import { WriteStream, createWriteStream, PathLike } from 'fs';
import { promisify } from 'util';

export class Logger {
    logFile: WriteStream;

    errorFile: WriteStream;

    write: (log: string) => Promise<void>;

    writeError: (log: string) => Promise<void>;

    constructor({ filePath }: { filePath: PathLike }) {
        this.logFile = createWriteStream(filePath);
        this.errorFile = createWriteStream(`${filePath}.err`);
        this.write = promisify(this.logFile.write.bind(this.logFile));
        this.writeError = promisify(this.errorFile.write.bind(this.logFile));

        const gracefulShutdown = () => {
            this.close();
            process.exit(0);
        };

        process.on('SIGINT', gracefulShutdown);
        process.on('SIGTERM', gracefulShutdown);
    }

    log(...args: (string | object | number)[]) {
        console.log(...args);
        return Promise.all(args.map((arg) => this.write(`${JSON.stringify(arg)}\n`)));
    }

    error(...args: (string | object | number)[]) {
        console.error(...args);
        return Promise.all(
            args.map((arg) =>
                Promise.all([
                    this.write(`${typeof arg === 'object' ? JSON.stringify(arg) : arg}\n`),
                    this.writeError(`${typeof arg === 'object' ? JSON.stringify(arg) : arg}\n`),
                ]),
            ),
        );
    }

    close() {
        this.logFile.close();
        this.errorFile.close();
        console.log(`Logfile available at ${this.logFile.path.toString()}`);
    }
}