// Original file created by Prof.Dr. Matthias Hopf

/*
 * Common functions and imports
 */

var common = {
    fs:   require('fs'),					// file sync
    http: require('http'),
    mongoose: require('mongoose'),			// Needed for db connection.
    //util: require('util'),				// Why is it needed here?
    //fork: require('child_process') .fork,	// What does that?

    // Generate Error object suitible for throwing or next()ing
	// For a better exception handling
    genError: function (code, message) {
        var err = new Error (common.http.STATUS_CODES[code] + (message != undefined && message != "" ? ": "+message : ""));
        err.status = code;
        // to generally disable stack traces for these manually created error Objects:
        delete err.stack;
        return err;
    },

    // Generate deep copy
    // Only include properties incl (all if undefined), strip properties excl (associative arrays)
    deepCopy: function (inp, incl, excl) {
        // For now, JSON is considered fastest / easiest
        var obj = JSON.parse (JSON.stringify (inp));
    	if (incl) {
            for (var k in obj) {
                if (incl[k] === undefined)
                    delete obj[k];
            }
        }
        if (excl) {
            for (var k in excl) {
                delete obj[k];
            }
        }
        return obj;
    },

    // Create shallow (1 level) copy of object, use obj if already present (merge)
    // Only include properties incl (all if undefined), strip properties excl (associative arrays)
    shallowCopy: function (inp, incl, excl, obj) {
        var keys = inp;
        if (obj === undefined)
            obj = {};
    	if (typeof inp == "array")
    	    obj = [];
    	if (incl !== undefined)
    	    keys = incl;
    	for (var k in keys) {
    	    if (inp[k] !== undefined && (excl === undefined || ! excl[k]))
                obj[k] = inp[k];
    	}
    	return obj;
    },

    // Create hash of 'true' entries for array/mongoose object
    arrayToHash: function (array) {
        var hash = {};
        for (var e=0; e < array.length; e++) {
            hash[array[e]] = true;
        }
        return hash;
    },

	// Log output session cookie
    debug: function (req) {
	console.log ("- " + req.headers.cookie + "\n+ " + req.session.id + "\n  " + JSON.stringify (req.session));
    },

    // Init config data
    init: function () {
        this.config = JSON.parse (this.fs.readFileSync ("server_config.json"));
    },
};

module.exports = common;