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 stream = require("stream");

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) {
  //YellowSquare 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...
}
class RequestBodyStream extends stream.Readable {
  constructor(sourceStream) {
    super();
    this.sourceStream = sourceStream;

    // When the source stream emits data, push it to the wrapper stream
    this.sourceStream.on('data', (chunk) => {
      this.push(chunk);
    });

    // When the source stream ends, push null to indicate the end of the wrapper stream
    this.sourceStream.on('end', () => {
      this.push(null);
    });
  }

  // Implement the _read method to handle the read operation
  _read() {}
}

class ErrorStream extends stream.Writable {
  constructor() {
    super();
    this.buffer = Buffer.alloc(0);
  }

  _write(chunk, encoding, callback) {
    // Concatenate the incoming chunk to the buffer
    this.buffer = Buffer.concat([this.buffer, chunk]);

    // Call the callback to indicate that the write operation is complete
    callback();
  }
}

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));

    function executeJSGI(fname, req, res, dh, jsgiRequestObject) {
      // Function to execute JSGI scripts
      if (!fname.match(/\.jsgi(?:\.js)?$/)) {
        elseCallback();
        return;
      }
      try {
        var JSGIApp = require(process.cwd() + "/" + fname);
        var jsgiResponseObject = {};
        if (typeof JSGIApp === "object" && JSGIApp.app) {
          jsgiResponseObject = JSGIApp.app(jsgiRequestObject);
        } else {
          throw new Error("JSGI app must have app key in exports objects!!!");
        }
        if (jsgiRequestObject.jsgi.errors.readable) jsgiRequestObject.jsgi.errors.end();
        var errors = jsgiRequestObject.jsgi.errors.buffer.toString();
        if (errors.trim().length > 0) {
          serverconsole.errmessage("There were JSGI application errors:");
          serverconsole.errmessage(errors);
        }
        if (!jsgiResponseObject.status) jsgiResponseObject.status = 200;
        if (!getCustomHeaders) {
          var aheaders = JSON.parse(JSON.stringify(configJSON.customHeaders));
        } else {
          var aheaders = getCustomHeaders();
        }
        if (jsgiResponseObject.headers) {
          var hKeys = Object.keys(jsgiResponseObject.headers);
          for (var i = 0; i < hKeys.length; i++) {
            aheaders[hKeys[i]] = jsgiResponseObject.headers[hKeys[i]];
          }
        }
        if (!jsgiResponseObject.body) jsgiResponseObject.body = [""];
        if (typeof jsgiResponseObject.body === "string") {
          res.writeHead(jsgiResponseObject.status, http.STATUS_CODES[jsgiResponseObject.status], aheaders);
          res.write(jsgiResponseObject.body);
          res.end();
        } else if (typeof jsgiResponseObject.body.forEach !== "function") {
          throw new Error("JSGI app must return body, which has forEach function.");
        } else {
          res.writeHead(jsgiResponseObject.status, http.STATUS_CODES[jsgiResponseObject.status], aheaders);
          jsgiResponseObject.body.forEach(function (chunk) {
            res.write(chunk);
          });
          res.end();
        }
      } catch (error) {
        if (!callServerError) {
          res.writeHead(500, {
            "Content-Type": "text/html",
            "Server": "YellowSquare/" + version
          });
          res.end("<html><head></head><body><h1>YellowSquare Error!</h1><p>Reason: " + error.message + "</p></body></html>");
        } else {
          callServerError(500, "YellowSquare/" + version, error);
        }
      }
    }

    function executeJSGIWithReqObj(a, b, req, res, pubip, port, software, dh, user) {
      // Function to set up request object and execute JSGI scripts
      var inputStream = new RequestBodyStream(req);
      var errorStream = new ErrorStream();
      var jsgiRequestObject = {
        version: req.httpVersion.split("."),
        method: req.method,
        headers: req.headers,
        input: inputStream,
        scriptName: a,
        pathInfo: decodeURIComponent(b),
        pathTranslated: b ? ((process.cwd() + decodeURIComponent(require("os").platform == "win32" ? b.replace(/\//g, "\\") : b)).replace((require("os").platform == "win32" ? /\\\\/g : /\/\//g), (require("os").platform == "win32" ? "\\" : "/"))) : "",
        scheme: req.socket.encrypted ? "https" : "http",
        env: {},
        jsgi: {
          version: [0, 3],
          errors: errorStream,
          multithread: false,
          multiprocess: true,
          runOnce: false,
          async: false,
          cgi: false,
          ext: {}
        },
        serverSoftware: software,
        remoteAddr: (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) {
        jsgiRequestObject.remotePort = req.socket.realRemotePort;
      } else if(!(req.socket.realRemoteAddress && !req.socket.realRemotePort)) {
        jsgiRequestObject.remotePort = req.socket.remotePort;
      }

      if (typeof user != "undefined") {
        if (user !== null) {
          if (req.headers.authorization) jsgiRequestObject.authType = req.headers.authorization.split(" ")[0];
          jsgiRequestObject.remoteUser = user;
        }
      } else if (req.headers.authorization && (typeof checkIfThereIsA401Rule == "undefined" || checkIfThereIsA401Rule())) {
        jsgiRequestObject.authType = req.headers.authorization.split(" ")[0];
        if (jsgiRequestObject.authType == "Basic") {
          var remoteCred = req.headers.authorization.split(" ")[1];
          if (!remoteCred) {
            jsgiRequestObject.remoteUser = "yellowsquare_jsgi_invalid_user";
          } else {
            var remoteCredDecoded = Buffer.from(remoteCred, "base64").toString("utf8");
            jsgiRequestObject.remoteUser = remoteCredDecoded.split(":")[0];
          }
        } else {
          jsgiRequestObject.remoteUser = "svrjs_this_property_is_not_yet_supported_by_yellowsquare_jsgi";
        }
      }
      jsgiRequestObject.queryString = req.url.split("?")[1];
      if (jsgiRequestObject.queryString == undefined || jsgiRequestObject.queryString == "undefined") jsgiRequestObject.queryString = "";
      if (pubip && (port !== null && port !== undefined)) {
        jsgiRequestObject.port = port;
        jsgiRequestObject.host = pubip.replace(/^::ffff:/i, "");
        if (jsgiRequestObject.host.indexOf(":") != -1) jsgiRequestObject.host = "[" + jsgiRequestObject.host + "]";
      }
      executeJSGI("." + a, req, res, dh, jsgiRequestObject);
    }

    if (href.match(new RegExp("^/jsgi-bin(?:$|[?#/])",os.platform() == "win32" ? "i" : ""))) {
      fs.stat("." + decodeURIComponent(href), function (err, stats) {
        if (!err) {
          if (!stats.isFile()) {
            elseCallback();
          } else {
            try {
              executeJSGIWithReqObj(
                decodeURIComponent(href),
                "",
                req,
                res,
                req.socket.localAddress,
                req.socket.localPort,
                getCustomHeaders ?
                getCustomHeaders()["Server"] +
                " YellowSquare/" +
                version :
                "SVR.JS/" +
                configJSON.version +
                " (" +
                os.platform()[0].toUpperCase() +
                os.platform().slice(1) +
                "; Node.JS/" +
                process.version +
                ") YellowSquare/" +
                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 +
                  ") YellowSquare/" +
                  version +
                  " " +
                  (req.headers.host == undefined ? "" : " on " + req.headers.host) +
                  "</p></body></html>"
                );
                res.end();
              } else {
                callServerError(500, "YellowSquare/" + version, ex);
              }
            }
          }
        } else if (err && err.code == "ENOTDIR") {
          function checkPath(pth, cb, a) {
            // Function to check the path of the file and execute CGI script
            var cpth = pth.split("/");
            if (cpth.length < 3) {
              cb(false);
              return;
            }
            if (!a) b = [];
            else var b = a.split("/");
            var isFile = false;
            fs.stat(pth, function (err, stats) {
              if (!err && stats.isFile()) {
                cb({
                  fpth: pth,
                  rpth: (a !== undefined ? "/" + a : "")
                })
              } else {
                b.unshift(cpth.pop());
                return checkPath(cpth.join("/"), cb, b.join("/"));
              }
            });
          }
          checkPath("." + decodeURIComponent(href), function (pathp) {
            if (!pathp) {
              elseCallback();
            } else {
              try {
                executeJSGIWithReqObj(
                  pathp.fpth.substr(1),
                  pathp.rpth,
                  req,
                  res,
                  req.socket.localAddress,
                  req.socket.localPort,
                  getCustomHeaders ?
                  getCustomHeaders()["Server"] +
                  " YellowSquare/" +
                  version :
                  "SVR.JS/" +
                  configJSON.version +
                  " (" +
                  os.platform()[0].toUpperCase() +
                  os.platform().slice(1) +
                  "; Node.JS/" +
                  process.version +
                  ") YellowSquare/" +
                  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 +
                    ") YellowSquare/" +
                    version +
                    " " +
                    (req.headers.host == undefined ? "" : " on " + req.headers.host) +
                    "</p></body></html>"
                  );
                  res.end();
                } else {
                  callServerError(500, "YellowSquare/" + version, ex);
                }
              }
            }
          });
        } else {
          elseCallback(); //Invoke default error handler
        }
      });
    } else {
      elseCallback();
    }
  }
}

module.exports = Mod;