'use strict';

module.exports.create = function (deps, conf, greenlockMiddleware) {
  var express = require('express');
  var app = express();
  var adminApp = require('./admin').create(deps, conf);
  var domainMatches = require('../match-domain').match;
  var proxyRoutes = [];

  var adminDomains = [
    /\blocalhost\.admin\./
  , /\blocalhost\.alpha\./
  , /\badmin\.localhost\./
  , /\balpha\.localhost\./
  ];

  function verifyHost(fullHost) {
    var host = /^(.*?)(:\d+)?$/.exec(fullHost)[1];

    if (host === 'localhost') {
      return fullHost.replace(host, 'localhost.daplie.me');
    }

    // Test for IPv4 and IPv6 addresses. These patterns will match some invalid addresses,
    // but since those still won't be valid domains that won't really be a problem.
    if (/^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/.test(host) || /^\[[0-9a-fA-F:]+\]$/.test(host)) {
      if (!conf.http.primaryDomain) {
        (conf.http.modules || []).some(function (mod) {
          return mod.domains.some(function (domain) {
            if (domain[0] !== '*') {
              conf.http.primaryDomain = domain;
              return true;
            }
          });
        });
      }
      return fullHost.replace(host, conf.http.primaryDomain || host);
    }

    return fullHost;
  }

  // We handle both HTTPS and HTTP traffic on the same ports, and we want to redirect
  // any unencrypted requests to the same port they came from unless it came in on
  // the default HTTP port, in which case there wont be a port specified in the host.
  var redirecters = {};
  function redirectHttps(req, res, next) {
    if (conf.http.allowInsecure) {
      next();
      return;
    }

    var port = (/:(\d+)$/.exec(req.headers.host) || [])[1];
    if (!redirecters[port]) {
      redirecters[port] = require('redirect-https')({
        port: port
      , trustProxy: conf.http.trustProxy
      });
    }

    // localhost and IP addresses cannot have real SSL certs (and don't contain any useful
    // info for redirection either), so we direct some hosts to either localhost.daplie.me
    // or the "primary domain" ie the first manually specified domain.
    req.headers.host = verifyHost(req.headers.host);

    redirecters[port](req, res, next);
  }

  function handleAdmin(req, res, next) {
    var admin = adminDomains.some(function (re) {
      return re.test(req.headers.host);
    });

    if (admin) {
      adminApp(req, res);
    } else {
      next();
    }
  }

  function respond404(req, res) {
    res.writeHead(404);
    res.end('Not Found');
  }

  function createProxyRoute(mod) {
    // This is the easiest way to override the createConnections function the proxy
    // module uses, but take note the since we don't have control over where this is
    // called the extra options availabled will be different.
    var agent = new require('http').Agent({});
    agent.createConnection = deps.net.createConnection;

    var proxy = require('http-proxy').createProxyServer({
      agent: agent
    , target: 'http://' + mod.address
    , xfwd: true
    , toProxy: true
    });

    // We want to override the default value for some headers with the extra information we
    // have available to us in the opts object attached to the connection.
    proxy.on('proxyReq', function (proxyReq, req) {
      var conn = req.connection;
      var opts = conn.__opts;
      proxyReq.setHeader('X-Forwarded-For', opts.remoteAddress || conn.remoteAddress);
    });

    proxy.on('error', function (err, req, res) {
      console.log(err);
      res.statusCode = 502;
      res.setHeader('Content-Type', 'text/html');
      res.setHeader('Connection', 'close');
      res.end(require('../proxy-err-resp').getRespBody(err, conf.debug));
    });

    return {
      web: function (req, res, next) {
        var hostname = req.headers.host.split(':')[0];
        var relevant = mod.domains.some(function (pattern) {
          return domainMatches(pattern, hostname);
        });

        if (relevant) {
          proxy.web(req, res);
        } else {
          next();
        }
      }
    , ws: function (req, socket, head, next) {
        var hostname = req.headers.host.split(':')[0];
        var relevant = mod.domains.some(function (pattern) {
          return domainMatches(pattern, hostname);
        });

        if (relevant) {
          proxy.ws(req, socket, head);
        } else {
          next();
        }
      }
    };
  }

  function createStaticRoute(mod) {
    var getStaticApp, staticApp;
    if (/:hostname/.test(mod.root)) {
      staticApp = {};
      getStaticApp = function (hostname) {
        if (!staticApp[hostname]) {
          staticApp[hostname] = express.static(mod.root.replace(':hostname', hostname));
        }
        return staticApp[hostname];
      };
    }
    else {
      staticApp = express.static(mod.root);
      getStaticApp = function () {
        return staticApp;
      };
    }

    return function (req, res, next) {
      var hostname = req.headers.host.split(':')[0];
      var relevant = mod.domains.some(function (pattern) {
        return domainMatches(pattern, hostname);
      });

      if (relevant) {
        getStaticApp(hostname)(req, res, next);
      } else {
        next();
      }
    };
  }

  app.use(greenlockMiddleware);
  app.use(redirectHttps);
  app.use(handleAdmin);

  (conf.http.modules || []).forEach(function (mod) {
    if (mod.name === 'proxy') {
      var proxyRoute = createProxyRoute(mod);
      proxyRoutes.push(proxyRoute);
      app.use(proxyRoute.web);
    }
    else if (mod.name === 'static') {
      app.use(createStaticRoute(mod));
    }
    else {
      console.warn('unknown HTTP module', mod);
    }
  });

  app.use(respond404);

  var server = require('http').createServer(function (req, res) {
    app(req, res)
  });

  server.on('upgrade', function (req, socket, head) {
    if (!proxyRoutes.length) {
      socket.end();
    }

    function proxyWs() {
      var proxyRoute = proxyRoutes.shift();
      if (!proxyRoute) {
        socket.end();
      }
      proxyRoute.ws(req, socket, head, proxyWs);
    }

    proxyWs();
  });

  return server;
};