var http = require('http'),
    url = require('url'),
    fs = require('fs');
var mime = require('mime');
var mysql = require('mysql');
var dateFormat = require('dateformat');
var log_file_err = fs.createWriteStream(__dirname + '/NodeError.log', { flags: 'a' });

var MySQLConnection = mysql.createConnection({
    host: "localhost",
    user: "---",
    password: "---",
    database: "---"
});

MySQLConnection.connect(function (err) {
    if (err) throw err;
});

var SelectSQL = function (SQLCommand, callback) {
    MySQLConnection.query(SQLCommand, function (err, data, fields) {
        if (err)
            console.log(err);
        else {
            callback(data);
        }
    });
};

var UpdateSQL = function (SQLCommand, callback) {
    MySQLConnection.query(SQLCommand, function (err, data, fields) {
        if (err)
            console.log(err);
        else {
            callback(data);
        }
    });
};

http.createServer(function (req, res) {
    var Nowdate = dateFormat(new Date(), "yyyy-mm-dd HH:MM:ss");
    var query = url.parse(req.url, true).query;

    process.on('uncaughtException', function (err) {
        log_file_err.write('Caught exception: ' + err.stack + '-> ' + Nowdate + 'n');
        console.log(err.stack);
    });

    var UniqID = query["id"];
    if (typeof UniqID === 'undefined') {
        res.end("Hello!");
    }
    var useragent = req.headers['user-agent'];
    var userip = req.headers['x-forwarded-for'] ||
        req.connection.remoteAddress ||
        req.socket.remoteAddress ||
        (req.connection.socket ? req.connection.socket.remoteAddress : null);
    if (userip.substr(0, 7) == "::ffff:") {
        userip = userip.substr(7)
    }

    function RunUpdateSQL(MySQLQuery) {
        UpdateSQL(MySQLQuery, function (data) {
        });
    }

    function RunSelectSQL() {
        SelectSQL("SELECT * FROM DownloadKey WHERE UniqueidPrimary='" + UniqID + "' order by id desc LIMIT 1", function (data) {
            var OutputInfo = '';
            var FileLoaded = false;
            if (Object.keys(data).length < 1) {
                OutputInfo = "Error Detected";
                res.writeHead(200, { 'Content-Type': 'text/plain; charset=utf-8' });
                res.end(OutputInfo);
            }
            else {
                var isLarger = new Date(Nowdate) > new Date(data[0].Timestamp);
                if (isLarger) {
                    OutputInfo = "Link Expired";
                    res.writeHead(200, { 'Content-Type': 'text/plain; charset=utf-8' });
                    res.end(OutputInfo);
                }
                else {
                    var newFileName = data[0].FilePath + data[0].FileName;
                    if (fs.existsSync(newFileName)) {
                        RunUpdateSQL("UPDATE DownloadKey SET Downloads=1 WHERE UniqueidPrimary='" + UniqID + "'");
                        res.setHeader('Content-disposition', 'attachment; filename*=UTF-8''' + encodeURIComponent(data[0].FileName));
                        res.setHeader('Content-Description', 'File Transfer');
                        res.setHeader('Content-Type','application/octet-stream');
                        res.setHeader('Content-Transfer-Encoding', 'Binary');
                        fs.readFile(newFileName, function (err, content) {
                            if (err) {
                                OutputInfo = "Link Is not Valid";
                                res.writeHead(200, { 'Content-Type': 'text/plain; charset=utf-8' });
                                res.end(OutputInfo);
                            } else {
                                res.setHeader('Content-Length', content.length);
                                res.end(content);
                            }
                        });
                    } else {
                        OutputInfo = "Link is Not Valid";
                        res.writeHead(200, { 'Content-Type': 'text/plain; charset=utf-8' });
                        res.end(OutputInfo);
                    }
                }
            }
        });
    }

    RunUpdateSQL("UPDATE DownloadKey SET UserAgent='" + useragent + "',UserIP='" + userip + "' WHERE UniqueidPrimary='" + UniqID + "'");
    RunSelectSQL();

}).listen(3333);
console.log("NodeJS WebApp running at http://localhost:3333/");