import * as _ from "lodash";
import * as assert from "assert";

import * as winston from "winston";
// import * as winston_logstash from "winston-logstash";


const TRANSPORT_OPTIONS: any = {

    File: function(config) {
        let options = _.extend({
            name: 'common',
            filename: 'service.log'
        }, config);
        return new winston.transports.File(options);
    },

    Console: function(config) {
        let options = _.extend({
            colorize: true,
            humanReadableUnhandledException: true
        }, config);
        return new winston.transports.Console(options);
    }

};
TRANSPORT_OPTIONS.file = TRANSPORT_OPTIONS.File;
TRANSPORT_OPTIONS.console = TRANSPORT_OPTIONS.Console;
let NODE_ENV = process.env.NODE_ENV || "development";
let IS_DEV = (NODE_ENV=="development");

let _create_transports = function  (config) {
    assert(config, "missing config");

    let transports = [];

    // each key/value is a transport
    _.each(config, function (options: any, name: string) {

        let _o = options as any;
        if (_.isObject(options) && !(_o.enabled===false)) {
            // transport destination can be explicit or implicit declared
            let type = _o.to || name;

            assert(TRANSPORT_OPTIONS[type], 'api:logger:transport:not-found:'+type);
            let logger = TRANSPORT_OPTIONS[type](options);
            transports.push(logger);
//            context.log({ code:  "api:logger:transport", name: name, message: "log to "+type } );
        }
    });

    if (IS_DEV && !(config.console || config.Console) ) {
        transports.push( TRANSPORT_OPTIONS.Console({ enabled: true }) );
        console.log( "development always logs to Console" );
    }
    return transports;
}

export function define_logger(options: any) {

    if (options.enabled===false) {
        console.log("logging is explicitly disabled");
        return null;
    }

    let _transports = _create_transports(options);
    assert(_transports, 'api:logger:transports:missing');

    return winston.createLogger({
        level: options.loglevel || IS_DEV?'debug':'info',
        format: winston.format.json(),
        transports: _transports
    });
}