Improve list browsing

CHANGELOG

@@ -1,2 +1,5 @@
+0.1.1:
+- Improve list browsing
+
 0.1.0:
 - Initial release

audio.go

@@ -154,7 +154,7 @@ func nextTrack() {
 	if mainBufferCursor-1 < len(mainBufferFiles)-1 {
 		mainBufferCursor++
 
-		audioFile, err := openFile(path.Join(mainBufferDirectory, mainBufferFiles[mainBufferCursor-1].File.Name()))
+		audioFile, err := openFile(path.Join(mainBufferDirectory, selectedEntry().File.Name()))
 		if err != nil {
 			return
 		}

gui.go

@@ -26,10 +26,10 @@ var (
 	topstatusbuf    *cview.TextView
 	bottomstatusbuf *cview.TextView
 
-	mainBufferText      string
 	mainBufferFiles     []*LibraryEntry
 	mainBufferCursor    int
 	mainBufferDirectory string
+	mainBufferOrigin    int
 
 	seekStart, seekEnd     int
 	volumeStart, volumeEnd int
@@ -86,14 +86,6 @@ func browseFolder(browse string) {
 
 	mainBufferFiles = scanFolder(browse)
 
-	var b strings.Builder
-	b.WriteString("..")
-	for _, entry := range mainBufferFiles {
-		b.WriteRune('\n')
-
-		b.WriteString(entry.String())
-	}
-
 	if len(mainBufferFiles) > 0 {
 		mainBufferCursor = 1
 	} else {
@@ -101,8 +93,6 @@ func browseFolder(browse string) {
 	}
 
 	mainBufferDirectory = browse
-	mainBufferText = b.String()
-
 	app.QueueUpdateDraw(updateMain)
 }
 
@@ -135,28 +125,34 @@ func updateMain() {
 	var printed int
 
 	var newBufferText string
-	if mainBufferCursor == 0 {
-		newBufferText += "[::r]"
-	}
-	var line string
-	if mainBufferDirectory == "/" {
-		line = "./"
-	} else {
-		line = "../"
-	}
-	newBufferText += line
-	for i := len(line); i < screenWidth-2; i++ {
-		newBufferText += " "
-	}
-	if mainBufferCursor == 0 {
-		newBufferText += "[-]"
-	}
-	if len(mainBufferFiles) > 0 {
-		newBufferText += "\n"
+	if mainBufferOrigin == 0 {
+		if mainBufferCursor == 0 {
+			newBufferText += "[::r]"
+		}
+		var line string
+		if mainBufferDirectory == "/" {
+			line = "./"
+		} else {
+			line = "../"
+		}
+		newBufferText += line
+		for i := len(line); i < screenWidth-2; i++ {
+			newBufferText += " "
+		}
+		if mainBufferCursor == 0 {
+			newBufferText += "[-]"
+		}
+		printed++
 	}
-	printed++
-
 	for i, entry := range mainBufferFiles {
+		if i < mainBufferOrigin-1 || i-mainBufferOrigin-1 > mainBufHeight-1 {
+			continue
+		}
+
+		if printed > 0 {
+			newBufferText += "\n"
+		}
+
 		if i == mainBufferCursor-1 {
 			newBufferText += "[::r]"
 		}
@@ -175,13 +171,9 @@ func updateMain() {
 		}
 
 		printed++
-		if printed == mainBufHeight {
+		if printed == mainBufHeight-2 {
 			break
 		}
-
-		if i < len(mainBufferFiles)-1 {
-			newBufferText += "\n"
-		}
 	}
 
 	mainbuf.SetText(newBufferText)
@@ -314,17 +306,16 @@ func selectTrack() {
 		browseFolder(path.Join(mainBufferDirectory, ".."))
 		return
 	}
-
 	nextStreamer = nil
 	nextFormat = beep.Format{}
 
-	selected := mainBufferFiles[mainBufferCursor-1]
-	if selected.File.IsDir() {
-		browseFolder(path.Join(mainBufferDirectory, path.Base(selected.File.Name())))
+	entry := selectedEntry()
+	if entry.File.IsDir() {
+		browseFolder(path.Join(mainBufferDirectory, path.Base(entry.File.Name())))
 		return
 	}
 
-	audioFile, err := openFile(path.Join(mainBufferDirectory, mainBufferFiles[mainBufferCursor-1].File.Name()))
+	audioFile, err := openFile(path.Join(mainBufferDirectory, entry.File.Name()))
 	if err != nil {
 		statusText = err.Error()
 		go func() {

gui_key.go

@@ -43,34 +43,28 @@ func handleKeyPress(event *tcell.EventKey) *tcell.EventKey {
 		updateStatus()
 		return nil
 	case 'j':
-		if mainBufferCursor < len(mainBufferFiles) {
-			mainBufferCursor++
-		}
-		updateMain()
+		listNext()
 		return nil
 	case 'k':
-		if mainBufferCursor > 0 {
-			mainBufferCursor--
-		}
-		updateMain()
+		listPrevious()
 		return nil
 	case 'p':
 		if mainBufferCursor > 1 {
-			if mainBufferFiles[mainBufferCursor-2].File.IsDir() {
+			if offsetEntry(-1).File.IsDir() {
 				return nil
 			}
 
-			mainBufferCursor--
+			listPrevious()
 			go selectTrack()
 		}
 		return nil
 	case 'n':
 		if mainBufferCursor < len(mainBufferFiles) {
-			if mainBufferFiles[mainBufferCursor].File.IsDir() {
+			if offsetEntry(1).File.IsDir() {
 				return nil
 			}
 
-			mainBufferCursor++
+			listNext()
 			go selectTrack()
 		}
 		return nil
@@ -89,16 +83,44 @@ func handleKeyPress(event *tcell.EventKey) *tcell.EventKey {
 	case tcell.KeyEnter:
 		go selectTrack()
 		return nil
+	case tcell.KeyDown:
+		listNext()
+		return nil
 	case tcell.KeyUp:
-		if mainBufferCursor > 0 {
-			mainBufferCursor--
+		listPrevious()
+		return nil
+	case tcell.KeyPgDn:
+		numEntries := len(mainBufferFiles)
+
+		if mainBufferOrigin >= numEntries-(mainBufHeight-1) {
+			mainBufferCursor = numEntries
+
+			updateMain()
+			return nil
 		}
+
+		mainBufferOrigin += (mainBufHeight - 1) - 2
+		if mainBufferOrigin > (numEntries-(mainBufHeight-1))+2 {
+			mainBufferOrigin = (numEntries - (mainBufHeight - 1)) + 2
+		}
+		mainBufferCursor = mainBufferOrigin
+
 		updateMain()
 		return nil
-	case tcell.KeyDown:
-		if mainBufferCursor < len(mainBufferFiles) {
-			mainBufferCursor++
+	case tcell.KeyPgUp:
+		if mainBufferOrigin == 0 {
+			mainBufferCursor = 0
+
+			updateMain()
+			return nil
+		}
+
+		mainBufferOrigin -= (mainBufHeight - 1) - 2
+		if mainBufferOrigin < 0 {
+			mainBufferOrigin = 0
 		}
+		mainBufferCursor = mainBufferOrigin
+
 		updateMain()
 		return nil
 	}

gui_list.go

@@ -0,0 +1,29 @@
+package main
+
+func listPrevious() {
+	if mainBufferOrigin > 0 && mainBufferCursor == mainBufferOrigin {
+		mainBufferOrigin--
+	}
+	if mainBufferCursor > 0 {
+		mainBufferCursor--
+	}
+	updateMain()
+}
+
+func listNext() {
+	if mainBufferCursor < len(mainBufferFiles) {
+		mainBufferCursor++
+		if mainBufferCursor-mainBufferOrigin > mainBufHeight-3 {
+			mainBufferOrigin++
+		}
+	}
+	updateMain()
+}
+
+func selectedEntry() *LibraryEntry {
+	return mainBufferFiles[mainBufferCursor-1]
+}
+
+func offsetEntry(offset int) *LibraryEntry {
+	return mainBufferFiles[(mainBufferCursor-1)+offset]
+}

gui_mouse.go

@@ -16,7 +16,7 @@ func handleMouse(event *cview.EventMouse) *cview.EventMouse {
 		if mouseY > 0 && mouseY < mainBufHeight+1 {
 			// TODO Delay playing while cursor is moved
 			if mouseY-1 < len(mainBufferFiles)+1 {
-				mainBufferCursor = mouseY - 1
+				mainBufferCursor = mainBufferOrigin + (mouseY - 1)
 				go selectTrack()
 			}
 			return nil