refactor(tracker/gioui): bind Alerts to Model during Layout

tracker/gioui/alerts.go

@@ -0,0 +1,98 @@
+package gioui
+
+import (
+	"image"
+	"image/color"
+	"time"
+
+	"gioui.org/layout"
+	"gioui.org/op"
+	"gioui.org/op/clip"
+	"gioui.org/op/paint"
+	"github.com/vsariola/sointu/tracker"
+)
+
+type (
+	AlertsState struct {
+		prevUpdate time.Time
+	}
+
+	AlertStyle struct {
+		Bg   color.NRGBA
+		Text LabelStyle
+	}
+
+	AlertStyles struct {
+		Info    AlertStyle
+		Warning AlertStyle
+		Error   AlertStyle
+		Margin  layout.Inset
+		Inset   layout.Inset
+	}
+
+	AlertsWidget struct {
+		Theme *Theme
+		Model *tracker.Alerts
+		State *AlertsState
+	}
+)
+
+func NewAlertsState() *AlertsState {
+	return &AlertsState{prevUpdate: time.Now()}
+}
+
+func Alerts(m *tracker.Alerts, th *Theme, st *AlertsState) AlertsWidget {
+	return AlertsWidget{
+		Theme: th,
+		Model: m,
+		State: st,
+	}
+}
+
+func (a *AlertsWidget) Layout(gtx C) D {
+	now := time.Now()
+	if a.Model.Update(now.Sub(a.State.prevUpdate)) {
+		gtx.Execute(op.InvalidateCmd{At: now.Add(50 * time.Millisecond)})
+	}
+	a.State.prevUpdate = now
+
+	var totalY float64 = float64(gtx.Dp(38))
+	for _, alert := range a.Model.Iterate {
+		var alertStyle *AlertStyle
+		switch alert.Priority {
+		case tracker.Warning:
+			alertStyle = &a.Theme.Alert.Warning
+		case tracker.Error:
+			alertStyle = &a.Theme.Alert.Error
+		default:
+			alertStyle = &a.Theme.Alert.Info
+		}
+		bgWidget := func(gtx C) D {
+			paint.FillShape(gtx.Ops, alertStyle.Bg, clip.Rect{
+				Max: gtx.Constraints.Min,
+			}.Op())
+			return D{Size: gtx.Constraints.Min}
+		}
+		labelStyle := Label(a.Theme, &alertStyle.Text, alert.Message)
+		a.Theme.Alert.Margin.Layout(gtx, func(gtx C) D {
+			return layout.S.Layout(gtx, func(gtx C) D {
+				defer op.Offset(image.Point{}).Push(gtx.Ops).Pop()
+				gtx.Constraints.Min.X = gtx.Constraints.Max.X
+				recording := op.Record(gtx.Ops)
+				dims := layout.Stack{Alignment: layout.Center}.Layout(gtx,
+					layout.Expanded(bgWidget),
+					layout.Stacked(func(gtx C) D {
+						return a.Theme.Alert.Inset.Layout(gtx, labelStyle.Layout)
+					}),
+				)
+				macro := recording.Stop()
+				delta := float64(dims.Size.Y + gtx.Dp(a.Theme.Alert.Margin.Bottom))
+				op.Offset(image.Point{0, int(-totalY*alert.FadeLevel + delta*(1-alert.FadeLevel))}).Add((gtx.Ops))
+				totalY += delta
+				macro.Add(gtx.Ops)
+				return dims
+			})
+		})
+	}
+	return D{}
+}