/**

* @file MVC架构

*

*/

var MVCObject;

(function() {

function Accessor(target, targetKey) {

var self = this;

self.target = target;

self.targetKey = targetKey;

}

Accessor.prototype.transform = function(from, to) {

var self = this;

self.from = from;

self.to = to;

self.target.notify(self.targetKey);

return self;

}

MVCObject = (function() {

var getterNameCache = {};

var setterNameCache = {};

var uuid = 0;

var bindings = '__bindings__';

var accessors = '__accessors__';

var uid = '__uid__';

function capitalize(str) {

return str.substr(0, 1).toUpperCase() + str.substr(1);

}

function getUid(obj) {

return obj[uid] || (obj[uid] = ++uuid);

}

function toKey(key) {

return '_' + key;

}

function getGetterName(key) {

if (getterNameCache.hasOwnProperty(key)) {

return getterNameCache[key];

} else {

return getterNameCache[key] = 'get' + capitalize(key);

}

}

function getSetterName(key) {

if (setterNameCache.hasOwnProperty(key)) {

return setterNameCache[key];

} else {

return setterNameCache[key] = 'set' + capitalize(key);

}

}

/**

* @description 这个函数的触发需要时机

* 在一个key所在的终端对象遍历到时触发

* 同时传播给所有直接、间接监听targetKey的对象

* 在调用MVCObject的set方法时开始遍历

*

* @param target {MVCObject} 继承了MVCObject的对象

* @param targetKey {String} 当前对象中被监听的字段

* @return {void}

*/

function triggerChange(target, targetKey) {

var evt = targetKey + '_changed';

/**

* 优先检测并执行目标对象key对应的响应方法

* 其次检测并执行默认方法

*/

if (target[evt]) {

target[evt]();

} else if (typeof target.changed === 'function') {

target.changed(targetKey);

}

if (target[bindings] && target[bindings][targetKey]) {

var ref = target[bindings][targetKey];

var bindingObj, bindingUid;

for (bindingUid in ref) {

if (ref.hasOwnProperty(bindingUid)) {

bindingObj = ref[bindingUid];

triggerChange(bindingObj.target, bindingObj.targetKey);

}

}

}

}

function MVCObject() {};

var proto = MVCObject.prototype;

/**

* @description 从依赖链中获取对应key的值

* @param {String} key 关键值

* @return {mixed} 对应的值

*/

proto.get = function(key) {

var self = this;

if (self[accessors] && self[accessors].hasOwnProperty(key)) {

var accessor = self[accessors][key];

var targetKey = accessor.targetKey;

var target = accessor.target;

var getterName = getGetterName(targetKey);

var value;

if (target[getterName]) {

value = target[getterName]();

} else {

value = target.get(targetKey);

}

if (accessor.to) {

value = accessor.to(value);

}

} else if (self.hasOwnProperty(toKey(key))) {

value = self[toKey(key)];

}

return value;

};

/**

* @description set方法遍历依赖链直到找到key的持有对象设置key的值;

* 有三个分支

* @param {String} key 关键值

* @param {all} value 要给key设定的值,可以是所有类型

* @return {this}

*/

proto.set = function(key, value) {

var self = this;

if (self[accessors] && self[accessors].hasOwnProperty(key)) {

var accessor = self[accessors][key];

var targetKey = accessor.targetKey;

var target = accessor.target;

var setterName = getSetterName(targetKey);

if (accessor.from) {

value = accessor.from(value);

}

if (target[setterName]) {

target[setterName](value);

} else {

target.set(targetKey, value);

}

} else {

this[toKey(key)] = value;

triggerChange(self, key);

}

return self;

};

/**

* @description 没个MVCObject对象各自的响应对应的key值变化时的逻辑

*/

proto.changed = function() {};

/**

* @description 手动触发对应key的事件传播

* @param {String} key 关键值

* @return {this}

*/

proto.notify = function(key) {

var self = this;

if (self[accessors] && self[accessors].hasOwnProperty(key)) {

var accessor = self[accessors][key];

var targetKey = accessor.targetKey;

var target = accessor.target;

target.notify(targetKey);

} else {

triggerChange(self, key);

}

return self;

};

proto.setValues = function(values) {

var self = this;

var key, setterName, value;

for (key in values) {

if (values.hasOwnProperty(key)) {

value = values[key];

setterName = getSetterName(key);

if (self[setterName]) {

self[setterName](value);

} else {

self.set(key, value);

}

}

}

return self;

};

proto.setOptions = proto.setValues;

/**

* @description 将当前对象的一个key与目标对象的targetKey建立监听和广播关系

* @param key {String} 当前对象上的key

* @param target {Object} 目标对象

* @param tarrgetKey {String} 目标对象上的key

* @param noNotify {Boolean}

* @return {Accessor}

*/

proto.bindTo = function(key, target, targetKey, noNotify) {

targetKey || (targetKey = key);

var self = this;

self.unbind(key);

self[accessors] || (self[accessors] = {});

target[bindings] || (target[bindings] = {});

target[bindings][targetKey] || (target[bindings][targetKey] = {});

var binding = new Accessor(self, key);

var accessor = new Accessor(target, targetKey);

self[accessors][key] = accessor;

target[bindings][targetKey][getUid(self)] = binding;

if (!noNotify) {

triggerChange(self, key);

}

return accessor;

};

/**

* @description 解除当前对象上key与目标对象的监听

* @param {String} key 关键字

* @return {this}

*/

proto.unbind = function(key) {

var self = this;

if (self[accessors]) {

var accessor = self[accessors][key];

if (accessor) {

var target = accessor.target;

var targetKey = accessor.targetKey;

self[toKey(key)] = self.get(key);

delete target[bindings][targetKey][getUid(self)];

delete self[accessors][key];

}

}

return self;

}

proto.unbindAll = function() {

var self = this;

if (self[accessors]) {

var ref = self[accessors];

for (var key in ref) {

if (ref.hasOwnProperty(key)) {

self.unbind(key);

}

}

}

return self;

};

proto.initOptions = function(options) {

for (var key in options) {

this[getGetterName(key)] = (function(key) {

return function () {

return this.get(key);

}

})(key);

this[getSetterName(key)] = (function(key) {

return function (value) {

this.set(key, value);

}

})(key);

this[toKey(key)] = options[key];

}

}

return MVCObject;

})();

})();