package main

import (
	"fmt"
	"io"
	"log"
	"os"
	"time"
)

type logWriter struct {
	level  string
	writer io.Writer
}

func (w logWriter) Write(bytes []byte) (int, error) {
	timestamp := time.Now().UTC().Format(time.RFC3339)
	return fmt.Fprintf(w.writer, timestamp + " ["+w.level+"]\t"+string(bytes))
}

type logger struct {
	infoLogger  *log.Logger
	errorLogger *log.Logger
	debugLogger *log.Logger
}

func newLogger(debug bool) *logger {
	infoLogWriter := logWriter{
		level:  "INFO",
		writer: os.Stdout,
	}
	infoLogger := log.New(infoLogWriter, "", 0)

	errorLogWriter := logWriter{
		level:  "ERROR",
		writer: os.Stderr,
	}
	errorLogger := log.New(errorLogWriter, "", 0)

	var baseDebugWriter io.Writer

	if debug {
		baseDebugWriter = os.Stdout
	} else {
		baseDebugWriter = io.Discard
	}

	debugLogWriter := logWriter{
		level:  "DEBUG",
		writer: baseDebugWriter,
	}
	debugLogger := log.New(debugLogWriter, "", log.Lshortfile)

	l := logger{
		infoLogger:  infoLogger,
		errorLogger: errorLogger,
		debugLogger: debugLogger,
	}

	return &l
}

func (l *logger) Infoln(v ...interface{}) {
	l.infoLogger.Println(v...)
}

func (l *logger) Infof(format string, v ...interface{}) {
	l.infoLogger.Printf(format, v...)
}

func (l *logger) Errorln(v ...interface{}) {
	l.errorLogger.Fatalln(v...)
}

func (l *logger) Errorf(format string, v ...interface{}) {
	l.errorLogger.Fatalf(format, v...)
}

func (l *logger) Debugln(v ...interface{}) {
	l.debugLogger.Println(v...)
}

func (l *logger) Debugf(format string, v ...interface{}) {
	l.debugLogger.Printf(format, v...)
}