package webfilesystem

import (
	"context"
	"errors"
	"strings"

	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/bson/primitive"
	"go.mongodb.org/mongo-driver/mongo"
)

type WebFileSystem struct {
	webfsCollection *mongo.Collection
	webfsFilesTable *mongo.Collection
	webfsFilesData  *mongo.Collection
	ctx             context.Context
}

func NewWebFileSystem(mongoClient *mongo.Client, dBName string, fsCollectionName string) *WebFileSystem {
	return &WebFileSystem{
		webfsCollection: mongoClient.Database(dBName).Collection(fsCollectionName), // TODO Check collection is exist
		webfsFilesTable: mongoClient.Database(dBName).Collection("webfs-table"),    // TODO Check collection is exist, //FIXME
		webfsFilesData:  mongoClient.Database(dBName).Collection("webfs-data"),     // TODO Check collection is exist, //FIXME
		ctx:             context.Background(),
	}
}

type FileHeader struct {
	MongoId primitive.ObjectID `bson:"_id"  json:"-"`
	Name    string             `bson:"name" json:"name"`
	Type    string             `bson:"type" json:"type"`
	Icon    string             `bson:"icon"    json:"icon"`
	Data    primitive.ObjectID `bson:"data_id" json:"-"` //TODO rename to DataId
}

func (fh *FileHeader) GetType() string {
	//TODO return by extension and etc
	return fh.Type
}

type BinaryFileData struct {
	MongoId primitive.ObjectID `bson:"_id"  json:"-"`
	Bin     []byte             `bson:"bin" json:"-"`
}

type PlainTextFileData struct {
	MongoId primitive.ObjectID `bson:"_id"  json:"-"`
	Data    string             `bson:"data" json:"data"`
}

// Deprecated
func (fs *WebFileSystem) ReadHeader(fileID primitive.ObjectID) (*FileHeader, error) {
	file := &FileHeader{}
	filter := primitive.M{
		"_id": fileID,
	}
	err := fs.webfsFilesTable.FindOne(fs.ctx, filter).Decode(file)
	return file, err
}

//TODO To private, get name from path and set it to file struct, force set newObjectID
func (fs *WebFileSystem) Write(filePath string, file *FileHeader, data interface{}) (primitive.ObjectID, primitive.ObjectID, error) {
	headerId, dataId, err := fs.writeFileToMongo(file, data)
	if err != nil {
		return primitive.NilObjectID, primitive.NilObjectID, err
	}
	parentPath := fs.GetParentPath(filePath)
	parentDir, err := fs.FindFile(parentPath)
	if err != nil {
		return primitive.NilObjectID, primitive.NilObjectID, err
	}

	if parentDir.IsZero() {
		return primitive.NilObjectID, primitive.NilObjectID, errors.New("parent dir not found")
	}
	err = fs.AppendChildToDirectory(headerId, parentDir)
	if err != nil {
		return primitive.NilObjectID, primitive.NilObjectID, err
	}
	return headerId, dataId, nil
}

func (fs *WebFileSystem) UpdateFileData(file *FileHeader, data interface{}) error {
	update := bson.M{"$set": data}
	// println("updating data file: " + file.MongoId.String())
	res, err := fs.webfsFilesData.UpdateByID(fs.ctx, file.Data, update)
	if err != nil {
		return err
	}
	if res.ModifiedCount < 1 {
		return errors.New("no data updated")
	}
	return err
}

func (fs *WebFileSystem) InitFS() error { //FIXME Can't set parent_id to itself
	rootData := DirectoryData{
		MongoId:  primitive.NewObjectID(),
		Parent:   primitive.NewObjectID(),
		Children: []primitive.ObjectID{},
	}
	rootHeader := FileHeader{
		MongoId: primitive.NewObjectID(),
		Name:    "/",
		Type:    "directory",
		Icon:    "",
	}
	_, _, err := fs.writeFileToMongo(&rootHeader, &rootData)
	if err != nil {
		return err
	}
	return nil
}

//TODO get on boot and safe to struct
func (fs *WebFileSystem) GetRootDir() (*FileHeader, *DirectoryData, error) {
	filter := primitive.M{
		"name": "/",
	}
	res := fs.webfsFilesTable.FindOne(fs.ctx, filter)
	if res == nil {
		return nil, nil, errors.New("TODO") //TODO
	}
	rootDir := FileHeader{}
	err := res.Decode(&rootDir)
	if res == nil {
		return nil, nil, err
	}

	filterData := primitive.M{
		"_id": rootDir.Data,
	}
	resData := fs.webfsFilesData.FindOne(fs.ctx, filterData)
	if resData.Err() != nil {
		return nil, nil, err
	}
	rootDirData := DirectoryData{}
	err = resData.Decode(&rootDirData)
	if err != nil {
		return nil, nil, err
	}
	return &rootDir, &rootDirData, nil
}

func (fs *WebFileSystem) Remove(filePath string) error {
	parentPath := fs.GetParentPath(filePath)
	parentDirId, err := fs.FindFile(parentPath)
	if err != nil {
		return err
	}
	//TODO: Check, if parent file is dir
	parentDirData := DirectoryData{}
	parentDir, err := fs.readFSDocs(parentDirId, &parentDirData)
	if err != nil {
		return err
	}

	fileId, err := fs.FindFile(filePath)
	if err != nil {
		return err
	}
	newChildren := []primitive.ObjectID{}
	for _, childId := range parentDirData.Children {
		if childId != fileId {
			newChildren = append(newChildren, childId)
		}
	}

	parentDirData.Children = newChildren
	err = fs.UpdateFileData(parentDir, parentDirData)
	if err != nil {
		return err
	}
	return nil
}

func (fs *WebFileSystem) SplitPath(path string) []string {
	resPath := []string{}
	splittedPath := strings.Split(path, "/")
	splittedPath[0] = "/"
	for _, split := range splittedPath {
		if split != "" {
			resPath = append(resPath, split)
		}
	}
	return resPath
}

func (fs *WebFileSystem) GetExtension(filename string) string {
	splittedName := strings.Split(filename, ".")

	return splittedName[len(splittedName)-1]
}

func (fs *WebFileSystem) GetParentPath(path string) string {
	splittedPath := fs.SplitPath(path)
	if len(splittedPath) > 1 {
		return "/" + strings.Join(splittedPath[1:len(splittedPath)-1], "/")
	}
	return "/"
}