package local

import (
	"bytes"
	"code.laria.me/petrific/config"
	"code.laria.me/petrific/objects"
	"code.laria.me/petrific/storage"
	"encoding/hex"
	"fmt"
	"io"
	"os"
	"strings"
)

func joinPath(parts ...string) string {
	return strings.Join(parts, string(os.PathSeparator))
}

func objectDir(id objects.ObjectId) string {
	return joinPath(string(id.Algo), hex.EncodeToString(id.Sum[0:1]))
}

// LocalStorage is a storage implementation that saves your objects on your local filesystem.
//
// Example config:
//
//     [storage.local_test]
//     method="local"
//     path="~/.local/share/petrific" # Save the objects here
type LocalStorage struct {
	Path  string
	index storage.Index
}

func LocalStorageFromConfig(conf config.Config, name string) (storage.Storage, error) {
	var path_wrap struct{ Path string }

	if err := conf.GetStorageConfData(name, &path_wrap); err != nil {
		return nil, err
	}

	return OpenLocalStorage(config.ExpandTilde(path_wrap.Path))
}

func OpenLocalStorage(path string) (l LocalStorage, err error) {
	l.Path = path
	l.index = storage.NewIndex()

	if fi, err := os.Stat(path); os.IsNotExist(err) {
		if err := os.MkdirAll(path, 0755); err != nil {
			return l, err
		}
	} else if err != nil {
		return l, err
	} else if !fi.Mode().IsDir() {
		return l, fmt.Errorf("%s: Not a directory", path)
	}

	f, err := os.Open(joinPath(path, "index"))
	if err != nil {
		if os.IsNotExist(err) {
			err = nil
		}
		return l, err
	}

	if err == nil {
		defer f.Close()
		err = l.index.Load(f)
	}

	return
}

func objectPath(id objects.ObjectId) string {
	return joinPath(objectDir(id), hex.EncodeToString(id.Sum[1:]))
}

func (l LocalStorage) Get(id objects.ObjectId) ([]byte, error) {
	f, err := os.Open(joinPath(l.Path, objectPath(id)))
	if os.IsNotExist(err) {
		return []byte{}, storage.ObjectNotFound
	} else if err != nil {
		return []byte{}, err
	}
	defer f.Close()

	buf := new(bytes.Buffer)
	_, err = io.Copy(buf, f)
	return buf.Bytes(), err
}

func (l LocalStorage) Has(id objects.ObjectId) (bool, error) {
	_, err := os.Stat(joinPath(l.Path, objectPath(id)))
	if err == nil {
		return true, nil
	} else if os.IsNotExist(err) {
		return false, nil
	} else {
		return false, err
	}
}

func (l LocalStorage) Set(id objects.ObjectId, typ objects.ObjectType, raw []byte) error {
	// First, check if the directory exists
	dir := joinPath(l.Path, objectDir(id))
	_, err := os.Stat(dir)
	if os.IsNotExist(err) {
		if err := os.MkdirAll(dir, 0755); err != nil {
			return err
		}
	} else if err != nil {
		return err
	}

	f, err := os.Create(joinPath(l.Path, objectPath(id)))
	if err != nil {
		return err
	}
	defer f.Close()

	_, err = f.Write(raw)
	l.index.Set(id, typ)
	return err
}

func (l LocalStorage) List(typ objects.ObjectType) ([]objects.ObjectId, error) {
	return l.index.List(typ), nil
}

func (l LocalStorage) Close() error {
	f, err := os.Create(joinPath(l.Path, "index"))
	if err != nil {
		return err
	}
	defer f.Close()

	return l.index.Save(f)
}