module.exports = {

    UploadObject: class UploadObject {
        constructor(db) {
            this.db = db;
            this.absrc = ['E', 'T', 'X', 'W', 'U', 'R', 'J', 'I', 'N', 'C'];
            this.loaded = false;
            this.fileCache = {};
        }

        new() {
            if (!this.loaded) {
                this.hashsalt = this.makeHash(10);
                this.adminhash = this.makeHash(10);
                var sql = this.db.prepare(`INSERT INTO "upload" (hashsalt, adminhash, upload_unix) VALUES (?, ?, ?)`);
                var result = sql.run(this.hashsalt, this.adminhash, Math.floor(Date.now() / 1000));
                this.id = result.lastInsertRowid;
                this.hashid = this.id2hashid(result.lastInsertRowid);
                this.dir = this.hashid+this.hashsalt;
                var fs = require('fs');
                
                if (!fs.existsSync("uploads/"+this.dir)){
                    fs.mkdirSync("uploads/"+this.dir);
                }

                this.loaded = true;
            }
        }

        load(hash) {
            if (!this.loaded) {
                var shash = this.splitHash(hash);
                this.hashid = shash[0];
                this.id = this.hashid2id(this.hashid)
                this.hashsalt = shash[1];
                this.dir = this.hashid+this.hashsalt;
                
                var sql = this.db.prepare(`SELECT EXISTS(SELECT 1 FROM "upload" WHERE id=? AND hashsalt=? LIMIT 1) AS "exists"`);
                var result = sql.get(this.id, this.hashsalt);
                if (result["exists"]) {
                    console.log("LOADED: ", result);
                    this.loaded = true;
                }
            }
        }
        
        isLoaded() {
            return this.loaded;
        }

        getDir() {
            return this.dir;
        }

        loadFiles() {
            this.files = this.db.prepare(`SELECT filename FROM "file" WHERE upload_id=?`).all(this.id);
            console.log(this.files);
        }

        getFiles() {
            this.loadFiles();
            return this.files;
        }

        registerFile(filename) {
            var sql = this.db.prepare(`INSERT INTO "file" (filename, upload_id) VALUES (?, ?)`);
            var result = sql.run(filename, this.id);
            return result;
        }

        delete() {

        }

        getHash() {
            return this.hashid+this.hashsalt;
        }
        
        getHashId() {
            return this.hashid;
        }

        getAdminHash() {
            return this.adminhash;
        }


        id2hashid(id) {
            var hashid = "";
            id = id.toString();
            for (var i = 0; i < id.length; i++) {
                hashid += this.absrc[id.charAt(i)];
            }
            return hashid;
        }

        hashid2id(hashid) {
            var id = "";
            for (var i = 0; i < hashid.length; i++) {
                var index = this.absrc.findIndex((letter) => letter == hashid.charAt(i));
                if (!(index < 0)) {
                    id = id + index.toString();
                };
            }
            return parseInt(id);
        }

        // https://stackoverflow.com/questions/1349404/generate-random-string-characters-in-javascript
        makeHash(len = 10) {
            let result = '';
            const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
            const charactersLength = characters.length;
            let counter = 0;
            while (counter < len) {
                result += characters.charAt(Math.floor(Math.random() * charactersLength));
                counter += 1;
            }
            return result;
        }

        splitHash(hash) {
            return [hash.slice(0, hash.length - 10), hash.slice(hash.length - 10, hash.length)]
        }

    },

    SqliteHandler: class SqliteHandler {
        constructor(path) {
            this.loaded = false;
            this.path = path;
            this.db = require('better-sqlite3')(this.path);
            this.db.prepare(`CREATE TABLE IF NOT EXISTS "user" (
            "id"	INTEGER NOT NULL UNIQUE,
            "name"	TEXT NOT NULL UNIQUE,
            "password"	TEXT NOT NULL,
            "email"	INTEGER,
            "admin"	INTEGER,
            PRIMARY KEY("id" AUTOINCREMENT)
            )`).run();

            this.db.prepare(`CREATE TABLE IF NOT EXISTS "upload" (
            "id"	INTEGER NOT NULL UNIQUE,
            "hashsalt"	TEXT NOT NULL UNIQUE,
            "adminhash"	TEXT NOT NULL UNIQUE,
            "desc"	TEXT,
            "password"	TEXT,
            "owner_id"	INTEGER,
            "upload_unix"	INTEGER,
            PRIMARY KEY("id" AUTOINCREMENT),
            FOREIGN KEY("owner_id") REFERENCES "user"("id")
            )`).run();

            this.db.prepare(`CREATE TABLE IF NOT EXISTS "file" (
                "id"	INTEGER NOT NULL UNIQUE,
                "filename"	TEXT NOT NULL,
                "upload_id"	INTEGER NOT NULL,
                "state" INTEGER NOT NULL,
                PRIMARY KEY("id" AUTOINCREMENT),
                FOREIGN KEY("upload_id") REFERENCES "upload"("id")
            )`).run();
        }

        getDatabaseObj() {
            return this.db;
        }
    }

}