From e897ca7848acaf42bd8ae80ea54612d71cf09772 Mon Sep 17 00:00:00 2001
From: Eric Rumsey <ehrumsey@gmail.com>
Date: Fri, 23 May 2025 17:37:51 -0500
Subject: [PATCH] Begin re-write in proper functional style

---
 src/lib/painter/canvas.ts | 102 ++++++++++++++++++++++----------------
 1 file changed, 59 insertions(+), 43 deletions(-)

diff --git a/src/lib/painter/canvas.ts b/src/lib/painter/canvas.ts
index 40b8e0a..7df02bf 100644
--- a/src/lib/painter/canvas.ts
+++ b/src/lib/painter/canvas.ts
@@ -1,47 +1,63 @@
-import { tryCatch } from '@maxmorozoff/try-catch-tuple';
-import type { CursorPosition } from '../util/terminal';
+import { type CursorPos } from 'node:readline'
 
-const setInitialEnd = (pos: {
-  origin: CursorPosition;
-  end?: CursorPosition;
-  lines?: number;
-}) => {
-  if (!pos.end || !pos.lines)
-    throw TypeError("One of 'end' or 'lines' must be set");
-  if (Object.keys(pos).includes('end') || Object.keys(pos).includes('end'))
-    throw TypeError("Cannot set both 'end' and 'lines'");
-  if (pos.end) return pos.end;
-  return {
-    row: pos.origin.row + pos.lines,
-    col: pos.origin.col,
-  };
-};
+// Cursor stuffs
+interface CursorPosX {
+  readonly _tag: 'X'
+  readonly value: number
+}
 
-export const createCanvas = (
-  pos: { origin: CursorPosition; end?: CursorPosition; lines?: number },
-  paint: () => Promise<number>,
-  cleanup?: () => Promise<number>
-) => {
-  let currentOrigin = pos.origin;
+interface CursorPosY {
+  readonly _tag: 'Y'
+  readonly value: number
+}
 
-  let currentEnd;
-  const [endVal, endError] = tryCatch(() => setInitialEnd(pos));
-  if (endError) throw endError;
-  currentEnd = endVal;
+const cursorPosX = (x: number): CursorPosX => ({_tag: 'X', value: x})
 
-  paint();
-  //
-  // Paint function
-  //
-  // Restore origin position
-  // Clear to cursor end position
-  //
-  // API
-  // ---
-  // get origin
-  // get end
-  // move end
-  // get line count
-  // clear canvas
-  return [1];
-};
+const cursorPosY = (x: number): CursorPosY => ({_tag: 'Y', value: x})
+
+type IsCursorPos =
+  (x: 'X' | 'Y') => (y: CursorPosX | CursorPosY) => boolean
+const isCursorPos: IsCursorPos = x => y => y._tag === x
+
+// Tagged types
+interface CanvasOrigin {
+  readonly _tag: 'Origin'
+  readonly value: CursorPos
+}
+
+interface CanvasEnd {
+  readonly _tag: 'End'
+  readonly value: CursorPos
+}
+
+// Canvas type using tagged positions
+type Canvas = {
+  origin: CanvasOrigin,
+  end: CanvasEnd,
+}
+
+// Cursor Position
+// const cursorPos: CursorPos = ()
+
+// Constructor helpers
+const origin = (pos: CursorPos): CanvasOrigin => ({
+  _tag: 'Origin',
+  value: pos,
+})
+
+const end = (pos: CursorPos): CanvasEnd => ({
+  _tag: 'End',
+  value: pos,
+})
+
+// Curried canvas creator with type safety
+const canvas =
+  (origin: CanvasOrigin) => (end: CanvasEnd): Canvas => ({
+    origin,
+    end,
+  })
+
+// Usage with proper type safety
+const myCanvas = canvas(origin({rows: 3, cols: 1}))(
+  end({rows: 8, cols: 1}),
+)