import bodyParser from "body-parser";
import cors from "cors";
import express from "express";
import { getLocalStorage } from ".";
import { KeyValueStorage } from "./basic";
import { HEADER_REPLYIER, HEADER_REQUESTER } from "./remote";

type Server = {
  close: () => Promise<void>
}

/**
 * Start a server compliant with RestRemoteStorage
 */
export function startRestServer(port: number, storage: KeyValueStorage): Promise<Server> {
  const app = express();
  app.use(
    cors({ exposedHeaders: [HEADER_REPLYIER] }),
    bodyParser.text(),
    (req, res, next) => {
      if (req.header(HEADER_REQUESTER)) {
        res.set(HEADER_REPLYIER, "ok");
        next();
      } else {
        res.status(400).send();
      }
    },
  );
  app.get("*", (req, res, next) => {
    storage.get(req.path).then(result => {
      if (result === null) {
        res.status(404).send();
      } else {
        res.send(result);
      }
    }).catch(next);
  });
  app.put("*", (req, res, next) => {
    storage.set(req.path, req.body).then(() => {
      res.send();
    }).catch(next);
  });
  app.delete("*", (req, res, next) => {
    storage.set(req.path, null).then(() => {
      res.send();
    }).catch(next);
  });

  return new Promise((resolve) => {
    const server = app.listen(port, () => {
      resolve({
        close: () => new Promise((resolve, reject) => {
          server.close((err) => err ? reject(err) : resolve());
        })
      })
    });
  });
}

if (typeof require !== "undefined" && require.main === module) {
  startRestServer(5001, getLocalStorage("tk-storage-server")).then(() => {
    console.log(`Server running, use http://localhost:5001 to connect`);
  });
}