/**
 * DataStore - Singleton pattern managing multiple store namespaces
 *
 * Usage:
 *   window.jvbStore = new DataStore();
 *   this.store = window.jvbStore.register('feed', { config });
 */
class DataStore {

	constructor() {
		// Singleton pattern
		if (DataStore.instance) {
			return DataStore.instance;
		}
		DataStore.instance = this;

		// Shared resources
		this.dbConfig = new Map();      // Definitions for the databases
		this.databases = new Map();     // Shared IndexedDB connections
		this.stores = new Map();        // Registered store namespaces
		this.subscribers = new Map();   // Per-store event subscribers
		this.pendingInits = new Map();  // Track initialization promises
		this.fetchQueue = [];

		// Global state
		this._initialized = false;
		this.body = document.body;
		this.loading = document.querySelector('dialog.loading');

		this.init();
	}

	async init() {
		if (this._initialized) return;
		this._initialized = true;

		if (!('indexedDB' in window)) {
			console.warn('IndexedDB not supported');
		}
	}

	/**
	 * Register a new store namespace
	 * @param {string} name Database Name
	 * @param {object|array} configs An object defining the store, or an array of objects defining the stores
	 * @param {number} version the database version
	 */
	register(name, configs = [], version = 1.1) {
		if (!Array.isArray(configs)) configs = [configs];
		if (configs.length === 0) return;

		if (!this.dbConfig.has(name)) {
			this.dbConfig.set(name, {
				dbName: `jvb_${name}`,
				version: version,
				stores: {},
				_initialized: false
			});
		}

		let dbEntry = this.dbConfig.get(name);

		configs.forEach(config => {
			if (!config.storeName) {
				throw new Error(`Store config for "${name}" missing storeName`);
			}
			if (!config.keyPath) {
				throw new Error(`Store "${config.storeName}" requires keyPath`);
			}

			const storeKey = `${name}_${config.storeName}`;

			const store = {
				config: {
					// Storage
					dbName: dbEntry.dbName,
					storeName: 'items',
					keyPath: 'id',
					indexes: [],

					// API
					endpoint: null,
					apiBase: jvbSettings.api,
					filters: {},
					required: null,

					// Cache
					TTL: 3600000, // 1 hour
					useHttpCaching: true,

					// Behavior
					showLoading: false,
					delayFetch: true,
					validateData: true,
					...config
				},
				dbKey: name,
				storeKey: storeKey,
				data: new Map(),
				cache: new Map(),
				filters: {...(config.filters || {})},
				isFetching: false,
				currentRequest: null,
				lastResponse: null,
				_initialized: false
			};

			store.config.headers = {
				'X-WP-Nonce': window.auth.getNonce(),
				...store.config.headers
			};

			dbEntry.stores[config.storeName] = storeKey;

			this.stores.set(storeKey, store);
			if (!this.subscribers.has(storeKey)) {
				this.subscribers.set(storeKey, new Set());
			}
		});

		// Initialize database asynchronously
		this.initDB(name).catch(error => {
			console.error(`Failed to initialize store "${name}":`, error);
		});

		const apis = {};
		for (const [storeName, storeKey] of Object.entries(dbEntry.stores)) {
			apis[storeName] = this.getStoreAPI(storeKey);
		}
		return apis;
	}

	/**
	 * Get the API object for a registered store
	 */
	getStoreAPI(name) {
		const api = {
			// Data methods
			fetch: () => this.fetch(name),
			save: (item) => this.save(name, item),
			delete: (id) => this.delete(name, id),
			get: (id) => this.get(name, id),
			getAll: () => this.getAll(name),
			getAllByIndex: (indexName, value) => this.getAllByIndex(name, indexName, value),
			filterByIndex: (criteria) => this.filterByIndex(name, criteria),
			getFiltered: () => this.getFiltered(name),
			clear: () => this.clear(name),

			// Filter methods
			setFilter: (key, value) => this.setFilter(name, key, value),
			setFilters: (filters) => this.setFilters(name, filters),
			removeFilter: (key) => this.removeFilter(name, key),
			clearFilters: () => this.clearFilters(name),

			// Cache methods
			clearCache: () => this.clearCache(name),

			// Event methods
			subscribe: (callback) => this.subscribe(name, callback),

			// Utility
			ensureInitialized: () => this.ensureStoreInitialized(name),

			// Exposed properties (read-only)
			get filters() {
				return { ...api.getStore().filters };
			},
			get lastResponse() {
				return api.getStore().lastResponse;
			},
			get data() {
				return api.getStore().data;
			},

			getStore: () => this.stores.get(name)
		};

		return api;
	}

	/**
	 * Convert FormData to plain object for storage
	 */
	formDataToObject(formData) {
		const obj = {
			_isFormData: true,
			entries: {}
		};

		for (const [key, value] of formData.entries()) {
			// Skip File/Blob objects - they're stored separately in UploadManager
			if (value instanceof File || value instanceof Blob) {
				continue;
			}

			// Handle multiple values for same key
			if (obj.entries[key]) {
				if (!Array.isArray(obj.entries[key])) {
					obj.entries[key] = [obj.entries[key]];
				}
				obj.entries[key].push(value);
			} else {
				obj.entries[key] = value;
			}
		}

		return obj;
	}

	/**
	 * Convert stored object back to FormData
	 */
	async objectToFormData(obj) {
		if (!obj._isFormData) return obj;

		const formData = new FormData();

		// Restore text entries
		for (const [key, value] of Object.entries(obj.entries)) {
			if (Array.isArray(value)) {
				value.forEach(v => formData.append(key, v));
			} else {
				formData.append(key, value);
			}
		}

		if (window.jvbUploads && obj.entries.upload_ids) {
			const uploadIds = JSON.parse(obj.entries.upload_ids);

			for (const uploadId of uploadIds) {
				const file = await window.jvbUploads.getBlobData(uploadId);
				if (file) {
					formData.append('files[]', file);
				}
			}
		}

		return formData;
	}

	/***********************************************************************
	 * DATABASE INITIALIZATION
	 ***********************************************************************/

	async initDB(name) {
		const db = this.dbConfig.get(name);
		if (!db || db._initialized) return;

		if (this.pendingInits.has(name)) {
			return this.pendingInits.get(name);
		}

		const initPromise = this._performDBInit(name);
		this.pendingInits.set(name, initPromise);

		try {
			await initPromise;
			db._initialized = true;
		} finally {
			this.pendingInits.delete(name);
		}
	}

	async _performDBInit(name) {
		const database = this.dbConfig.get(name);
		const { dbName, version } = database;
		const stores = Object.values(database.stores);

		try {
			if (!this.databases.has(dbName)) {
				const db = await this.openDatabase(dbName, version, (db) => {
					stores.forEach(store => {
						let storeObj = this.stores.get(store);
						if (storeObj) {
							this.setupStores(db, storeObj.config);
						}
					});
				});
				this.databases.set(dbName, db);
			}

			stores.forEach(storeName => {
				let store = this.stores.get(storeName);
				if (store) {
					store.db = this.databases.get(dbName);
					store._initialized = true;
					this.loadStoreDataInBackground(storeName);
					this.notify(storeName, 'db-init');
				}
			});

		} catch (error) {
			console.error(`Failed to initialize database for store "${name}":`, error);
			throw error;
		}
	}

	openDatabase(dbName, version, onUpgrade) {
		return new Promise((resolve, reject) => {
			const request = indexedDB.open(dbName, version);

			request.onupgradeneeded = (e) => {
				if (onUpgrade) {
					onUpgrade(e.target.result, e.oldVersion, e.newVersion);
				}
			};

			request.onsuccess = (e) => resolve(e.target.result);
			request.onerror = (e) => reject(e.target.error);
			request.onblocked = () => {
				console.warn(`Database ${dbName} blocked. Close other tabs.`);
			};
		});
	}

	setupStores(db, config) {
		// Main store
		if (!db.objectStoreNames.contains(config.storeName)) {
			const store = db.createObjectStore(config.storeName, {
				keyPath: config.keyPath
			});

			config.indexes.forEach(index => {
				store.createIndex(
					index.name,
					index.keyPath || index.name,
					{ unique: index.unique || false }
				);
			});
		}

		// Cache store (now includes HTTP headers)
		if (config.endpoint && !db.objectStoreNames.contains('cache')) {
			const cacheStore = db.createObjectStore('cache', { keyPath: 'key' });
			cacheStore.createIndex('timestamp', 'timestamp', { unique: false });
		}
	}

	/**
	 * Generic loader for any object store
	 */
	async loadFromObjectStore(name, storeName, processItem) {
		const store = this.stores.get(name);
		if (!store?.db || !store.db.objectStoreNames.contains(storeName)) {
			return [];
		}

		return new Promise((resolve) => {
			const tx = store.db.transaction([storeName], 'readonly');
			const objectStore = tx.objectStore(storeName);
			const request = objectStore.getAll();

			request.onsuccess = (e) => {
				const items = e.target.result || [];
				items.forEach(processItem);
				resolve(items);
			};

			request.onerror = () => resolve([]);
		});
	}

	loadStoreDataInBackground(name) {
		const store = this.stores.get(name);
		if (!store?.db) return;

		Promise.all([
			// Load main data
			this.loadFromObjectStore(name, store.config.storeName, (item) => {
				const key = this.getItemKey(item, store.config.keyPath);
				store.data.set(key, item);
			}),

			// Load cache (includes HTTP headers now!)
			this.loadFromObjectStore(name, 'cache', (item) => {
				if (this.isCacheValid(item, store.config.TTL)) {
					store.cache.set(item.key, item);
				}
			})
		])
			.then(() => {
				this.notify(name, 'data-ready');

				// Add to fetch queue instead of immediate fetch
				if (store.config.endpoint && store.config.delayFetch) {
					this.fetchQueue.push(name);

					// Start processing queue if not already running
					if (this.fetchQueue.length === 1) {
						this.processFetchQueue();
					}
				} else if (store.config.endpoint && !store.config.delayFetch) {
					// Immediate fetch
					if ('requestIdleCallback' in window) {
						requestIdleCallback(() => this.fetch(name), { timeout: 2000 });
					} else {
						setTimeout(() => this.fetch(name), 100);
					}
				}
			})
			.catch(error => {
				console.error(`Background load error for store "${name}":`, error);
			});
	}

	async processFetchQueue() {
		if (this.fetchQueue.length === 0) return;

		const name = this.fetchQueue.shift();
		const store = this.stores.get(name);

		if (!store) {
			// Store was removed, continue with next
			return this.processFetchQueue();
		}

		try {
			await this.fetch(name);
		} catch (error) {
			console.error(`Queue fetch error for "${name}":`, error);
		}

		// Process next item with idle callback
		if (this.fetchQueue.length > 0) {
			if ('requestIdleCallback' in window) {
				requestIdleCallback(() => this.processFetchQueue(), { timeout: 2000 });
			} else {
				setTimeout(() => this.processFetchQueue(), 50);
			}
		}
	}

	async ensureStoreInitialized(name) {
		const store = this.stores.get(name);
		if (!store) {
			throw new Error(`Store "${name}" not registered`);
		}

		if (!store._initialized) {
			await this.initDB(store.dbKey);
		}
	}

	/***********************************************************************
	 * TRANSACTION HELPER
	 ***********************************************************************/

	/**
	 * Create transaction helper - reduces boilerplate
	 */
	async withTransaction(name, storeNames, mode, callback) {
		const store = this.stores.get(name);
		if (!store?.db) return null;

		// Ensure storeNames is an array
		if (typeof storeNames === 'string') storeNames = [storeNames];

		return new Promise((resolve, reject) => {
			const tx = store.db.transaction(storeNames, mode);
			const stores = storeNames.map(name => tx.objectStore(name));
			const objectStore = stores.length === 1 ? stores[0] : stores;

			let result;
			tx.oncomplete = () => resolve(result);
			tx.onerror = () => reject(tx.error);

			// Call callback immediately to queue operations
			try {
				result = callback(objectStore, tx);
			} catch (error) {
				reject(error);
			}
		});
	}

	/***********************************************************************
	 * FETCH & DATA PROCESSING
	 ***********************************************************************/

	async fetch(name) {
		await this.ensureStoreInitialized(name);

		const store = this.stores.get(name);

		if (store.isFetching) return;

		// Check required filters
		if (store.config.required) {
			const required = Array.isArray(store.config.required)
				? store.config.required
				: [store.config.required];

			const missing = required.some(key =>
				!store.filters[key] || store.filters[key] === ''
			);

			if (missing) return;
		}

		store.isFetching = true;

		try {
			// Check cache
			const cacheKey = this.generateCacheKey(store.filters);
			const cached = store.cache.get(cacheKey);

			if (cached && this.isCacheValid(cached, store.config.TTL)) {
				this.notify(name, 'data-loaded', {
					cached: true,
					items: cached.items || []
				});
				return cached;
			}

			if (store.config.showLoading) {
				this.setLoading(true);
			}

			const url = this.buildFetchUrl(name);
			const headers = { ...store.config.headers };

			// Use HTTP cache headers from cache entry
			if (store.config.useHttpCaching && cached) {
				if (cached.etag) headers['If-None-Match'] = cached.etag;
				if (cached.lastModified) headers['If-Modified-Since'] = cached.lastModified;
			}

			const controller = new AbortController();
			store.currentRequest = controller;

			const response = await fetch(url, {
				method: 'GET',
				headers,
				signal: controller.signal
			});

			if (response.status === 304) {
				// 304 means "Not Modified" - use cached data if available
				if (cached) {
					this.notify(name, 'data-loaded', {
						cached: true,
						notModified: true,
						items: cached.items || []
					});
					return cached;
				}

				// No cached data but server says not modified - return empty result
				this.notify(name, 'data-loaded', {
					cached: false,
					notModified: true,
					items: []
				});

				// Initialize empty lastResponse
				store.lastResponse = {
					has_more: false,
					total: 0,
					pages: 1,
					queue_stats: {}
				};

				return { items: [] };
			}

			// Now check for other non-OK responses
			if (!response.ok) {
				throw new Error(`HTTP ${response.status}: ${response.statusText}`);
			}

			const data = await response.json();

			await this.processFetchedData(name, data, cacheKey, response);

			this.notify(name, 'data-loaded', {
				cached: false,
				items: data.items || []
			});

			return data;

		} catch (error) {
			if (error.name !== 'AbortError') {
				console.error(`Fetch error for store "${name}":`, error);
				this.notify(name, 'fetch-error', { error });
			}
			throw error;

		} finally {
			store.isFetching = false;
			store.currentRequest = null;

			if (store.config.showLoading) {
				this.setLoading(false);
			}
		}
	}

	buildFetchUrl(name) {
		const store = this.stores.get(name);
		const params = new URLSearchParams();

		Object.entries(store.filters).forEach(([key, value]) => {
			if (value !== null && value !== undefined && value !== '') {
				if (typeof value === 'object') {
					params.set(key, JSON.stringify(value));
				} else {
					params.set(key, value);
				}
			}
		});

		const baseUrl = store.config.apiBase + store.config.endpoint;
		return params.toString() ? `${baseUrl}?${params}` : baseUrl;
	}

	/**
	 * Process fetched data (batch from server)
	 */
	async processFetchedData(name, data, cacheKey, response) {
		const store = this.stores.get(name);
		const items = data.items || [];
		const changes = []; // Track all changes

		// Batch process with single transaction
		if (store.db && items.length > 0) {
			await this.withTransaction(name, store.config.storeName, 'readwrite', (objectStore) => {
				items.forEach(item => {
					try {
						// Use shared save logic
						const changeInfo = this._saveItem(name, item);
						changes.push(changeInfo);

						// Queue for batch write
						objectStore.put(changeInfo.processed);
					} catch (error) {
						console.error(`Error processing item:`, error);
					}
				});
			});
		}

		// Update cache (now includes HTTP headers!)
		const cacheEntry = {
			key: cacheKey,
			items: items.map(item => this.getItemKey(item, store.config.keyPath)),
			timestamp: Date.now(),
			endpoint: store.config.endpoint,
			filters: { ...store.filters },
			etag: response.headers.get('ETag'),
			lastModified: response.headers.get('Last-Modified')
		};

		store.cache.set(cacheKey, cacheEntry);

		// Save cache to IndexedDB
		if (store.db?.objectStoreNames.contains('cache')) {
			await this.withTransaction(name, 'cache', 'readwrite', (objectStore) => {
				objectStore.put(cacheEntry);
			});
		}

		// Update lastResponse metadata
		store.lastResponse = {
			...data,
			has_more: data.has_more || false,
			total: data.total || items.length,
			pages: data.pages || 1,
			queue_stats: data.queue_stats || {}
		};

		// Emit events for items with status changes
		changes.forEach(changeInfo => {
			if (changeInfo.statusChanged) {
				this.notify(name, 'item-saved', {
					item: changeInfo.item,
					key: changeInfo.key,
					previousItem: changeInfo.previousItem
				});
			}
		});
	}

	/***********************************************************************
	 * SAVE OPERATIONS
	 ***********************************************************************/

	/**
	 * Internal method: Save a single item with full tracking
	 * Returns change info without writing to IndexedDB (caller handles that)
	 */
	_saveItem(name, item) {
		const store = this.stores.get(name);

		const result = this.processForStorage(item, store.config.validateData);
		if (!result.valid) {
			throw new Error(`Non-serializable data: ${result.error}`);
		}
		const processed = result.data;

		const key = this.getItemKey(processed, store.config.keyPath);

		// Capture previous state
		const previousItem = store.data.get(key);

		// Update in-memory store (with original data intact)
		store.data.set(key, item);

		// Return change info for event emission
		return {
			item,
			previousItem,
			key,
			processed,
			statusChanged: previousItem && previousItem.status !== item.status
		};
	}

	/**
	 * Save single item (public API)
	 */
	async save(name, item) {
		const store = this.stores.get(name);
		const changeInfo = this._saveItem(name, item);

		// Write to IndexedDB immediately for single saves
		await this.withTransaction(name, store.config.storeName, 'readwrite', (objectStore) => {
			objectStore.put(changeInfo.processed);
		});

		// Always emit for explicit saves
		this.notify(name, 'item-saved', {
			item: changeInfo.item,
			key: changeInfo.key,
			previousItem: changeInfo.previousItem
		});

		return changeInfo.key;
	}

	processForStorage(obj, validate = true, path = 'root') {
		if (obj === null || obj === undefined) return { valid: true, data: obj };

		const type = typeof obj;

		// Handle primitives
		if (['string', 'number', 'boolean'].includes(type)) {
			return { valid: true, data: obj };
		}

		// Reject functions
		if (type === 'function') {
			if (validate) return { valid: false, error: `Function at ${path}` };
			console.debug(`[DataStore] Stripped function at ${path}`);
			return { valid: true, data: undefined };
		}

		// DOM elements
		if (obj instanceof HTMLElement || obj.nodeType !== undefined) {
			if (validate) return { valid: false, error: `DOM element at ${path}` };
			console.debug(`[DataStore] Stripped DOM element at ${path}`);
			return { valid: true, data: undefined };
		}

		// FormData - convert and continue
		if (obj instanceof FormData) {
			if (validate) return { valid: false, error: `FormData at ${path}` };
			console.debug(`[DataStore] Converted FormData at ${path}`);
			return { valid: true, data: this.formDataToObject(obj) };
		}

		// Preserve safe types
		if (obj instanceof Date || obj instanceof ArrayBuffer || ArrayBuffer.isView(obj) || obj instanceof Blob) {
			return { valid: true, data: obj };
		}

		// Convert Sets to Arrays
		if (obj instanceof Set) {
			return this.processForStorage(Array.from(obj), validate, path);
		}

		// Convert Maps to Objects
		if (obj instanceof Map) {
			obj = Object.fromEntries(obj);
		}

		// Arrays
		if (Array.isArray(obj)) {
			const processed = [];
			for (let i = 0; i < obj.length; i++) {
				const result = this.processForStorage(obj[i], validate, `${path}[${i}]`);
				if (!result.valid) return result;
				if (result.data !== undefined) processed.push(result.data);
			}
			return { valid: true, data: processed };
		}

		// Objects
		if (type === 'object') {
			const processed = {};
			for (const [key, value] of Object.entries(obj)) {
				const result = this.processForStorage(value, validate, `${path}.${key}`);
				if (!result.valid) return result;
				if (result.data !== undefined) processed[key] = result.data;
			}
			return { valid: true, data: processed };
		}

		if (validate) return { valid: false, error: `Unknown type at ${path}` };
		console.debug(`[DataStore] Stripped unknown type at ${path}`);
		return { valid: true, data: undefined };
	}

	/***********************************************************************
	 * DATA ACCESS
	 ***********************************************************************/

	async delete(name, id) {
		const store = this.stores.get(name);
		store.data.delete(id);

		await this.withTransaction(name, store.config.storeName, 'readwrite', (objectStore) => {
			objectStore.delete(id);
		});

		this.notify(name, 'item-deleted', { id });
	}

	get(name, id) {
		const store = this.stores.get(name);
		return store.data.get(id);
	}

	getAll(name) {
		const store = this.stores.get(name);
		return Array.from(store.data.values());
	}
	/**
	 * Filter in-memory data by multiple index/value pairs
	 * @param {string} name - Store name
	 * @param {Object} criteria - Object of { indexName: acceptedValue(s) }
	 * @returns {Array} - Items matching ALL criteria
	 *
	 * @example
	 * filterByIndex(name, { field: 'upload_123', status: ['queued', 'uploading'] })
	 */
	filterByIndex(name, criteria) {
		const store = this.stores.get(name);
		if (!store) return [];

		return Array.from(store.data.values()).filter(item => {
			return Object.entries(criteria).every(([key, value]) => {
				const accepted = Array.isArray(value) ? value : [value];
				return accepted.includes(item[key]);
			});
		});
	}
	/**
	 * Get all items matching an index value
	 * @param {string} name - Store name
	 * @param {string} indexName - Name of the index to query
	 * @param {*} value - Value to match
	 * @returns {Promise<Array>} - Matching items
	 */
	async getAllByIndex(name, indexName, value) {
		const store = this.stores.get(name);
		const values = Array.isArray(value) ? value : [value];

		// Try IndexedDB index query first (more efficient for large datasets)
		if (store.db && store.db.objectStoreNames.contains(store.config.storeName)) {
			try {
				const tx = store.db.transaction([store.config.storeName], 'readonly');
				const objectStore = tx.objectStore(store.config.storeName);

				if (objectStore.indexNames.contains(indexName)) {
					const index = objectStore.index(indexName);

					const results = await Promise.all(
						values.map(v => new Promise((resolve, reject) => {
							const request = index.getAll(v);
							request.onsuccess = () => resolve(request.result || []);
							request.onerror = () => reject(request.error);
						}))
					);

					return results.flat();
				}
			} catch (error) {
				console.warn(`Index query failed for "${indexName}", falling back to filter:`, error);
			}
		}

		// Fallback: filter in-memory data
		return Array.from(store.data.values()).filter(item => values.includes(item[indexName]));
	}

	getFiltered(name) {
		const store = this.stores.get(name);
		const cacheKey = this.generateCacheKey(store.filters);
		const cacheEntry = store.cache.get(cacheKey);

		if (cacheEntry && cacheEntry.items) {
			return cacheEntry.items.reduce((acc, id) => {
				const item = store.data.get(id);
				if (item) acc.push(item);
				return acc;
			}, []);
		}

		return this.getAll(name);
	}

	async clear(name) {
		const store = this.stores.get(name);
		store.data.clear();
		store.cache.clear();

		await this.withTransaction(name, store.config.storeName, 'readwrite', (objectStore) => {
			objectStore.clear();
		});

		this.notify(name, 'data-cleared');
	}

	/***********************************************************************
	 * FILTER OPERATIONS
	 ***********************************************************************/
	async updateFilters(name, updates, clearAll = false) {
		const store = this.stores.get(name);
		const oldFilters = { ...store.filters };

		if (clearAll) {
			store.filters = { ...store.config.filters };
		} else {
			// Apply updates (null/undefined/'' = delete)
			Object.entries(updates).forEach(([key, value]) => {
				if (value === null || value === undefined || value === '') {
					delete store.filters[key];
				} else {
					store.filters[key] = value;
				}
			});
		}

		this.notify(name, 'filters-changed', {
			oldFilters,
			filters: store.filters,
			updates
		});

		if (store.config.endpoint) {
			await this.fetch(name);
		}
	}

	setFilter(name, key, value) {
		return this.updateFilters(name, { [key]: value });
	}

	async setFilters(name, filters) {
		const store = this.stores.get(name);

		const hasChanges = Object.keys(filters).some(
			key => store.filters[key] !== filters[key]
		);

		if (!hasChanges) return;

		return this.updateFilters(name, filters);
	}

	removeFilter(name, key) {
		return this.updateFilters(name, { [key]: null });
	}

	clearFilters(name) {
		return this.updateFilters(name, {}, true);
	}

	/***********************************************************************
	 * CACHE OPERATIONS
	 ***********************************************************************/

	clearCache(name) {
		const store = this.stores.get(name);
		store.cache.clear();

		if (store.db?.objectStoreNames.contains('cache')) {
			this.withTransaction(name, 'cache', 'readwrite', (objectStore) => {
				objectStore.clear();
			});
		}

		this.notify(name, 'cache-cleared');
	}

	generateCacheKey(filters) {
		const normalized = Object.keys(filters)
			.sort()
			.reduce((acc, key) => {
				acc[key] = filters[key];
				return acc;
			}, {});
		return JSON.stringify(normalized);
	}

	isCacheValid(entry, ttl) {
		if (!entry || !entry.timestamp) return false;
		const age = Date.now() - entry.timestamp;
		return age < ttl;
	}

	/***********************************************************************
	 * EVENT SYSTEM
	 ***********************************************************************/

	subscribe(name, callback) {
		if (!this.subscribers.has(name)) {
			this.subscribers.set(name, new Set());
		}
		const subscribers = this.subscribers.get(name);
		subscribers.add(callback);
		return () => subscribers.delete(callback);
	}

	notify(name, event, data = {}) {
		const subscribers = this.subscribers.get(name);
		if (!subscribers) return;

		subscribers.forEach(callback => {
			try {
				callback(event, data);
			} catch (error) {
				console.error(`Subscriber error for store "${name}":`, error);
			}
		});
	}

	/***********************************************************************
	 * UTILITIES
	 ***********************************************************************/

	getItemKey(item, keyPath) {
		if (typeof keyPath === 'function') {
			return keyPath(item);
		}

		const keys = keyPath.split('.');
		let value = item;

		for (const key of keys) {
			value = value?.[key];
		}

		return value;
	}

	setLoading(on) {
		this.body.classList.toggle('loading', on);
		if (on) {
			this.loading?.showModal();
		} else {
			this.loading?.close();
		}
	}

	destroy() {
		this.stores.forEach(store => {
			if (store.currentRequest) {
				store.currentRequest.abort();
			}
		});

		this.databases.forEach(db => db.close());
		this.stores.clear();
		this.subscribers.clear();
		this.databases.clear();
		this.pendingInits.clear();
	}
}

// Initialize singleton on DOMContentLoaded
document.addEventListener('DOMContentLoaded', async function() {
	window.auth.subscribe((event) => {
		if (event === 'auth-loaded') {
			window.jvbStore = new DataStore();
		}
	});
});