package images

import (
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"strings"
)

var ErrNotAnImage = errors.New("not an image")

func (s *Service) getMime(path string) (mimeType string, err error) {
	info, err := s.fs.Stat(path)
	if err != nil {
		err = fmt.Errorf("image file info could not be fetched")
	}

	if mimer, ok := info.(interface{ ContentType() string }); ok {
		mimeType = mimer.ContentType()
	}

	return
}

func (s *Service) GetImage(ctx context.Context, uid string) (img io.Reader, mimeType string, err error) {
	path, err := PathFromUID(uid)
	if err != nil {
		err = fmt.Errorf("could not get path: %w", err)
		return
	}
	mimeType, err = s.getMime(path)
	if err != nil {
		return
	}

	if !strings.HasPrefix(mimeType, "image") {
		err = ErrNotAnImage
		return
	}

	file, err := s.fs.Read(path)
	if err != nil {
		err = fmt.Errorf("image file could not be fetched")
	}

	return bytes.NewBuffer(file), mimeType, err
}