const ObjectID    = require("mongodb").ObjectID;
const {connect}   = require('mm')

module.exports = async (dbName='hipstagram') => {
    const {Savable, slice} = await connect(dbName)

    async function getModels({id}){
        const SlicedSavable = slice([id, 'user'])

        class User extends SlicedSavable {
            constructor(...params){
                super(...params)
                //TODO: calc likes count by getter (no two-way relation for this to avoid overflow on many Kilos of likes
                //cached like count, which incremented and decremented
                //
                //following and followers array

            }


            static get relations(){ //don't needed due to ___owner in most cases
                return {
                    avatar : "userAvatar",
                    incomings: "to",
                    followers: ["following"],
                    following: ["followers"],
                }
            }

            static get guestRelations(){
                return ["followers"]
            }
        }
        SlicedSavable.addClass(User)

        class OwnerSlicedSavable extends SlicedSavable {
            get owner(){
                if (!this.___owner) return this.___owner

                return SlicedSavable.m.User.findOne({_id: ObjectID(this.___owner)})
            }
        }

        class Like extends OwnerSlicedSavable {
            constructor(...params){
                super(...params)
                //TODO: 
                //entity
                //entityLikesCount?
            }



            static get relations(){
                return {
                }
            }

            static get defaultPermissions(){
                return {
                    //savable refs, objectid's, words like 'tags' or 'roles'
                    read: ['owner', 'user'],
                    write: ['owner'],
                    create: ['user'],
                    delete: ['owner'],

                    /*permission
                     * TODO: permissions for read and write permissions
                     *
                     */
                }
            }
        }
        SlicedSavable.addClass(Like)

        class Post extends OwnerSlicedSavable {
            constructor(...params){
                super(...params)
                //TODO: calc likes count by getter (no two-way relation for this to avoid overflow on many Kilos of likes
                //cached like count, which incremented and decremented
                //

            }

            get likes(){
                return (async () => {
                    let result = []
                    for (let like of SlicedSavable.m.Like.find({'post._id': this._id}, {limit: [100], sort: ['_id', 1]})){
                        try {await like; result.push(like) } catch(e) {}
                    }
                    return result;
                })()
            }


            static get relations(){
                return {
                    images: ["posts"],
                    comments: "post",
                    directs: "post",
                    collections: ["posts"]
                }
            }

            static get guestRelations(){
                return ["comments", "directs"]
            }

            static get defaultPermissions(){
                return {
                    //savable refs, objectid's, words like 'tags' or 'roles'
                    read: ['owner', 'user'],
                    write: ['owner'],
                    create: ['user'],
                    delete: ['owner', 'admin'],

                    /*permission
                     * TODO: permissions for read and write permissions
                     *
                     */
                }
            }
        }
        SlicedSavable.addClass(Post)

        class Image extends OwnerSlicedSavable {
            constructor(...params){
                super(...params)
            }


            static async fromFileData(fileData){
                let image  = new Image({})
                image.fileData = fileData
                image.url      = `images/${fileData.filename}`
                image.originalFileName = fileData.originalname
                await image.save()
                return image;
            }

            async save(...params){
                if (this.userAvatar){
                    if (this.userAvatar._id.toString() !== id){
                        throw new ReferenceError(`You can't set ava for other user`)
                    }
                }

                return await super.save(...params)
            }

            static get relations(){
                return {
                    userAvatar: "avatar", //if it is ava
                    posts: ["images"],      //if in post: m2m with posts
                    directs: "image",     //if in direct: m2o with directs
                }
            }

        }
        SlicedSavable.addClass(Image)

        class Comment extends OwnerSlicedSavable {
            constructor(...params){
                super(...params)
                //TODO: calc likes count by getter (no two-way relation for this to avoid overflow on many Kilos of likes
                //cached like count, which incremented and decremented
            }


            static get relations(){
                return {
                    post: ["comments"],
                    answers: "answerTo",
                    answerTo: ["answers"],
                }
            }

            static get guestRelations(){
                return ["answers"]
            }
        }
        SlicedSavable.addClass(Comment)


        class Direct extends OwnerSlicedSavable {
            constructor(...params){
                super(...params)
            }


            static get relations(){
                return {
                    to: ["incomings"],
                    image: ["directs"],
                    likes: "entity",
                }
            }

            static get guestRelations(){
                return ["to", "likes"]
            }
        }
        SlicedSavable.addClass(Direct)

        class Collection extends OwnerSlicedSavable {
            constructor(...params){
                super(...params)
            }

                        

            static get relations(){
                return {
                    posts: "collections"
                }
            }
        }
        SlicedSavable.addClass(Collection)





        const thisUser = await Savable.m.User.findOne({_id: ObjectID(id)})

        return {models: {
                            SlicedSavable, ...SlicedSavable.classes
                        }, 
                thisUser}
    }

    return {
        Savable, 
        slice,
        getModels
    }
}