/**
 * Plugin developed to save html forms data to LocalStorage to restore them after browser crashes, tabs closings
 * and other disasters.
 *
 * @author Alexander Kaupanin <kaupanin@gmail.com>
 */
	
//$.sisyphus().setOptions({timeout: 15})
( function( $ ) {
	$.sisyphus = function() {
		return Sisyphus.getInstance();
	};

	$.fn.sisyphus = function( options ) {
		var sisyphus = Sisyphus.getInstance();
		sisyphus.setOptions( options )
		sisyphus.protect( this );
		return sisyphus;
	};

	
	Sisyphus = ( function() {
		var params = {
			instantiated: null,
			started: null
		};
	
		function init () {
		
			return {
			
			
				/**
				 * Set plugin initial options
				 *
				 * @param [Object] options
				 *
				 * @return void
				 */
				setInitialOptions: function ( options ) {
					var defaults = {
						excludeFields: null,
						customKeyPrefix: "",
						timeout: 0,
						onSave: function() {},
						onRestore: function() {},
						onRelease: function() {}
					};
					this.options = this.options || $.extend( defaults, options );
				}, 
			
				/**
				 * Set plugin options
				 *
				 * @param [Object] options
				 *
				 * @return void
				 */
				setOptions: function ( options ) {
					this.options = this.options || this.setInitialOptions( options );
					this.options = $.extend( this.options, options );
				}, 
			
			
				/**
				 * Protect specified forms, store it's fields data to local storage and restore them on page load
				 *
				 * @param [Object] targets    forms object(s), result of jQuery selector
				 * @param Object options      plugin options
				 *
				 * @return void
				 */
				protect: function( targets ) {
					targets = targets || {};
					var self = this;
					this.targets = this.targets || [];
					this.href = location.hostname + location.pathname + location.search;
				
					this.targets = $.merge( this.targets, targets );
					this.targets = $.unique( this.targets );
					this.targets = $( this.targets );
					if ( ! this.isLocalStorageAvailable() ) {
						return false;
					}
				
					self.restoreAllData();
					self.bindReleaseData();
					if ( ! params.started ) {
						self.bindSaveData();
						params.started = true;
					}
				},
			
			
				/**
				 * Check if local storage is available
				 *
				 * @return Boolean
				 */
				isLocalStorageAvailable: function() {
					try {
						return localStorage.getItem;
					} catch ( e ) {
						return false;
					}
				},
			
			
				/**
				 * Bind saving data
				 *
				 * @return void
				 */
				bindSaveData: function() {
					var self = this;
				
					if ( self.options.timeout ) {
						self.saveDataByTimeout();
					}
				
					self.targets.each( function() {
						var targetFormId = $( this ).attr( "id" );
						var fieldsToProtect = $( this ).find( ":input" ).not( ":submit" ).not( ":reset" ).not( ":button" );
						
						fieldsToProtect.each( function() {
							if ( $.inArray( this, self.options.excludeFields ) !== -1 ) {
								// Returning non-false is the same as a continue statement in a for loop; it will skip immediately to the next iteration.
								return true;
							}
							var field = $( this );
							var prefix = self.href + targetFormId + field.attr( "name" ) + self.options.customKeyPrefix;
							if ( field.is( ":text" ) || field.is( "textarea" ) ) {
								if ( ! self.options.timeout ) {
									self.bindSaveDataImmediately( field, prefix );
								}
							} else {
								self.bindSaveDataOnChange( field, prefix );
							}
						} );
					} )
				},
			
			
				/**
				 * Save all protected forms data to Local Storage.
				 * Common method, necessary to not lead astray user firing 'data are saved' when select/checkbox/radio
				 * is changed and saved, while textfield data are saved only by timeout
				 *
				 * @return void
				 */
				saveAllData: function() {
					var self = this;
					self.targets.each( function() {
						var targetFormId = $( this ).attr( "id" );
						var fieldsToProtect = $( this ).find( ":input" ).not( ":submit" ).not( ":reset" ).not( ":button" );
						
						fieldsToProtect.each( function() {
							if ( $.inArray( this, self.options.excludeFields ) !== -1 ) {
								// Returning non-false is the same as a continue statement in a for loop; it will skip immediately to the next iteration.
								return true;
							}
							var field = $( this );
							var prefix = self.href + targetFormId + field.attr( "name" ) + self.options.customKeyPrefix;
							var value = field.val();
						
							if ( field.is(":checkbox") ) {
								if ( field.attr( "name" ).indexOf( "[" ) != -1 ) {
									value = [];
									$( "[name='" + field.attr( "name" ) +"']:checked" ).each( function() {
										value.push( $( this ).val() );
									} );
								} else {
									value = field.is( ":checked" );
								}
								self.saveToLocalStorage( prefix, value, false );
							} else if ( field.is( ":radio" ) ) {
								if ( field.is( ":checked" ) ) {
									value = field.val();
									self.saveToLocalStorage( prefix, value, false );
								}
							} else {
								self.saveToLocalStorage( prefix, value, false );
							}
						} );
					} );
					if ( $.isFunction( self.options.onSave ) ) {
						self.options.onSave.call();
					}
				},
			
			
				/**
				 * Restore forms data from Local Storage
				 *
				 * @return void
				 */
				restoreAllData: function() {
					var self = this;
					var restored = false;
				
					self.targets.each( function() {
						var target = $( this );
						var targetFormId = target.attr( "id" );
						var fieldsToProtect = target.find( ":input" ).not( ":submit" ).not( ":reset" ).not( ":button" );
						
						fieldsToProtect.each( function() {
							if ( $.inArray( this, self.options.excludeFields ) !== -1 ) {
								// Returning non-false is the same as a continue statement in a for loop; it will skip immediately to the next iteration.
								return true;
							}
							var field = $( this );
							var prefix = self.href + targetFormId + field.attr( "name" ) + self.options.customKeyPrefix;
							var resque = localStorage.getItem( prefix );
							if ( resque ) {
								self.restoreFieldsData( field, resque );
								restored = true;
							}
						} );
					} );
				
					if ( restored && $.isFunction( self.options.onRestore ) ) {
						self.options.onRestore.call();
					}
				},
			
			
				/**
				 * Restore form field data from local storage
				 *
				 * @param Object field    jQuery form element object
				 * @param String resque   previously stored fields data
				 *
				 * @return void
				 */
				restoreFieldsData: function( field, resque ) {
					if ( field.is(":checkbox") && resque !== 'false' && field.attr("name").indexOf("[") === -1 ) {
						field.attr( "checked", "checked" );
					} else if ( field.is(":radio") ) {
						if (field.val() === resque) {
							field.attr("checked", "checked");
						}
					} else if ( field.attr( "name" ).indexOf( "[" ) === -1 ) {
						field.val( resque ); 
					} else {
						resque = resque.split( "," );
						field.val( resque ); 
					}
				},
			
			
				/**
				 * Bind immediate saving (on typing/checking/changing) field data to local storage when user fills it
				 *
				 * @param Object field    jQuery form element object
				 * @param String prefix   prefix used as key to store data in local storage
				 *
				 * @return void
				 */
				bindSaveDataImmediately: function( field, prefix ) {
					var self = this;
					if ( $.browser.msie == null ) {
						field.get(0).oninput = function() {
							self.saveToLocalStorage( prefix, field.val() );
						}
					} else {
						field.get(0).onpropertychange = function() {
							self.saveToLocalStorage( prefix, field.val() );
						}
					}
				},
			
			
				/**
				 * Save data to Local Storage and fire callback if defined
				 *
				 * @param String key
				 * @param String value
				 * @param Boolean [true] fireCallback
				 *
				 * @return void
				 */
				saveToLocalStorage: function( key, value, fireCallback ) {
					// if fireCallback is undefined it should be true
					fireCallback = fireCallback == null ? true : fireCallback;
					try {
						localStorage.setItem( key, value + "" );
					} catch (e) { 
						//QUOTA_EXCEEDED_ERR
					}
					if ( fireCallback && value !== "" && $.isFunction( this.options.onSave ) ) {
						this.options.onSave.call();
					}
				},
			
			
				/**
				 * Bind saving field data on change
				 *
				 * @param Object field    jQuery form element object
				 * @param String prefix   prefix used as key to store data in local storage
				 *
				 * @return void
				 */
				bindSaveDataOnChange: function( field, prefix ) {
					var self = this;
					field.change( function() {
						self.saveAllData();
					} );
				},
			
			
				/**
				 * Saving (by timeout) field data to local storage when user fills it
				 *
				 * @return void
				 */
				saveDataByTimeout: function() {
					var self = this;
					var targetForms = self.targets;
					setTimeout( ( function( targetForms ) {
						function timeout() {
							self.saveAllData();
							setTimeout( timeout, self.options.timeout * 1000 );
						}
						return timeout;
					} )( targetForms ), self.options.timeout * 1000 );
				},
			
			
				/**
				 * Bind release form fields data from local storage on submit/reset form
				 *
				 * @return void
				 */
				bindReleaseData: function() {
					var self = this;
					self.targets.each( function( i ) {
						var target = $( this );
						var fieldsToProtect = target.find( ":input" ).not( ":submit" ).not( ":reset" ).not( ":button" );
						var formId = target.attr( "id" );
						$( this ).bind( "submit reset", function() {
							self.releaseData( formId, fieldsToProtect );
						} )
					} )
				
				
				},
			
			
				/**
				 * Bind release form fields data from local storage on submit/resett form
				 *
				 * @param String targetFormId
				 * @param Object fieldsToProtect    jQuery object contains form fields to protect
				 *
				 * @return void
				 */
				releaseData: function( targetFormId, fieldsToProtect ) {
					var released = false;
					var self = this;
					fieldsToProtect.each( function() {
						if ( $.inArray( this, self.options.excludeFields ) !== -1 ) {
							// Returning non-false is the same as a continue statement in a for loop; it will skip immediately to the next iteration.
							return true;
						}
						var field = $( this );
						var prefix = self.href + targetFormId + field.attr( "name" ) + self.options.customKeyPrefix;
						localStorage.removeItem( prefix );
						released = true;
					} );
				
					if ( released && $.isFunction( self.options.onRelease ) ) {
						self.options.onRelease.call();
					}
				}
			
			};
		}
	
		return {
		
			getInstance: function() {
				if ( ! params.instantiated ) {
					params.instantiated = init();
					params.instantiated.setInitialOptions();
				}
				return params.instantiated; 
			},
		
			free: function() {
				params = {};
				return null;
			}
		};
	} )();
} )( jQuery );