kanban

commit 1abf2bffd7ed608e2f20799d0e6acba24e4132fd
parent c2dca132470300c0b68dcf1a2e365d767918d9d5
Author: Jack Mordaunt <jackmordaunt@gmail.com>
Date:   Sat, 27 Feb 2021 16:02:50 +0800

ref: sync project state upon reassignment

This change allows for naive Project assignment, where any extra setup (like allocating panels for the Project stages) occurs automatically. The alternative is to force Project assignment to go through a getter method. Naturally a getter method could be circumvented by a naive assignment and cause bugs.

Diffstat:
M
cmd/kanban/ui.go
 | 
48
+++++++++++++++++++++++++++++++++++++-----------

1 file changed, 37 insertions(+), 11 deletions(-)
diff --git a/cmd/kanban/ui.go b/cmd/kanban/ui.go
@@ -60,6 +60,10 @@ type UI struct {
 	// nil value implies no active project.
 	Project *kanban.Project
 
+	// previous is used to detect when the active project has change in order to
+	// run init code like allocating panels.
+	previous *kanban.Project
+
 	// Panels render the active Project stages.
 	// Shares the same lifetime as the active project.
 	Panels []*control.Panel
@@ -102,6 +106,9 @@ func (ui *UI) Loop() error {
 		return fmt.Errorf("loading projects: %v", err)
 	}
 	ui.Projects = projects
+	if len(ui.Projects) > 0 {
+		ui.Project = &ui.Projects[0]
+	}
 	for event := range events {
 		switch event := (event).(type) {
 		case system.DestroyEvent:
@@ -132,6 +139,9 @@ func (ui *UI) Shutdown() error {
 // and others are for the devs.
 // Currently errors are just printed; not great for windowed applications.
 func (ui *UI) Update(gtx C) {
+	if ui.Project != ui.previous {
+		ui.sync()
+	}
 	for _, event := range gtx.Events(ui) {
 		if k, ok := event.(key.Event); ok {
 			switch k.Name {
@@ -184,18 +194,7 @@ func (ui *UI) Update(gtx C) {
 		if ui.Project == nil || ui.Project.Name != p {
 			project, ok := ui.Projects.Find(p)
 			if ok {
-				ui.Clear()
 				ui.Project = project
-				ui.Panels = func() (panels []*control.Panel) {
-					for _, s := range project.Stages {
-						panels = append(panels, &control.Panel{
-							Label:     s.Name,
-							Color:     color.NRGBA{R: 100, B: 100, G: 200, A: 255},
-							Thickness: unit.Dp(50),
-						})
-					}
-					return panels
-				}()
 			}
 		}
 	}
@@ -540,3 +539,30 @@ func (ui *UI) Save() {
 		log.Printf("error: saving projects: %v", err)
 	}
 }
+
+// sync any project dependent state when a project has changed.
+func (ui *UI) sync() {
+	ui.Clear()
+	ui.previous = ui.Project
+	// Allocate one panel per stage.
+	ui.Panels = func() (panels []*control.Panel) {
+		for ii, s := range ui.Project.Stages {
+			panels = append(panels, &control.Panel{
+				Label: s.Name,
+				// First 4 panel colors are hardcoded.
+				// Where to store UI state? Ideally not alongside the stage, since it's
+				// purely a UI concern.
+				// If we have more than four stages, just wrap the colors.
+				// @improve
+				Color: []color.NRGBA{
+					{R: 100, B: 100, G: 200, A: 255},
+					{R: 100, B: 200, G: 100, A: 255},
+					{R: 200, B: 100, G: 100, A: 255},
+					{R: 200, B: 200, G: 100, A: 255},
+				}[ii%4],
+				Thickness: unit.Dp(50),
+			})
+		}
+		return panels
+	}()
+}