package webfilesystem

import (
	"errors"

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

type V3FileHeader struct {
	MongoId primitive.ObjectID `bson:"_id"  json:"-"`
	Name    string             `bson:"name" json:"name"`
	Type    string             `bson:"type" json:"type"`
	Icon    string             `bson:"-"    json:"icon"`
	Data    primitive.ObjectID `bson:"data_id" json:"-"`
}
type V3FileBinaryData struct {
	MongoId primitive.ObjectID `bson:"_id"  json:"-"`
	Bin     []byte             `bson:"bin" json:"-"`
}

func (fs *WebFileSystem) V3ReadHeader(fileID primitive.ObjectID) (*V3FileHeader, error) {
	file := &V3FileHeader{}
	filter := primitive.M{
		"_id": fileID,
	}
	err := fs.webfsFilesTable.FindOne(fs.ctx, filter).Decode(file)
	return file, err
}

func (fs *WebFileSystem) V3Read(fileID primitive.ObjectID, fileData interface{}) (*V3FileHeader, error) {
	fileHeader := &V3FileHeader{}
	filter := primitive.M{
		"_id": fileID,
	}
	err := fs.webfsFilesTable.FindOne(fs.ctx, filter).Decode(fileHeader)
	if err != nil {
		return nil, err
	}
	if fileData != nil {
		filter := primitive.M{
			"_id": fileHeader.Data,
		}
		err := fs.webfsFilesData.FindOne(fs.ctx, filter).Decode(fileData)
		if err != nil {
			return nil, err
		}
	}
	return fileHeader, nil
}

func (fs *WebFileSystem) V3Write(filePath string, file *V3FileHeader, data interface{}) (primitive.ObjectID, primitive.ObjectID, error) {
	headerId, dataId, err := fs.v3WriteFileToMongo(file, data)
	if err != nil {
		return primitive.NilObjectID, primitive.NilObjectID, err
	}
	parentPath := fs.GetParentPath(filePath)
	parentDir, err := fs.V3FindFile(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.V3AppendChildToDirectory(headerId, parentDir)
	if err != nil {
		return primitive.NilObjectID, primitive.NilObjectID, err
	}
	return headerId, dataId, nil
}

func (fs *WebFileSystem) v3WriteFileToMongo(file *V3FileHeader, data interface{}) (primitive.ObjectID, primitive.ObjectID, error) {
	resData, err := fs.webfsFilesData.InsertOne(fs.ctx, data)
	if err != nil {
		return primitive.NilObjectID, primitive.NilObjectID, err
	}
	file.Data = resData.InsertedID.(primitive.ObjectID)
	resHeader, err := fs.webfsFilesTable.InsertOne(fs.ctx, file)
	if err != nil {
		return primitive.NilObjectID, primitive.NilObjectID, err
	}
	return resHeader.InsertedID.(primitive.ObjectID), resData.InsertedID.(primitive.ObjectID), err
}

func (fs *WebFileSystem) V3WriteUpdateData(file *V3FileHeader, 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) V3InitFS() error { //FIXME Can't set parent_id to itself
	rootData := V3DirectoryData{
		MongoId:  primitive.NewObjectID(),
		Parent:   primitive.NewObjectID(),
		Children: []primitive.ObjectID{},
	}
	rootHeader := V3FileHeader{
		MongoId: primitive.NewObjectID(),
		Name:    "/",
		Type:    "directory",
		Icon:    "",
	}
	_, _, err := fs.v3WriteFileToMongo(&rootHeader, &rootData)
	if err != nil {
		return err
	}
	return nil
}

func (fs *WebFileSystem) V3GetRootDir() (*V3FileHeader, *V3DirectoryData, error) {
	filter := primitive.M{
		"name": "/",
	}
	res := fs.webfsFilesTable.FindOne(fs.ctx, filter)
	if res == nil {
		return nil, nil, errors.New("TODO") //TODO
	}
	rootDir := V3FileHeader{}
	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 := V3DirectoryData{}
	err = resData.Decode(&rootDirData)
	if err != nil {
		return nil, nil, err
	}
	return &rootDir, &rootDirData, nil
}

func (fs *WebFileSystem) V3Remove(filePath string) error {
	parentPath := fs.GetParentPath(filePath)
	parentDirId, err := fs.V3FindFile(parentPath)
	if err != nil {
		return err
	}
	//TODO: Check, if parent file is dir
	parentDirData := V3DirectoryData{}
	parentDir, err := fs.V3Read(parentDirId, &parentDirData)
	if err != nil {
		return err
	}

	fileId, err := fs.V3FindFile(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.V3WriteUpdateData(parentDir, parentDirData)
	if err != nil {
		return err
	}
	return nil
}

func (fs *WebFileSystem) removeFromMongo(fileId primitive.ObjectID) error {
	return errors.New("todo not implemented yet")
}