/**
 Utilities is a node modules created to make tasks like
 including html files easier for me programming.
 */

//used for file io
const fs = require('fs');

const whiskers = require('whiskers');


const includes = require("../includes/includes");


module.exports=
{



    /**
     * Method which return the contents of a file as a string
     * @param fileName
     * @return {*}
     */
    getFileContents: function(fileName)
    {
        try
        {
            return fs.readFileSync(fileName);
        }
        catch (e)
        {
            console.log("Could not find " + fileName);
        }
        return '';
    },


    /**
     *
     * @param fileName
     * @returns {any}
     */
    getFileAsJSON: function(fileName)
    {
        return JSON.parse(fs.readFileSync(fileName, 'utf8'));
    },


    /**
     * Returns all the contents of a file as a single line
     * with no break lines.
     *
     * @param fileName
     * @return {*}
     */
    getFileLine: function(fileName)
    {
        try
        {
            return fs.readFileSync(fileName, "utf8").split('\n').join('');
        }
        catch (e)
        {
            console.log("Could not find " + fileName);
        }
        return '';
    },


    /**
     * Function which is responsible for returning all post data.
     *
     * @param request sent by user in initial server call
     * @return the post data
     */
    getPostData: function(req)
    {
        return new Promise(function(resolve, reject)
        {
            if(req.method == 'POST')
            {
                var body = '';

                req.on('data', function (data)
                {
                    body += data;

                    //Kills request, don't steal my RAM!!
                    //You can only download so much ram ;)
                    if (body.length > 1e6)
                    {
                        req.connection.destroy();
                        reject();
                    }
                });

                req.on('end', function ()
                {
                    resolve(body);
                });
            }
            else
            {
                resolve(0);
            }
        });
    },


    /**
     * Displays 404 error to user
     *
     * @param result
     * @returns {*}
     */
    print404: function(result)
    {
        includes.include("includes/html/404.html").then(function(html)
        {
            result.write(html);
            result.end();
        })
    },


    constructAdminPage: function(request, result, templateFiller)
    {
        var templateContext = Object();
        var promises = [];

        promises.push(includes.fetchTemplate("admin/adminMain.html"));
        promises.push(includes.printAdminHeader(templateContext));
        promises.push(includes.printFooter(templateContext));

        if(module.exports.loggedIn(request))
        {
            templateContext.loggedIn = true;
            promises.push(templateFiller(templateContext));
        }
        else
        {
            //login
            const clientAddress = (request.headers['x-forwarded-for'] || '').split(',')[0]
                || request.connection.remoteAddress;
            promises.push(require("../admin/login").main(request, clientAddress,templateContext));
        }

        Promise.all(promises).then(function(content)
        {
            result.write(whiskers.render(content[0], templateContext));
            result.end();
        }).catch(function(err)
        {
            console.log(err);
            throw err;
        });
    },

    adminPostPageWithOutput: function(request, result, templateFiller)
    {
        module.exports.getPostData(request).then(function(postData)
        {
            var templateContext = Object();
            var promises = [];

            promises.push(includes.fetchTemplate("admin/adminMain.html"));
            promises.push(includes.printAdminHeader(templateContext));
            promises.push(includes.printFooter(templateContext));

            if (module.exports.loggedIn(request))
            {
                templateContext.loggedIn = true;
                promises.push(templateFiller(templateContext, postData));
            }
            else
            {
                //login
                const clientAddress = (request.headers['x-forwarded-for'] || '').split(',')[0]
                    || request.connection.remoteAddress;
                promises.push(require("../admin/login").main(request, clientAddress, templateContext));
            }

            Promise.all(promises).then(function (content)
            {
                result.write(whiskers.render(content[0], templateContext));
                result.end();
            }).catch(function (err) {
                console.log(err);
                throw err;
            });
        });
    },

    adminPostRoute: function(request, templateFiller)
    {
        return new Promise(function(resolve, reject)
        {
            module.exports.getPostData(request).then(function(postData)
            {
                templateFiller(postData).then(function()
                {
                    resolve();
                })
            }).catch(function(e)
            {
                reject(e);
            })
        })

    },


    loggedIn(request)
    {
        return(request.session && request.session.user);
    }
};