/**
 * Timestamps extension for Pi.
 *
 * - Shows elapsed session time in footer (updates every second)
 * - Shows how long the last turn took (from your message to agent completion)
 */

import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";

// Track session time and turn durations
let sessionStart = Date.now();
let timerHandle: ReturnType<typeof setInterval> | null = null;
let turnStartTime: number | null = null;
let lastTurnDuration: number | null = null;

function formatElapsed(ms: number): string {
	const seconds = Math.floor(ms / 1000);
	const minutes = Math.floor(seconds / 60);
	const hours = Math.floor(minutes / 60);

	if (hours > 0) {
		return `${hours}h ${minutes % 60}m`;
	} else if (minutes > 0) {
		return `${minutes}m ${seconds % 60}s`;
	} else {
		return `${seconds}s`;
	}
}

function formatDuration(ms: number): string {
	if (ms < 1000) return `${ms}ms`;
	if (ms < 60000) return `${(ms / 1000).toFixed(1)}s`;
	return `${(ms / 60000).toFixed(1)}m`;
}

export default function (pi: ExtensionAPI) {
	const updateStatus = (ctx: { ui: { setStatus: (id: string, text: string | undefined) => void; theme: { fg: (color: string, text: string) => string } } }) => {
		const elapsed = Date.now() - sessionStart;
		let status = ctx.ui.theme.fg("dim", `⏱ ${formatElapsed(elapsed)}`);

		// Show last turn duration if available
		if (lastTurnDuration !== null) {
			status += ctx.ui.theme.fg("muted", ` | took ${formatDuration(lastTurnDuration)}`);
		}

		ctx.ui.setStatus("timestamps", status);
	};

	// Start timer on session start
	pi.on("session_start", async (_event, ctx) => {
		sessionStart = Date.now();
		turnStartTime = null;
		lastTurnDuration = null;

		// Clear any existing timer
		if (timerHandle) clearInterval(timerHandle);

		// Update status every second
		timerHandle = setInterval(() => updateStatus(ctx), 1000);
		updateStatus(ctx);
	});

	// Track turn timing
	pi.on("turn_start", async () => {
		turnStartTime = Date.now();
	});

	pi.on("turn_end", async (_event, ctx) => {
		if (turnStartTime !== null) {
			lastTurnDuration = Date.now() - turnStartTime;
			turnStartTime = null;
			updateStatus(ctx);
		}
	});

	// Clean up on shutdown
	pi.on("session_shutdown", async () => {
		if (timerHandle) {
			clearInterval(timerHandle);
			timerHandle = null;
		}
	});
}