/*
 * email: bigablecat@hotmail.com
 * Date: 2018-04-14
 */

/**
 * @param zTreeId the ztree id used to get the ztree object
 * @param searchField selector of your input for fuzzy search
 * @param isHighLight whether highlight the match words, default true
 * @param isExpand whether to expand the node, default false
 * 
 * @returns
 */	
 function fuzzySearch(zTreeId, searchField, isHighLight, isExpand){
	let zTreeObj = $.fn.zTree.getZTreeObj(zTreeId);//get the ztree object by ztree id
	if(!zTreeObj){
		alert("fail to get ztree object");
	}
	let nameKey = zTreeObj.setting.data.key.name; //get the key of the node name
	isHighLight = isHighLight===false?false:true;//default true, only use false to disable highlight
	isExpand = isExpand?true:false; // not to expand in default
	zTreeObj.setting.view.nameIsHTML = isHighLight; //allow use html in node name for highlight use

	let metaChar = '[\\[\\]\\\\\^\\$\\.\\|\\?\\*\\+\\(\\)]'; //js meta characters
	let rexMeta = new RegExp(metaChar, 'gi');//regular expression to match meta characters
	
	// keywords filter function 
	function ztreeFilter(zTreeObj,_keywords,callBackFunc) {
		if(!_keywords){
			_keywords =''; //default blank for _keywords 
		}
		
		// function to find the matching node
		function filterFunc(node) {
			if(node && node.oldname && node.oldname.length>0){
				node[nameKey] = node.oldname; //recover oldname of the node if exist
			}
			zTreeObj.updateNode(node); //update node to for modifications take effect
			if (_keywords.length == 0) {
				//return true to show all nodes if the keyword is blank
				zTreeObj.showNode(node);
				zTreeObj.expandNode(node,isExpand);
				return true;
			}
			//transform node name and keywords to lowercase
			if (node[nameKey] && node[nameKey].toLowerCase().indexOf(_keywords.toLowerCase())!=-1) {
				if(isHighLight){ //highlight process
					//a new variable 'newKeywords' created to store the keywords information 
					//keep the parameter '_keywords' as initial and it will be used in next node
					//process the meta characters in _keywords thus the RegExp can be correctly used in str.replace
					let newKeywords = _keywords.replace(rexMeta,function(matchStr){
						//add escape character before meta characters
						return '\\' + matchStr;
					});
					node.oldname = node[nameKey]; //store the old name  
					let rexGlobal = new RegExp(newKeywords, 'gi');//'g' for global,'i' for ignore case
					//use replace(RegExp,replacement) since replace(/substr/g,replacement) cannot be used here
					node[nameKey] = node.oldname.replace(rexGlobal, function(originalText){
						//highlight the matching words in node name
						let highLightText =
							'<span style="color: whitesmoke;background-color: darkred;">'
							+ originalText
							+'</span>';
						return 	highLightText;					
					});
					zTreeObj.updateNode(node); //update node for modifications take effect
				}
				zTreeObj.showNode(node);//show node with matching keywords
				return true; //return true and show this node
			}
			
			zTreeObj.hideNode(node); // hide node that not matched
			return false; //return false for node not matched
		}

		let nodesShow = zTreeObj.getNodesByFilter(filterFunc); //get all nodes that would be shown
		processShowNodes(nodesShow, _keywords);//nodes should be reprocessed to show correctly
	}
	
	/**
	 * reprocess of nodes before showing
	 */
	function processShowNodes(nodesShow,_keywords){
		if(nodesShow && nodesShow.length>0){
			//process the ancient nodes if _keywords is not blank
			if(_keywords.length>0){ 
				$.each(nodesShow, function(n,obj){
					let pathOfOne = obj.getPath();//get all the ancient nodes including current node
					if(pathOfOne && pathOfOne.length>0){ 
						//i < pathOfOne.length-1 process every node in path except self
						for(let i=0;i<pathOfOne.length-1;i++){
							zTreeObj.showNode(pathOfOne[i]); //show node 
							zTreeObj.expandNode(pathOfOne[i],true); //expand node
						}
					}
				});	
			}else{ //show all nodes when _keywords is blank and expand the root nodes
				let rootNodes = zTreeObj.getNodesByParam('level','0');//get all root nodes
				$.each(rootNodes,function(n,obj){
					zTreeObj.expandNode(obj,true); //expand all root nodes
				});
			}
		}
	}
	
	//listen to change in input element
	$(searchField).bind('input propertychange', function() {
		let _keywords = $(this).val();
		searchNodeLazy(_keywords); //call lazy load
	});

	let timeoutId = null;
  let lastKeyword = '';
	// excute lazy load once after input change, the last pending task will be cancled  
	function searchNodeLazy(_keywords) {
		if (timeoutId) { 
			//clear pending task
			clearTimeout(timeoutId);
		}
		timeoutId = setTimeout(function() {
      if (lastKeyword === _keywords) {
        return;
      }
			ztreeFilter(zTreeObj,_keywords); //lazy load ztreeFilter function 
			// $(searchField).focus();//focus input field again after filtering
      lastKeyword = _keywords;
		}, 500);
	}
}