import * as plugins from '../plugins.js';
import { LoginSessionManager } from './classes.loginsessionmanager.js';
import { User } from './classes.user.js';

export type TRefreshTokenValidationResult = 'current' | 'invalid' | 'invalidated' | 'reused';

/**
 * a LoginSession keeps track of a login over the whole time of the user being loggedin
 */
@plugins.smartdata.Manager()
export class LoginSession extends plugins.smartdata.SmartDataDbDoc<
  LoginSession,
  plugins.idpInterfaces.data.ILoginSession,
  LoginSessionManager
> {
  // ======
  // static
  // ======
  public static async createLoginSessionForUser(userArg: User, deleteOtherSessions = false) {
    const loginSession = new LoginSession();
    loginSession.id = plugins.smartunique.shortId();
    loginSession.data.userId = userArg.id;
    await loginSession.save();
    return loginSession;
  }

  public static async clearLoginSessionsForUser(userArg: User) {
    // lets find existing sessions
    const existingSessions = await LoginSession.getInstances({
      id: userArg.id,
    });

    for (const existingSession of existingSessions) {
      await existingSession.delete();
    }
  }

  public static async getLoginSessionBySessionId(sessionIdArg: string) {
    return await LoginSession.getInstance({
      id: sessionIdArg,
    });
  }

  public static async getLoginSessionByRefreshToken(refreshTokenArg: string) {
    const refreshTokenHash = await LoginSession.hashSessionToken(refreshTokenArg);
    let loginSession = await LoginSession.getInstance({
      'data.refreshTokenHash': refreshTokenHash,
    });
    if (loginSession) {
      return loginSession;
    }
    loginSession = await LoginSession.getInstance({
      data: {
        refreshToken: refreshTokenArg,
      },
    });
    return loginSession;
  }

  public static async hashSessionToken(tokenArg: string) {
    return plugins.smarthash.sha256FromString(tokenArg);
  }

  public static createOpaqueToken(prefixArg: string) {
    return `${prefixArg}${plugins.crypto.randomBytes(32).toString('base64url')}`;
  }

  // ========
  // INSTANCE
  // ========
  @plugins.smartdata.unI()
  public id: string;

  @plugins.smartdata.svDb()
  public data: plugins.idpInterfaces.data.ILoginSession['data'] = {
    userId: null,
    validUntil: Date.now() + plugins.smarttime.getMilliSecondsFromUnits({ weeks: 1 }),
    invalidated: false,
    refreshToken: null,
    refreshTokenHash: null,
    rotatedRefreshTokenHashes: [],
    transferTokenHash: null,
    transferTokenExpiresAt: null,
    deviceId: null,
    deviceInfo: null,
    createdAt: Date.now(),
    lastActive: Date.now(),
  };

  public transferToken: string | null = null;

  constructor() {
    super();
  }

  /**
   * invalidates a session
   */
  public async invalidate() {
    this.data.invalidated = true;
    this.data.refreshToken = null;
    this.data.refreshTokenHash = null;
    this.data.transferTokenHash = null;
    this.data.transferTokenExpiresAt = null;
    await this.save();
  }

  /**
   * a refresh token is unique to a login session and rotated whenever it is issued
   * @returns
   */
  public async getRefreshToken() {
    if (this.data.invalidated) {
      return null;
    }
    const previousRefreshTokenHash =
      this.data.refreshTokenHash ||
      (this.data.refreshToken
        ? await LoginSession.hashSessionToken(this.data.refreshToken)
        : null);

    if (previousRefreshTokenHash) {
      this.data.rotatedRefreshTokenHashes = [
        ...(this.data.rotatedRefreshTokenHashes || []),
        previousRefreshTokenHash,
      ].slice(-5);
    }

    const refreshToken = LoginSession.createOpaqueToken('refresh_');
    this.data.refreshTokenHash = await LoginSession.hashSessionToken(refreshToken);
    this.data.refreshToken = null;
    this.data.lastActive = Date.now();
    await this.save();
    return refreshToken;
  }

  public async getTransferToken() {
    this.transferToken = LoginSession.createOpaqueToken('transfer_');
    this.data.transferTokenHash = await LoginSession.hashSessionToken(this.transferToken);
    this.data.transferTokenExpiresAt =
      Date.now() + plugins.smarttime.getMilliSecondsFromUnits({ minutes: 5 });
    await this.save();
    return this.transferToken;
  }

  public async validateRefreshToken(
    refreshTokenArg: string
  ): Promise<TRefreshTokenValidationResult> {
    if (this.data.invalidated) {
      return 'invalidated';
    }

    const refreshTokenHash = await LoginSession.hashSessionToken(refreshTokenArg);

    if (
      this.data.refreshTokenHash === refreshTokenHash ||
      (!!this.data.refreshToken && this.data.refreshToken === refreshTokenArg)
    ) {
      return 'current';
    }

    if ((this.data.rotatedRefreshTokenHashes || []).includes(refreshTokenHash)) {
      return 'reused';
    }

    return 'invalid';
  }

  public async validateTransferToken(transferTokenArg: string) {
    if (this.data.invalidated || !this.data.transferTokenHash) {
      return false;
    }

    if (
      this.data.transferTokenExpiresAt &&
      this.data.transferTokenExpiresAt < Date.now()
    ) {
      this.data.transferTokenHash = null;
      this.data.transferTokenExpiresAt = null;
      await this.save();
      return false;
    }

    const result =
      this.data.transferTokenHash ===
      (await LoginSession.hashSessionToken(transferTokenArg));

    // a transfer token can only be used once, so we invalidate it here
    if (result) {
      this.transferToken = null;
      this.data.transferTokenHash = null;
      this.data.transferTokenExpiresAt = null;
      await this.save();
    }
    return result;
  }
}