import { Buffer } from "node:buffer";
import config from "../config.ts"
import User from "../data/User.ts"
import crypto from 'node:crypto'

interface Token {
    author: string
    auth: string
    made_time: number
    expired_time: number
}

function normalizeKey(key: string, keyLength = 32) {
    const hash = crypto.createHash('sha256')
    hash.update(key)
    const keyBuffer = hash.digest()
    return keyLength ? keyBuffer.slice(0, keyLength) : keyBuffer
}

export default class TokenManager {
    // TODO: 單令牌 -》 單 + 刷新 with 多設備管理
    static makeAuth(user: User) {
        return crypto.createHash("sha256").update(user.bean.id + user.getPassword() + config.salt).digest().toString('hex')
    }
    static encode(token: Token) {
        return crypto.createCipheriv("aes-256-gcm", normalizeKey(config.aes_key), '01234567890123456').update(
            JSON.stringify(token)
        ).toString('hex')
    }
    static decode(token: string) {
        return JSON.parse(crypto.createDecipheriv("aes-256-gcm", normalizeKey(config.aes_key), '01234567890123456').update(
            Buffer.from(token, 'hex')
        ).toString()) as Token
    }

    static make(user: User, time: number = Date.now()) {
        return this.encode({
            author: user.bean.id,
            auth: this.makeAuth(user),
            made_time: time,
            expired_time: time + (1 * 1000 * 60 * 60 * 24),
        })
    }
    static makeNewer(user: User, token: string) {
        if (this.check(user, token))
            return this.make(user, Date.now() + (1 * 1000 * 60 * 60 * 24))
    }
    static check(user: User, token: string) {
        const tk = this.decode(token)

        return this.makeAuth(user) == tk.auth
    }
}