import * as express from 'express';
import * as cors from 'cors';
import * as cookieParser from 'cookie-parser';
import * as bodyParser from 'body-parser';
import { R, log, constants, fsPath } from '../libs';

const listEndpoints = require('express-list-endpoints');

export const Router = express.Router;
export { staticRoutes } from './middleware/staticRoutes';

export type Request = express.Request;
export type Response = express.Response;

const IS_PRODUCTION = process.env.NODE_ENV === 'production';

interface IErrorStack {
  message: string;
  stack: string[];
}

/**
 * Turns an Error stack into a friendlier JSON value.
 */
function formatErrorStack(stack: string = ''): IErrorStack {
  const lines = stack.split('\n');
  const message = lines[0];
  lines.shift();
  return {
    message,
    stack: lines.map(line => line.trim()),
  };
}

/**
 * Sends an HTTP error to the client, with full stack details
 * if running locally in development.
 */
export function sendError(code: number, res: express.Response, err: Error) {
  const error = IS_PRODUCTION ? err.message : formatErrorStack(err.stack);
  res.status(code).send({
    status: code,
    error,
  });
}

/**
 * Create an express app.
 */
export function app(
  options: {
    cors?: cors.CorsOptions;
    json?: bodyParser.OptionsJson;
    static?: string;
  } = {},
) {
  const app = express()
    .use(cors(options.cors))
    .use(bodyParser.json(options.json) as any) // HACK: avoid type incompatibility.
    .use(cookieParser());

  if (options.static) {
    app.use(express.static(options.static));
  }

  return app;
}

/**
 * Creates an express router.
 * NB:
 *    This is a helper that makes it easier to create
 *    and export a router without the annoying typescript
 *    errors complaining about the `express-serve-static-core`
 *    reference requirement.
 */
export function router() {
  const routes = express.Router();
  return routes as express.Router;
}

/**
 * Retrieves a list of all routes that have been registered.
 */
export function routes(router: express.Router): RouteInfo[] {
  const items = listEndpoints(router) as RouteInfo[];
  return items.reduce(
    (acc, next) => {
      const index = acc.findIndex(r => r.path === next.path);
      if (index > -1) {
        // Route already exist, merge in the methods.
        const route = items[index];
        route.methods = R.uniq([...route.methods, ...next.methods]);
        return acc;
      }
      return [...acc, next];
    },
    [] as RouteInfo[],
  );
}
export type RouteInfo = {
  path: string;
  methods: Array<'GET' | 'POST' | 'PUT' | 'DELETE' | 'PATCH'>;
};

/**
 * Standard logger for when the express application starts.
 */
export function logStarted(port: number, args: {} = {}) {
  const PACKAGE = require(fsPath.resolve('./package.json'));
  log.info(`\n> Ready on ${log.cyan('localhost')}:${log.magenta(port)}`);
  log.info();
  log.info.gray(`  name:  ${log.white(PACKAGE.name)}@${PACKAGE.version}`);
  log.info.gray(`  dev:   ${constants.IS_DEV}`);
  log.info();
}