From c57e57f5ba31db9b8d57f58ce98aab6eac9e48d7 Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Thu, 5 Jan 2017 23:43:39 +0100
Subject: changes: Diffing!

---
 modules/changes/changes.html | 59 ++++++++++++++++++++++++++++++++++--
 modules/changes/changes.js   | 72 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 128 insertions(+), 3 deletions(-)

diff --git a/modules/changes/changes.html b/modules/changes/changes.html
index 739cb28..a7cd439 100644
--- a/modules/changes/changes.html
+++ b/modules/changes/changes.html
@@ -44,6 +44,7 @@ function focusData(data){
 	if(!header.firstChild)header.appendChild(document.createTextNode(data.url));
 	else header.firstChild.nodeValue=data.url;
 	header.setAttribute("href",data.url);
+	document.getElementById("diffbox").innerHTML="";
 
 	var l=tbody.children,i;
 	for(i=l.length-1;i>=0;i--)tbody.removeChild(l[i]);
@@ -66,6 +67,22 @@ function focusData(data){
 		td.appendChild(document.createTextNode(s));
 		tr.appendChild(td);
 
+		td=document.createElement("td");
+		e=document.createElement("input");
+		e.setAttribute("type","radio");
+		e.setAttribute("name","diffold");
+		e.setAttribute("value",data.timeline[i][0]);
+		td.appendChild(e);
+		tr.appendChild(td);
+
+		td=document.createElement("td");
+		e=document.createElement("input");
+		e.setAttribute("type","radio");
+		e.setAttribute("name","diffnew");
+		e.setAttribute("value",data.timeline[i][0]);
+		td.appendChild(e);
+		tr.appendChild(td);
+
 		td=document.createElement("td");
 		e=document.createElement("a");
 		e.href="javascript:void(0)";
@@ -182,6 +199,30 @@ function addURLbutton(){
 	});
 }
 
+function doShowDiff(){
+	var oldradio=document.querySelector("input[name=diffold]:checked");
+	var newradio=document.querySelector("input[name=diffnew]:checked");
+	if(!oldradio||!newradio){
+		alert("Select two different records to perform a diff");
+		return;
+	}
+	var olddate=oldradio.value;
+	var newdate=newradio.value;
+	var url=document.getElementById("timelineheader").firstChild.nodeValue;
+	fetch("POST","/changes/diff",
+	      JSON.stringify({url:url,olddate:olddate,newdate:newdate}),
+	      function(status,body){
+		var diffbox;
+		if(status==200){
+			diffbox=document.getElementById("diffbox");
+			if(diffbox.firstChild)diffbox.removeChild(diffbox.firstChild);
+			diffbox.appendChild(document.createTextNode(body));
+		} else {
+			alert("Error: ("+status+") "+body);
+		}
+	});
+}
+
 function addURLkeypress(ev){
 	if(ev.keyCode==10||ev.keyCode==13)addURLbutton();
 }
@@ -251,8 +292,13 @@ h1{
 #timelinetbl td, #timelinetbl th{
 	border:1px #888 solid;
 }
-#timelinetbl td:nth-child(3){
+#timelinetbl td:nth-child(3), #timelinetbl td:nth-child(4){
+	text-align:center;
+}
+#timelinetbl td:nth-child(5){
 	font-size:10px;
+	padding-left:40px;
+	padding-right:10px;
 }
 
 tr.repeated{
@@ -285,9 +331,16 @@ tr.repeated{
 <div id="timelinecontainer">
 	<h2><a id="timelineheader"></a></h2>
 	<table id="timelinetbl">
-		<thead><tr><th>Date</th><th>Hash</th></tr></thead>
+		<thead><tr>
+			<th>Date</th>
+			<th>Hash</th>
+			<th>Old</th>
+			<th>New</th>
+		</tr></thead>
 		<tbody id="timelinetbody"></tbody>
-	</table>
+	</table> <br>
+	<input type="button" value="Show diff" onclick="doShowDiff();"> <br>
+	<pre id="diffbox"></pre>
 </div>
 </body>
 </html>
diff --git a/modules/changes/changes.js b/modules/changes/changes.js
index 7cbe7ee..8a0b3d9 100644
--- a/modules/changes/changes.js
+++ b/modules/changes/changes.js
@@ -5,6 +5,7 @@ var cmn=require("../$common.js"),
     crypto=require("crypto"),
     http=require("http"),
     https=require("https"),
+    fs=require("fs"),
     URL=require("url"),
     child_process=require("child_process");
 
@@ -376,4 +377,75 @@ module.exports=function(app,io,_moddir){
 		refreshURLs();
 		res.send();
 	});
+	app.post("/changes/diff",function(req,res){
+		var param;
+		try {param=JSON.parse(req.body);}
+		catch(e){
+			res.status(400);
+			res.send("Invalid JSON sent");
+			return;
+		}
+		var url=param.url;
+		var newdate=new Date(param.newdate);
+		var olddate=new Date(param.olddate);
+		if(!urls[url]){
+			res.status(404);
+			res.send("URL not found in watch list");
+			return;
+		}
+		if(newdate.getTime()==NaN||olddate.getTime()==NaN){
+			res.status(400);
+			res.send("Invalid time(s) sent");
+			return;
+		}
+		if(newdate.getTime()==olddate.getTime()){
+			res.status(400);
+			res.send("Please select different records to diff");
+			return;
+		}
+		var tl=urls[url].timeline;
+		var newi=-1,oldi=-1,i;
+		for(i=0;i<tl.length;i++){
+			if(tl[i][0].getTime()==newdate.getTime()){
+				newi=i;
+			}
+			if(tl[i][0].getTime()==olddate.getTime()){
+				oldi=i;
+			}
+		}
+		if(newi==-1||oldi==-1){
+			res.status(404);
+			res.send("Times not found in timeline for URL");
+			return;
+		}
+		//res.send(tl[newi][1]+"\n"+tl[oldi][1]+"\n");
+		fs.mkdtemp("/tmp/changes-diff-tmp-",function(err,folder){
+			if(err){
+				console.log(err);
+				res.status(500);
+				res.send();
+				return;
+			}
+			var counter=0;
+			var fscb=function(err){
+				if(err){
+					console.log(err);
+					res.status(500);
+					res.send();
+					return;
+				}
+				counter++;
+				if(counter<2)return;
+				var proc=child_process.spawn(
+					"diff",
+					[folder+"/old.html",folder+"/new.html"],
+					{stdio:[process.stdin,fs.openSync(folder+"/diff.txt","w"),process.stderr]});
+				proc.on("exit",function(code,signal){
+					fs.createReadStream(folder+"/diff.txt").pipe(res);
+				});
+			};
+			fs.writeFile(folder+"/old.html",tl[oldi][2],fscb);
+			fs.writeFile(folder+"/new.html",tl[newi][2],fscb);
+		});
+	});
 };
-- 
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