/**
 * ess_ruler_mod.js V1.1.9
 * 此脚本实现了地理距离计算
 * V1.1.9在IE6/7/8(Windows XP/2003/Vista/2008)、Firefox 2/3(Windows XP/2003/Vista/2008、Ubuntu Linux 8.10)下测试通过
 */

/**
 * 本示例用一个双向链表维护用户设定的标注，能够容易的实现标注的遍历和删除
 * 每个链表结点 m 有如下字段：
 * m.prev			前驱标注
 * m.next			后继标注
 * m.segPrev		连接本标注与前驱标注的线段
 * m.segNext		连接本标注与后继标注的线段
 */
 
function GRulerControl() {
	var me = this;
	
	//可本地化的字符串
	me.RESET_BUTTON_TITLE_ = "清除所有测距标注";
	me.POINT_TITLE_ = "测距关键点，单击可删除";
	
	me.RESET_BUTTON_IMAGE_ = _mStaticPath + "ruler_clear.png";
	me.BACKGROUND_IMAGE_ = _mStaticPath + "ruler_background.png"
	
	me.KILOMETER_ = "公里";
	me.METER_ = "米";
}

GRulerControl.prototype = new GControl();

/**
 * 初始化标尺控件
 */
GRulerControl.prototype.initialize = function(map) {
	var me = this;
	var container = document.createElement("div");
	me.setButtonStyle_(container);
	
	//“重置”按钮
	var btnReset = document.createElement("img");
	btnReset.width = btnReset.height = 19;
	btnReset.src = me.RESET_BUTTON_IMAGE_;
	btnReset.title = me.RESET_BUTTON_TITLE_;
	GEvent.addDomListener(btnReset, "click", 
		function() {
			me.reset();
		}
	);
	container.appendChild(btnReset);

	//距离标签
	var txtInfo = document.createElement("div");
	txtInfo.style.font = "small Arial";
	txtInfo.style.fontWeight = "bold";
	txtInfo.style.fontSize = "9pt";
	txtInfo.style.width = "82px";
	container.appendChild(txtInfo);
	
	//初始化内部变量
	map.rulerControl_ = me;
	me.map_ = map;
	me.head_ = new Object();
	me.tail_ = new Object();
	me.head_.next_ = me.tail_;
	me.tail_.prev_ = me.head_;
	me.btnReset_ = btnReset;
	me.txtInfo_ = txtInfo;
	me.setEnabled(true);
	
	map.getContainer().appendChild(container);
	return container;
}


/**
 * 设置控件的格式
 */
GRulerControl.prototype.setButtonStyle_ = function(button) {
	button.style.backgroundImage = "url(" + this.BACKGROUND_IMAGE_ + ")";
	button.style.font = "small Arial";
	button.style.border = "1px solid #888888";
	button.style.padding = "4px";
	button.style.textAlign = "right";
	button.style.cursor = "pointer";
}

/**
 * 用恰当的格式表示距离
 */
GRulerControl.prototype.formatDistance = function(len) {
	var me = this;
	
	len = Math.round(len);
	if (len <= 1000) {
		return len + " " + me.METER_;
	} else if (len <= 1000000) {
		return len / 1000 + " " + me.KILOMETER_;
	}
	return Math.round(len / 1000) + " " + me.KILOMETER_;
}

/**
 * 返回控件的默认位置
 */
GRulerControl.prototype.getDefaultPosition = function() {
	if (1 == this.map_.getMapTypes().length) {
		return new GControlPosition(G_ANCHOR_TOP_RIGHT, new GSize(7, 8));
	}
	else {
		return new GControlPosition(G_ANCHOR_TOP_RIGHT, new GSize(7, 28));
	}
}

/**
 * 返回控件是否已启用
 */
GRulerControl.prototype.isEnabled = function() {
	return this.enabled_;
}

/**
 * 设置控件的“启用/禁用"状态
 */
GRulerControl.prototype.setEnabled = function(value) {
	var me = this;
	if (value == me.enabled_)
		return;
	me.enabled_ = value;
	
	if (me.enabled_) {
		me.mapClickHandle_ = GEvent.addListener(me.map_, "click", me.onMapClick_);
		me.txtInfo_.style.display = "block";
		me.btnReset_.style.display = "inline";
		me.updateDistance_();
	} else {
		GEvent.removeListener(me.mapClickHandle_);
		me.txtInfo_.style.display = "none";
		me.btnReset_.style.display = "none";
	}
}

GRulerControl.prototype.setEsosoControl = function(esoso) {
	this.esoso_ = esoso;
}

/**
 * 事件处理函数：当用户单击地图时，要在该位置添加一个标注
 */
GRulerControl.prototype.onMapClick_ = function(marker, point) {
	var me = this.rulerControl_;
	
	//如果用户单击的是标注，不在这里处理
	if (marker)
		return;

	//创建标注，并添加到链表中
	var newIcon = new EwMapIcon();
	newIcon.image = _mStaticPath + "point.png";
	newIcon.iconSize = new GSize(12, 12);
	newIcon.iconAnchor = new GPoint(6, 6);
	newIcon.shadow = "";

	var center = (me.esoso_.ieVersion > 7) ? me.esoso_.getMouseLatLng() : point;	//GMap API对IE8支持不好，单击的point位置不正确
	var newMarker = new GMarker(center, {icon : newIcon, draggable: true, clickable : true, title : me.POINT_TITLE_});

	var pos = me.tail_.prev_;
	newMarker.prev_ = pos;
	newMarker.next_ = pos.next_;
	pos.next_.prev_ = newMarker;
	pos.next_ = newMarker;

	//为标注添加事件处理函数：拖拽标注时要更新连接线段和距离
	GEvent.addListener(newMarker, "dragend",
		function() {
			me.map_.closeInfoWindow();
			me.updateSegments_(newMarker);
			me.updateDistance_();
		}
	);

	//为标注添加事件处理函数
	GEvent.addListener(newMarker, "click",
		function() {
			if (window.clickTimer) {
				window.clearTimeout(clickTimer);
			}

			rulerControl = me;
			clickObject = newMarker;
			clickTimer = window.setTimeout("removePoint();", 120);
		}
	);

	GEvent.addListener(newMarker, "dblclick", finish);
	
	function finish() {
		if (window.clickTimer) {
			window.clearTimeout(clickTimer);
		}
		clickTimer = null;

		var len = me.getDistance();
		window.alert(me.formatDistance(len));
		me.reset();
	}
	
	//将创建的标注添加到地图中
	me.map_.addOverlay(newMarker);

	if (newMarker.prev_ != me.head_) {
		//如果这不是第一个标注，则创建连接到上一个标注的线段，并显示在地图中
		var segment = [newMarker.prev_.getPoint(), center];
		newMarker.segPrev_ = new GPolyline(segment);
		newMarker.prev_.segNext_ = newMarker.segPrev_;
		me.map_.addOverlay(newMarker.segPrev_);

		//更新距离显示
		me.updateDistance_();
	}
}

var clickTimer = null;
var clickObject = null;
var rulerControl = null;
function removePoint() {
	if (null != clickObject && null != rulerControl) {
		rulerControl.removePoint_(clickObject);
		rulerControl.updateDistance_();
		
		clickObject = null;
		rulerControl = null;
		clickTimer = null;
	}
}

/**
 * 统计总距离，并显示在网页中
 */
GRulerControl.prototype.updateDistance_ = function() {
	var me = this;
	var len = me.getDistance();
	
	//结果显示在网页中
	me.txtInfo_.innerHTML = me.formatDistance(len);
}

/**
 * 遍历链表，统计总距离
 */
GRulerControl.prototype.getDistance = function() {
	var me = this;
	var len = 0;
	
	//周游链表，累计相邻两个标注间的距离
	for (var m = me.head_; m != me.tail_; m = m.next_) {
		if (m.prev_ && m.prev_.getPoint)
			len += m.prev_.getPoint().distanceFrom(m.getPoint());
	}
	return len;
}

/**
 * 清除所有标注，初始化链表
 */
GRulerControl.prototype.reset = function() {
	var me = this;
	
	for (var m = me.head_.next_; m != me.tail_; m = m.next_) {
		me.map_.removeOverlay(m);
		if (m.segNext_)
			me.map_.removeOverlay(m.segNext_);
	}
	me.head_ = new Object();
	me.tail_ = new Object();
	me.head_.next_ = me.tail_;
	me.tail_.prev_ = me.head_;
	
	me.updateDistance_();
}


/**
 * 事件处理函数：当用户拖拽标注、标注坐标改变时被调用，这里要更新与该标注连接的线段
 * @param {GMarker} marker 被拖拽的标注
 */
GRulerControl.prototype.updateSegments_ = function(marker) {
	var me = this;
	var segment;
	
	//更新连接前驱的线段
	if (marker.segPrev_ && marker.prev_.getPoint) {
		//从地图上删除旧的线段
		me.map_.removeOverlay(marker.segPrev_);
		
		//根据标注的当前坐标构造新的线段，并更新链表结点的相关字段
		segment = [marker.prev_.getPoint(), marker.getPoint()];
		marker.segPrev_ = new GPolyline(segment);
		marker.prev_.segNext_ = marker.segPrev_;
		
		//将新线段添加到地图中
		me.map_.addOverlay(marker.segPrev_);
	}
	
	//更新连接后继的线段，与上类似
	if (marker.segNext_ && marker.next_.getPoint) {
		me.map_.removeOverlay(marker.segNext_);
		segment = [marker.getPoint(), marker.next_.getPoint()];
		marker.segNext_ = new GPolyline(segment);
		marker.next_.segPrev_ = marker.segNext_;
		me.map_.addOverlay(marker.segNext_);
	}
}


/**
 * 事件处理函数：当用户选择删除标注时被调用，这里要删除与该标注连接的线段
 * @param {GMarker} marker 要删除的标注
 */
GRulerControl.prototype.removePoint_ = function(marker) {
	var me = this;
	
	//先从地图上删除该标注
	me.map_.removeOverlay(marker);
	
	//对于中间结点，还要把它的前驱和后继用线段连接起来
	if (marker.prev_.getPoint && marker.next_.getPoint) {
		var segment = [marker.prev_.getPoint(), marker.next_.getPoint()];
		var polyline = new GPolyline(segment);
		marker.prev_.segNext_ = polyline;
		marker.next_.segPrev_ = polyline;
		me.map_.addOverlay(polyline);
	}
	marker.prev_.next_ = marker.next_;
	marker.next_.prev_ = marker.prev_;
	
	if (marker.segPrev_)
		me.map_.removeOverlay(marker.segPrev_);
	if (marker.segNext_)
		me.map_.removeOverlay(marker.segNext_);
}