From cb3289bfb26bc142488ff8d4a15fbd47e960600f Mon Sep 17 00:00:00 2001
From: Matthias Wirth <matthias.wirth@gmail.com>
Date: Thu, 28 Nov 2019 17:15:59 +0100
Subject: [PATCH] temporary trails via config option

---
 html/config.js      |  4 ++++
 html/defaults.js    |  4 ++++
 html/planeObject.js | 25 ++++++++++++++++++++++++-
 html/script.js      | 14 ++++++++++----
 4 files changed, 42 insertions(+), 5 deletions(-)

diff --git a/html/config.js b/html/config.js
index 0d1770c..735f7a3 100644
--- a/html/config.js
+++ b/html/config.js
@@ -163,6 +163,10 @@ BingMapsAPIKey = null;
 // enable/disable mouseover/hover aircraft information
 //enableMouseover = true;
 
+// enable/disable temporary aircraft trails
+//tempTrails = false;
+//tempTrailsTimeout = 90;
+
 // Columns that have a // in front of them are shown.
 HideCols = [
 	"#icao",
diff --git a/html/defaults.js b/html/defaults.js
index 67bb029..67a964b 100644
--- a/html/defaults.js
+++ b/html/defaults.js
@@ -193,6 +193,10 @@ var mlatTimeout = 30;
 // enable/disable mouseover/hover aircraft information
 var enableMouseover = true;
 
+// enable/disable temporary aircraft trails
+var tempTrails = false;
+var tempTrailsTimeout = 90;
+
 // Columns that have a // in front of them are shown.
 var HideCols = [
 	"#icao",
diff --git a/html/planeObject.js b/html/planeObject.js
index de5ed35..39beb47 100644
--- a/html/planeObject.js
+++ b/html/planeObject.js
@@ -275,6 +275,7 @@ PlaneObject.prototype.updateTrack = function(now, last) {
 			altitude: this.alt_rounded,
 			alt_real: this.altitude,
 			speed: this.speed,
+			ts: now,
 		};
 		this.track_linesegs.push(newseg);
 		this.history_size ++;
@@ -348,7 +349,9 @@ PlaneObject.prototype.updateTrack = function(now, last) {
 			this.track_linesegs.push({ fixed: new ol.geom.LineString([projPrev]),
 				feature: null,
 				altitude: 0,
-				estimated: true });
+				estimated: true,
+				ts: this.prev_time,
+			});
 			this.history_size += 2;
 		} else {
 			// Keep appending to the existing dashed line; keep every point
@@ -370,6 +373,7 @@ PlaneObject.prototype.updateTrack = function(now, last) {
 			altitude: this.prev_alt_rounded,
 			alt_real: this.prev_alt,
 			speed: this.prev_speed,
+			ts: this.prev_time,
 		});
 		this.history_size += 2;
 
@@ -393,6 +397,7 @@ PlaneObject.prototype.updateTrack = function(now, last) {
 
 	if (
 		this.prev_alt_rounded !== lastseg.altitude
+		|| tempTrails
 		//lastseg.ground != on_ground
 		//|| (!on_ground && isNaN(alt_change))
 		//|| (alt_change > 700)
@@ -413,6 +418,7 @@ PlaneObject.prototype.updateTrack = function(now, last) {
 			alt_real: this.prev_alt,
 			speed: this.prev_speed,
 			ground: on_ground,
+			ts: this.prev_time,
 		});
 
 		this.history_size += 2;
@@ -1370,3 +1376,20 @@ PlaneObject.prototype.getAircraftData = function() {
 			console.log(this.icao + ': Database load error: ' + textStatus + ' at URL: ' + jqXHR.url);
 	}.bind(this));
 }
+
+
+PlaneObject.prototype.reapTrail = function() {
+	const oldSegs = this.track_linesegs;
+	this.track_linesegs = [];
+	this.history_size = 0;
+	for (var i in oldSegs) {
+		const seg = oldSegs[i];
+		if (seg.ts + tempTrailsTimeout > now) {
+			this.history_size += seg.fixed.getCoordinates().length;
+			this.track_linesegs.push(seg);
+		}
+	}
+	if (this.track_linesegs.length != oldSegs.length) {
+		this.remakeTrail();
+	}
+}
diff --git a/html/script.js b/html/script.js
index 6dd4c77..8492329 100644
--- a/html/script.js
+++ b/html/script.js
@@ -736,7 +736,6 @@ function parse_history() {
 		for (var i in PlanesOrdered)
 			setupPlane(PlanesOrdered[i].icao,PlanesOrdered[i]);
 	}
-	try {
 
 	PositionHistoryBuffer = null;
 	console.timeEnd("Loaded aircraft tracks from History");
@@ -749,6 +748,10 @@ function parse_history() {
 
 	// Setup our timer to poll from the server.
 	window.setInterval(reaper, 60000);
+	if (tempTrails) {
+		window.setInterval(trailReaper, 10000);
+		trailReaper(now);
+	}
 	if (enable_pf_data) {
 		window.setInterval(fetchPfData, RefreshInterval*10.314);
 	}
@@ -766,9 +769,6 @@ function parse_history() {
 	if (localStorage['sidebar_visible'] == "false")
 		toggleSidebarVisibility();
 
-	} catch (error) {
-		alert(error.message);
-	}
 }
 
 // Make a LineString with 'points'-number points
@@ -2821,3 +2821,9 @@ function findPlanes(query, byIcao, byCallsign, byReg) {
 		console.log("No match found for query: " + query);
 	}
 }
+
+function trailReaper() {
+	for (var i in PlanesOrdered) {
+		PlanesOrdered[i].reapTrail();
+	}
+}