/*
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements.  See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License.  You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package main

import (
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"path"
	"path/filepath"
	"strings"
	"time"

	"github.com/shurcooL/httpfs/filter"
	"github.com/shurcooL/vfsgen"
)

func main() {
	if len(os.Args) != 2 {
		println("usage: vfs-gen directory")
		os.Exit(1)
	}

	dirName := os.Args[1]
	dir, err := os.Stat(dirName)
	if err != nil {
		log.Fatalln(err)
	}
	if !dir.IsDir() {
		fmt.Printf("path %s is not a directory\n", dirName)
		os.Exit(1)
	}

	var exclusions []string
	if err := filepath.Walk(dirName, func(resPath string, info os.FileInfo, err error) error {
		if info.IsDir() {
			ignoreFileName := path.Join(resPath, ".vfsignore")
			_, err := os.Stat(ignoreFileName)
			if err == nil {
				rel, err := filepath.Rel(dirName, resPath)
				if err != nil {
					log.Fatalln(err)
				}
				if !strings.HasPrefix(rel, "/") {
					rel = "/" + rel
				}
				exclusions = append(exclusions, rel)
			} else if !os.IsNotExist(err) {
				log.Fatalln(err)
			}
		}
		return nil
	}); err != nil {
		log.Fatalln(err)
	}

	var fs http.FileSystem = modTimeFS{
		fs: http.Dir(dirName),
	}
	fs = filter.Skip(fs, filter.FilesWithExtensions(".go"))
	fs = filter.Skip(fs, func(path string, fi os.FileInfo) bool {
		for _, ex := range exclusions {
			if strings.HasPrefix(path, ex) {
				return true
			}
		}
		return false
	})

	resourceFile := path.Join(dirName, "resources.go")
	err = vfsgen.Generate(fs, vfsgen.Options{
		Filename:    resourceFile,
		PackageName: path.Base(dirName),
	})
	if err != nil {
		log.Fatalln(err)
	}

	header := `/*
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements.  See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License.  You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

`
	content, err := ioutil.ReadFile(resourceFile)
	if err != nil {
		log.Fatalln(err)
	}
	var finalContent []byte
	finalContent = append(finalContent, []byte(header)...)
	finalContent = append(finalContent, content...)
	if err := ioutil.WriteFile(resourceFile, finalContent, 0777); err != nil {
		log.Fatalln(err)
	}

}

// modTimeFS wraps http.FileSystem to set mod time to 0 for all files
type modTimeFS struct {
	fs http.FileSystem
}

func (fs modTimeFS) Open(name string) (http.File, error) {
	f, err := fs.fs.Open(name)
	if err != nil {
		return nil, err
	}
	return modTimeFile{f}, nil
}

type modTimeFile struct {
	http.File
}

func (f modTimeFile) Stat() (os.FileInfo, error) {
	fi, err := f.File.Stat()
	if err != nil {
		return nil, err
	}
	return modTimeFileInfo{fi}, nil
}

type modTimeFileInfo struct {
	os.FileInfo
}

func (modTimeFileInfo) ModTime() time.Time {
	return time.Time{}
}