const express = require("express");
const bodyParser = require("body-parser");
const { JSONRPCServer } = require("json-rpc-2.0");

const server = new JSONRPCServer();

// First parameter is a method name.
// Second parameter is a method itself.
// A method takes JSON-RPC params and returns a result.
// It can also return a promise of the result.
server.addMethod("echo", ({ text }) => text);
server.addMethod("log", ({ message }) => console.log(message));

const app = express();
app.use(bodyParser.json());

app.post("/json-rpc", (req, res) => {
  const jsonRPCRequest = req.body;
  // server.receive takes a JSON-RPC request and returns a promise of a JSON-RPC response.
  // It can also receive an array of requests, in which case it may return an array of responses.
  // Alternatively, you can use server.receiveJSON, which takes JSON string as is (in this case req.body).
  server.receive(jsonRPCRequest).then((jsonRPCResponse) => {
    if (jsonRPCResponse) {
      res.json(jsonRPCResponse);
    } else {
      // If response is absent, it was a JSON-RPC notification method.
      // Respond with no content status (204).
      res.sendStatus(204);
    }
  });
});

app.listen(80);

const server = new JSONRPCServer();

// The method can also take a custom parameter as the second parameter.
// Use this to inject whatever information that method needs outside the regular JSON-RPC request.
server.addMethod("echo", ({ text }, { userID }) => `${userID} said ${text}`);

app.post("/json-rpc", (req, res) => {
  const jsonRPCRequest = req.body;
  const userID = getUserID(req);

  // server.receive takes an optional second parameter.
  // The parameter will be injected to the JSON-RPC method as the second parameter.
  server.receive(jsonRPCRequest, { userID }).then((jsonRPCResponse) => {
    if (jsonRPCResponse) {
      res.json(jsonRPCResponse);
    } else {
      res.sendStatus(204);
    }
  });
});

const getUserID = (req) => {
  // Do whatever to get user ID out of the request
};

const server = new JSONRPCServer();

// next will call the next middleware
const logMiddleware = (next, request, serverParams) => {
  console.log(`Received ${JSON.stringify(request)}`);
  return next(request, serverParams).then((response) => {
    console.log(`Responding ${JSON.stringify(response)}`);
    return response;
  });
};

const exceptionMiddleware = async (next, request, serverParams) => {
  try {
    return await next(request, serverParams);
  } catch (error) {
    if (error.code) {
      return createJSONRPCErrorResponse(request.id, error.code, error.message);
    } else {
      throw error;
    }
  }
};

// Middleware will be called in the same order they are applied
server.applyMiddleware(logMiddleware, exceptionMiddleware);

import { JSONRPCClient } from "json-rpc-2.0";

// JSONRPCClient needs to know how to send a JSON-RPC request.
// Tell it by passing a function to its constructor. The function must take a JSON-RPC request and send it.
const client = new JSONRPCClient((jsonRPCRequest) =>
  fetch("http://localhost/json-rpc", {
    method: "POST",
    headers: {
      "content-type": "application/json",
    },
    body: JSON.stringify(jsonRPCRequest),
  }).then((response) => {
    if (response.status === 200) {
      // Use client.receive when you received a JSON-RPC response.
      return response
        .json()
        .then((jsonRPCResponse) => client.receive(jsonRPCResponse));
    } else if (jsonRPCRequest.id !== undefined) {
      return Promise.reject(new Error(response.statusText));
    }
  })
);

// Use client.request to make a JSON-RPC request call.
// The function returns a promise of the result.
client
  .request("echo", { text: "Hello, World!" })
  .then((result) => console.log(result));

// Use client.notify to make a JSON-RPC notification call.
// By definition, JSON-RPC notification does not respond.
client.notify("log", { message: "Hello, World!" });

const client = new JSONRPCClient(
  // It can also take a custom parameter as the second parameter.
  (jsonRPCRequest, { token }) =>
    fetch("http://localhost/json-rpc", {
      method: "POST",
      headers: {
        "content-type": "application/json",
        authorization: `Bearer ${token}`, // Use the passed token
      },
      body: JSON.stringify(jsonRPCRequest),
    }).then((response) => {
      // ...
    })
);

// Pass the custom params as the third argument.
client.request("echo", { text: "Hello, World!" }, { token: "foo's token" });
client.notify("log", { message: "Hello, World!" }, { token: "foo's token" });

const webSocket = new WebSocket("ws://localhost");

const serverAndClient = new JSONRPCServerAndClient(
  new JSONRPCServer(),
  new JSONRPCClient((request) => {
    try {
      webSocket.send(JSON.stringify(request));
      return Promise.resolve();
    } catch (error) {
      return Promise.reject(error);
    }
  })
);

webSocket.onmessage = (event) => {
  serverAndClient.receiveAndSend(JSON.parse(event.data.toString()));
};

// On close, make sure to reject all the pending requests to prevent hanging.
webSocket.onclose = (event) => {
  serverAndClient.rejectAllPendingRequests(
    `Connection is closed (${event.reason}).`
  );
};

serverAndClient.addMethod("echo", ({ text }) => text);

serverAndClient
  .request("add", { x: 1, y: 2 })
  .then((result) => console.log(`1 + 2 = ${result}`));

server.addMethod("fail", () =>
  Promise.reject(new Error("This is an error message."))
);

client.request("fail").then(
  () => console.log("This does not get called"),
  (error) => console.error(error.message) // Outputs "This is an error message."
);