/**
 * /ask [message]   — read-only: drop write/edit, append system constraint; optional message sent after switch
 * /agent [message] — restore tools from before ask; optional message sent after switch
 *
 * New/switched sessions reset to agent. Does not filter bash; use a sandbox for hard isolation.
 *
 * Not supported with pi -p / print mode: pi.sendUserMessage is fire-and-forget, so -p may exit
 * before the follow-up turn finishes. Use the interactive TUI instead.
 */

import type { ExtensionAPI, ExtensionContext } from "@earendil-works/pi-coding-agent";

const WRITE = new Set(["edit", "write"]);

export default function (pi: ExtensionAPI): void {
	let ask = false;
	let prev: string[] | undefined;

	function setMode(on: boolean, ctx: ExtensionContext): void {
		if (ask === on) return;
		ask = on;
		if (on) {
			prev = pi.getActiveTools();
			pi.setActiveTools(prev.filter((t) => !WRITE.has(t)));
		} else {
			pi.setActiveTools(prev ?? pi.getAllTools().map((t) => t.name));
			prev = undefined;
		}
		// Mode indicator: footer status only (no notify)
		ctx.ui.setStatus("ask-mode", on ? ctx.ui.theme.fg("warning", "ask") : undefined);
	}

	function run(on: boolean, args: string, ctx: ExtensionContext): void {
		setMode(on, ctx);
		const text = args.trim();
		if (text) {
			pi.sendUserMessage(text);
		}
	}

	pi.registerCommand("ask", {
		description: "Switch to ask mode",
		handler: async (args, ctx) => run(true, args, ctx),
	});
	pi.registerCommand("agent", {
		description: "Switch to agent mode",
		handler: async (args, ctx) => run(false, args, ctx),
	});

	pi.on("before_agent_start", async (event) => {
		if (!ask) return;
		return {
			systemPrompt:
				event.systemPrompt +
				"\n\n[Ask mode] File modifications are disabled (no write/edit). " +
				"All other tools and commands remain available — including bash for network lookups (e.g. curl). " +
				"If the user asks you to create or edit files, tell them to run /agent first.",
		};
	});

	pi.on("session_start", async (_event, ctx) => {
		if (ask) {
			pi.setActiveTools(prev ?? pi.getAllTools().map((t) => t.name));
		}
		ask = false;
		prev = undefined;
		ctx.ui.setStatus("ask-mode", undefined);
	});
}