import * as Express from "express";
import Router from "express-promise-router";
import * as jwt from "jsonwebtoken";

import ApiError from "@common/ApiError";
import { ErrorCode } from "@common/ErrorCode";
import {
  TokenGrantPasswordRequest,
  TokenGrantRefreshRequest,
  TokenGrantRequest,
  TokenGrantResponse
} from "@common/httpApi";
import * as tok from "@common/TokenClaims";
import { User } from "@server/entities";
import { ServerState } from "@server/state";

const JWT_SECRET = process.env.JWT_SECRET!;
if (!JWT_SECRET) {
  throw new Error("Must specify JWT_SECRET environment variable");
}

const ISSUER = "sprinklers3";

const ACCESS_TOKEN_LIFETIME = 30 * 60; // 30 minutes
const REFRESH_TOKEN_LIFETIME = 7 * 24 * 60 * 60; // 7 days

function signToken(
  claims: tok.TokenClaimTypes,
  opts?: jwt.SignOptions
): Promise<string> {
  const options: jwt.SignOptions = {
    issuer: ISSUER,
    ...opts
  };
  return new Promise((resolve, reject) => {
    jwt.sign(claims, JWT_SECRET, options, (err: Error, encoded: string) => {
      if (err) {
        reject(err);
      } else {
        resolve(encoded);
      }
    });
  });
}

export function verifyToken<
  TClaims extends tok.TokenClaimTypes = tok.TokenClaimTypes
>(token: string, type?: TClaims["type"]): Promise<TClaims & tok.BaseClaims> {
  return new Promise((resolve, reject) => {
    jwt.verify(
      token,
      JWT_SECRET,
      {
        issuer: ISSUER
      },
      (err, decoded) => {
        if (err) {
          if (err.name === "TokenExpiredError") {
            reject(
              new ApiError(
                "The specified token is expired",
                ErrorCode.BadToken,
                err
              )
            );
          } else if (err.name === "JsonWebTokenError") {
            reject(new ApiError("Invalid token", ErrorCode.BadToken, err));
          } else {
            reject(err);
          }
        } else {
          const claims: tok.TokenClaims = decoded as any;
          if (type != null && claims.type !== type) {
            reject(
              new ApiError(
                `Expected a "${type}" token, received a "${claims.type}" token`,
                ErrorCode.BadToken
              )
            );
          }
          resolve(claims as TClaims & tok.BaseClaims);
        }
      }
    );
  });
}

export function generateAccessToken(user: User): Promise<string> {
  const accessTokenClaims: tok.AccessToken = {
    aud: user.id,
    name: user.name,
    type: "access"
  };

  return signToken(accessTokenClaims, { expiresIn: ACCESS_TOKEN_LIFETIME });
}

export function generateRefreshToken(user: User): Promise<string> {
  const refreshTokenClaims: tok.RefreshToken = {
    aud: user.id,
    name: user.name,
    type: "refresh"
  };

  return signToken(refreshTokenClaims, { expiresIn: REFRESH_TOKEN_LIFETIME });
}

export function generateDeviceRegistrationToken(): Promise<string> {
  const deviceRegTokenClaims: tok.DeviceRegistrationToken = {
    type: "device_reg"
  };
  return signToken(deviceRegTokenClaims);
}

export function generateDeviceToken(
  id: number,
  deviceId: string
): Promise<string> {
  const deviceTokenClaims: tok.DeviceToken = {
    type: "device",
    aud: deviceId,
    id
  };
  return signToken(deviceTokenClaims);
}

export function generateSuperuserToken(): Promise<string> {
  const superuserClaims: tok.SuperuserToken = {
    type: "superuser"
  };
  return signToken(superuserClaims);
}