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

const choices = ["welcome", "hours"];
const deskInfo: Record<string, string> = {
	welcome: "Welcome to the fictional community seed library. This lesson cannot change real stock. Try /seeds hours.",
	hours: "Our fictional desk opens Saturday, 10:00-12:00. No booking has been made.",
};

type WelcomeDetails =
	| { op: "discover"; scope: "fictional-desk"; operations: string[]; topics: string[]; quiet: boolean }
	| { op: "inspect"; scope: "fictional-desk"; topic: "welcome" | "hours" };

export default async function seedWelcome(pi: ExtensionAPI) {
	const description = await Bun.file(new URL("./tool.txt", import.meta.url)).text();
	const z = pi.zod;
	const parameters = z.object({ op: z.enum(["discover", "inspect"]), topic: z.enum(["welcome", "hours"]).optional() });
	pi.registerTool<typeof parameters, WelcomeDetails>({
		name: "seed_welcome",
		label: "Seed desk welcome",
		description,
		parameters,
		approval: "read",
		loadMode: "essential",
		async execute(_id, params, signal) {
			signal?.throwIfAborted();
			if (params.op === "discover") {
				return {
					content: [{ type: "text", text: "Fictional seed desk. Inspect topic welcome or hours. No stock-changing operations exist." }],
					details: { op: "discover", scope: "fictional-desk", operations: ["discover", "inspect"], topics: choices, quiet: pi.getFlag("seed-quiet") === true },
				};
			}
			if (!params.topic) throw new Error("Inspect requires topic welcome or hours. Nothing changed.");
			const text = deskInfo[params.topic];
			if (!text) throw new Error("Inspect requires topic welcome or hours. Nothing changed.");
			return { content: [{ type: "text", text }], details: { op: "inspect", scope: "fictional-desk", topic: params.topic } };
		},
	});
	pi.registerFlag("seed-quiet", {
		description: "Hide the seed desk's startup notification",
		type: "boolean",
		default: false,
	});

	pi.on("session_start", (_event, ctx) => {
		if (ctx.hasUI && pi.getFlag("seed-quiet") !== true) {
			ctx.ui.notify("Fictional community seed desk ready. Try /seeds welcome.", "info");
		}
	});

	pi.registerCommand("seeds", {
		description: "Visit the fictional community seed desk: welcome | hours",
		getArgumentCompletions(prefix) {
			const matches = choices.filter(value => value.startsWith(prefix.trimStart()));
			// A completed sole match MUST release Enter to submit the command.
			if (matches.length === 1 && matches[0] === prefix.trim()) return null;
			return matches.length ? matches.map(value => ({ value: `${value} `, label: value })) : null;
		},
		async handler(args, ctx) {
			const verb = args.trim() || "welcome";
			const text = Object.hasOwn(deskInfo, verb) ? deskInfo[verb]! : "Unknown request. Use /seeds welcome or /seeds hours. Nothing changed.";
			if (ctx.hasUI) ctx.ui.notify(text, choices.includes(verb) ? "info" : "warning");
			else pi.sendMessage({ customType: "seed-desk", content: text, display: true }, { triggerTurn: false });
		},
	});
}