diaspora-orm/diaspora

import { isEmpty, difference, keys, omit } from 'lodash';
import { Logger as WLogger, createLogger, transports, format } from 'winston';

import { Logger, ELoggingLevel } from './logger';

const LoggerHash = {
    [ELoggingLevel.Silly]: 'silly',
    [ELoggingLevel.Verbose]: 'verbose',
    [ELoggingLevel.Debug]: 'debug',
    [ELoggingLevel.Log]: 'log',
    [ELoggingLevel.Warn]: 'warn',
    [ELoggingLevel.Error]: 'error',
    [ELoggingLevel.Silent]: 'silent',
};

export class NodeLogger extends Logger {
    public set level( level: ELoggingLevel ) {
        this.logger.level = LoggerHash[level];
        this._level = level;
    }
    public get level() {
        return this._level;
    }
    protected logger: WLogger;
    
    public constructor() {
        const { combine, json } = format;
        
        const log = createLogger( {
            level: LoggerHash[ELoggingLevel.Silly],
            format: json(),
            transports: [
                //
                // - Write to all logs with level `info` and below to `combined.log`
                // - Write all logs error (and below) to `error.log`.
                //
            ],
        } );
        
        log.add( new transports.Console( {
            format: combine(
                format.colorize(),
                format.printf( NodeLogger.format )
            ),
        } ) );
        super( {
            silly: log.silly.bind( log ),
            verbose: log.verbose.bind( log ),
            debug: log.debug.bind( log ),
            log: log.info.bind( log ),
            warn: log.warn.bind( log ),
            error: log.error.bind( log ),
        } );
        this.logger = log;
    }
    
    /**
     * Trims the string to the provided length, using the sufficient number of filler characters on the left or rigth
     * 
     * @author Gerkin
     * @param str    - String to trim to the target length
     * @param len    - Desired length of the string, that will be reached using filler chars
     * @param filler - Chars to repeat in order to fill the missing space in string
     * @param left   - Set to false to trim on the right
     */
    protected static trimToLength(
        str: string | number,
        len: number = 2,
        filler = '0',
        left = true
    ){
        filler = filler.repeat( len );
        str = left ? filler + str : str + filler;
        return str.slice( left ? -len : len );
    }
    
    /**
     * Format the date to a readable format
     * 
     * @author Gerkin
     * @param date - Date to convert to string
     */
    protected static formatDate( date = new Date() ){
        const datePart = `${NodeLogger.trimToLength( date.getDay() )}/${NodeLogger.trimToLength( date.getMonth() + 1 )}/${NodeLogger.trimToLength( date.getFullYear(), 4 )}`;
        const timePart = `${NodeLogger.trimToLength( date.getHours() )}:${NodeLogger.trimToLength( date.getMinutes() )}:${NodeLogger.trimToLength( date.getSeconds() )}`;
        return `${datePart} ${timePart}:${NodeLogger.trimToLength( date.getMilliseconds(), 3 )}`;
    }
    
    /**
     * Main logger function used by Diaspora on node environment, disaplying `Diaspora`, colors & the date
     * 
     * @author Gerkin
     * @param infos - Winston message infos
     */
    protected static format( infos: { [x: string]: any; level: string; message: any } ){
        const LEVEL = Symbol.for( 'level' );

        // Ugly patch related to [a known typescript missing feature](https://github.com/Microsoft/TypeScript/issues/24587)
        // TODO: Remove this `any` cast.
        const level = infos[LEVEL as any];
        // Add 'Diaspora: ' before the log level name
        infos.level = infos.level.replace( level, 'Diaspora: ' + level );
        
        let message = `${infos.level} @ ${NodeLogger.formatDate()} => ${infos.message}`;
        const omittedKeys = ['level', 'message', 'splat'];
        if ( !isEmpty( difference( keys( infos ), omittedKeys ) ) ) {
            message += ' ' + JSON.stringify( omit( infos, omittedKeys ) );
        }

        return message;
    }
}