package.json

@@ -5,8 +5,7 @@
   "main": "index.js",
   "scripts": {
     "back": "node src/back",
-    "front:debug": "parcel serve src/front/index.html",
-    "front:prod": "npx parcel build src/front/index.html --no-source-maps --no-autoinstall",
+    "front": "parcel serve src/front/index.html",
     "lint": "eslint ."
   },
   "keywords": [],

src/front/map.js

@@ -239,6 +239,7 @@ const createMap = target =>
 
     // Course on which the view is currently focused
     let focusedCourse = null;
+    const focusZoom = 17;
 
     const startFocus = courseId =>
     {
@@ -247,6 +248,7 @@ const createMap = target =>
             const course = simulInstance.courses[courseId];
             view.animate({
                 center: course.position,
+                zoom: focusZoom,
                 duration: 500,
             }, () => focusedCourse = courseId);
         }
@@ -292,6 +294,7 @@ const createMap = target =>
                 if (course.id === focusedCourse)
                 {
                     view.setCenter(course.position);
+                    // view.setZoom(focus);
                 }
             }
         }

src/tam/realtime.js

@@ -2,6 +2,18 @@ const tam = require('./sources/tam');
 const util = require('../util');
 const network = require('./network.json');
 
+/**
+ * Comparison function between two stop passings.
+ *
+ * @param passing1 First stop passing.
+ * @param passing2 Second stop passing.
+ * @return Negative value if passing1 is sooner than passing2, positive
+ * otherwise, zero if they occur at the same time.
+ */
+const passingCompare = ({arrivalTime: time1}, {arrivalTime: time2}) => (
+    time1 - time2
+);
+
 // Time at which the course data needs to be updated next
 let nextUpdate = null;
 
@@ -19,8 +31,9 @@ let currentCourses = null;
  * - `id`: Unique identifier for the course.
  * - `line`: Line number.
  * - `finalStop`: The final stop to which the course is headed.
- * - `nextPassings`: Next passings of the vehicle, as a dictionary associating
- *   each next stop to the passing timestamp.
+ * - `nextPassings`: Next passings of the vehicle, sorted by increasing
+ *   arrival time, containing both the stop identifier (`stopId`) and the
+ *   expected arrival timestamp (`arrivalTime`).
  *
  * @return Mapping from active course IDs to information about each course.
  */
@@ -56,9 +69,9 @@ const getCourses = () => new Promise((res, rej) =>
                 }
                 else
                 {
-                    for (let stopId of Object.keys(course.nextPassings))
+                    for (let passing of course.nextPassings)
                     {
-                        if (!(stopId in network.stops))
+                        if (!(passing.stopId in network.stops))
                         {
                             delete courses[courseId];
                             break;
@@ -67,6 +80,13 @@ const getCourses = () => new Promise((res, rej) =>
                 }
             }
 
+            // End of courses information stream. Sort next stops by increasing
+            // arrival time in each course then save result in memory cache
+            for (let course of Object.values(courses))
+            {
+                course.nextPassings.sort(passingCompare);
+            }
+
             currentCourses = courses;
             res(currentCourses);
             return;
@@ -93,12 +113,12 @@ const getCourses = () => new Promise((res, rej) =>
         {
             courses[id] = {
                 id, line, finalStop,
-                nextPassings: {[stopId]: arrivalTime},
+                nextPassings: [{stopId, arrivalTime}],
             };
         }
         else
         {
-            courses[id].nextPassings[stopId] = arrivalTime;
+            courses[id].nextPassings.push({stopId, arrivalTime});
         }
     });
 });

src/tam/simulation.js

@@ -4,170 +4,188 @@ const network = require('./network.json');
 
 const server = 'http://localhost:4321';
 
-class Course
+const arriveAtStop = (course, stop) =>
 {
-    constructor(data)
+    course.state = 'stopped';
+    course.currentStop = stop;
+    delete course.departureStop;
+    delete course.arrivalStop;
+    delete course.arrivalTime;
+    delete course.traveledDistance;
+    delete course.speed;
+};
+
+const moveToStop = (course, stop, arrivalTime) =>
+{
+    course.state = 'moving';
+    course.departureStop = course.currentStop;
+    course.arrivalStop = stop;
+    course.arrivalTime = arrivalTime;
+    course.traveledDistance = 0;
+    course.speed = 0;
+    delete course.currentStop;
+
+    const segment = `${course.departureStop}-${course.arrivalStop}`;
+
+    if (!(segment in network.segments))
     {
-        this.id = data.id;
-        this.passings = {};
-        this.state = null;
-
-        // Attributes for the `stopped` state
-        this.currentStop = null;
-
-        // Attributes for the `moving` state
-        this.departureStop = null;
-        this.arrivalStop = null;
-        this.arrivalTime = 0;
-        this.traveledDistance = 0;
-        this.speed = 0;
-
-        this.position = [0, 0];
-        this.angle = 0;
-
-        this.history = [];
-    }
-
-    get currentSegment()
-    {
-        if (this.state !== 'moving')
-        {
-            return undefined;
-        }
-
-        return network.segments[`${this.departureStop}-${this.arrivalStop}`];
-    }
-
-    updateData(data)
-    {
-        this.line = data.line;
-        this.finalStop = data.finalStop;
-        Object.assign(this.passings, data.nextPassings);
-
-        const now = Date.now();
-
-        // Make sure we’re on the right `stopped`/`moving` state
-        if (this.state === null)
-        {
-            let previousStop = null;
-            let departureTime = 0;
-
-            let nextStop = null;
-            let arrivalTime = Infinity;
-
-            for (let [stopId, time] of Object.entries(this.passings))
-            {
-                if (time > now && time < arrivalTime)
-                {
-                    nextStop = stopId;
-                    arrivalTime = time;
-                }
-
-                if (time < now && time > departureTime)
-                {
-                    previousStop = stopId;
-                    departureTime = time;
-                }
-            }
-
-            if (nextStop === null)
-            {
-                return false;
-            }
-
-            if (previousStop === null)
-            {
-                // Teleport to the first known stop
-                this.arriveToStop(nextStop);
+        // There is no segment between the two requested stops, jump
+        // directly to the arrival stop
+        arriveAtStop(course, course.arrivalStop);
     }
     else
     {
-                // Teleport to the first known segment
-                this.arriveToStop(previousStop);
-                this.moveToStop(nextStop, arrivalTime);
+        updateSpeed(course);
     }
-        }
-        else if (this.state === 'moving')
-        {
-            // Should already be at the next stop
-            if (this.passings[this.arrivalStop] <= now)
-            {
-                this.arriveToStop(this.arrivalStop);
-            }
-            // On the right track, update the arrival time
-            else
-            {
-                this.arrivalTime = this.passings[this.arrivalStop];
-            }
-        }
-        else // this.state === 'stopped'
-        {
-            // Try moving to the next stop
-            let nextStop = null;
-            let arrivalTime = Infinity;
+};
 
-            for (let [stopId, time] of Object.entries(this.passings))
+const getCurrentSegment = course =>
+{
+    if (course.state === 'stopped')
     {
-                if (time > now && time < arrivalTime)
-                {
-                    nextStop = stopId;
-                    arrivalTime = time;
-                }
+        return null;
     }
 
-            if (nextStop === null)
-            {
-                // This course is finished
-                return false;
-            }
+    return network.segments[`${course.departureStop}-${course.arrivalStop}`];
+};
 
-            if (nextStop !== this.currentStop)
-            {
-                this.moveToStop(nextStop, arrivalTime);
-            }
-        }
-
-        if (this.state === 'moving')
-        {
-            this.speed = this.computeTheoreticalSpeed();
-        }
-
-        return true;
-    }
-
-    tick(time)
-    {
-        if (this.state === null)
-        {
-            // Ignore uninitalized courses
-        }
-        else if (this.state === 'moving')
-        {
-            // Integrate current speed in travelled distance
-            const delta = this.speed * time;
-
-            const segment = this.currentSegment;
+const updateSpeed = course =>
+{
+    const segment = getCurrentSegment(course);
     const length = segment.points[segment.points.length - 1].distance;
-            this.traveledDistance += delta;
 
-            if (this.traveledDistance >= length)
+    const remainingTime = course.arrivalTime - Date.now();
+    const remainingDistance = length - course.traveledDistance;
+
+    if (remainingTime <= 0 || remainingDistance <= 0)
     {
-                this.arriveToStop(this.arrivalStop);
+        arriveAtStop(course, course.arrivalStop);
         return;
     }
 
+    course.speed = remainingDistance / remainingTime;
+};
+
+const updateFromTam = async (courses) =>
+{
+    const currentCourses = (await axios.get(`${server}/courses`)).data;
+
+    for (let [id, course] of Object.entries(currentCourses))
+    {
+        // Find out the next stop, ignoring the ones that are in the past
+        let nextStop = null;
+        let arrivalTime = null;
+
+        for (let {stopId, arrivalTime: time} of course.nextPassings)
+        {
+            if (time > Date.now())
+            {
+                nextStop = stopId;
+                arrivalTime = time;
+                break;
+            }
+        }
+
+        if (nextStop === null)
+        {
+            continue;
+        }
+
+        // Update an existing course
+        if (id in courses)
+        {
+            const prev = courses[id];
+
+            if (prev.state === 'stopped')
+            {
+                if (prev.currentStop !== nextStop)
+                {
+                    // Start traveling from the current stop to the next
+                    moveToStop(prev, nextStop, arrivalTime);
+                }
+            }
+            else
+            {
+                // Update the ETA if we’re still headed to the same stop
+                if (prev.arrivalStop === nextStop)
+                {
+                    prev.arrivalTime = arrivalTime;
+                    updateSpeed(prev);
+                }
+                // Otherwise, we missed a stop, try to go directly to the
+                // next segment
+                else
+                {
+                    arriveAtStop(prev, prev.arrivalStop);
+                    moveToStop(prev, nextStop, arrivalTime);
+                }
+            }
+        }
+        // Create a new course
+        else
+        {
+            courses[id] = {
+                id,
+                line: course.line,
+                finalStop: course.finalStop,
+                position: [0, 0],
+                angle: 0,
+            };
+
+            arriveAtStop(courses[id], nextStop);
+        }
+    }
+
+    // Remove stale courses
+    for (let id of Object.keys(courses))
+    {
+        if (!(id in currentCourses))
+        {
+            delete courses[id];
+        }
+    }
+};
+
+const updatePositions = (courses, time) =>
+{
+    for (let [id, course] of Object.entries(courses))
+    {
+        if (course.state === 'moving')
+        {
+            // Increase the travelled distance respective to the current speed
+            const delta = course.speed * time;
+
+            const segment = getCurrentSegment(course);
+            const length = segment.points[segment.points.length - 1].distance;
+
+            if (course.traveledDistance + delta >= length)
+            {
+                course.traveledDistance = length;
+            }
+            else
+            {
+                course.traveledDistance += delta;
+            }
+
             // Recompute updated position
-            const departureStop = network.stops[this.departureStop];
-            const arrivalStop = network.stops[this.arrivalStop];
+            const departureStop = network.stops[course.departureStop];
+            const arrivalStop = network.stops[course.arrivalStop];
             const nextNodeIndex = segment.points.findIndex(
-                ({distance}) => distance >= this.traveledDistance);
+                ({distance}) => distance >= course.traveledDistance);
 
             if (nextNodeIndex === 0)
             {
-                this.position = turf.toMercator([
-                    departureStop.lon,
-                    departureStop.lat
-                ]);
+                course.position = {
+                    lat: departureStop.lat,
+                    lon: departureStop.lon
+                };
+            }
+            else if (nextNodeIndex === -1)
+            {
+                course.position = {
+                    lat: arrivalStop.lat,
+                    lon: arrivalStop.lon
+                };
             }
             else
             {
@@ -184,161 +202,33 @@ class Course
                     nextNode.lat
                 ]);
 
-                const curLength = this.traveledDistance
+                const curLength = course.traveledDistance
                     - previousNode.distance;
                 const totalLength = nextNode.distance
                     - previousNode.distance;
                 const t = curLength / totalLength;
 
-                this.position = [
+                course.position = [
                     t * nextPoint[0] + (1 - t) * previousPoint[0],
                     t * nextPoint[1] + (1 - t) * previousPoint[1],
                 ];
 
-                this.angle = Math.atan2(
+                course.angle = Math.atan2(
                     previousPoint[1] - nextPoint[1],
                     nextPoint[0] - previousPoint[0],
                 );
             }
         }
-        else // this.state === 'stopped'
+        else
         {
-            const currentNode = network.stops[this.currentStop];
+            const currentNode = network.stops[course.currentStop];
 
-            this.position = turf.toMercator([
+            course.position = turf.toMercator([
                 currentNode.lon,
                 currentNode.lat
             ]);
         }
     }
-
-    /**
-     * Transition this course to a state where it has arrived to a stop.
-     *
-     * @param stop Identifier for the stop to which the course arrives.
-     */
-    arriveToStop(stop)
-    {
-        this.state = 'stopped';
-        this.currentStop = stop;
-        this.position = turf.toMercator([
-            network.stops[this.currentStop].lon,
-            network.stops[this.currentStop].lat,
-        ]);
-        this.history.push(['arriveToStop', stop]);
-    }
-
-    /**
-     * Transition this course to a state where it is moving to a stop.
-     *
-     * @param stop Next stop for this course.
-     * @param arrivalTime Planned arrival time to that stop.
-     */
-    moveToStop(stop, arrivalTime)
-    {
-        if (!(`${this.currentStop}-${stop}` in network.segments))
-        {
-            console.warn(`Course ${this.id} is cannot go from stop
-${this.currentStop} to stop ${stop}. Teleporting to ${stop}`);
-            this.arriveToStop(stop);
-            return;
-        }
-
-        this.state = 'moving';
-        this.departureStop = this.currentStop;
-        this.arrivalStop = stop;
-        this.arrivalTime = arrivalTime;
-        this.traveledDistance = 0;
-        this.speed = 0;
-        this.position = turf.toMercator([
-            network.stops[this.departureStop].lon,
-            network.stops[this.departureStop].lat,
-        ]);
-        this.history.push(['moveToStop', stop, arrivalTime]);
-
-        console.info(`Course ${this.id} leaving stop ${this.currentStop} \
-with initial speed ${this.computeTheoreticalSpeed() * 3600} km/h`);
-    }
-
-    /**
-     * Compute the speed that needs to be maintained to arrive on time.
-     */
-    computeTheoreticalSpeed()
-    {
-        if (this.state !== 'moving')
-        {
-            return 0;
-        }
-
-        const segment = this.currentSegment;
-        const length = segment.points[segment.points.length - 1].distance;
-
-        const remainingTime = this.arrivalTime - Date.now();
-        const remainingDistance = length - this.traveledDistance;
-
-        if (remainingDistance <= 0)
-        {
-            return 0;
-        }
-        else if (remainingTime <= 0)
-        {
-            // We’re late, go to maximum speed
-            return 50 / 3600; // 50 km/h
-        }
-        else
-        {
-            return remainingDistance / remainingTime;
-        }
-    }
-}
-
-const updateData = async (courses) =>
-{
-    const dataset = (await axios.get(`${server}/courses`)).data;
-
-    // Update or create new courses
-    for (let [id, data] of Object.entries(dataset))
-    {
-        if (id in courses)
-        {
-            if (!courses[id].updateData(data))
-            {
-                console.info(`Course ${id} is finished.`);
-                delete courses[id];
-            }
-        }
-        else
-        {
-            const newCourse = new Course(data);
-
-            if (!newCourse.updateData(data))
-            {
-                console.info(`Ignoring course ${id} which is outdated.`);
-            }
-            else
-            {
-                console.info(`Course ${id} starting.`);
-                courses[id] = newCourse;
-            }
-        }
-    }
-
-    // Remove stale courses
-    for (let id of Object.keys(courses))
-    {
-        if (!(id in dataset))
-        {
-            delete courses[id];
-        }
-    }
-};
-
-const tick = (courses, time) =>
-{
-    for (let course of Object.values(courses))
-    {
-        course.tick(time);
-    }
 };
 
 const start = () =>
@@ -354,12 +244,12 @@ const start = () =>
         if (lastUpdate === null || lastUpdate + 5000 <= now)
         {
             lastUpdate = now;
-            updateData(courses);
+            updateFromTam(courses);
         }
 
         const time = lastFrame === null ? 0 : now - lastFrame;
         lastFrame = now;
-        tick(courses, time);
+        updatePositions(courses, time);
     };
 
     return {courses, update};