package logging

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

// Setup sets up/configures a FileLogger and prepares it for use.
func (l *FileLogger) Setup() {

	var err error
	var multi io.Writer

	l.Logger = log.Default()
	l.Logger.SetPrefix(l.Prefix + " ")
	if l.writer, err = os.OpenFile(l.Path, appendFlags, logPerm); err != nil {
		log.Panicf("could not open log file \"%v\" for writing: %v\n", l.Path, err)
	}
	// https://stackoverflow.com/a/36719588/733214
	if l.EnableStdOut {
		multi = io.MultiWriter(os.Stdout, l.writer)
	} else {
		multi = l.writer
	}
	l.Logger.SetOutput(multi)
}

// Shutdown cleanly shuts down a FileLogger.
func (l *FileLogger) Shutdown() {

	var err error

	if err = l.writer.Close(); err != nil {
		log.Panicf("could not close log file \"%v\": %v\n", l.Path, err)
	}

}

// GetPrefix returns the prefix used by this FileLogger.
func (l *FileLogger) GetPrefix() string {
	return l.Prefix
}

/*
	DoDebug sets the debug state of this FileLogger.
	Note that this merely acts as a *safety filter* for debug messages to avoid sensitive information being written to the log.
*/
func (l *FileLogger) DoDebug(d bool) {
	l.EnableDebug = d
}

// SetPrefix sets the prefix for this FileLogger.
func (l *FileLogger) SetPrefix(prefix string) {

	l.Prefix = prefix + " "
	l.Logger.SetPrefix(prefix + " ")
}

// Alert writes an ALERT-level message to this FileLogger.
func (l *FileLogger) Alert(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	l.renderWrite(msg, "ALERT")

	return
}

// Crit writes an CRITICAL-level message to this FileLogger.
func (l *FileLogger) Crit(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	l.renderWrite(msg, "CRITICAL")

	return
}

// Debug writes a DEBUG-level message to this FileLogger.
func (l *FileLogger) Debug(s string, v ...interface{}) (err error) {

	if !l.EnableDebug {
		return
	}

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	l.renderWrite(msg, "DEBUG")

	return
}

// Emerg writes an EMERGENCY-level message to this FileLogger.
func (l *FileLogger) Emerg(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	l.renderWrite(msg, "EMERGENCY")

	return
}

// Err writes an ERROR-level message to this FileLogger.
func (l *FileLogger) Err(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	l.renderWrite(msg, "ERROR")

	return
}

// Info writes an INFO-level message to this FileLogger.
func (l *FileLogger) Info(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	l.renderWrite(msg, "INFO")

	return
}

// Notice writes a NOTICE-level message to this FileLogger.
func (l *FileLogger) Notice(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	l.renderWrite(msg, "NOTICE")

	return
}

// Warning writes a WARNING/WARN-level message to this FileLogger.
func (l *FileLogger) Warning(s string, v ...interface{}) (err error) {

	var msg string

	if v != nil {
		msg = fmt.Sprintf(s, v...)
	} else {
		msg = s
	}

	l.renderWrite(msg, "WARNING")

	return
}

// renderWrite prepares/formats a log message to be written to this FileLogger.
func (l *FileLogger) renderWrite(msg, prio string) {

	s := fmt.Sprintf("[%v] %v", prio, msg)

	l.Logger.Println(s)

	return
}