From e0b348b9416f42289230c6178ff30cca4b99660a Mon Sep 17 00:00:00 2001
From: Timothy Warren <twarren@nabancard.com>
Date: Tue, 30 Mar 2021 14:42:59 -0400
Subject: [PATCH] Make PageUp and PageDown work

---
 editor/editor.go | 43 +++++++++++++++++++++++++++++--------------
 editor/keymap.go |  6 ++++++
 2 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/editor/editor.go b/editor/editor.go
index db14733..7dede1d 100644
--- a/editor/editor.go
+++ b/editor/editor.go
@@ -31,7 +31,7 @@ func (e *editor) ProcessKeypress() bool {
 	var runes []rune
 
 	// for ch, size := terminal.ReadKey(); size != 0; ch, size = terminal.ReadKey() {
-	for i := 0; i < 3; i++ {
+	for i := 0; i < 4; i++ {
 		ch, size := terminal.ReadKey()
 		if size == 0 {
 			break
@@ -45,9 +45,14 @@ func (e *editor) ProcessKeypress() bool {
 		}
 
 		runes = append(runes, ch)
+
+		// Break early for arrow keys
+		if i == 2 && ch >= 'A' && ch <= 'D' {
+			break
+		}
 	}
 
-	terminal.Write("%v", runes)
+	// terminal.Write("%v", runes)
 	str := string(runes)
 	runes = runes[:0]
 
@@ -56,7 +61,7 @@ func (e *editor) ProcessKeypress() bool {
 		code := strings.TrimPrefix(str, terminal.EscPrefix)
 
 		switch code {
-		case KeyArrowUp, KeyArrowDown, KeyArrowLeft, KeyArrowRight:
+		case KeyArrowUp, KeyArrowDown, KeyArrowLeft, KeyArrowRight, KeyPageUp, KeyPageDown:
 			e.moveCursor(code)
 			runes = runes[:0]
 			return true
@@ -69,17 +74,27 @@ func (e *editor) ProcessKeypress() bool {
 	return true
 }
 
-func (e *editor) moveCursor (rawKey string) {
-	key := keyMap[rawKey]
-
+func (e *editor) moveCursor (key string) {
 	switch key {
-	case keyLeft:
-		e.cursor.x -= 1
-	case keyRight:
-		e.cursor.x += 1
-	case keyUp:
-		e.cursor.y -= 1
-	case keyDown:
-		e.cursor.y += 1
+	case KeyArrowLeft:
+		if e.cursor.x != 0 {
+			e.cursor.x -= 1
+		}
+	case KeyArrowRight:
+		if e.cursor.x != e.screen.Cols-1 {
+			e.cursor.x += 1
+		}
+	case KeyArrowUp:
+		if e.cursor.y != 0 {
+			e.cursor.y -= 1
+		}
+	case KeyArrowDown:
+		if e.cursor.y != e.screen.Rows-1 {
+			e.cursor.y += 1
+		}
+	case KeyPageUp:
+		e.cursor.y = 0
+	case KeyPageDown:
+		e.cursor.y = e.screen.Rows
 	}
 }
\ No newline at end of file
diff --git a/editor/keymap.go b/editor/keymap.go
index a8676b0..74d7495 100644
--- a/editor/keymap.go
+++ b/editor/keymap.go
@@ -9,6 +9,8 @@ const(
 	KeyArrowDown = "B"
 	KeyArrowRight = "C"
 	KeyArrowLeft = "D"
+	KeyPageUp = "5~"
+	KeyPageDown = "6~"
 )
 
 // ----------------------------------------------------------------------------
@@ -20,6 +22,8 @@ const (
 	keyDown = '↓'
 	keyLeft = '←'
 	keyRight = '→'
+	keyPageUp = '⭱'
+	keyPageDown = '⭳'
 )
 
 var keyMap = map[string]rune{
@@ -27,4 +31,6 @@ var keyMap = map[string]rune{
 	KeyArrowDown: keyDown,
 	KeyArrowLeft: keyLeft,
 	KeyArrowRight: keyRight,
+	KeyPageUp: keyPageUp,
+	KeyPageDown: keyPageDown,
 }
\ No newline at end of file