var uid = 0;
var users = [];
var transactions = [];

function User(uid) {

    // If the uid is an object, we copy the properties of
    // that object into this new object.
    if( typeof uid === 'object') {
        for(var prop in uid) {
            this[prop] = uid[prop];
        }
    } else {
        // The unique identifier for this game.
        this.uid = this.uid || uid;

        /*
         * Identification
         */

        this.username = 'admin';
        // default username
        this.password = 'admin';
        // default password

        this.dob = -1;
        // placeholder dob
        this.doc = -1;
        // placeholder doc

        /*
         * Financial
         */

        this.balance = -1;
        this.knownTransactions = [];

    }
}

//********************************************************************************//

function Transaction() {
    this.amount = 0;
    this.to
    this.from
}

//********************************************************************************//

checkPassword = function(user, pass) {
    for(var i = 0; i < users.length; i++) {
        if(users[i].username === user) {
            return (users[i].password === pass);
        }
    }
    return false;
}
//********************************************************************************//
//********************************************************************************//
//********************************************************************************//

/*
 * Methods used by the user
 */

User.prototype.transfer = function(to, amount) {
    var tran = new Transaction(to, this.username, amount);
    var found = 0;
    var complete = 0;


    for(var i = 0; i < users.length; i++) {
        if(users[i].username === to)
        {
            found = 1;
            if (this.balance - amount < 0)
            {
            this.balance -= amount;
            users[i].balance += amount;
            complete = 1;
            }
        }
    }


    if (found === 0)
    {
        // transaction incomplete, invalid id
        // quitting
    }

    if (complete === 0)
    {
        // inssufficient founds
    }

    /*
     * TODO:
     *
     * three states:
     * return:successfully withdrawn
     * return: failure to withdrawn: inssufficient funds
     * return: failure to transfer: invalid recipient
     * */

    path.exists(transDB, function(exists) {
        if(!exists) {

            var transactions = newUser ? [tran] : [];
            var json = JSON.stringify(transactions);

            saveTransDB(transactions, function() {
                res.render('transfer', {
                    'title' : 'transfer'
                });
            });
        } else {
            loadTransDB(function(transactions) {

                transactions.push(tran);

                saveTransDB(transactions, function() {
                    res.render('transfer', {
                        'title' : 'transfer'
                    });
                });
            });
        }
    });
}

User.prototype.withdraw = function(amount) {
    var tran = new Transaction(-1, this.username, amount);
    if (this.balance - amount < 0)
    {
        // return, inssufficient funds
    }
    this.balance -= amount;


    path.exists(transDB, function(exists) {
        if(!exists) {

            var transactions = newUser ? [tran] : [];
            var json = JSON.stringify(transactions);

            saveTransDB(transactions, function() {
                res.render('withdraw', {
                    'title' : 'withdraw'
                });
            });
        } else {
            loadTransDB(function(transactions) {

                transactions.push(tran);

                saveTransDB(transactions, function() {
                    res.render('withdraw', {
                        'title' : 'Withdraw'
                    });
                });
            });
        }
    });
    /*
     * TODO:
     * add to list of the known transactions
     * return: withdrawn $x
     * return: failure to withdraw: inssufucient funds
     */

}

User.prototype.deposit = function(amount) {
    var temp = new Transaction(this.username, -1, amount);
    this.balance += amount;

    path.exists(transDB, function(exists) {
        if(!exists) {

            var transactions = newUser ? [tran] : [];
            var json = JSON.stringify(transactions);

            saveTransDB(transactions, function() {
                res.render('deposit', {
                    'title' : 'deposit'
                });
            });
        } else {
            loadTransDB(function(transactions) {

                transactions.push(tran);

                saveTransDB(transactions, function() {
                    res.render('deposit', {
                        'title' : 'deposit'
                    });
                });
            });
        }
    });
    /*
     * TODO:
     * add to the list of the known transactions
     *
     */

}
//********************************************************************************//
//********************************************************************************//
//********************************************************************************//

/*
 * Methods used backend
 */

User.prototype.createUser = function(username, password, dob) {
    if (typeof(username) !== 'string' || typeof(password) !== 'string')
    {
        // username or password are not strings
    }
    var patt = new RegExp("\d{1,2}\/\d{1,2}\/\d{1,4}"); // not used yet, very simple regex

    this.username = username;
    this.password = password;
    this.dob = dob;
    this.balance = 0;

    var currentTime = new Date();
    var month = currentTime.getMonth() + 1;
    var day = currentTime.getDate();
    var year = currentTime.getFullYear();

    this.doc = month + "/" + day + "/" + year;

    /*
     * TODO:
     * check date of birth to be in the appropriate format
     *
     * return: user sucessfully created
     * return: error: user already exists
     * return: error: inccorrect format for date of birth
     */
}

User.prototype.updateTransactions = function() {
    /*
     * TODO:
     * figure out how to implement this function
     */
}

User.prototype.getTransactions = function() {
    var ret = '';
    /*
     * TODO:
     * possibly update transactions
     * return an html object with alternating colors (list items, css) of the list of the transactions
     */
}

User.prototype.getName = function() {
    return this.username;
}

User.prototype.addTransaction = function(id) {
    /*
     * TODO: given transaction ID add it to array of known transactions
     */
}
//********************************************************************************//
//********************************************************************************//
//********************************************************************************//

/*
 * Transactions
 */

Transaction.prototype.transfer = function(to, from, amount) {
    for(var i = 0; i < users.length; i++) {
        if(users[i].username === to)
            users[i].balance += amount;
    }

    for(var i = 0; i < users.length; i++) {
        if(users[i].username === from)
            users[i].balance -= amount;
    }

    // notify if fail

    /*
     * TODO:
     * find the appropriate users and add transaction to list of transactions
     * change their money
     */

}

Transaction.prototype.toString = function() {
    var ret = '';
    if(this.to !== -1 && this.from !== -1)
        ret = 'Transferred $' + this.amount + ' from ' + this.from + ' to ' + this.to;
    else if(this.to === -1 && this.from !== -1)
        ret = 'Withdrawn $' + amount + ' from ' + this.from;
    else if(this.to !== -1 && this.from === 1)
        ret = 'Deposited $' + amount + ' to ' + this.to;
    return ret;
}
//********************************************************************************//
//********************************************************************************//
//********************************************************************************//

/*
 * views
 */

exports.readme = function(req, res) {
    // The instructions for the assignment.
    res.render('readme', {
        title : 'Midterm'
    });
};
//********************************************************************************//

exports.create = function(req, res) {

    var uname = req.query.username;
    var pw = req.query.password;
    var dob = req.query.dob;

    var newUser = new User(uid++);
    newUser.createUser(uname, pw, dob);

    path.exists(usersDB, function(exists) {
        if(!exists) {

            var users = newUser ? [newUser] : [];
            var json = JSON.stringify(users);

            saveUsersDB(users, function() {
                res.render('create', {
                    'title' : 'Create New User'
                });
            });
        } else {
            loadUsersDB(function(users) {
                if(newUser) {
                    var dupe = 0;
                    for(var i = 0; i < users.length; i++) {
                        if(users[i].username === uname) {
                            dupe = 1;
                        }
                    }
                    if(dupe === 0)
                        users.push(newUser);
                }
                saveUsersDB(users, function() {
                    res.render('create', {
                        'title' : 'Create'
                    });
                });
            });
        }
    });
};
//********************************************************************************//

exports.login = function(req, res) {
    // req has properties username and password

    path.exists(usersDB, function(exists) {
        if(!exists) {
            var users = [];
            var json = JSON.stringify(users);
            saveUsersDB(users, function() {
                res.render('login', {
                    'title' : 'No userdatabase'
                });
            });
        } else {
            loadUsersDB(function(users) {
                var uname = req.query.username;
                var pw = req.query.password;
                for(var i = 0; i < users.length; i++) {
                    if(users[i].username === uname) {
                        if(users[i].password === pw)
                        ;
                        req.session.user = users[i];
                    }
                }
                res.render('login', {
                    'title' : 'logged in as ' + req.session.user.username
                });
            });
        }
        // TODO: user login
    });
}
//********************************************************************************//

exports.logout = function(req, res) {
    req.session.destroy();
    // TODO: user logout
};
//********************************************************************************//

exports.transactions = function(req, res) {
    res.render('transactions', {
        title : 'Transactions',
        msg : 'Logged in as ' + req.session.username
    });
    // TODO: transaction list
};
//********************************************************************************//

exports.deposit = function(req, res) {
    res.render('deposit', {
        title : 'Deposit',
        user: req.session.user.username
    });
    var amount = req.query.amt;
    var user = new User(req.session.user);
    // TODO: account deposit
};
//********************************************************************************//

exports.withdraw = function(req, res) {
    var user = new User(req.session.user);
    res.render('withdraw', {
        title : 'Withdraw'
    });
    // TODO: account withdrawal
};
//********************************************************************************//

exports.transfer = function(req, res) {
    res.render('transfer', {
        title : 'Transfer'
    });
    // TODO: account transfer
};
//********************************************************************************//

exports.report = function(req, res) {
    res.render('report', {
        title: 'Report'
    });
}
//********************************************************************************//
//********************************************************************************//
//********************************************************************************//

/*
 * Persistance
 */

var fs = require('fs');
var path = require('path');

var usersDB = 'users.json';
var transDB = 'trans.json';

function loadUsersDB(cb) {
    fs.readFile(usersDB, function(err, data) {
        if(err) {
            throw new Error('Error reading database: ' + err);
        }
        cb(JSON.parse(data));
    });
}

function loadTransDB(cb) {
    fs.readFile(trans, function(err, data) {
        if(err) {
            throw new Error('Error reading database: ' + err);
        }
        cb(JSON.parse(data));
    });
}

function saveUsersDB(users, cb) {
    var json = JSON.stringify(users);
    fs.writeFile(usersDB, json, function(err) {
        if(err) {
            throw new Error('Could not write ' + dbfile);
        }
        cb();
    });
}

function saveTransDB(transactions, cb) {
    var json = JSON.stringify(transactions);
    fs.writeFile(transDB, json, function(err) {
        if(err) {
            throw new Error('Could not write ' + dbfile);
        }
        cb();
    });
}

//********************************************************************************//
//********************************************************************************//
//********************************************************************************//

// Random stuff

// Generate list of Users

function toList(users) {
    var s = '<ul>';
    for(var i = 0; i < users.length; i++)
    s += '<li>' + users[i].username + '</li>';
    s += '</ul>';
    return s;
}