package progress

import (
	"fmt"
	"os"
	"path/filepath"
)

// progressLogger provides a wrapper around an os.File that can either
// write to the file or ignore all writes completely.
type progressLogger struct {
	writeData bool
	log       *os.File
}

// Write will write to the file and perform a Sync() if writing succeeds.
func (l *progressLogger) Write(b []byte) error {
	if l.writeData {
		if _, err := l.log.Write(b); err != nil {
			return err
		}
		return l.log.Sync()
	}
	return nil
}

// Close will call Close() on the underlying file
func (l *progressLogger) Close() error {
	if l.log != nil {
		return l.log.Close()
	}
	return nil
}

// Shutdown will cause the logger to ignore any further writes. It should
// be used when writing causes an error.
func (l *progressLogger) Shutdown() {
	l.writeData = false
}

// newProgressLogger creates a progressLogger with a log file path.
// If a log file is able to be created, the logger will write to the file. If
// there is an err creating the file, the logger will ignore all writes.
func newProgressLogger(logPath string) (*progressLogger, error) {

	if len(logPath) == 0 {
		return &progressLogger{}, nil
	}
	if !filepath.IsAbs(logPath) {
		return &progressLogger{}, fmt.Errorf("GIT_LFS_PROGRESS must be an absolute path")
	}

	cbDir := filepath.Dir(logPath)
	if err := os.MkdirAll(cbDir, 0755); err != nil {
		return &progressLogger{}, err
	}

	file, err := os.OpenFile(logPath, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0666)
	if err != nil {
		return &progressLogger{}, err
	}

	return &progressLogger{true, file}, nil
}