import * as crypto from "crypto";
import * as bcrypt  from "bcryptjs";
import * as jsonwebtoken from "jsonwebtoken";
import { Config } from "./Config";
import { TokenUser } from "./Message";

export class Crypt {
    static encryption_key:string = Config.aes_secret.substr(0,32); // must be 256 bytes (32 characters)
    static iv_length:number = 16; // for AES, this is always 16
    static bcrypt_salt_rounds:number = 12;

    static encrypt(text:string):string {
        let iv:Buffer = crypto.randomBytes(Crypt.iv_length);
        let cipher:crypto.Cipher = crypto.createCipheriv("aes-256-cbc", Buffer.from(Crypt.encryption_key), iv);
        let encrypted:Buffer = cipher.update((text as any));
        encrypted = Buffer.concat([encrypted, cipher.final()]);
        return iv.toString("hex") + ":" + encrypted.toString("hex");
    }

    static decrypt(text:string):string {
        let textParts:string[] = text.split(":");
        let iv:Buffer = Buffer.from(textParts.shift(), "hex");
        let encryptedText:Buffer = Buffer.from(textParts.join(":"), "hex");
        let decipher:crypto.Decipher = crypto.createDecipheriv("aes-256-cbc", Buffer.from(Crypt.encryption_key), iv);
        let decrypted:Buffer = decipher.update(encryptedText);
        decrypted = Buffer.concat([decrypted, decipher.final()]);
        return decrypted.toString();
    }

    static async hash(password: string):Promise<string> {
        return new Promise<string>(async (resolve, reject) => {
            try {
                bcrypt.hash(password, Crypt.bcrypt_salt_rounds, async (error, hash)=> {
                    if(error) { return reject(error); }
                    resolve(hash);
                });
            } catch (error) {
                reject(error);
            }
        });
    }

    static async compare(password: string, passwordhash:string):Promise<boolean> {
        return new Promise<boolean>(async (resolve, reject) => {
            try {
                bcrypt.compare(password, passwordhash, async (error, res)=> {
                    if(error) { return reject(error); }
                    resolve(res);
                });
            } catch (error) {
                reject(error);
            }
        });
    }

    static createToken(user: TokenUser): string {
        var token:string = jsonwebtoken.sign({ data: user }, Crypt.encryption_key,
            { expiresIn: "1h" }); // 60 (seconds), "2 days", "10h", "7d"
        return token;
    }

    static verityToken(token: string): TokenUser {
        var o:any = jsonwebtoken.verify(token, Crypt.encryption_key);
        o.data = TokenUser.assign(o.data);
        return o.data;
    }
}