feat(coding-agent): allow hiding working loader

closes #3674

packages/coding-agent/examples/extensions/border-status-editor.ts

@@ -0,0 +1,148 @@
+import {
+	CustomEditor,
+	type ExtensionAPI,
+	type ExtensionContext,
+	type KeybindingsManager,
+} from "@mariozechner/pi-coding-agent";
+import type { Component, EditorTheme, TUI } from "@mariozechner/pi-tui";
+import { truncateToWidth, visibleWidth } from "@mariozechner/pi-tui";
+
+function fitBorder(left: string, right: string, width: number, fill: (text: string) => string): string {
+	if (width <= 0) return "";
+	if (width === 1) return fill("─");
+
+	let leftText = left;
+	let rightText = right;
+	const edgeWidth = 1;
+	const minimumGap = 1;
+
+	while (
+		edgeWidth * 2 + visibleWidth(leftText) + visibleWidth(rightText) + minimumGap > width &&
+		visibleWidth(rightText) > 0
+	) {
+		rightText = truncateToWidth(rightText, Math.max(0, visibleWidth(rightText) - 1), "");
+	}
+	while (
+		edgeWidth * 2 + visibleWidth(leftText) + visibleWidth(rightText) + minimumGap > width &&
+		visibleWidth(leftText) > 0
+	) {
+		leftText = truncateToWidth(leftText, Math.max(0, visibleWidth(leftText) - 1), "");
+	}
+
+	const gapWidth = Math.max(0, width - edgeWidth * 2 - visibleWidth(leftText) - visibleWidth(rightText));
+	return `${fill("─")}${leftText}${fill("─".repeat(gapWidth))}${rightText}${fill("─")}`;
+}
+
+function formatCwd(cwd: string): string {
+	const home = process.env.HOME;
+	if (home && cwd.startsWith(home)) {
+		return `~${cwd.slice(home.length)}`;
+	}
+	return cwd;
+}
+
+function formatContext(ctx: ExtensionContext): string {
+	const usage = ctx.getContextUsage();
+	if (!usage || usage.tokens === null || usage.percent === null) {
+		return "context unknown";
+	}
+	return `${Math.round(usage.percent)}% of ${(usage.contextWindow / 1000).toFixed(1)}k`;
+}
+
+function formatSessionCost(ctx: ExtensionContext): string {
+	let totalCost = 0;
+	for (const entry of ctx.sessionManager.getEntries()) {
+		if (entry.type === "message" && entry.message.role === "assistant") {
+			totalCost += entry.message.usage.cost.total;
+		}
+	}
+	return `$${totalCost.toFixed(3)}`;
+}
+
+class EmptyFooter implements Component {
+	render(): string[] {
+		return [];
+	}
+
+	invalidate(): void {}
+}
+
+export default function (pi: ExtensionAPI) {
+	let isWorking = false;
+	let spinnerIndex = 0;
+	let spinnerTimer: ReturnType<typeof setInterval> | undefined;
+	let activeTui: TUI | undefined;
+	const spinnerFrames = ["⠋", "⠙", "⠹", "⠸", "⠼", "⠴", "⠦", "⠧", "⠇", "⠏"];
+
+	const stopSpinner = () => {
+		if (spinnerTimer) {
+			clearInterval(spinnerTimer);
+			spinnerTimer = undefined;
+		}
+	};
+
+	pi.on("agent_start", () => {
+		isWorking = true;
+		stopSpinner();
+		spinnerTimer = setInterval(() => {
+			spinnerIndex = (spinnerIndex + 1) % spinnerFrames.length;
+			activeTui?.requestRender();
+		}, 80);
+		activeTui?.requestRender();
+	});
+
+	pi.on("agent_end", () => {
+		isWorking = false;
+		stopSpinner();
+		activeTui?.requestRender();
+	});
+
+	pi.on("session_shutdown", () => {
+		stopSpinner();
+		activeTui = undefined;
+	});
+
+	pi.on("session_start", (_event, ctx) => {
+		ctx.ui.setWorkingVisible(false);
+		ctx.ui.setFooter(() => new EmptyFooter());
+
+		let branch: string | undefined;
+
+		const refreshBranch = async () => {
+			const result = await pi.exec("git", ["branch", "--show-current"], { cwd: ctx.cwd }).catch(() => undefined);
+			const stdout = result?.stdout.trim();
+			branch = stdout && stdout.length > 0 ? stdout : undefined;
+			activeTui?.requestRender();
+		};
+		void refreshBranch();
+
+		class BorderStatusEditor extends CustomEditor {
+			constructor(tui: TUI, theme: EditorTheme, keybindings: KeybindingsManager) {
+				super(tui, theme, keybindings, { paddingX: 0 });
+				activeTui = tui;
+			}
+
+			render(width: number): string[] {
+				const lines = super.render(width);
+				if (lines.length < 2) return lines;
+
+				const thm = ctx.ui.theme;
+				const model = ctx.model ? `(${ctx.model.provider}) ${ctx.model.id}` : "no model";
+				const thinking = pi.getThinkingLevel();
+				const workingText = isWorking ? `${spinnerFrames[spinnerIndex]} working` : "idle";
+				const topLeft = thm.fg("muted", ` ${formatContext(ctx)} · ${formatSessionCost(ctx)} `);
+				const topRight = thm.fg("muted", ` ${model} · ${thinking} `);
+				const bottomLeft = isWorking ? thm.fg("accent", ` ${workingText} `) : thm.fg("muted", ` ${workingText} `);
+				const bottomRight = thm.fg("muted", ` ${formatCwd(ctx.cwd)}${branch ? ` (${branch})` : ""} `);
+
+				lines[0] = fitBorder(topLeft, topRight, width, (text) => this.borderColor(text.replace(/ /g, "─")));
+				lines[lines.length - 1] = fitBorder(bottomLeft, bottomRight, width, (text) =>
+					this.borderColor(text.replace(/ /g, "─")),
+				);
+				return lines;
+			}
+		}
+
+		ctx.ui.setEditorComponent((tui, theme, keybindings) => new BorderStatusEditor(tui, theme, keybindings));
+	});
+}