import jwt from "jsonwebtoken";

interface APNsUrl {
  fullUrl: string;
  path: string;
  host: string;
}

class AppleNotificationSender {
  private apnsToken: string | undefined = undefined;
  private _lastRefreshedTimeMs: number | undefined = undefined;

  private lastReloadedTimeForAPNsIsTooRecent() {
    const thirtyMinutesMs = 1800000;
    return this._lastRefreshedTimeMs && Date.now() - this._lastRefreshedTimeMs < thirtyMinutesMs;
  }

  private reloadAPNsTokenIfTimePassed() {
    if (this.lastReloadedTimeForAPNsIsTooRecent()) {
      return;
    }

    const keyId = process.env.APNS_KEY_ID;
    const teamId = process.env.APNS_TEAM_ID;

    const privateKeyBase64 = process.env.APNS_PRIVATE_KEY;
    if (!privateKeyBase64) return;
    const privateKey = Buffer.from(privateKeyBase64, 'base64').toString('utf-8');

    const tokenHeader = {
      alg: "ES256",
      "kid": keyId,
    };

    const nowMs = Date.now();
    const claimsPayload = {
      "iss": teamId,
      "iat": Math.ceil(nowMs / 1000),  // APNs requires number of seconds since Epoch
    };

    this.apnsToken = jwt.sign(claimsPayload, privateKey, {
      algorithm: "ES256",
      header: tokenHeader
    });
    this._lastRefreshedTimeMs = nowMs;
  }

  public sendNotificationImmediately(notification: any) {
    // TODO Send the notification
  }

  public static getAPNsFullUrlToUse(deviceId: string): APNsUrl {
    // Construct the fetch request
    const devBaseUrl = "https://api.development.push.apple.com"
    const prodBaseUrl = "https://api.push.apple.com"

    let hostToUse = devBaseUrl;
    if (process.env.APNS_IS_PRODUCTION === "1") {
      hostToUse = prodBaseUrl;
    }

    const path = "/3/device/" + deviceId;
    const fullUrl = hostToUse + path;

    const constructedObject = {
      fullUrl,
      host: hostToUse,
      path,
    }
    return constructedObject;
  }

}