = exportUIState();
      expect(json).toBeTruthy();
      
      const parsed = JSON.parse(json);
      expect(parsed.theme).toBe('dark');
    });

    it('should export prettified JSON', () => {
      saveUIState(DEFAULT_UI_STATE);
      
      const json = exportUIState();
      expect(json).toContain('\n'); // Contains newlines (prettified)
      expect(json).toContain('  '); // Contains indentation
    });
  });

  describe('importUIState', () => {
    it('should import valid JSON state', () => {
      const exportedState = {
        ...DEFAULT_UI_STATE,
        theme: 'dark' as const,
        visualization: {
          ...DEFAULT_UI_STATE.visualization,
          nodeSize: 15,
        },
      };

      const json = JSON.stringify(exportedState);
      const success = importUIState(json);
      expect(success).toBe(true);

      const loaded = loadUIState();
      expect(loaded.theme).toBe('dark');
      expect(loaded.visualization.nodeSize).toBe(15);
    });

    it('should reject invalid JSON', () => {
      const success = importUIState('invalid json');
      expect(success).toBe(false);
    });

    it('should reject invalid state structure', () => {
      const invalidState = { foo: 'bar' }; // Missing required fields
      const success = importUIState(JSON.stringify(invalidState));
      expect(success).toBe(false);
    });
  });

  describe('localStorage unavailable scenarios', () => {
    it('should handle localStorage errors gracefully', () => {
      // Save original setItem
      const originalSetItem = Storage.prototype.setItem;
      
      // Override with throwing version
      Storage.prototype.setItem = function() {
        throw new Error('QuotaExceededError');
      };

      const success = saveUIState(DEFAULT_UI_STATE);
      expect(success).toBe(false);

      // Restore original
      Storage.prototype.setItem = originalSetItem;
    });

    it('should return default state when localStorage throws on getItem', () => {
      // Save original getItem
      const originalGetItem = Storage.prototype.getItem;
      
      // Override with throwing version
      Storage.prototype.getItem = function() {
        throw new Error('SecurityError');
      };

      const state = loadUIState();
      expect(state).toEqual(DEFAULT_UI_STATE);

      // Restore original
      Storage.prototype.getItem = originalGetItem;
    });
  });
});