const projectId = "<ProjectID>";
const loginProjectId = "<LoginID>";

const serverOauthClientId = <OAuthClientID>;
const serverOauthClientSecret = "<OAuthSecretKey>";

exports.getXsollaLoginToken = functions.https.onCall((data, context) => {
  if (!context.auth) {
    throw new functions.https.HttpsError(
        "failed-precondition",
        "The function must be called while authenticated."
    );
  }

  const postData =
      "grant_type=client_credentials" +
      `&client_secret=${serverOauthClientSecret}`+
      `&client_id=${serverOauthClientId}`;

  const options = {
    hostname: "login.xsolla.com",
    port: 443,
    path: "/api/oauth2/token",
    method: "POST",
    headers: {
      "Content-Type": "application/x-www-form-urlencoded",
      "Content-Length": postData.length,
    },
  };

  return new Promise( (resolve, reject) => {
    const req = https.request(options, (res) => {
      if (res.statusCode !== 200) {
        reject(
            new functions.https.HttpsError(
                "internal",
                "Server token not received"
            )
        );
      }
      let body = [];
      res.on("data", (d) => {
        body.push(d);
      });
      res.on("end", () => {
        try {
          body = JSON.parse(Buffer.concat(body).toString());
        } catch (e) {
          reject(
              new functions.https.HttpsError(
                  "internal",
                  "Malformed server token response"
              )
          );
        }
        getClientToken(context.auth.uid, body.access_token, resolve, reject);
      });
    });
    req.on("error", (e) => {
      reject(new functions.https.HttpsError(
          "internal",
          "Internal error while server token flow"
      ));
    });

    req.write(postData);
    req.end();
  });
});

// eslint-disable-next-line require-jsdoc
function getClientToken(userId, serverToken, resolve, reject) {
  const postData = JSON.stringify(
      {
        "server_custom_id": userId,
      }
  );

  const path =
      "/api/users/login/server_custom_id?" +
      `projectId=${loginProjectId}&` +
      `publisher_project_id=${projectId}`;

  const options = {
    hostname: "login.xsolla.com",
    port: 443,
    path: path,
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "Content-Length": postData.length,
      "X-Server-Authorization": serverToken,
    },
  };

  const req = https.request(options, (res) => {
    if (res.statusCode !== 200) {
      reject(
          new functions.https.HttpsError(
              "internal",
              "Client token not received"
          )
      );
    }
    let body = [];
    res.on("data", (d) => {
      body.push(d);
    });
    res.on("end", () => {
      try {
        body = JSON.parse(Buffer.concat(body).toString());
      } catch (e) {
        reject(
            new functions.https.HttpsError(
                "internal",
                "Malformed client token response"
            )
        );
      }
      resolve({
        "token": body.token,
      });
    });
  });
  req.on("error", (e) => {
    reject(new functions.https.HttpsError(
        "internal",
        "Internal error while client token flow"
    ));
  });

  req.write(postData);
  req.end();
}

handlers.GetXsollaLoginToken = function (args) {

    // TODO replace with production credentials
    const projectId = <ProjectID>;
    const loginProjectId = "<LoginID>";
    const serverOauthClientId = <OAuthClientID>;
    const serverOauthClientSecret = "<OAuthSecretKey>";

    const getServerTokenBody =
        "grant_type=client_credentials" +
        `&client_secret=${serverOauthClientSecret}` +
        `&client_id=${serverOauthClientId}`;

    const serverTokenResponse = JSON.parse(
        http.request(
            "https://login.xsolla.com/api/oauth2/token",
            "post",
            getServerTokenBody,
            "application/x-www-form-urlencoded",
            {})
    );

    let serverToken = ""
    if ('access_token' in serverTokenResponse) {
        serverToken = serverTokenResponse.access_token;
    } else {
        return {
            "error_message": "Server token not received"
        }
    }

    const getUserTokenHeaders = {
        "X-Server-Authorization": serverToken
    }

    const getUserTokenBody = JSON.stringify(
        {
            "server_custom_id": currentPlayerId,
        }
    );

    const getUserTokenPath =
        "/api/users/login/server_custom_id?" +
        `projectId=${loginProjectId}&` +
        `publisher_project_id=${projectId}`;

    const userTokenResponse = JSON.parse(
        http.request(
            "https://login.xsolla.com" + getUserTokenPath,
            "post",
            getUserTokenBody,
            "application/json",
            getUserTokenHeaders)
    );

    if ('token' in userTokenResponse) {
        return {
            "token": userTokenResponse.token
        }
    } else {
        return {
            "error_message": "User token not received"
        }
    }
}