import config from "config";
import {v4 as uuid} from "uuid";
import Log from "./models/Log";
import {bufferToUuid} from "./Utils";
import ModelFactory from "./db/ModelFactory";

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

export type LogLevelKeys = keyof typeof LogLevel;

/**
 * TODO: make logger not static
 */
export default class Logger {
    private static logLevel: LogLevel = LogLevel[<LogLevelKeys>config.get<string>('log.level')];
    private static dbLogLevel: LogLevel = LogLevel[<LogLevelKeys>config.get<string>('log.db_level')];
    private static verboseMode: boolean = config.get<boolean>('log.verbose');

    public static verbose(): void {
        this.verboseMode = true;
        if (LogLevel[this.logLevel + 1]) this.logLevel++;
        if (LogLevel[this.dbLogLevel + 1]) this.dbLogLevel++;
        Logger.info('Verbose mode');
    }

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

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

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

    public static warn(...message: unknown[]): void {
        this.log(LogLevel.WARN, message);
    }

    public static info(...message: unknown[]): void {
        this.log(LogLevel.INFO, message);
    }

    public static debug(...message: unknown[]): void {
        this.log(LogLevel.DEBUG, message);
    }

    public static dev(...message: unknown[]): void {
        this.log(LogLevel.DEV, message);
    }

    private static log(level: LogLevel, message: unknown[], error?: Error, silent: boolean = false): string | null {
        if (level <= this.logLevel) {
            if (error) {
                if (level > LogLevel.ERROR) this.warn(`Wrong log level ${level} with attached error.`);
            } else {
                if (level <= 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: string | unknown[] | Record<string, unknown>) => {
                        if (!Array.isArray(value) && value instanceof Object) {
                            if (value.type === 'Buffer' && typeof value.data === 'string') {
                                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 = level <= this.dbLogLevel;

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

            const logId = Buffer.alloc(16);
            uuid({}, logId);
            const strLogId = bufferToUuid(logId);
            if (shouldSaveToDB) output += `${strLogId} - `;

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

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

            if (shouldSaveToDB && ModelFactory.has(Log)) {
                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() {
        // disable constructor
    }
}