/**
 * Argument parser for /vault commands.
 *
 * Splits raw input into a typed subcommand plus remaining args[].
 * This supports current single-arg subcommands and future multi-arg
 * commands like `/vault export age` or `/vault backend keychain`.
 */

const SUBCOMMANDS = [
	"show",
	"verify",
	"providers",
	"setup",
	"import",
	"export",
	"path",
	"help",
] as const;

export type Subcommand = (typeof SUBCOMMANDS)[number];

export interface ParsedCommand {
	readonly subcommand: Subcommand;
	readonly args: readonly string[];
}

export function isSubcommand(value: string): value is Subcommand {
	return (SUBCOMMANDS as readonly string[]).includes(value);
}

/**
 * Parse raw command input into subcommand + args.
 * Returns undefined when input is empty (settings panel path).
 * Throws on unrecognized subcommand.
 */
export function parseVaultArgs(raw: string): ParsedCommand | undefined {
	const tokens = raw
		.trim()
		.split(/\s+/)
		.filter((t) => t.length > 0);

	if (tokens.length === 0) {
		return undefined;
	}

	const first = tokens[0];
	if (!first) {
		return undefined;
	}

	const candidate = first.toLowerCase();
	if (!isSubcommand(candidate)) {
		return undefined;
	}

	return {
		subcommand: candidate,
		args: tokens.slice(1),
	};
}

export function getSubcommands(): readonly Subcommand[] {
	return SUBCOMMANDS;
}

export function getSubcommandDescription(cmd: Subcommand): string {
	switch (cmd) {
		case "show":
			return "Backend status and managed providers";
		case "verify":
			return "Check backend health";
		case "providers":
			return "List managed vs excluded providers";
		case "setup":
			return "Guided first-time setup";
		case "import":
			return "Import existing auth.json credentials into vault";
		case "export":
			return "Export credentials to another backend or rewrite current";
		case "path":
			return "Config and vault file locations";
		case "help":
			return "Usage summary";
	}
}