import type { ExtensionAPI, ExtensionCommandContext } from "@mariozechner/pi-coding-agent";
import { type InstallScope, installPackage } from "../packages/install.js";
import { notify } from "../utils/notify.js";

export const INSTALL_USAGE = "Usage: /extensions install <source> [--project|--global]";

interface ParsedInstallArgs {
	source: string;
	scope?: InstallScope;
	errors: string[];
}

interface InstallParseState {
	sourceParts: string[];
	scope?: InstallScope;
	errors: string[];
}

type InstallOptionHandler = (state: InstallParseState) => void;

const INSTALL_OPTION_HANDLERS: Record<string, InstallOptionHandler> = {
	"--project": (state) => {
		if (state.scope === "global") {
			state.errors.push("Use either --project or --global, not both");
		}
		state.scope = "project";
	},
	"-l": (state) => {
		if (state.scope === "global") {
			state.errors.push("Use either --project or --global, not both");
		}
		state.scope = "project";
	},
	"--global": (state) => {
		if (state.scope === "project") {
			state.errors.push("Use either --project or --global, not both");
		}
		state.scope = "global";
	},
};

function parseInstallArgs(tokens: string[]): ParsedInstallArgs {
	const state: InstallParseState = {
		sourceParts: [],
		errors: [],
	};

	for (const token of tokens) {
		const optionHandler = INSTALL_OPTION_HANDLERS[token];
		if (optionHandler) {
			optionHandler(state);
		} else {
			state.sourceParts.push(token);
		}
	}

	return {
		source: state.sourceParts.join(" ").trim(),
		...(state.scope ? { scope: state.scope } : {}),
		errors: state.errors,
	};
}

export async function handleInstallSubcommand(
	tokens: string[],
	ctx: ExtensionCommandContext,
	pi: ExtensionAPI,
): Promise<void> {
	const parsed = parseInstallArgs(tokens);

	if (parsed.errors.length > 0) {
		notify(ctx, parsed.errors.join("\n"), "warning");
		notify(ctx, INSTALL_USAGE, "info");
		return;
	}

	if (!parsed.source) {
		notify(ctx, INSTALL_USAGE, "info");
		return;
	}

	await installPackage(parsed.source, ctx, pi, parsed.scope ? { scope: parsed.scope } : undefined);
}