const config = require('config');
const express = require('express');
const fileUpload = require('express-fileupload');
const pug = require("pug");
const session = require("express-session");
const SequelizeSessionStore = require('connect-session-sequelize')(session.Store);
const bodyParser = require("body-parser");
const path = require("path");

const passport = require('passport');
const LocalStrategy = require('passport-local').Strategy;
const fs = require('fs');

module.exports = function () {
    var server = {}; 

    server.run = (db) => {
        console.log("Starting Server")
        return new Promise((resolve, reject) => {
            

            const app = express();

            app.use(fileUpload());

            app.set("view engine", "pug");
            app.set("views", path.resolve("server/views"));

            // compile pug views below so that they are rendered quicker
            var pugPages = {};

            var modelDir = path.join(__dirname, './views');
            fs.readdirSync(modelDir)
                .filter(file => {
                    return file.endsWith(".pug");
                })
                .forEach(file => {
                    const name = file.split(".pug")[0];

                    pugPages[name] = pug.compileFile(path.join(modelDir, file))
                });
            
            // Set up middleware to make use of the compiled pugjs views
            app.use((request, response, next) => {
                // This is cheating...
                response.display = (view, options) => {
                    options.domain = config.get("server.domain");
                    options.urlEndpoint = request.originalUrl;
                    options.query = request.query;
                    // Set a default pageTitle...
                    options.pageTitle = options.pageTitle ? options.pageTitle : "Mantra";
                    options.errorMessage = (error) => {
                        // TODO: Make error human readable...
                        return error.message;
                    }
                    if(config.get("server.compiled-render")) {
                        if(pugPages[view]) {
                            response.send(pugPages[view](options))
                        } else {
                            response.send(pugPages["404"](options))
                        }
                    } else {
                        response.render(view, options);
                    }
                }
                next();
            })
            app.use('/static', express.static("server/static"));

            // Session related stuff...
            function extendDefaultFields(defaults, session) {
                return {
                  data: defaults.data,
                  expires: session.cookie && session.cookie.expires ? session.cookie.expires : defaults.expires, // 157680000
                  userId: session.passport.user
                };
            }
            
            var sessionStore = new SequelizeSessionStore({
                db: db.sequelize,
                table: 'session',
                extendDefaultFields: extendDefaultFields
                // TODO: Define expiry and clean up...
            });

            app.use(session({ 
                store: sessionStore,
                secret: config.get("server.secret"),
                resave: false,
                saveUninitialized: false,
                cookie: config.get("server.cookie")
            }));

            app.use(bodyParser.urlencoded({ extended: true }));
            app.use(bodyParser.json());


            passport.use(new LocalStrategy(
                function(username, password, done) {
                    username = username != null ? username.trim().toLowerCase() : "";
                    password = password != null ? password : "";
                    return db.User.findOne({
                        include: [
                            {
                                association: db.User.Passwords
                            },
                            {
                                association: db.User.UserEmails,
                                required: true,
                                where: {
                                    emailAddress: {
                                        [db.Sequelize.Op.like]: username
                                    }
                                }
                            },
                            {
                                association: db.User.UserRoles,
                                // required: true,
                                include: [
                                    {
                                        association: db.UserRole.Role,
                                        // required: true,
                                        // where: {
                                        //     type: {
                                        //         [db.Sequelize.Op.or]: roles
                                        //     }
                                        // }
                                    }
                                ]
                            }
                        ]
                    }).then(
                        user => {
                            // Validate Password
                            if(user) {
                                if (!user.passwords[0].validPassword(password)) {
                                    return done(null, false, { 
                                        username: username,
                                        message: 'Invalid username or password.' 
                                    });
                                } else {
                                    return done(null, user);
                                }
                            } else {
                                console.error("User Doesn't Exist: ", username);
                                return done(null, false, { 
                                    username: username,
                                    message: 'Invalid username or password.' 
                                });
                            }
                            
                        },
                        err => {
                            console.error("Authentication Failed: " + err);
                            
                            return done(null, false, { message: 'Incorrect username or password.' });
                        }
                    ).catch(error => {
                        console.log("Passport Error: ", error);
                        return done(error);
                    })
                }
            ));

            passport.serializeUser(function(user, done) {
                done(null, user.id);
            });
            
            passport.deserializeUser(function(id, done) {
                // TODO: Add memberships and things like that...
                return db.User.findByPk(id, {
                    include: [
                        {
                            association: db.User.UserRoles,
                            // required: true,
                            include: [
                                {
                                    association: db.UserRole.Role,
                                    // required: true,
                                    // where: {
                                    //     type: {
                                    //         [db.Sequelize.Op.or]: roles
                                    //     }
                                    // }
                                }
                            ]
                        },
                        {
                            association: db.User.IndividualEntityUser,
                            include: [
                                {
                                    association: db.IndividualEntityUser.EntityUser,
                                    include: [
                                        {
                                            association: db.EntityUser.Entity
                                        }
                                    ]
                                }
                            ]
                        }
                    ]
                })
                .then(user => {
                    return done(null, user);
                }).catch(error => {
                    return done(error);
                })
            });

            app.use(passport.initialize());
            app.use(passport.session());

            sessionStore.sync();

            // TODO: check that user has an individualEntityUser....
            var router = require('./router/index.js')({
                app: app,
                express: express,
                db: db,
                passport: passport
            });
            app.use('/', router);
            
            

            // 404 pages...
            app.use((request, response, next) => {

                if(!response.headersSent) {
                    response.status(404);

                    if (request.accepts('html')) {
                        response.display("404", {
                            user: request.user,
                            pageTitle: "Page Not Found - Mantra"
                        })
                        return;
                    }
                    
                    if (request.accepts('application/json')) {
                        response.json({
                            message: "URL not accessible"
                        });
                        return;
                    }
                    
                    response.type('txt').send('Resource Not found');
                }
            });

            // 500 pages... 
            app.use((error, request, response, next) => {
                console.error(`${response.getHeader("id")} - `, error);
                if(error && !response.headersSent) {
                    response.status(500);

                    // TODO: Check if production and then show stack...
                    if (request.accepts('html')) {
                        response.display("error", {
                            user: request.user,
                            pageTitle: "Internal Error - Mantra",
                            error: error
                        })
                        return;
                    }
                    
                    if (request.xhr) {
                        response.json({
                            message: "Internal Error, Please check your tires.",
                            error: error
                        });
                        return;
                    }
                    
                    response.type('txt').send('Internal server error');
                }
            });
            
            const port = process.env.PORT || config.get("server.port");

            app.listen(port);
            resolve(port);
        });
    }
    
    return server;
};