var fs = require('fs');
var nodePath = require('path');

var dir = __dirname + '/../';

var read = function(path){
	return fs.readFileSync(nodePath.join(dir, path)).toString();
}

var write = function(path, data){
	return fs.writeFileSync(nodePath.join(dir, path), data);
}

var rm = require('./fsrm');

var mk = function(path){
	path = nodePath.join(dir, path);
  if(fs.existsSync(path)){ return }
	fs.mkdirSync(path);
}

var rn = function(path, newPath){
	path = nodePath.join(dir, path)
	newPath = nodePath.join(dir, newPath)
  if(fs.existsSync(newPath)){ return }
	fs.renameSync(path, newPath);
}

var between = function(text, start, end){
	end = end || start;
	var s = text.indexOf(start);
	if(s < 0){ return ''}
	s += start.length;
	var e = text.indexOf(end, s);
	if(e < 0){ return '' }
	var code = text.slice(s, e);
	return {s: s, t: code, e: e};
}

var next = function(start, end){
	end = end || start;
	if(!next.text){
		next.text = start;
		return;
	}
	var code = between(next.text, start, end);
	next.text = next.text.slice(code.e + end.length);
	return code.t;
}

var path = function(p){
	var code = next(',', ')');
	var path;
	try{path = eval(code);
	}catch(e){console.log("fail", e)};
	if(!path){ return }
	if('.js' !== path.slice(-3)){
		path += '.js';
	}
	return nodePath.join('./'+(p||'src'), path);
}

var undent = function(code, n){
	var regex = /\n\t\t/g;
	if(1 === n){
		regex = /\n\t/g;
	}
	return code.replace(regex, '\n');
}

;(function(){

	var arg = process.argv[2] || 'gun';

	var g;
	if('gun' === arg){
		g = 'gun';
		rn('./src','./old_src');
		mk('./src');
		mk('./src/polyfill');
		mk('./src/adapters');
	} else {
		g = arg;
		rn('./'+arg,'./old_'+arg);
		mk('./'+arg);
	}
	console.log("unbuild:", arg+'.js')

	var f = read(arg+'.js');
	var code = next(f);


	code = next("/* UNBUILD */");
	
	if('gun' === g){
		write('src/polyfill/unbuild.js', undent(code, 1));
		arg = '';
	}

	(function recurse(c){
		code = next(";USE(function(module){", "})(USE");
		if(!code){ return }
		var file = path(arg);
		if(!file){ return }
		code = code.replace(/\bUSE\(/g, 'require(');
		code = undent(code);
		var rcode;
		try{ rcode = read('old_'+file); } catch(e){}
		// console.log(rcode);
		if(rcode != code){
			console.log("unbuild:","update",file);
		}
		code = ";(function(){\n"+code+"\n}());";
		write(file, code);
		recurse();
	}());
	if('gun' === g){
		rm('./old_src');
	}else{
		rm('./old_'+g);
	}
	
}());