Demo: serve only the featured trip

The synthetic commute/errand world around the fictional centre is gone;
the demo dataset is exactly the embedded road trip, so the map holds
only the trip corridor and the KPIs describe the trip itself. README
GIF re-recorded accordingly.

Author: Greg

docs/demo.gif

@@ -5,14 +5,13 @@ import (
 	_ "embed"
 	"encoding/json"
 	"math"
-	"math/rand"
 	"sort"
 	"strconv"
 	"time"
 )
 
-// demoStore generates deterministic synthetic data around a fictional area so
-// the app runs and renders with no database. No real locations are used.
+// demoStore serves the embedded featured road trip so the app runs and
+// renders with no database.
 type demoStore struct {
 	drives   []demoDrive
 	charges  []demoCharge
@@ -79,100 +78,11 @@ type demoTrip struct {
 	} `json:"charges"`
 }
 
-// Centre of the synthetic world (a neutral land point used only for demo
-// geometry, not a real address).
-const demoLat, demoLon = 50.06, 19.94
-
-type demoPlace struct {
-	name     string
-	lat, lng float64
-}
-
+// The demo dataset is exactly the embedded featured trip — nothing else, so
+// the map holds only the trip's corridor.
 func newDemoStore(units string) *demoStore {
-	rng := rand.New(rand.NewSource(42))
 	s := &demoStore{units: units}
-	now := time.Now()
-
-	home := demoPlace{"Home", demoLat, demoLon}
-	work := demoPlace{"Work", demoLat + 0.05, demoLon + 0.08}
-	gym := demoPlace{"Gym", demoLat + 0.02, demoLon - 0.06}
-	lake := demoPlace{"Lakeside", demoLat - 0.4, demoLon + 0.55}
-	hills := demoPlace{"Hillcrest", demoLat + 0.5, demoLon - 0.45}
-	superNorth := demoPlace{"Supercharger Northgate", demoLat + 0.24, demoLon + 0.3}
-	hotel := demoPlace{"Riverside Hotel", lake.lat + 0.01, lake.lng + 0.01}
-
-	nextDrive, nextCharge := 1000, 2000
-	addDrive := func(day int, hour int, from, to demoPlace) {
-		start := now.AddDate(0, 0, -day).Truncate(time.Hour).Add(time.Duration(hour) * time.Hour)
-		coords := wander(from.lng, from.lat, to.lng, to.lat, 24, rng)
-		km := pathKm(coords)
-		durMin := int(km / (40 + rng.Float64()*30) * 60)
-		if durMin < 8 {
-			durMin = 8
-		}
-		speedMax := 0.0
-		for _, c := range coords {
-			if c[2] > speedMax {
-				speedMax = c[2]
-			}
-		}
-		s0 := 45 + rng.Intn(50)
-		s1 := s0 - int(km*0.18)
-		if s1 < 5 {
-			s1 = 5
-		}
-		s.drives = append(s.drives, demoDrive{
-			id: nextDrive, start: start, km: round1(km), durMin: durMin,
-			speedMax: math.Round(speedMax), from: from.name, to: to.name,
-			s0: s0, s1: s1, kwh: round1(km * 0.16), coords: coords,
-		})
-		nextDrive++
-	}
-	addCharge := func(day, hour int, p demoPlace, category string, kwh float64, durMin int) {
-		start := now.AddDate(0, 0, -day).Truncate(time.Hour).Add(time.Duration(hour) * time.Hour)
-		s0 := 18 + rng.Intn(40)
-		s1 := s0 + int(kwh/75*100)
-		if s1 > 100 {
-			s1 = 100
-		}
-		peakKw := 11.0
-		if category == "supercharger" {
-			peakKw = math.Round(120 + rng.Float64()*70)
-		}
-		title := p.name
-		if category == "home" {
-			title = p.name
-		} else if category == "destination" {
-			title = p.name + " (destination)"
-		}
-		s.charges = append(s.charges, demoCharge{
-			id: nextCharge, start: start, kwh: round1(kwh), durMin: durMin,
-			s0: s0, s1: s1, peakKw: peakKw, category: category, title: title,
-			pt: []float64{p.lng, p.lat},
-		})
-		nextCharge++
-	}
-
-	// Commutes and errands over ~90 days, home charging every few days.
-	spots := []demoPlace{work, gym, superNorth}
-	for day := 2; day < 90; day += 2 {
-		to := spots[rng.Intn(2)]
-		addDrive(day, 8, home, to)
-		addDrive(day, 17, to, home)
-		if day%6 == 0 {
-			addCharge(day, 20, home, "home", 12+rng.Float64()*38, 90+rng.Intn(300))
-		}
-	}
-	// A few longer weekend trips with supercharger and destination stops.
-	for _, day := range []int{7, 21, 49, 77} {
-		addDrive(day, 9, home, superNorth)
-		addCharge(day, 10, superNorth, "supercharger", 30+rng.Float64()*25, 18+rng.Intn(18))
-		addDrive(day, 11, superNorth, lake)
-		addCharge(day, 19, hotel, "destination", 35+rng.Float64()*15, 480)
-		addDrive(day-1, 10, lake, hills)
-		addDrive(day-1, 16, hills, home)
-	}
-	s.addFeaturedTrip(now)
+	s.addFeaturedTrip(time.Now())
 	return s
 }
 
@@ -404,37 +314,4 @@ func (s *demoStore) Detail(ctx context.Context, id string) (*Detail, error) {
 	return nil, nil
 }
 
-// wander draws a jittered polyline from start to end with a plausible speed
-// profile: slow near the endpoints, faster mid-route.
-func wander(x0, y0, x1, y1 float64, n int, rng *rand.Rand) [][]float64 {
-	out := make([][]float64, 0, n+1)
-	base := 60 + rng.Float64()*60
-	for i := 0; i <= n; i++ {
-		t := float64(i) / float64(n)
-		jx := (rng.Float64() - 0.5) * 0.01
-		jy := (rng.Float64() - 0.5) * 0.01
-		ramp := math.Min(1, math.Min(float64(i), float64(n-i))/4)
-		speed := math.Round(25 + (base-25)*ramp*(0.75+0.25*math.Sin(float64(i)*0.7)))
-		out = append(out, []float64{x0 + (x1-x0)*t + jx, y0 + (y1-y0)*t + jy, speed})
-	}
-	return out
-}
-
 func round1(f float64) float64 { return math.Round(f*10) / 10 }
-
-func pathKm(c [][]float64) float64 {
-	var km float64
-	for i := 1; i < len(c); i++ {
-		km += haversine(c[i-1][1], c[i-1][0], c[i][1], c[i][0])
-	}
-	return km
-}
-
-func haversine(lat1, lon1, lat2, lon2 float64) float64 {
-	const R = 6371.0
-	dLat := (lat2 - lat1) * math.Pi / 180
-	dLon := (lon2 - lon1) * math.Pi / 180
-	a := math.Sin(dLat/2)*math.Sin(dLat/2) +
-		math.Cos(lat1*math.Pi/180)*math.Cos(lat2*math.Pi/180)*math.Sin(dLon/2)*math.Sin(dLon/2)
-	return R * 2 * math.Atan2(math.Sqrt(a), math.Sqrt(1-a))
-}