const wu=require("./wuLib.js");
const path=require("path");
const fs=require("fs");
const {VM}=require('vm2');
const cssbeautify=require('cssbeautify');
const csstree=require('css-tree');
function doWxss(dir,cb){
	function GwxCfg(){}
	GwxCfg.prototype={$gwx(){}};
	for(let i=0;i<300;i++)GwxCfg.prototype["$gwx"+i]=GwxCfg.prototype.$gwx;
	let runList={},pureData={},result={},actualPure={},importCnt={},frameName="",onlyTest=true,blockCss=[];//custom block css file which won't be imported by others.(no extension name)
	function cssRebuild(data){//need to bind this as {cssFile:__name__} before call
		let cssFile;
		function statistic(data){
			function addStat(id){
				if(!importCnt[id])importCnt[id]=1,statistic(pureData[id]);
				else ++importCnt[id];
			}
			if(typeof data==="number")return addStat(data);
			for(let content of data)if(typeof content==="object"&&content[0]==2)addStat(content[1]);
		}
		function makeup(data){
			var isPure=typeof data==="number";
			if(onlyTest){
				statistic(data);
				if(!isPure){
					if(data.length==1&&data[0][0]==2)data=data[0][1];
					else return "";
				}
				if(!actualPure[data]&&!blockCss.includes(wu.changeExt(wu.toDir(cssFile,frameName),""))){
					console.log("Regard "+cssFile+" as pure import file.");
					actualPure[data]=cssFile;
				}
				return "";
			}
			let res=[],attach="";
			if(isPure&&actualPure[data]!=cssFile){
				if(actualPure[data])return '@import "'+wu.changeExt(wu.toDir(actualPure[data],cssFile),".wxss")+'";\n';
				else{
					res.push("/*! Import by _C["+data+"], whose real path we cannot found. */");
					attach="/*! Import end */";
				}
			}
			let exactData=isPure?pureData[data]:data;
			for(let content of exactData)
				if(typeof content==="object"){
					switch(content[0]){
					case 0://rpx
						res.push(content[1]+"rpx");
						break;
					case 1://add suffix, ignore it for restoring correct!
						break;
					case 2://import
						res.push(makeup(content[1]));
						break;
					}
				}else res.push(content);
			return res.join("")+attach;
		}
		return ()=>{
			cssFile=this.cssFile;
			if(!result[cssFile])result[cssFile]="";
			result[cssFile]+=makeup(data);
		};
	}
	function runVM(name,code){
		let wxAppCode={},handle={cssFile:name};
		let vm=new VM({sandbox:Object.assign(new GwxCfg(),{__wxAppCode__:wxAppCode,setCssToHead:cssRebuild.bind(handle)})});
		vm.run(code);
		for(let name in wxAppCode)if(name.endsWith(".wxss")){
			handle.cssFile=path.resolve(frameName,"..",name);
			wxAppCode[name]();
		}
	}
	function preRun(dir,frameFile,mainCode,files,cb){
		wu.addIO(cb);
		runList[path.resolve(dir,"./app.wxss")]=mainCode;
		for(let name of files)if(name!=frameFile){
			wu.get(name,code=>{
				code=code.slice(0,code.indexOf("\n"));
				if(code.indexOf("setCssToHead")>-1)runList[name]=code.slice(code.indexOf("setCssToHead"));
			});
		}
	}
	function runOnce(){
		for(let name in runList)runVM(name,runList[name]);
	}
	function transformCss(style){
		let ast=csstree.parse(style);
		csstree.walk(ast,function(node){
			if(node.type=="Comment"){//Change the comment because the limit of css-tree
				node.type="Raw";
				node.value="\n/*"+node.value+"*/\n";
			}
			if(node.type=="TypeSelector"){
				if(node.name.startsWith("wx-"))node.name=node.name.slice(3);
				else if(node.name=="body")node.name="page";
			}
			if(node.children){
				const removeType=["webkit","moz","ms","o"];
				let list={};
				node.children.each((son,item)=>{
					if(son.type=="Declaration"){
						if(list[son.property]){
							let a=item,b=list[son.property],x=son,y=b.data,ans=null;
							if(x.value.type=='Raw'&&x.value.value.startsWith("progid:DXImageTransform")){
								node.children.remove(a);
								ans=b;
							}else if(y.value.type=='Raw'&&y.value.value.startsWith("progid:DXImageTransform")){
								node.children.remove(b);
								ans=a;
							}else{
								let xValue=x.value.children&&x.value.children.head&&x.value.children.head.data.name,yValue=y.value.children&&y.value.children.head&&y.value.children.head.data.name;
								if(xValue&&yValue)for(let type of removeType)if(xValue==`-${type}-${yValue}`){
									node.children.remove(a);
									ans=b;
									break;
								}else if(yValue==`-${type}-${xValue}`){
									node.children.remove(b);
									ans=a;
									break;
								}else{
									let mValue=`-${type}-`;
									if(xValue.startsWith(mValue))xValue=xValue.slice(mValue.length);
									if(yValue.startsWith(mValue))yValue=yValue.slice(mValue.length);
								}
								if(ans===null)ans=b;
							}
							list[son.property]=ans;
						}else list[son.property]=item;
					}
				});
				for(let name in list)if(!name.startsWith('-'))
					for(let type of removeType){
						let fullName=`-${type}-${name}`;
						if(list[fullName]){
							node.children.remove(list[fullName]);
							delete list[fullName];
						}
					}
			}
		});
		return cssbeautify(csstree.generate(ast),{indent:'    ',autosemicolon:true});
	}
	wu.scanDirByExt(dir,".html",files=>{
		let frameFile="";
		if(fs.existsSync(path.resolve(dir,"page-frame.html")))
			frameFile=path.resolve(dir,"page-frame.html");
		else if(fs.existsSync(path.resolve(dir,"app-wxss.js")))
			frameFile=path.resolve(dir,"app-wxss.js");
		else if(fs.existsSync(path.resolve(dir,"page-frame.js")))
			frameFile=path.resolve(dir,"page-frame.js");
		else throw Error("page-frame-like file is not found in the package by auto.");
		wu.get(frameFile,code=>{
			code=code.slice(code.indexOf('var setCssToHead = function(file, _xcInvalid'));
			code=code.slice(code.indexOf('\nvar _C= ')+1);
			let oriCode=code;
			code=code.slice(0,code.indexOf('\n'));
			let vm=new VM({sandbox:{}});
			pureData=vm.run(code+"\n_C");
			let mainCode=oriCode.slice(oriCode.indexOf("setCssToHead"),oriCode.lastIndexOf(";var __pageFrameEndTime__"));
			console.log("Guess wxss(first turn)...");
			preRun(dir,frameFile,mainCode,files,()=>{
				frameName=frameFile;
				onlyTest=true;
				runOnce();
				onlyTest=false;
				console.log("Import count info: %j",importCnt);
				for(let id in pureData)if(!actualPure[id]){
					if(!importCnt[id])importCnt[id]=0;
					if(importCnt[id]<=1){
						console.log("Cannot find pure import for _C["+id+"] which is only imported "+importCnt[id]+" times. Let importing become copying.");
					}else{
						let newFile=path.resolve(dir,"__wuBaseWxss__/"+id+".wxss");
						console.log("Cannot find pure import for _C["+id+"], force to save it in ("+newFile+").");
						id=Number.parseInt(id);
						actualPure[id]=newFile;
						cssRebuild.call({cssFile:newFile},id)();
					}
				}
				console.log("Guess wxss(first turn) done.\nGenerate wxss(second turn)...");
				runOnce()
				console.log("Generate wxss(second turn) done.\nSave wxss...");
				for(let name in result)wu.save(wu.changeExt(name,".wxss"),transformCss(result[name]));
				let delFiles={};
				for(let name of files)delFiles[name]=8;
				delFiles[frameFile]=4;
				cb(delFiles);
			});
		});
	});
}
module.exports={doWxss:doWxss};
if(require.main===module){
    wu.commandExecute(doWxss,"Restore wxss files.\n\n<dirs...>\n\n<dirs...> restore wxss file from a unpacked directory(Have page-frame.html (or app-wxss.js) and other html file).");
}