From e6d38239bc41ff447b7266f447cfd6615dfe9f6e Mon Sep 17 00:00:00 2001
From: Chapman Pendery <cpendery@vt.edu>
Date: Sat, 7 Oct 2023 11:41:33 -0700
Subject: [PATCH] feat: add arrow navigation support to input field

Signed-off-by: Chapman Pendery <cpendery@vt.edu>
---
 package-lock.json |  1 +
 package.json      |  3 ++-
 src/ui/input.tsx  | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 src/ui/ui.tsx     | 21 +++++----------------
 4 files changed, 55 insertions(+), 17 deletions(-)
 create mode 100644 src/ui/input.tsx

diff --git a/package-lock.json b/package-lock.json
index 38842bc..c319c61 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -10,6 +10,7 @@
       "license": "MIT",
       "dependencies": {
         "@withfig/autocomplete": "^2.633.0",
+        "chalk": "^5.3.0",
         "commander": "^11.0.0",
         "ink": "^4.4.1",
         "react": "^18.2.0",
diff --git a/package.json b/package.json
index c973c09..ab9328c 100644
--- a/package.json
+++ b/package.json
@@ -23,6 +23,7 @@
   "homepage": "https://github.com/microsoft/clac#readme",
   "dependencies": {
     "@withfig/autocomplete": "^2.633.0",
+    "chalk": "^5.3.0",
     "commander": "^11.0.0",
     "ink": "^4.4.1",
     "react": "^18.2.0",
@@ -38,4 +39,4 @@
     "ts-jest": "^29.1.1",
     "typescript": "^5.2.2"
   }
-}
\ No newline at end of file
+}
diff --git a/src/ui/input.tsx b/src/ui/input.tsx
new file mode 100644
index 0000000..1fe4d8b
--- /dev/null
+++ b/src/ui/input.tsx
@@ -0,0 +1,47 @@
+import React, { useState, useEffect } from "react";
+import { useInput, Text } from "ink";
+import chalk from "chalk";
+
+const BlinkSpeed = 530;
+const CursorColor = "#FFFFFF";
+
+export default function Input({ value, setValue, prompt }: { value: string; setValue: (_: string) => void; prompt: string }) {
+  const [cursorLocation, setCursorLocation] = useState(value.length);
+  const [cursorBlink, setCursorBlink] = useState(true);
+
+  useEffect(() => {
+    setTimeout(() => {
+      setCursorBlink(!cursorBlink);
+    }, BlinkSpeed);
+  }, [cursorBlink]);
+
+  // TODO: arrow key navigation shortcuts (emacs & vim modes)
+  useInput((input, key) => {
+    if (key.backspace) {
+      setValue([...value].slice(0, Math.max(cursorLocation - 1, 0)).join("") + [...value].slice(cursorLocation).join(""));
+      setCursorLocation(Math.max(cursorLocation - 1, 0));
+    } else if (key.delete) {
+      setValue([...value].slice(0, cursorLocation).join("") + [...value].slice(Math.min(value.length, cursorLocation + 1)).join(""));
+    } else if (key.leftArrow) {
+      setCursorLocation(Math.max(cursorLocation - 1, 0));
+    } else if (key.rightArrow) {
+      setCursorLocation(Math.min(cursorLocation + 1, value.length));
+    } else if (input) {
+      setValue([...value].slice(0, cursorLocation).join("") + input + [...value].slice(cursorLocation).join(""));
+      setCursorLocation(cursorLocation + input.length);
+    }
+  });
+
+  const cursoredCommand = value + " ";
+  const cursoredText =
+    [...cursoredCommand].slice(0, cursorLocation).join("") +
+    (cursorBlink ? chalk.bgHex(CursorColor).inverse([...cursoredCommand].at(cursorLocation)) : [...cursoredCommand].at(cursorLocation)) +
+    [...cursoredCommand].slice(cursorLocation + 1).join("");
+
+  return (
+    <Text>
+      {prompt}
+      {cursoredText}
+    </Text>
+  );
+}
diff --git a/src/ui/ui.tsx b/src/ui/ui.tsx
index 2257402..fe7fe11 100644
--- a/src/ui/ui.tsx
+++ b/src/ui/ui.tsx
@@ -1,13 +1,14 @@
 import React, { useCallback, useEffect, useState } from "react";
-import { Text, Box, useInput, render as inkRender, measureElement, DOMElement } from "ink";
+import { Text, Box, render as inkRender, measureElement, DOMElement, useApp } from "ink";
 import wrapAnsi from "wrap-ansi";
+
 import { getSuggestions } from "../runtime/runtime.js";
 import { Suggestion } from "../runtime/model.js";
-import Cursor from "./cursor.js";
 import Suggestions from "./suggestions.js";
-
+import Input from "./input.js";
 const Prompt = "> ";
 
+// TODO: support tab completion
 function UI() {
   const [command, setCommand] = useState("");
   const [activeSuggestion, setActiveSuggestion] = useState<Suggestion>();
@@ -28,23 +29,11 @@ function UI() {
     });
   }, [command]);
 
-  useInput((input, key) => {
-    if (key.backspace) {
-      setCommand([...command].slice(0, -1).join(""));
-    } else {
-      setCommand(command + input);
-    }
-  });
-
   return (
     <Box flexDirection="column" ref={measureRef}>
       <Box>
         <Text>
-          <Text>
-            {Prompt}
-            {command}
-          </Text>
-          <Cursor />
+          <Input value={command} setValue={setCommand} prompt={Prompt} />
         </Text>
       </Box>
       <Suggestions leftPadding={leftPadding} setActiveSuggestion={setActiveSuggestion} suggestions={suggestions} />