//index.db.js;

window.indexedDB = window.indexedDB ||
	window.mozIndexedDB ||
	window.webkitIndexedDB ||
	window.msIndexedDB;

window.IDBTransaction = window.IDBTransaction ||
	window.webkitIDBTransaction ||
	window.msIDBTransaction;

window.IDBKeyRange = window.IDBKeyRange ||
	window.webkitIDBKeyRange ||
	window.msIDBKeyRange;

(function (window) {
	'use strict';
	var db = {

		version: 1, // important: only use whole numbers!
		objectStoreName: 'tasks',

		instance: {},

		upgrade: function (e) {
			var
				_db = e.target.result,
				names = _db.objectStoreNames,
				name = db.objectStoreName;
			if (!names.contains(name)) {

				_db.createObjectStore(
					name, {
					keyPath: 'id',
					autoIncrement: true
				});
			}
		},

		errorHandler: function (error) {
			window.alert('error: ' + error.target.code);
			debugger;
		},

		open: function (callback) {
			var request = window.indexedDB.open(
				db.objectStoreName, db.version);

			request.onerror = db.errorHandler;

			request.onupgradeneeded = db.upgrade;

			request.onsuccess = function (e) {

				db.instance = request.result;

				db.instance.onerror =
					db.errorHandler;

				callback();
			};
		},

		getObjectStore: function (mode) {
			var txn, store;

			mode = mode || 'readonly';

			txn = db.instance.transaction(
				[db.objectStoreName], mode);

			store = txn.objectStore(
				db.objectStoreName);
			return store;
		},

		save: function (data, callback) {

			db.open(function () {
				var store, request,
					mode = 'readwrite';

				store = db.getObjectStore(mode),

					request = data.id ?
						store.put(data) :
						store.add(data);

				request.onsuccess = callback;
			});
		},

		getAll: function (callback) {

			db.open(function () {
				var
					store = db.getObjectStore(),
					cursor = store.openCursor(),
					data = [];

				cursor.onsuccess = function (e) {
					var result = e.target.result;
					if (result &&
						result !== null) {

						data.push(result.value);
						result.continue();

					} else {

						callback(data);
					}
				};

			});
		},

		get: function (id, callback) {

			id = parseInt(id);

			db.open(function () {
				var
					store = db.getObjectStore(),
					request = store.get(id);

				request.onsuccess = function (e) {
					callback(e.target.result);
				};
			});
		},
		'delete': function (id, callback) {

			id = parseInt(id);

			db.open(function () {
				var
					mode = 'readwrite',
					store, request;

				store = db.getObjectStore(mode);

				request = store.delete(id);

				request.onsuccess = callback;
			});
		},

		deleteAll: function (callback) {

			db.open(function () {
				var mode, store, request;

				mode = 'readwrite';
				store = db.getObjectStore(mode);
				request = store.clear();

				request.onsuccess = callback;
			});

		}
	};

	window.app = window.app || {};
	window.app.db = db;

}(window));