begin work on adding search to albums page

ui/browsingpane.go

@@ -0,0 +1,104 @@
+package ui
+
+import (
+	"context"
+	"time"
+
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/container"
+	"fyne.io/fyne/v2/widget"
+)
+
+type Page interface {
+	fyne.Widget
+}
+
+type Searchable interface {
+	OnSearched(string)
+}
+
+type BrowsingPane struct {
+	widget.BaseWidget
+
+	searchBar           *searchField
+	searchTimer         time.Timer
+	pendingSearch       bool
+	cancelPendingSearch context.CancelFunc
+	curPage             Page
+
+	container    *fyne.Container
+	pageContaner *fyne.Container
+}
+
+type blankPage struct {
+	widget.Separator
+}
+
+type searchField struct {
+	widget.Entry
+	height float32
+}
+
+func NewSearchField() *searchField {
+	sf := &searchField{}
+	sf.ExtendBaseWidget(sf)
+	// this is a bit hacky
+	sf.height = widget.NewEntry().MinSize().Height
+	sf.PlaceHolder = "Search"
+	return sf
+}
+
+func (s *searchField) MinSize() fyne.Size {
+	return fyne.NewSize(200, s.height)
+}
+
+func NewBrowsingPane() *BrowsingPane {
+	b := &BrowsingPane{}
+	b.ExtendBaseWidget(b)
+	b.searchBar = NewSearchField()
+	b.searchBar.OnChanged = b.onSearchTextChanged
+	b.curPage = &blankPage{}
+	b.searchTimer = *time.NewTimer(0)
+	b.pageContaner = container.NewMax(b.curPage)
+	b.container = container.NewBorder(container.NewHBox(b.searchBar), nil, nil, nil, b.pageContaner)
+	return b
+}
+
+func (b *BrowsingPane) SetPage(p Page) {
+	if b.cancelPendingSearch != nil {
+		b.cancelPendingSearch()
+		b.cancelPendingSearch = nil
+	}
+	b.curPage = p
+	b.pageContaner.Objects[0] = p
+	b.Refresh()
+}
+
+func (b *BrowsingPane) onSearchTextChanged(text string) {
+	b.searchTimer.Reset(300 * time.Millisecond)
+	if s, ok := b.curPage.(Searchable); ok {
+		s.OnSearched(text)
+	}
+	if !b.pendingSearch {
+		/*
+			ctx, cancel := context.WithCancel(context.Background())
+			b.cancelPendingSearch = cancel
+			b.pendingSearch = true
+			go func(ctx context.Context) {
+				select {
+				case <-ctx.Done():
+					b.pendingSearch = false
+				case <-b.searchTimer.C:
+					if s, ok := b.curPage.(Searchable); ok {
+						s.OnSearched(b.searchBar.Text)
+					}
+					b.pendingSearch = false
+				}
+			}(ctx)
+		*/
+	}
+}
+
+func (b *BrowsingPane) CreateRenderer() fyne.WidgetRenderer {
+	return widget.NewSimpleRenderer(b.container)
+}