From 8bd23a575f2d28a34b0af7a20edaf11f63a8060f Mon Sep 17 00:00:00 2001
From: JT Olds <hello@jtolds.com>
Date: Tue, 31 May 2016 16:02:42 -0600
Subject: [PATCH] Add CursorPageUp and CursorPageDown actions

---
 cmd/micro/bindings.go | 22 +++++++++++++++++++++
 cmd/micro/cursor.go   | 45 ++++++++++++++++++++++++++-----------------
 2 files changed, 49 insertions(+), 18 deletions(-)

diff --git a/cmd/micro/bindings.go b/cmd/micro/bindings.go
index c450ce19..7e6f7081 100644
--- a/cmd/micro/bindings.go
+++ b/cmd/micro/bindings.go
@@ -19,6 +19,8 @@ var helpBinding string
 var bindingActions = map[string]func(*View) bool{
 	"CursorUp":            (*View).CursorUp,
 	"CursorDown":          (*View).CursorDown,
+	"CursorPageUp":        (*View).CursorPageUp,
+	"CursorPageDown":      (*View).CursorPageDown,
 	"CursorLeft":          (*View).CursorLeft,
 	"CursorRight":         (*View).CursorRight,
 	"CursorStart":         (*View).CursorStart,
@@ -884,6 +886,26 @@ func (v *View) PageDown() bool {
 	return false
 }
 
+// CursorPageUp places the cursor a page up
+func (v *View) CursorPageUp() bool {
+	if v.Cursor.HasSelection() {
+		v.Cursor.SetLoc(v.Cursor.CurSelection[0])
+		v.Cursor.ResetSelection()
+	}
+	v.Cursor.UpN(v.height)
+	return true
+}
+
+// CursorPageDown places the cursor a page up
+func (v *View) CursorPageDown() bool {
+	if v.Cursor.HasSelection() {
+		v.Cursor.SetLoc(v.Cursor.CurSelection[1])
+		v.Cursor.ResetSelection()
+	}
+	v.Cursor.DownN(v.height)
+	return true
+}
+
 // HalfPageUp scrolls the view up half a page
 func (v *View) HalfPageUp() bool {
 	if v.Topline > v.height/2 {
diff --git a/cmd/micro/cursor.go b/cmd/micro/cursor.go
index d3a6176c..2284501a 100644
--- a/cmd/micro/cursor.go
+++ b/cmd/micro/cursor.go
@@ -276,30 +276,39 @@ func (c *Cursor) RuneUnder(x int) rune {
 	return line[x]
 }
 
+// UpN moves the cursor up N lines (if possible)
+func (c *Cursor) UpN(amount int) {
+	proposedY := c.Y - amount
+	if proposedY < 0 {
+		proposedY = 0
+	} else if proposedY >= c.buf.NumLines {
+		proposedY = c.buf.NumLines - 1
+	}
+	if proposedY == c.Y {
+		return
+	}
+
+	c.Y = proposedY
+	runes := []rune(c.buf.Lines[c.Y])
+	c.X = c.GetCharPosInLine(c.Y, c.LastVisualX)
+	if c.X > len(runes) {
+		c.X = len(runes)
+	}
+}
+
+// DownN moves the cursor down N lines (if possible)
+func (c *Cursor) DownN(amount int) {
+	c.UpN(-amount)
+}
+
 // Up moves the cursor up one line (if possible)
 func (c *Cursor) Up() {
-	if c.Y > 0 {
-		c.Y--
-
-		runes := []rune(c.buf.Lines[c.Y])
-		c.X = c.GetCharPosInLine(c.Y, c.LastVisualX)
-		if c.X > len(runes) {
-			c.X = len(runes)
-		}
-	}
+	c.UpN(1)
 }
 
 // Down moves the cursor down one line (if possible)
 func (c *Cursor) Down() {
-	if c.Y < c.buf.NumLines-1 {
-		c.Y++
-
-		runes := []rune(c.buf.Lines[c.Y])
-		c.X = c.GetCharPosInLine(c.Y, c.LastVisualX)
-		if c.X > len(runes) {
-			c.X = len(runes)
-		}
-	}
+	c.DownN(1)
 }
 
 // Left moves the cursor left one cell (if possible) or to the last line if it is at the beginning