move implementation to internal/ directory (#828)

internal/client/status/viewmodel/bytesprogresshistory.go

@@ -0,0 +1,49 @@
+package viewmodel
+
+import "time"
+
+type byteProgressMeasurement struct {
+	time time.Time
+	val  uint64
+}
+
+type bytesProgressHistory struct {
+	last        *byteProgressMeasurement // pointer as poor man's optional
+	changeCount int
+	lastChange  time.Time
+}
+
+func (p *bytesProgressHistory) Update(currentVal uint64) (bytesPerSecondAvg int64, changeCount int) {
+
+	if p.last == nil {
+		p.last = &byteProgressMeasurement{
+			time: time.Now(),
+			val:  currentVal,
+		}
+		return 0, 0
+	}
+
+	if p.last.val != currentVal {
+		p.changeCount++
+		p.lastChange = time.Now()
+	}
+
+	if time.Since(p.lastChange) > 3*time.Second {
+		p.last = nil
+		return 0, 0
+	}
+
+	var deltaV int64
+	if currentVal >= p.last.val {
+		deltaV = int64(currentVal - p.last.val)
+	} else {
+		deltaV = -int64(p.last.val - currentVal)
+	}
+	deltaT := time.Since(p.last.time)
+	rate := float64(deltaV) / deltaT.Seconds()
+
+	p.last.time = time.Now()
+	p.last.val = currentVal
+
+	return int64(rate), p.changeCount
+}