import crypto from "node:crypto";
import { type Session } from "@prisma/client";

import Snowflake from "~/utils/snowflake";

/** Represents a Session token, without expiry data. */
export default class SessionToken {
  userId: bigint;
  sessionId: bigint;
  sessionToken: Buffer;

  constructor(userId: bigint, sessionId?: bigint, sessionToken?: Buffer) {
    this.userId = userId;
    this.sessionId = sessionId ?? new Snowflake().state;
    this.sessionToken = sessionToken ?? crypto.randomBytes(64);
  }

  /** Creates SessionToken from a string.
   * @param string The strinct to create from.
   * @returns The SessionToken object.
   */
  static fromString(string: string): SessionToken {
    const parameters = string.split(".");
    return new SessionToken(
      Buffer.from(parameters[0], "base64").readBigUInt64LE(),
      Buffer.from(parameters[1], "base64").readBigUInt64LE(),
      Buffer.from(parameters[2], "base64"),
    );
  }

  toString(): string {
    const stringUserId = Buffer.copyBytesFrom(new BigUint64Array([this.userId])).toString("base64");
    const stringSessionId = Buffer.copyBytesFrom(new BigUint64Array([this.sessionId])).toString("base64");
    const stringSessionToken = this.sessionToken.toString("base64");
    return `${stringUserId}.${stringSessionId}.${stringSessionToken}`;
  }

  /** Returns this SessionToken as Prisma object.
   * For use in where parameter.
   * @returns this as prisma object.
   */
  toPrisma(): Omit<Session, "expiry_date"> {
    return {
      id: this.sessionId,
      userId: this.userId,
      sessionToken: this.sessionToken,
    };
  }
}