"use strict";

var cmn=require("../$common.js"),
    persist=require("node-persist"),
    crypto=require("crypto"),
    http=require("http"),
    https=require("https"),
    URL=require("url");

var moddir=null;

persist=persist.create({
	dir:"persist/changes",
	continuous:false,
	interval:false
});
persist.initSync();

//urls: map(url => URLobject)
//url: String
//URLobject: {url, timeline: [[Date, hash, contents]]}
var urls=persist.getItemSync("urls");
if(!urls){
	urls={};
	persist.setItemSync("urls",urls);
}


function URLobject(url){
	if(!(this instanceof URLobject))return new URLobject(url);
	this.url=url;
	this.timeline=[];
}

function fetch(method,url,data/*?*/,cb){
	var cbcalled=false;

	if(!cb){
		cb=data;
		data=undefined;
		if(!cb)throw new Error("No callback passed to fetch");
	}

	try {
		url=URL.parse(url);
	} catch(e){
		cb(-1,null);
		return;
	}

	var httpclass;
	switch(url.protocol){
		case "http:": httpclass=http; break;
		case "https:": httpclass=https; break;
		default:
			cb(-1,null);
			return;
	}

	url.method=method;

	var req=httpclass.request(url,function(res){
		var body="";
		res.on("data",function(data){
			body+=data;
		});
		res.on("end",function(){
			if(!cbcalled)cb(res.statusCode,body);
			cbcalled=true;
		});
		res.on("error",function(err){
			if(!cbcalled)cb(-1,err);
			cbcalled=true;
		});
	});
	req.on("error",function(err){
		if(!cbcalled)cb(-1,err);
		cbcalled=true;
	});
	if(data)req.write(data);
	req.end();
}

var refresh_persist_timeout=null;

function refreshURLs(){
	var hashes={};
	var i;
	var url;
	for(url in urls){
		console.log("Fetching <"+url+">");
		fetch("GET",url,function(url,status,body){
			console.log("Got <"+url+">; status = "+status);
			if(status==-1){
				hashes[url]=[new Date(),null,null];
			} else {
				var hash=crypto.createHash("sha256");
				hash.update(body);
				hashes[url]=[new Date(),hash.digest("hex"),body];
			}

			if(!urls[url]){
				console.log("WARNING: url <"+url+"> from hashes not found in urls!");
				return;
			}
			//var last=urls[url].timeline[urls[url].timeline.length-1];
			//if(last==undefined||hashes[url][1]==null||hashes[url][1]!=last[1]){
				urls[url].timeline.push(hashes[url]);
			//}

			if(refresh_persist_timeout!=null)clearTimeout(refresh_persist_timeout);
			refresh_persist_timeout=setTimeout(function(){
				persist.setItemSync("urls",urls);
				console.log("(persisted after refresh)")
				refresh_persist_timeout=null;
			},2000);
		}.bind(null,url));
	}
}


module.exports=function(app,io,_moddir){
	moddir=_moddir;
	app.all(["/changes","/changes/*"],cmn.authgen());
	app.get("/changes",function(req,res){
		res.sendFile(moddir+"/changes.html");
	});
	app.get("/changes/urls",function(req,res){
		var list=[];
		var url;
		for(url in urls)list.push(url);
		res.send(JSON.stringify(list));
	});
	app.get("/changes/url",function(req,res){
		var url=req.query.url;
		if(!urls[url]){
			res.status(404);
			res.send("URL not found in watch list");
			return;
		}
		res.send(JSON.stringify(urls[url]));
	});
	app.post("/changes/url",function(req,res){
		var url=req.body;
		urls[url]=new URLobject(url);
		persist.setItemSync("urls",urls);
		// refreshURLs();
		res.send();
	});
	app.delete("/changes/url",function(req,res){
		var url=req.body;
		if(!urls[url]){
			res.status(404);
			res.send("URL not found in watch list");
			return;
		}
		delete urls[url];
		persist.setItemSync("urls",urls);
		res.send();
	});
	app.delete("/changes/url/delete",function(req,res){
		var param;
		try {param=JSON.parse(req.body);}
		catch(e){
			res.status(400);
			res.send("Invalid JSON sent");
		}
		var url=param.url;
		var todate=new Date(param.todate);
		if(!urls[url]){
			res.status(404);
			res.send("URL not found in watch list");
			return;
		}
		if(todate.getTime()==NaN){
			res.status(400);
			res.send("Invalid time sent");
		}
		var tl=urls[url].timeline;
		var i;
		for(i=0;i<tl.length;i++){
			if(tl[i][0]<=todate){
				tl.splice(i,1);
				i--;
			}
		}
		res.status(200);
		res.send();
	});
	app.post("/changes/refresh",function(req,res){
		refreshURLs();
		res.send();
	});
};