import config from "config";
import {v4 as uuid} from "uuid";
import Log from "./models/Log";
import {bufferToUUID} from "./Utils";

export default class Logger {
    private static logLevel: LogLevelKeys = <LogLevelKeys>config.get<string>('log_level');
    private static dbLogLevel: LogLevelKeys = <LogLevelKeys>config.get<string>('db_log_level');
    private static verboseMode: boolean = false;

    public static verbose() {
        this.verboseMode = true;
        this.logLevel = <LogLevelKeys>LogLevel[LogLevel[this.logLevel] + 1] || this.logLevel;
        this.dbLogLevel = <LogLevelKeys>LogLevel[LogLevel[this.dbLogLevel] + 1] || this.dbLogLevel;
        Logger.info('Verbose mode');
    }

    public static isVerboseMode(): boolean {
        return this.verboseMode;
    }

    public static silentError(error: Error, ...message: any[]): string {
        return this.log('ERROR', message, error, true) || '';
    }

    public static error(error: Error, ...message: any[]): string {
        return this.log('ERROR', message, error) || '';
    }

    public static warn(...message: any[]) {
        this.log('WARN', message);
    }

    public static info(...message: any[]) {
        this.log('INFO', message);
    }

    public static debug(...message: any[]) {
        this.log('DEBUG', message);
    }

    public static dev(...message: any[]) {
        this.log('DEV', message);
    }

    private static log(level: LogLevelKeys, message: any[], error?: Error, silent: boolean = false): string | null {
        const levelIndex = LogLevel[level];
        if (levelIndex <= LogLevel[this.logLevel]) {
            if (error) {
                if (levelIndex > LogLevel.ERROR) this.warn(`Wrong log level ${level} with attached error.`);
            } else {
                if (levelIndex <= LogLevel.ERROR) this.warn(`No error attached with log level ${level}.`);
            }

            const computedMsg = message.map(v => {
                if (typeof v === 'string') {
                    return v;
                } else {
                    return JSON.stringify(v, (key: string, value: any) => {
                        if (value instanceof Object) {
                            if (value.type === 'Buffer') {
                                return `Buffer<${Buffer.from(value.data).toString('hex')}>`;
                            } else if (value !== v) {
                                return `[object Object]`;
                            }
                        }
                        if (typeof value === 'string' && value.length > 96) {
                            return value.substr(0, 96) + '...';
                        }
                        return value;
                    }, 4);
                }
            }).join(' ');

            const shouldSaveToDB = levelIndex <= LogLevel[this.dbLogLevel];

            let output = `[${level}] `;
            const pad = output.length;

            const logID = Buffer.alloc(16);
            uuid({}, logID);
            let strLogID = bufferToUUID(logID);
            if (shouldSaveToDB) output += `${strLogID} - `;

            output += computedMsg.replace(/\n/g, '\n' + ' '.repeat(pad));

            switch (level) {
                case "ERROR":
                    if (silent || !error) {
                        console.error(output);
                    } else {
                        console.error(output, error);
                    }
                    break;
                case "WARN":
                    console.warn(output);
                    break;
                case "INFO":
                    console.info(output);
                    break;
                case "DEBUG":
                case "DEV":
                    console.debug(output);
                    break;
            }

            if (shouldSaveToDB) {
                const log = Log.create({});
                log.setLevel(level);
                log.message = computedMsg;
                log.setError(error);
                log.setLogID(logID);
                log.save().catch(err => {
                    if (!silent && err.message.indexOf('ECONNREFUSED') < 0) {
                        console.error({save_err: err, error});
                    }
                });
            }
            return strLogID;
        }
        return null;
    }

    private constructor() {
    }
}

export enum LogLevel {
    ERROR,
    WARN,
    INFO,
    DEBUG,
    DEV,
}

export type LogLevelKeys = keyof typeof LogLevel;