From 771ff1d0f246774ebf9423804a8a2d825dbe23ed Mon Sep 17 00:00:00 2001
From: Krishna Acondy <kc.acondy@outlook.com>
Date: Thu, 1 Apr 2021 02:07:29 +0100
Subject: [PATCH] fix(text-input): make cursor reflect current position (#300)

---
 lib/elements/text.js | 31 ++++++++++++++++++++---
 test/text.js         | 59 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+), 4 deletions(-)
 create mode 100644 test/text.js

diff --git a/lib/elements/text.js b/lib/elements/text.js
index eee731b5..ee78181a 100644
--- a/lib/elements/text.js
+++ b/lib/elements/text.js
@@ -25,6 +25,7 @@ class TextPrompt extends Prompt {
     this.value = ``;
     this.errorMsg = opts.error || `Please Enter A Valid Value`;
     this.cursor = Number(!!this.initial);
+    this.cursorOffset = 0;
     this.clear = clear(``, this.out.columns);
     this.render();
   }
@@ -48,6 +49,7 @@ class TextPrompt extends Prompt {
   reset() {
     this.value = ``;
     this.cursor = Number(!!this.initial);
+    this.cursorOffset = 0;
     this.fire();
     this.render();
   }
@@ -78,6 +80,8 @@ class TextPrompt extends Prompt {
 
   async submit() {
     this.value = this.value || this.initial;
+    this.cursorOffset = 0;
+    this.cursor = this.rendered.length;
     await this.validate();
     if (this.error) {
       this.red = true;
@@ -104,6 +108,7 @@ class TextPrompt extends Prompt {
   moveCursor(n) {
     if (this.placeholder) return;
     this.cursor = this.cursor+n;
+    this.cursorOffset += n;
   }
 
   _(c, key) {
@@ -116,12 +121,17 @@ class TextPrompt extends Prompt {
   }
 
   delete() {
-    if (this.cursor === 0) return this.bell();
+    if (this.isCursorAtStart()) return this.bell();
     let s1 = this.value.slice(0, this.cursor-1);
     let s2 = this.value.slice(this.cursor);
     this.value = `${s1}${s2}`;
     this.red = false;
-    this.moveCursor(-1);
+    if (this.isCursorAtStart()) {
+      this.cursorOffset = 0
+    } else {
+      this.cursorOffset++;
+      this.moveCursor(-1);
+    }
     this.render();
   }
 
@@ -131,6 +141,11 @@ class TextPrompt extends Prompt {
     let s2 = this.value.slice(this.cursor+1);
     this.value = `${s1}${s2}`;
     this.red = false;
+    if (this.isCursorAtEnd()) {
+      this.cursorOffset = 0;
+    } else {
+      this.cursorOffset++;
+    }
     this.render();
   }
 
@@ -156,6 +171,14 @@ class TextPrompt extends Prompt {
     this.render();
   }
 
+  isCursorAtStart() {
+    return this.cursor === 0 || (this.placeholder && this.cursor === 1);
+  }
+
+  isCursorAtEnd() {
+    return this.cursor === this.rendered.length || (this.placeholder && this.cursor === this.rendered.length + 1)
+  }
+
   render() {
     if (this.closed) return;
     if (!this.firstRender) {
@@ -178,8 +201,8 @@ class TextPrompt extends Prompt {
           .reduce((a, l, i) => a + `\n${i ? ' ' : figures.pointerSmall} ${color.red().italic(l)}`, ``);
     }
 
-    this.out.write(erase.line + cursor.to(0) + this.outputText + cursor.save + this.outputError + cursor.restore);
+    this.out.write(erase.line + cursor.to(0) + this.outputText + cursor.save + this.outputError + cursor.restore + cursor.move(this.cursorOffset, 0));
   }
 }
 
-module.exports = TextPrompt;
+module.exports = TextPrompt;
\ No newline at end of file
diff --git a/test/text.js b/test/text.js
new file mode 100644
index 00000000..37d7493c
--- /dev/null
+++ b/test/text.js
@@ -0,0 +1,59 @@
+'use strict';
+
+const test = require('tape');
+const TextPrompt = require('../lib/elements/text');
+
+test('move', (t) => {
+  t.plan(6);
+
+  const textPrompt = new TextPrompt();
+  textPrompt.value = 'Hello, world!';
+  textPrompt.last()
+  textPrompt.render()
+
+  t.same(textPrompt.cursorOffset, 0, 'cursorOffset is 0 at start');
+  t.same(textPrompt.cursor, textPrompt.rendered.length, 'cursor starts at 0')
+
+  textPrompt.right();
+  t.same(textPrompt.cursorOffset, 0, 'cursorOffset is unaffected when moved right from the end');
+  t.same(textPrompt.cursor, textPrompt.rendered.length, 'cursor is unaffected when moved right from the end')
+
+  textPrompt.left();
+  t.equal(textPrompt.cursorOffset, -1, 'cursorOffset is -1 when moved left');
+
+  textPrompt.right();
+  t.equal(textPrompt.cursorOffset, 0, 'cursorOffset is 0 when moved left');
+
+  t.end();
+});
+
+test('delete', (t) => {
+  t.plan(4);
+
+  const textPrompt = new TextPrompt();
+  textPrompt.value = 'Hello, world!';
+  textPrompt.last();
+  textPrompt.render();
+
+  textPrompt.delete();
+  t.same(textPrompt.cursorOffset, 0, 'cursorOffset is 0 after delete');
+  t.same(textPrompt.cursor, textPrompt.rendered.length, 'cursor stays at end of line')
+
+  textPrompt.left();
+  textPrompt.deleteForward()
+  t.same(textPrompt.cursorOffset, 0, 'cursorOffset is 0 after deleteForward');
+  t.same(textPrompt.cursor, textPrompt.rendered.length, 'cursor stays at end of line')
+
+  textPrompt.submit();
+  t.end()
+});
+
+test('submit', (t) => {
+  t.plan(2)
+  const textPrompt = new TextPrompt();
+  textPrompt.value = 'Hello, world!';
+  textPrompt.submit()
+
+  t.same(textPrompt.cursorOffset, 0, 'cursorOffset is reset on submit')
+  t.same(textPrompt.cursor, textPrompt.rendered.length, 'cursor is reset to end of line on submit')
+})