Add my-rainbow-editor extension for pi

my-rainbow-editor.ts

@@ -0,0 +1,62 @@
+/**
+ * My Rainbow Editor Extension for pi
+ *
+ * This extension provides a custom TUI editor component for the pi coding agent.
+ * It takes the rendered lines of the default editor and applies a continuous 
+ * rainbow color pattern to all characters. To prevent the TUI from breaking, 
+ * it safely ignores and preserves existing ANSI escape codes (such as cursor 
+ * placement and text selection sequences) during the colorization process.
+ *
+ * Usage: pi --extension ./my-rainbow-editor.ts
+ */
+import { CustomEditor, type ExtensionAPI } from "@mariozechner/pi-coding-agent";
+
+const COLORS: [number, number, number][] = [
+	[233, 137, 115], // coral
+	[228, 186, 103], // yellow
+	[141, 192, 122], // green
+	[102, 194, 179], // teal
+	[121, 157, 207], // blue
+	[157, 134, 195], // purple
+	[206, 130, 172], // pink
+];
+const RESET = "\x1b[0m";
+// Regex to split string on ANSI escape codes, keeping them intact
+const ANSI_REGEX = /(\x1b(?:\[[0-9;?]*[a-zA-Z]|(?:\]|_)[^\x07\x1b]*(?:\x07|\x1b\\)))/;
+
+function colorizeSafe(line: string): string {
+	const parts = line.split(ANSI_REGEX);
+	let out = "";
+	let charIndex = 0;
+	
+	for (const part of parts) {
+		if (!part) continue;
+		// If this is an ANSI sequence, pass it through without colorizing
+		if (part.startsWith("\x1b")) {
+			out += part;
+		} else {
+			// Colorize regular characters individually
+			for (const char of part) {
+				const [r, g, b] = COLORS[charIndex % COLORS.length]!;
+				out += `\x1b[38;2;${r};${g};${b}m${char}`;
+				charIndex++;
+			}
+		}
+	}
+	// Append a single reset at the end of the line just to be safe
+	return out + RESET;
+}
+
+class MyRainbowEditor extends CustomEditor {
+	render(width: number): string[] {
+		// Render the original editor line, but safely add our rainbow colors 
+		// on top without breaking the terminal cursor/selection ANSI sequences
+		return super.render(width).map(line => colorizeSafe(line));
+	}
+}
+
+export default function (pi: ExtensionAPI) {
+	pi.on("session_start", (_event, ctx) => {
+		ctx.ui.setEditorComponent((tui, theme, kb) => new MyRainbowEditor(tui, theme, kb));
+	});
+}