import { ExecaSyncError, execa, execaCommand } from 'execa';
import { BanConfig } from './IConfig';
import pino from 'pino';
import { Database } from './Database';
import { Address6 } from 'ip-address';
import { isIP } from 'net';

export class BanManager {
	private cfg: BanConfig;
	private logger: pino.Logger;
	private db: Database | undefined;

	constructor(config: BanConfig, db: Database | undefined) {
		this.cfg = config;
		this.logger = pino({
			name: 'CVMTS.BanManager'
		});
		this.db = db;
	}

	private formatIP(ip: string) {
		switch (isIP(ip)) {
			case 4:
				// If IPv4, just return as-is
				return ip;
			case 6: {
				// If IPv6, return the /64 equivalent
				let addr = new Address6(ip);
				addr.subnetMask = 64;
				return addr.startAddress().canonicalForm() + '/64';
			}
			case 0:
			default:
				// Invalid IP
				throw new Error('Invalid IP address (what the hell did you even do???)');
		}
	}

	async BanUser(ip: string, username: string) {
		ip = this.formatIP(ip);
		// If cvmban enabled, write to DB
		if (this.cfg.cvmban) {
			if (!this.db) throw new Error('CVMBAN enabled but Database is undefined');
			await this.db.banIP(ip, username);
		}
		// If ban command enabled, run it
		try {
			if (Array.isArray(this.cfg.bancmd)) {
				let args: string[] = this.cfg.bancmd.map((a: string) => this.banCmdArgs(a, ip, username));
				if (args.length || args[0].length) {
					this.logger.info(`Running "${JSON.stringify(args)}"`);
					await execa(args.shift()!, args, { stdout: process.stdout, stderr: process.stderr });
				}
			} else if (typeof this.cfg.bancmd == 'string') {
				let cmd: string = this.banCmdArgs(this.cfg.bancmd, ip, username);
				if (cmd.length) {
					// Run through JSON.stringify for char escaping
					this.logger.info(`Running ${JSON.stringify(cmd)}`);
					await execaCommand(cmd, { stdout: process.stdout, stderr: process.stderr });
				}
			}
		} catch (e) {
			this.logger.error(`Failed to ban ${ip} (${username}): ${(e as ExecaSyncError).shortMessage}`);
		}
	}

	async isIPBanned(ip: string) {
		ip = this.formatIP(ip);
		if (!this.db) return false;
		if (await this.db.isIPBanned(ip)) {
			this.logger.info(`Banned IP ${ip} tried connecting.`);
			return true;
		}
		return false;
	}

	private banCmdArgs(arg: string, ip: string, username: string): string {
		return arg.replace(/\$IP/g, ip).replace(/\$NAME/g, username);
	}
}