(function(){
    'strict mode';
    
    /* Global var accessible from any loaded module */
    global.cloudcmd     = {};
    
    var DIR, LIBDIR, SRVDIR, JSONDIR, HTMLDIR,
        Util,
        
        SLASH,
        ISWIN32,
        ext,
        path, fs, zlib, url,
        
        OK, FILE_NOT_FOUND,
        
        Config = {
            server  : true,
            socket  : true,
            port    : 80
        };
    
    /* Consts */
    
    exports.OK          = OK                = 200;
    exports.FILE_NOT_FOUND = FILE_NOT_FOUND = 404;
    exports.REQUEST                         = 'request';
    exports.RESPONSE                        = 'response';
    
    /* Native Modules*/
    exports.crypto                          = require('crypto'),
    exports.child_process                   = require('child_process'),
    exports.fs          = fs                = require('fs'),
    exports.http                            = require('http'),
    exports.https                           = require('https'),
    exports.path        = path              = require('path'),
    exports.url         = url               = require('url'),
    exports.querystring                     = require('querystring'),
    
    /* Constants */
    /* current dir + 2 levels up */
    exports.WIN32       = ISWIN32           = isWin32();
    exports.SLASH       = SLASH             = ISWIN32 ? '\\' : '/',
    
    exports.SRVDIR      = SRVDIR            = __dirname + SLASH,
    exports.LIBDIR      = LIBDIR            = path.normalize(SRVDIR + '../'),
    exports.DIR         = DIR               = path.normalize(LIBDIR + '../'),
    exports.HTMLDIR     = HTMLDIR           = DIR + 'html' + SLASH,
    exports.JSONDIR     = JSONDIR           = DIR + 'json' + SLASH,
    
    /* Functions */
    exports.require                         = mrequire,
    exports.librequire                      = librequire,
    exports.srvrequire                      = srvrequire,
    exports.rootrequire                     = rootrequire,
    
    exports.generateHeaders                 = generateHeaders,
    exports.getQuery                        = getQuery,
    exports.isGZIP                          = isGZIP,
    
    exports.sendFile                        = sendFile,
    exports.sendResponse                    = sendResponse,
    exports.sendError                       = sendError,
    
    exports.checkParams                     = checkParams,
    
    /* compitability with old versions of node */
    exports.fs.exists                       = exports.fs.exists || exports.path.exists,
    
    /* Needed Modules */
    exports.util        = Util              = require(LIBDIR + 'util'),
    
    exports.zlib        = zlib              = mrequire('zlib'),
    
    /* Main Information */
    exports.modules                         = jsonrequire('modules');
    exports.ext         = ext               = jsonrequire('ext');
    exports.mainpackage                     = rootrequire('package');
    /* base configuration */
    exports.config                          = Config,
    
    
    /* 
     * Any of loaded below modules could work with global var so
     * it should be initialized first. Becouse of almost any of
     * moudles do not depends on each other all needed information
     * for all modules is initialized hear.
     */
    global.cloudcmd.main                    = exports;
    
    exports.VOLUMES                         = getVolumes(),
    
    /* Additional Modules */
    exports.socket                          = srvrequire('socket'),
    exports.auth                            = srvrequire('auth').auth,
    exports.appcache                        = srvrequire('appcache'),
    exports.cache                           = srvrequire('cache').Cache,
    exports.cloudfunc                       = librequire('cloudfunc'),
    exports.rest                            = srvrequire('rest').api,
    exports.update                          = srvrequire('update'),
    exports.ischanged                       = srvrequire('ischanged');
    exports.commander                       = srvrequire('commander');
    exports.minify                          = srvrequire('minify').Minify;
    /*
     * second initializing after all modules load, so global var is
     * totally filled of all information that should know all modules
     */
    global.cloudcmd.main            = exports;
    /**
     * function do safe require of needed module
     * @param {Strin} pSrc
     */
    function mrequire(pSrc){
        var lModule,
        lError = Util.tryCatch(function(){
            lModule = require(pSrc);
        });
        
        if(lError){
            Util.log('Module ' + pSrc + ' not connected');
            Util.log('Change json/config.json to prevent this message');
            Util.log('or install module ' + pSrc);
        }
        
        return lModule;
    }
    
    function rootrequire(pSrc){ return mrequire(DIR + pSrc); }
    
    function librequire(pSrc){ return mrequire(LIBDIR + pSrc); }
    
    function srvrequire(pSrc){ return mrequire(SRVDIR + pSrc); }
    
    function jsonrequire(pSrc){ return mrequire(JSONDIR + pSrc);}
    
    /**
     * function check is current platform is win32
     */
    function isWin32(){ return process.platform === 'win32'; }
    
    /**
     * get volumes if win32 or get nothing if nix
     */
    function getVolumes(){
        var lRet = ISWIN32 ? [] : '/';
                
        if(ISWIN32)
            srvrequire('win').getVolumes(function(pVolumes){
                console.log(pVolumes);
                exports.VOLUMES = pVolumes;
            });

        return lRet;
    }
    
    /**
     * Функция создаёт заголовки файлов
     * в зависимости от расширения файла
     * перед отправкой их клиенту
     * @param pParams
     *  name - имя файла
     * gzip - данные сжаты gzip'ом
     * query
     * https://developers.google.com/speed/docs/best-practices/caching?hl=ru#LeverageProxyCaching
     */
    function generateHeaders(pParams){
        var lRet    = Util.checkObjTrue(pParams, ['name']),
            p       = pParams;
        
        if(lRet){
            var lExt                = Util.getExtension(p.name),
                lType               = ext[lExt] || 'text/plain',
                lContentEncoding    = '';
            
            /* if type of file any, but img - then we shoud specify charset */
            if( !Util.isContainStr(lType, 'img') )
                lContentEncoding = '; charset=UTF-8';
            
            if( Util.isContainStr(p.query, 'download') )
                lType = 'application/octet-stream';
            
            
            lRet = {
                'Content-Type': lType + lContentEncoding,
                'last-modified': new Date().toString(),
                'Vary': 'Accept-Encoding'
            };
            
            if( !Util.strCmp(lExt, '.appcache') && exports.config.cache){
                var lCacheControl = 31337 * 21;
                lRet['cache-control']       = 'max-age=' + lCacheControl;
            }
            
            if(p.gzip)
                lRet['content-encoding']    = 'gzip';
        }
        
        return lRet;
    }
    
    /**
     * send file to client thru pipe
     * and gzip it if client support
     * 
     * @param pName - имя файла
     * @param pGzip - данные сжаты gzip'ом
     */
    function sendFile(pParams){
        var lRet,
            lName, lReq, lRes, lGziped;
        
        if(pParams){
            lName   = pParams.name,
            lReq    = pParams.request,
            lRes    = pParams.response;
            lGziped = pParams.gziped;
        }
        if(lName && lRes && lReq){
            var lGzip   = isGZIP(lReq),
                
                lReadStream = fs.createReadStream(lName, {
                    'bufferSize': 4 * 1024
                });
            
            lReadStream.on('error', function(pError){
                lRes.writeHead(FILE_NOT_FOUND, 'OK');
                lRes.end(String(pError));
            });
            
            lRes.writeHead(OK, generateHeaders({
                name    : lName,
                gzip    : lGzip,
                query   : getQuery(lReq)
            }) );
            
            if (lGzip && !lGziped)
                lReadStream = lReadStream.pipe( zlib.createGzip() );
            
            lReadStream.pipe(lRes);
            
            lRet = true;
        }
        
        return lRet;
    }
     
     
    /**
     * Функция высылает ответ серверу
     * @param pHead     - заголовок
     * @param Data      - данные
     * @param pName     - имя отсылаемого файла
     */
    function sendResponse(pParams, pData){
         var lRet = Util.checkObjTrue(pParams,
            ['name', 'request', 'response']);
        
        if(lRet){
            var p = pParams;
            
            var lQuery      = getQuery(p.request),
                /* download, json */
                lGzip       = isGZIP(p.request),
                lHead       = generateHeaders({
                    name    : p.name,
                    gzip    : lGzip,
                    query   : lQuery
                });
                        
            /* если браузер поддерживает gzip-сжатие - сжимаем данные*/
            Util.ifExec(!lGzip,
                function(pParams){
                    var lRet = Util.checkObj(pParams, ['data']);
                    
                    if(lRet){
                        p.status    = pParams.status || p.status;
                        p.data      = pParams.data;
                    }
                    
                    p.response.writeHead(p.status || OK, lHead);
                    p.response.end(p.data);
                    
                    Util.log( p.name + ' sended');
                },
                
                function(pCallBack){
                    zlib.gzip (p.data || pData, Util.call(gzipData, {
                        callback    : pCallBack
                    }));
                });
        }
    }
    
    function sendError(pParams, pError){
        var lRet = Util.checkObjTrue(pParams,
            ['name', 'request', 'response']);
        
        if(lRet){
            var p       = pParams;
            p.status    = FILE_NOT_FOUND;
            p.data      = p.data || pError.toString();
            sendResponse(p);
        }
    }
    
    /**
     * Функция получает сжатые данные
     * @param pHeader - заголовок файла
     * @pName
     */
    function gzipData(pParams){
        var lRet = checkCallBackParams(pParams);
        
        if(lRet)
            lRet = Util.checkObj(pParams.params, ['callback']);
        
        if(lRet){
            var p           = pParams,
                c           = pParams.params,
                lParams       = {};
            
            if(!p.error)
                lParams.data      = p.data;
            else{
                lParams.status    = FILE_NOT_FOUND;
                lParams.data      = p.error.toString();
            }
            
            Util.exec(c.callback, lParams);
        }
    }
    
    
    function checkCallBackParams(pParams){
        return Util.checkObj(pParams, ['error', 'data', 'params']);
    }
    
    function checkParams(pParams, pAdditional){
        var lRet = Util.checkObjTrue( pParams, ['name', 'request', 'response'] );
        
        if(lRet && pAdditional)
            lRet = Util.checkObjTrue( pParams, pAdditional);
        
        return lRet;
    }
    
    function getQuery(pReq){
        var lQuery, lParsedUrl;
        
        if(pReq){
            lParsedUrl  = url.parse(pReq.url);
            lQuery      = lParsedUrl.query;
        }
        
        return lQuery;
    }
    
    function isGZIP(pReq){
        var lEnc, lGZIP;
        if(pReq){
            lEnc        = pReq.headers['accept-encoding'] || '';
            lGZIP       = lEnc.match(/\bgzip\b/);
        }
        
        return lGZIP;
    }
    
    
    function linuxWatch(pFile, pCallBack){
        fs.watchFile(pFile, function(pCurr, pPrev){
            if(pCurr.mtime !== pPrev.mtime)
                Util.exec(pCallBack);
        });
    }
    
})();