package helper

import (
	"fmt"
	"log"
	"os"
	"path/filepath"
	"runtime"
	"time"
)

type Level int

var (
	DefaultPrefix      = ""
	DefaultCallerDepth = 2

	logger     *log.Logger
	logPrefix  = ""
	levelFlags = []string{"DEBUG", "INFO", "WARN", "ERROR", "FATAL"}
)

const (
	DEBUG Level = iota
	INFO
	WARNING
	ERROR
	FATAL
)

// Setup initialize the log instance
func Setup() {
	logger = log.New(os.Stdout, DefaultPrefix, log.Flags()&^(log.Ldate|log.Ltime))
}

// Debug output logs at debug level
func Debug(v ...interface{}) {
	setPrefix(DEBUG)
	logger.Println(v...)
}

// Info output logs at info level
func Info(v ...interface{}) {
	setPrefix(INFO)
	logger.Println(v...)
}

// Warn output logs at warn level
func Warn(v ...interface{}) {
	setPrefix(WARNING)
	logger.Println(v...)
}

// Error output logs at error level
func Error(v ...interface{}) {
	prefix := setPrefix(ERROR)
	logger.Println(v...)

	prefix.msg = v
}

// Fatal output logs at fatal level
func Fatal(v ...interface{}) {
	setPrefix(FATAL)
	logger.Fatalln(v...)
}

// setPrefix set the prefix of the log output
func setPrefix(level Level) prefix {
	_, file, line, ok := runtime.Caller(DefaultCallerDepth)
	if ok {
		logPrefix = fmt.Sprintf("[%s:%d] [%s] ", filepath.Base(file), line, levelFlags[level])
	} else {
		logPrefix = fmt.Sprintf("[%s] ", levelFlags[level])
	}

	logPrefix += "| " + time.Now().Format("01.02.2006 15:04:05") + " | "

	logger.SetPrefix(logPrefix)
	return prefix{prefix: logPrefix}
}

type prefix struct {
	prefix string
	msg    interface{}
}