Finish kilo chapter 4, text viewer

editor/draw.go

@@ -4,6 +4,7 @@ package editor
 import (
 	"fmt"
 	"strings"
+	"time"
 	"timshome.page/gilo/terminal"
 )
 
@@ -21,6 +22,7 @@ func (e *editor) RefreshScreen() {
 
 	e.drawRows(ab)
 	e.drawStatusBar(ab)
+	e.drawMessageBar(ab)
 
 	ab.append(terminal.MoveCursor(e.renderX - e.offset.x, e.cursor.y - e.offset.y))
 
@@ -151,3 +153,13 @@ func (e *editor) drawStatusBar(ab *buffer) {
 
 	ab.append(terminal.ResetColor)
 }
+
+func (e *editor) drawMessageBar(ab *buffer) {
+	ab.append("\r\n")
+	ab.append(terminal.ClearLine)
+
+	msg := truncateString(e.status.message, e.screen.Cols)
+	if len(msg) > 0 && time.Since(e.status.created).Seconds() < 5.0 {
+		ab.append(msg)
+	}
+}

editor/editor.go

@@ -1,6 +1,8 @@
 package editor
 
 import (
+	"fmt"
+	"time"
 	"timshome.page/gilo/terminal"
 )
 
@@ -13,29 +15,40 @@ type point struct {
 	y int
 }
 
+type statusMsg struct {
+	message string
+	created time.Time
+}
+
 type editor struct {
 	screen *terminal.Screen
 	cursor *point
 	offset *point
 	document *document
+	status *statusMsg
 	renderX int
 }
 
 func New() *editor {
 	screen := terminal.Size()
 
-	// Subtract rows for status bar and prompt
-	screen.Rows -= 1
+	// Subtract rows for status bar and message bar/prompt
+	screen.Rows -= 2
 
 	cursor := &point { 0, 0 }
 	offset := &point { 0, 0 }
 	document := newDocument()
+	status := &statusMsg{
+		"",
+		time.Now(),
+	}
 
 	return &editor{
 		screen,
 		cursor,
 		offset,
 		document,
+		status,
 		0,
 	}
 }
@@ -44,6 +57,13 @@ func (e *editor) Open(filename string) {
 	e.document.open(filename)
 }
 
+func (e *editor) SetStatusMessage(template string, a ...interface{}) {
+	e.status = &statusMsg {
+		fmt.Sprintf(template, a...),
+		time.Now(),
+	}
+}
+
 func (e *editor) ProcessKeypress() bool {
 	var str string
 
@@ -110,7 +130,7 @@ func (e *editor) moveCursor (key string) {
 			e.cursor.y -= 1
 		}
 	case keyDown:
-		if e.cursor.y < (e.document.rowCount() - 1) {
+		if e.cursor.y < e.document.rowCount() {
 			e.cursor.y += 1
 		}
 	case keyPageUp:

gilo.go

@@ -29,6 +29,8 @@ func main() {
 		e.Open(os.Args[1])
 	}
 
+	e.SetStatusMessage("HELP: Ctrl-Q = quit");
+
 	// The input loop
 	for {
 		e.RefreshScreen()