var https = require("https");
var os = require("os");
var http = require("http");
var url = require("url");
var fs = require("fs");
var path = require("path");
var net = require("net");
var version = "UNKNOWN";
try {
  version = JSON.parse(fs.readFileSync(__dirname + "/mod.info")).version;
} catch (ex) {
  // Can't determine version
}
var configJSONS = {};
try {
  configJSONS = JSON.parse(fs.readFileSync(__dirname + "/../../../config.json")); // Read configuration JSON
} catch(ex) {
  //OrangeCircle will not care about configJSONS in SVR.JS 3.x and newer
  //SVR.JS 2.x and older will fail to start with broken configuration file anyway...
}
var scgiConf = {};
try {
  scgiConf = JSON.parse(fs.readFileSync(__dirname + "/../../../orangecircle-config.json"));
} catch (ex) {
  // Use defaults
}

// Load default configuration
if (scgiConf.path === undefined) scgiConf.path = "/scgi";
scgiConf.path = scgiConf.path.replace(/([^\/])\/+$/, "$1");
if (scgiConf.host === undefined) scgiConf.host = "localhost";
if (scgiConf.port === undefined) scgiConf.port = 4000;

var disableModExposeSupported = process.versions.svrjs && process.versions.svrjs.match(/^(?:Nightly-|(?:[4-9]|[123][0-9])[0-9]*\.|3\.(?:[1-9][0-9]+\.|9\.(?:[1-9])|4\.(?:(?:[3-9]|[12][0-9])[0-9]+|29)))/i);

function Mod() {}

Mod.prototype.callback = function (req, res, serverconsole, responseEnd, href, ext, uobject, search, defaultpage, users, page404, head, foot, fd, elseCallback, configJSON, callServerError, getCustomHeaders, origHref, redirect, parsePostData, authUser) {
  return function () {
    if (!configJSON) {
      configJSON = configJSONS;
    }

    function checkIfThereIsA401Rule() {
      var actually401 = false;

      function createRegex(regex) {
        var regexObj = regex.split("/");
        if (regexObj.length == 0) throw new Error("Invalid regex!");
        var modifiers = regexObj.pop();
        regexObj.shift();
        var searchString = regexObj.join("/");
        return new RegExp(searchString, modifiers);
      }

      if(configJSON.nonStandardCodes) {
        configJSON.nonStandardCodes.every(function (nonscode) {
          if (nonscode.scode == 401) {
            if (nonscode.regex && (req.url.match(createRegex(nonscode.regex)) || href.match(createRegex(nonscode.regex)))) {
              actually401 = true;
              return true;
            } else if (nonscode.url && (nonStandardCodes[i].url == href || (os.platform() == "win32" && nonStandardCodes[i].url.toLowerCase() == href.toLowerCase()))) {
              actually401 = true;
              return true;
            }
          }
          return false;
        });
      }
      return actually401;
    }

    if (!getCustomHeaders) {
      var bheaders = JSON.parse(JSON.stringify(configJSON.customHeaders));
    } else {
      var bheaders = getCustomHeaders();
    }

    bheaders["Content-Type"] = "text/html"; // HTML output

    if (!getCustomHeaders) {
      bheaders["Server"] =
        "SVR.JS/" +
        configJSON.version +
        " (" +
        os.platform()[0].toUpperCase() +
        os.platform().slice(1) +
        ")"; // Add Server header
    }

    var abheaders = JSON.parse(JSON.stringify(bheaders));
    var socket = {};

    function executeSCGI(req, res, dh, nEnv) {
      // Function to execute SCGI scripts
      var env = JSON.parse(JSON.stringify(process.env));
      var nEnvKeys = Object.keys(nEnv);
      for (var i = 0; i < nEnvKeys.length; i++) {
        env[nEnvKeys[i]] = nEnv[nEnvKeys[i]];
      }
      var buffer = "";
      var headerendline = -1;
      var cned = false;
      var dataHandler = function (data) {
        if (!cned) buffer += data.toString("latin1");
        var m = null;
        if (!cned) m = buffer.match(/(?:\r\n\r\n|\n\r\n\r|\n\n|\r\r)/);
        if (!cned && m) {
          cned = true;
          eol = m[0];
          headerendline = m.index;
          var bheaders = buffer.substr(0, headerendline).split(/(?:\r\n|\n\r|\n|\r)/);
          var bheaderso = {};
          if (dh) bheaderso = dh;
          var code = 200;
          var msg = "OK";
          if (bheaders[0].indexOf("HTTP/") == 0) {
            var heada = bheaders.shift();
            var hso = heada.split(" ");
            code = hso[1];
            if (hso[2] !== undefined) msg = heada.split(" ").splice(2).join(" ");
          } else if (bheaders[0].indexOf(":") == -1) {
            var heada = bheaders.shift();
            var hso = heada.split(" ");
            if (hso[0].match(/^[0-9]{3}$/)) {
              code = hso[0];
              if (hso[1] !== undefined) msg = heada.split(" ").splice(1).join(" ");
            }
          }
          var hasLocation = false;
          for (var i = 0; i < bheaders.length; i++) {
            var headerp = bheaders[i].split(": ");
            var headern = headerp.shift();
            var headerv = headerp.join(": ");
            if (headern.toLowerCase() == "status") {
              code = headerv.split(" ")[0];
              if (headerv.split(" ")[1] !== undefined) msg = headerv.split(" ").splice(1).join(" ");
            } else if (headern.toLowerCase() == "set-cookie") {
              if (!bheaderso["Set-Cookie"]) bheaderso["Set-Cookie"] = [];
              bheaderso["Set-Cookie"].push(headerv);
            } else {
              if (headern.toLowerCase() == "location") hasLocation = true;
              bheaderso[headern] = headerv;
            }
          }

          if ((code < 300 || code > 399) && hasLocation) {
            code = 302;
            msg = "Found";
          }

          try {
            res.writeHead(code, msg, bheaderso);
            res.write(Buffer.from(buffer.substr(headerendline + eol.length), "latin1"));
          } catch (ex) {
            socket.removeAllListeners("data");
            socket.removeAllListeners("end");
            if (!callServerError) {
              res.writeHead(500);
              res.end(ex.stack);
            } else {
              callServerError(500, "OrangeCircle/" + version, ex);
            }
            return;
          }
        } else {
          if (cned && !res.finished) {
            res.write(data);
            socket.removeListener("data", dataHandler);
            socket.pipe(res, {end: false});
          }
        }
      };

      socket = net.createConnection({
        host: scgiConf.host,
        port: scgiConf.port,
      }, function () {
        socket.on("data", dataHandler);
        socket.on("end", function () {
          res.end();
        });
        var envEncoded = "";
        var envNames = Object.keys(env);
        for (var i = 0; i < envNames.length; i++) {
          var envName = String(envNames[i]).replace(/\0/g, "");
          var envValue = String(env[envNames[i]]).replace(/\0/g, "");
          if(envName == "CONTENT_LENGTH") {
            // CONTENT_LENGTH environment variable must be first!!!
            envEncoded = envName + "\0" + envValue + "\0" + envEncoded;
          } else {
            envEncoded += envName + "\0" + envValue + "\0";
          }
        }
        socket.write(envEncoded.length + ":" + envEncoded + ",");
        req.pipe(socket, {end: false});
      }).on("error", function (error) {
        var errorcode = (error.code == "ENOTFOUND" || error.code == "EHOSTUNREACH" || error.code == "ECONNREFUSED") ? 503 : 500;
        if (!callServerError) {
          res.writeHead(errorcode, {
            "Content-Type": "text/html",
            "Server": "OrangeCircle/" + version
          });
          res.end("<html><head></head><body><h1>OrangeCircle Error!</h1><p>Reason: " + error.message + "</p></body></html>");
        } else {
          callServerError(errorcode, "OrangeCircle/" + version, error);
        }
      });

    }

    function executeSCGIWithEnv(a, req, res, pubip, port, software, dh, user) {
      // Function to set up environment variables and execute sCGI scripts
      var b = href.replace(scgiConf.path,"")
      var nEnv = {};
      if (typeof user != "undefined") {
        if (user !== null) {
          if (req.headers.authorization) nEnv["AUTH_TYPE"] = req.headers.authorization.split(" ")[0];
          nEnv["REMOTE_USER"] = user;
        }
      } else if (req.headers.authorization && (typeof checkIfThereIsA401Rule == "undefined" || checkIfThereIsA401Rule())) {
        nEnv["AUTH_TYPE"] = req.headers.authorization.split(" ")[0];
        if (nEnv["AUTH_TYPE"] == "Basic") {
          var remoteCred = req.headers.authorization.split(" ")[1];
          if (!remoteCred) {
            nEnv["REMOTE_USER"] = "orangecircle_cgi_invalid_user";
          } else {
            var remoteCredDecoded = Buffer.from(remoteCred, "base64").toString("utf8");
            nEnv["REMOTE_USER"] = remoteCredDecoded.split(":")[0];
          }
        } else {
          nEnv["REMOTE_USER"] = "svrjs_this_property_is_not_yet_supported_by_orangecircle_cgi";
        }
      }
      nEnv["QUERY_STRING"] = req.url.split("?")[1];
      if (nEnv["QUERY_STRING"] == undefined || nEnv["QUERY_STRING"] == "undefined") nEnv["QUERY_STRING"] = "";
      nEnv["SERVER_SOFTWARE"] = software;
      nEnv["SERVER_PROTOCOL"] = "HTTP/" + req.httpVersion;
      if (pubip && (port !== null && port !== undefined)) {
        nEnv["SERVER_PORT"] = port;
        nEnv["SERVER_ADDR"] = pubip.replace(/^::ffff:/i, "");
        if (nEnv["SERVER_ADDR"].indexOf(":") != -1) nEnv["SERVER_ADDR"] = "[" + nEnv["SERVER_ADDR"] + "]";
      }
      if(configJSON.serverAdministratorEmail && configJSON.serverAdministratorEmail != "[no contact information]") {
        nEnv["SERVER_ADMIN"] = configJSON.serverAdministratorEmail;
      }
      nEnv["SERVER_NAME"] = req.headers.host;
      nEnv["DOCUMENT_ROOT"] = process.cwd();
      nEnv["SCRIPT_NAME"] = scgiConf.path;
      nEnv["PATH_INFO"] = decodeURIComponent(b);
      nEnv["PATH_TRANSLATED"] = b ? ((process.cwd() + decodeURIComponent(require("os").platform == "win32" ? b.replace(/\//g, "\\") : b)).replace((require("os").platform == "win32" ? /\\\\/g : /\/\//g), (require("os").platform == "win32" ? "\\" : "/"))) : "";
      nEnv["REQUEST_METHOD"] = req.method;
      nEnv["SCGI"] = "1";
      nEnv["REQUEST_URI"] = (!origHref || origHref == href) ? req.url : (origHref + (uobject.search ? ("?" + uobject.search) : ""));
      nEnv["REMOTE_ADDR"] = (req.socket.realRemoteAddress ? req.socket.realRemoteAddress : ((req.headers["x-forwarded-for"] && configJSON.enableIPSpoofing) ? req.headers["x-forwarded-for"].split(",")[0].replace(/ /g, "") : req.socket.remoteAddress)).replace(/^::ffff:/i, "");
      if(req.socket.realRemoteAddress && req.socket.realRemotePort) {
        nEnv["REMOTE_PORT"] = req.socket.realRemotePort;
      } else if(!(req.socket.realRemoteAddress && !req.socket.realRemotePort)) {
        nEnv["REMOTE_PORT"] = req.socket.remotePort;
      }
      if (req.socket.encrypted) nEnv["HTTPS"] = "ON";
      if (req.headers["content-type"]) nEnv["CONTENT_TYPE"] = req.headers["content-type"];
      nEnv["CONTENT_LENGTH"] = "0";
      if (req.headers["content-length"]) nEnv["CONTENT_LENGTH"] = req.headers["content-length"];
      var nh = JSON.parse(JSON.stringify(req.headers));
      delete nh["content-type"];
      delete nh["content-length"];
      var nhKeys = Object.keys(nh);
      for (var i = 0; i < nhKeys.length; i++) {
        nEnv["HTTP_" + nhKeys[i].replace(/[^0-9A-Za-z]+/g, "_").toUpperCase()] = req.headers[nhKeys[i]];
      }
      executeSCGI(req, res, dh, nEnv);
    }

    if (href == scgiConf.path || href.indexOf(scgiConf.path + "/") == 0) {
      try {
        executeSCGIWithEnv(
          decodeURIComponent(href),
          req,
          res,
          req.socket.localAddress,
          req.socket.localPort,
          getCustomHeaders ?
          getCustomHeaders()["Server"] +
          (disableModExposeSupported && (configJSON.exposeModsInErrorPages || configJSON.exposeModsInErrorPages === undefined) ?
          " OrangeCircle/" +
          version : "") :
          "SVR.JS/" +
          configJSON.version +
          " (" +
          os.platform()[0].toUpperCase() +
          os.platform().slice(1) +
          "; Node.JS/" +
          process.version +
          ") OrangeCircle/" +
          version,
          bheaders,
          authUser
        );
      } catch (ex) {
        if (!callServerError) {
          res.writeHead(500, "Internal Server Error", abheaders);
          res.write(
            "<html><head><title>500 Internal Server Error</title></head><body><h1>500 Internal Server Error</h1><p>A server had unexpected exception. Below, the stack trace of the error is shown:</p><code>" +
            ex.stack.replace(/\r\n/g, "<br/>").replace(/\n/g, "<br/>").replace(/\r/g, "<br/>").replace(/ /g, "&nbsp;") +
            "</code><p>Please contact the developer/administrator of the website.</p><p style=\"font-style: italic; font-weight: normal;\">SVR.JS " +
            configJSON.version +
            " (" +
            os.platform()[0].toUpperCase() +
            os.platform().slice(1) +
            "; Node.JS/" +
            process.version +
            ") OrangeCircle/" +
            version +
            " " +
            (req.headers.host == undefined ? "" : " on " + req.headers.host) +
            "</p></body></html>"
          );
          res.end();
        } else {
          callServerError(500, "OrangeCircle/" + version, ex);
        }
      }
    } else if ((href == "/orangecircle-config.json" || (os.platform() == "win32" && href.toLowerCase() == "/orangecircle-config.json")) && path.normalize(__dirname + "/../../..") == process.cwd()) {
      if (!callServerError) {
        res.writeHead(200, "OK", {
          "Content-Type": "application/json",
          "Server": "OrangeCircle/" + version
        });
        res.end(JSON.stringify(exttointerpreteruser, null, 2));
      } else {
        callServerError(200, "OrangeCircle/" + version, exttointerpreteruser);
      }
    } else {
      elseCallback();
    }
  }
}

module.exports = Mod;