package logger

import (
	"io"
	"log"
	"os"
	"path/filepath"
	"sync"

	"gopkg.in/natefinch/lumberjack.v2"
)

var (
	defaultLogger *Logger
	once          sync.Once
)

// Logger wraps the standard log.Logger with file and stdout output
type Logger struct {
	*log.Logger
	fileWriter io.WriteCloser
}

// Init initializes the default logger with both file and stdout output
func Init(logDir, logFileName string, maxSizeMB int, maxBackups int, maxAgeDays int) error {
	var err error
	once.Do(func() {
		defaultLogger, err = New(logDir, logFileName, maxSizeMB, maxBackups, maxAgeDays)
		if err != nil {
			return
		}
		// Replace standard log output with the multi-writer
		multiWriter := io.MultiWriter(os.Stdout, defaultLogger.fileWriter)
		log.SetOutput(multiWriter)
		log.SetFlags(log.LstdFlags | log.Lshortfile)
	})
	return err
}

// New creates a new logger that writes to both stdout and a log file
func New(logDir, logFileName string, maxSizeMB int, maxBackups int, maxAgeDays int) (*Logger, error) {
	// Ensure log directory exists
	if err := os.MkdirAll(logDir, 0755); err != nil {
		return nil, err
	}

	logPath := filepath.Join(logDir, logFileName)

	// Create file writer with rotation
	fileWriter := &lumberjack.Logger{
		Filename:   logPath,
		MaxSize:    maxSizeMB,    // megabytes
		MaxBackups: maxBackups,   // number of backup files
		MaxAge:     maxAgeDays,   // days
		Compress:   true,         // compress old log files
	}

	// Create multi-writer that writes to both stdout and file
	multiWriter := io.MultiWriter(os.Stdout, fileWriter)

	// Create logger with standard flags
	logger := log.New(multiWriter, "", log.LstdFlags|log.Lshortfile)

	return &Logger{
		Logger:     logger,
		fileWriter: fileWriter,
	}, nil
}

// Close closes the file writer
func (l *Logger) Close() error {
	if l.fileWriter != nil {
		return l.fileWriter.Close()
	}
	return nil
}

// GetDefault returns the default logger instance
func GetDefault() *Logger {
	return defaultLogger
}

// Printf logs a formatted message
func Printf(format string, v ...interface{}) {
	if defaultLogger != nil {
		defaultLogger.Printf(format, v...)
	} else {
		log.Printf(format, v...)
	}
}

// Print logs a message
func Print(v ...interface{}) {
	if defaultLogger != nil {
		defaultLogger.Print(v...)
	} else {
		log.Print(v...)
	}
}

// Println logs a message with newline
func Println(v ...interface{}) {
	if defaultLogger != nil {
		defaultLogger.Println(v...)
	} else {
		log.Println(v...)
	}
}

// Fatal logs a message and exits
func Fatal(v ...interface{}) {
	if defaultLogger != nil {
		defaultLogger.Fatal(v...)
	} else {
		log.Fatal(v...)
	}
}

// Fatalf logs a formatted message and exits
func Fatalf(format string, v ...interface{}) {
	if defaultLogger != nil {
		defaultLogger.Fatalf(format, v...)
	} else {
		log.Fatalf(format, v...)
	}
}