tiled.go

/*
Copyright (c) 2017 Lauris Bukšis-Haberkorns <lauris@nix.lv>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

package tiled

import (
	"encoding/xml"
	"io"
	"io/fs"
	"os"
	"path/filepath"
)

// LoadReader function loads tiled map in TMX format from io.Reader
// baseDir is used for loading additional tile data, current directory is used if empty
func LoadReader(baseDir string, r io.Reader, options ...LoaderOption) (*Map, error) {
	l := newLoader(options...)
	return l.LoadReader(baseDir, r)
}

// LoadFile function loads tiled map in TMX format from file
func LoadFile(fileName string, options ...LoaderOption) (*Map, error) {
	l := newLoader(options...)
	return l.LoadFile(fileName)
}

// loader provides configuration on how TMX maps and resources are loaded.
type loader struct {
	// A FileSystem that is used for loading TMX files and any external
	// resources it may reference.
	//
	// A nil FileSystem uses the local file system.
	FileSystem fs.FS
}

// LoaderOption is used with LoadReader and LoadFile functions to pass additional options
type LoaderOption func(*loader)

func newLoader(options ...LoaderOption) *loader {
	l := &loader{}
	for _, opt := range options {
		opt(l)
	}
	return l
}

// open opens the given file using the Loader's FileSystem, or uses os.Open
// if l or l.FileSystem is nil.
func (l *loader) open(name string) (fs.File, error) {
	if l == nil || l.FileSystem == nil {
		return os.Open(name)
	}
	return l.FileSystem.Open(name)
}

// WithFileSystem returns an option to load level from a passed filesystem
func WithFileSystem(fileSystem fs.FS) LoaderOption {
	return func(l *loader) {
		l.FileSystem = fileSystem
	}
}

// LoadReader function loads tiled map in TMX format from io.Reader
// baseDir is used for loading additional tile data, current directory is used if empty
func (l *loader) LoadReader(baseDir string, r io.Reader) (*Map, error) {
	d := xml.NewDecoder(r)

	m := &Map{
		loader:  l,
		baseDir: baseDir,
	}
	if err := d.Decode(m); err != nil {
		return nil, err
	}

	return m, nil
}

// LoadFile function loads tiled map in TMX format from file
func (l *loader) LoadFile(fileName string) (*Map, error) {
	f, err := l.open(fileName)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	dir := filepath.Dir(fileName)
	return l.LoadReader(dir, f)
}