Merge pull request #1 from freeart/cursor-movements

Cursor movements

lib/widgets/textarea.js

@@ -34,6 +34,9 @@ function Textarea(options) {
 
   this.screen._listenKeys(this);
 
+  this.offsetY = 0;
+  this.offsetX = 0;
+
   this.value = options.value || '';
 
   this.__updateCursor = this._updateCursor.bind(this);
@@ -69,15 +72,44 @@ Textarea.prototype.__proto__ = Input.prototype;
 
 Textarea.prototype.type = 'textarea';
 
+Textarea.prototype.getCursor = function(){
+  return {x: this.offsetX, y: this.offsetY};
+}
+
+Textarea.prototype.moveCursor = function(x, y){
+  var prevLine = (this._clines.length - 1) + this.offsetY;
+  let sync = false;
+  if (y <= 0 && y > (this._clines.length * -1)){
+    sync = this.offsetY !== y;
+    this.offsetY = y;
+  }
+  var currentLine = (this._clines.length - 1) + this.offsetY;
+  var currentText = this._clines[currentLine];
+
+  if (sync){
+    var prevText = this._clines[prevLine];
+    var positionFromBegin = this.strWidth(prevText) + this.offsetX;
+    x = (Math.max(0, this.strWidth(currentText) - positionFromBegin)) * -1;
+  }
+  if (x <= 0 && x >= (this.strWidth(currentText) * -1)){
+    this.offsetX = x;
+  }
+  this._updateCursor(true);
+
+  this.screen.render();
+}
+
 Textarea.prototype._updateCursor = function(get) {
   if (this.screen.focused !== this) {
     return;
   }
 
   var lpos = get ? this.lpos : this._getCoords();
+
   if (!lpos) return;
 
-  var last = this._clines[this._clines.length - 1]
+  const currentLine = (this._clines.length - 1) + this.offsetY
+  var currentText = this._clines[currentLine]
     , program = this.screen.program
     , line
     , cx
@@ -87,12 +119,12 @@ Textarea.prototype._updateCursor = function(get) {
   // and the last cline appears to always be empty from the
   // _typeScroll `+ '\n'` thing.
   // Maybe not necessary anymore?
-  if (last === '' && this.value[this.value.length - 1] !== '\n') {
-    last = this._clines[this._clines.length - 2] || '';
+  if (currentText === '' && this.value[this.value.length - 1] !== '\n') {
+    currentText = this._clines[currentLine - 1] || '';
   }
 
   line = Math.min(
-    this._clines.length - 1 - (this.childBase || 0),
+    currentLine - (this.childBase || 0),
     (lpos.yl - lpos.yi) - this.iheight - 1);
 
   // When calling clearValue() on a full textarea with a border, the first
@@ -101,7 +133,7 @@ Textarea.prototype._updateCursor = function(get) {
   line = Math.max(0, line);
 
   cy = lpos.yi + this.itop + line;
-  cx = lpos.xi + this.ileft + this.strWidth(last);
+  cx = this.offsetX + lpos.xi + this.ileft + this.strWidth(currentText);
 
   // XXX Not sure, but this may still sometimes
   // cause problems when leaving editor.
@@ -218,7 +250,20 @@ Textarea.prototype._listener = function(ch, key) {
   // TODO: Handle directional keys.
   if (key.name === 'left' || key.name === 'right'
       || key.name === 'up' || key.name === 'down') {
-    ;
+        var cursor = this.getCursor();
+
+        if (key.name === "left") {
+          cursor.x--;
+        } else if (key.name === "right") {
+          cursor.x++;
+        }
+        if (key.name === "up") {
+          cursor.y--;
+        } else if (key.name === "down") {
+          cursor.y++;
+        }
+
+        this.moveCursor(cursor.x, cursor.y);
   }
 
   if (this.options.keys && key.ctrl && key.name === 'e') {
@@ -239,12 +284,28 @@ Textarea.prototype._listener = function(ch, key) {
           this.value = this.value.slice(0, -1);
         }
       } else {
-        this.value = this.value.slice(0, -1);
+        if (this.offsetX === 0 && this.offsetY === 0){
+          this.value = this.value.slice(0, -1);
+        } else if (this.offsetX > (this.value.length * -1)) {
+          const currentLine = (this._clines.length - 1) + this.offsetY
+          const copy = this._clines.slice();
+          const cursorPosition = copy[currentLine].length + this.offsetX;
+          copy[currentLine] = copy[currentLine].slice(0, cursorPosition - 1) + copy[currentLine].slice(cursorPosition);
+          this.value = copy.join('\n');
+        }
       }
     }
   } else if (ch) {
     if (!/^[\x00-\x08\x0b-\x0c\x0e-\x1f\x7f]$/.test(ch)) {
-      this.value += ch;
+      if (this.offsetX === 0 && this.offsetY === 0){
+        this.value += ch;
+      } else if (this.offsetX >= (this.value.length * -1)) {
+        const currentLine = (this._clines.length - 1) + this.offsetY
+        const copy = this._clines.slice();
+        const cursorPosition = copy[currentLine].length + this.offsetX;
+        copy[currentLine] = copy[currentLine].slice(0, cursorPosition) + ch + copy[currentLine].slice(cursorPosition);
+        this.value = copy.join('\n');
+      }
     }
   }
 
@@ -257,7 +318,8 @@ Textarea.prototype._typeScroll = function() {
   // XXX Workaround
   var height = this.height - this.iheight;
   if (this._clines.length - this.childBase > height) {
-    this.scroll(this._clines.length);
+    const currentLine = (this._clines.length) + this.offsetY
+    this.scroll(currentLine);
   }
 };