/*
   Copyright 2017-2019 Jan Dittberner

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this program 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 boardvoting

//go:generate go-bindata -pkg $GOPACKAGE -o assets.go ./migrations/... ./static/... ./templates/...

import (
	"bytes"
	"errors"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"
)

var defaultFileTimestamp = time.Now()

type AssetFS struct {
	Asset     func(path string) ([]byte, error)
	AssetDir  func(path string) ([]string, error)
	AssetInfo func(path string) (os.FileInfo, error)
}

type FakeFile struct {
	Path      string
	Dir       bool
	Len       int64
	Timestamp time.Time
}

func (f *FakeFile) Name() string {
	_, name := filepath.Split(f.Path)
	return name
}

func (f *FakeFile) Size() int64 { return f.Len }

func (f *FakeFile) Mode() os.FileMode {
	mode := os.FileMode(0644)
	if f.Dir {
		return mode | os.ModeDir
	}
	return mode
}

func (f *FakeFile) ModTime() time.Time { return f.Timestamp }
func (f *FakeFile) IsDir() bool        { return f.Dir }
func (f *FakeFile) Sys() interface{}   { return nil }

type AssetFile struct {
	*bytes.Reader
	io.Closer
	FakeFile
}

func NewAssetFile(name string, content []byte, timestamp time.Time) *AssetFile {
	if timestamp.IsZero() {
		timestamp = defaultFileTimestamp
	}
	return &AssetFile{
		bytes.NewReader(content),
		ioutil.NopCloser(nil),
		FakeFile{name, false, int64(len(content)), timestamp},
	}
}

func (f *AssetFile) Readdir(count int) ([]os.FileInfo, error) {
	return nil, errors.New("not a directory")
}

func (f *AssetFile) Size() int64 {
	return f.FakeFile.Size()
}

func (f *AssetFile) Stat() (os.FileInfo, error) {
	return f, nil
}

type AssetDirectory struct {
	AssetFile
	ChildrenRead int
	Children     []os.FileInfo
}

func (f *AssetDirectory) Readdir(count int) ([]os.FileInfo, error) {
	if count <= 0 {
		return f.Children, nil
	}
	if f.ChildrenRead+count > len(f.Children) {
		count = len(f.Children) - f.ChildrenRead
	}
	rv := f.Children[f.ChildrenRead : f.ChildrenRead+count]
	f.ChildrenRead += count
	return rv, nil
}

func (f *AssetDirectory) Stat() (os.FileInfo, error) {
	return f, nil
}

func NewAssetDirectory(name string, children []string, fs *AssetFS) *AssetDirectory {
	fileInfos := make([]os.FileInfo, 0, len(children))
	for _, child := range children {
		_, err := fs.AssetDir(filepath.Join(name, child))
		fileInfos = append(fileInfos, &FakeFile{child, err == nil, 0, time.Time{}})
	}
	return &AssetDirectory{
		AssetFile{
			bytes.NewReader(nil),
			ioutil.NopCloser(nil),
			FakeFile{name, true, 0, time.Time{}},
		},
		0,
		fileInfos}
}

func (f *AssetFS) Open(name string) (http.File, error) {
	if len(name) > 0 && name[0] == '/' {
		name = name[1:]
	}
	if b, err := f.Asset(name); err == nil {
		timestamp := defaultFileTimestamp
		if f.AssetInfo != nil {
			if info, err := f.AssetInfo(name); err == nil {
				timestamp = info.ModTime()
			}
		}
		return NewAssetFile(name, b, timestamp), nil
	}
	if children, err := f.AssetDir(name); err == nil {
		return NewAssetDirectory(name, children, f), nil
	} else {
		if strings.Contains(err.Error(), "not found") {
			return nil, os.ErrNotExist
		}
		return nil, err
	}
}

func GetAssetFS() *AssetFS {
	return &AssetFS{Asset: Asset, AssetDir: AssetDir, AssetInfo: AssetInfo}
}