package maymoon

import (
	"sourcecode.social/reiver/go-errhttp"

	"errors"
	"io/fs"
)

var (
	errNilFile       = errors.New("nil file")
	errNilFileSystem = errors.New("nil file-system")
)

func openFile(filesystem fs.FS, requestpath string) (fs.File, error) {

	if nil == filesystem {
/////////////// RETURN
		return nil, errhttp.InternalServerErrorWrap(errNilFileSystem)
	}

	var relpath string
	{
		var requestpath0 byte = requestpath[0]

		if '/' == requestpath0 {
			relpath = requestpath[1:]
		}
	}

	var file fs.File
	{
		var err error

		file, err = filesystem.Open(relpath)
		if nil != err {
			if errors.Is(err, fs.ErrNotExist) {
/////////////////////////////// RETURN
				return nil, errhttp.ErrNotFound
			}

/////////////////////// RETURN
			return nil, errhttp.InternalServerErrorWrap(err)
		}
		if nil == file {
/////////////////////// RETURN
			return nil, errhttp.InternalServerErrorWrap(errNilFile)
		}
	}

	return file, nil
}