import * as nip19 from 'nostr-tools/nip19';
import { Relay } from 'nostr-tools';

/**
 * Validates if the given npub is a valid Nostr Public Key.
 * @param npub - The npub (Nostr Public Key) to validate.
 * @returns A boolean indicating if the npub is valid.
 */
const isValidNpub = (npub: string): boolean => {
	try {
		// Decode the npub using NIP-19
		const { type, data } = nip19.decode(npub);
		// Check if the type is 'npub' and the data length is 32 bytes
		return type === 'npub' && data.length === 64;
	} catch (e) {
		// If any error is thrown, the npub is not valid
		return false;
	}
};

/**
 * Validates if the given URL is a valid Nostr relay.
 * @param url - The URL of the Nostr relay to validate.
 * @returns A Promise<boolean> indicating if the URL is a valid Nostr relay.
 */
const isValidNostrRelay = async (url: string): Promise<boolean> => {
	try {
		const relay: Relay = await Relay.connect(url);

		// If the relay is successfully connected, it's a valid Nostr relay
		if (relay.connected) {
			// Close the connection to clean up
			relay.close();
			return true;
		}

		return false;
	} catch (e) {
		// If any error is thrown, the URL is not a valid Nostr relay
		return false;
	}
};

/**
 * Validates if the given parameter is a valid hex public key.
 * @param pubkey - The public key to validate.
 * @returns A boolean indicating if the public key is valid.
 */
const isValidHexPubKey = (pubkey: string): boolean => {
	return /^[0-9a-f]{64}$/i.test(pubkey);
};

/**
 * Checks if a parameter is a valid pubkey or npub and converts npub to pubkey.
 * @param input - The input string to check and convert.
 * @returns The pubkey if valid, otherwise null.
 */

const getPubKey = (input: string): string | null => {
	try {
		// If input is a valid hex public key
		if (isValidHexPubKey(input)) {
			return input;
		}

		// Try to decode the input as npub
		const { type, data } = nip19.decode(input);

		// Check if the decoded type is 'npub' and the data length is 64 characters (32 bytes in hex)
		if (type === 'npub' && data.length === 64) {
			return data;
		}

		return null;
	} catch (e) {
		// If any error is thrown, the input is not valid
		return null;
	}
};

export { isValidNpub, isValidNostrRelay, isValidHexPubKey, getPubKey };