'use strict';

module.exports.create = function (deps, config) {
  var PromiseA = require('bluebird');
  var server;

  function curState() {
    var addr = server && server.address();
    if (!addr) {
      return PromiseA.resolve({running: false});
    }
    return PromiseA.resolve({
      running: true
    , port: addr.port
    });
  }

  function start(port) {
    if (server) {
      return curState();
    }

    server = require('socksv5').createServer(function (info, accept) {
      accept();
    });

    // It would be nice if we could use `server-destroy` here, but we can't because
    // the socksv5 library will not give us access to any sockets it actually
    // handles, so we have no way of keeping track of them or closing them.
    server.on('close', function () {
      server = null;
    });

    server.useAuth(require('socksv5').auth.None());

    return new PromiseA(function (resolve, reject) {
      server.on('error', function (err) {
        if (!port && err.code === 'EADDRINUSE') {
          server.listen(0);
        } else {
          server = null;
          reject(err);
        }
      });
      server.listen(port || 1080, function () {
        resolve(curState());
      });
    });
  }

  function stop() {
    if (!server) {
      return curState();
    }
    return new PromiseA(function (resolve, reject) {
      server.close(function (err) {
        if (err) {
          reject(err);
        } else {
          resolve(curState());
        }
      });
    });
  }

  var configEnabled = false;
  function updateConf() {
    var wanted = config.socks5 && config.socks5.enabled;

    if (configEnabled && !wanted) {
      stop().catch(function (err) {
        console.error('failed to stop socks5 proxy on config change', err);
      });
      configEnabled = false;
    }
    if (wanted && !configEnabled) {
      start(config.socks5.port).catch(function (err) {
        console.error('failed to start Socks5 proxy', err);
      });
      configEnabled = true;
    }
  }
  process.nextTick(updateConf);

  return {
    curState
  , start
  , stop
  , updateConf
  };
};