const fs = require ('fs');

try {
    var data = JSON.parse (fs.readFileSync ('./data.json').toString ());
    log.write ('Opened data file');
}
catch (error) {
    var data = {
        users: []
    };
    fs.writeFileSync ('./data.json', JSON.stringify (data, null, 2));
}

const persistData = () => {
    var content = {
        users: []
    };
    Object.keys (users).forEach ((user) => {
        content.users.push ({
            username: user,
            password: users[user].password,
            vlan: users[user].vlan
        });
    });
    fs.writeFileSync ('./data.json', JSON.stringify (content, null, 2));
}

users = {};
data.users.forEach ((e) => {
    users[e.username] = {
        password: e.password,
        vlan: e.vlan
    }
});

module.exports = {
    authUser: (username, password) => {
        if (users[username] && users[username].password == password) {
            return { 
                vlan: users[username].vlan 
            };
        }
        else {
            return false;
        }
    },

    createUser: (payload, callback) => {
        try {
            payload = JSON.parse (payload);
            var username = payload.username;
            var password = payload.password;
            var description = payload.description || "";
            var vlan = payload.vlan;
            users[username] = {
                password: password,
                vlan: vlan,
                description: description
            };
            persistData ();
            callback ("OK\n\n", null);
        }
        catch (error) {
            callback (null, "Error\n\n");
        }
    },

    getUsers: (callback) => {
        try {
            var response = Object.keys (users).map ((username) => {
                return {
                    username: username,
                    password: users[username].password,
                    description: users[username].description,
                    vlan: users[username].vlan
                }
            });
            callback (response, null);
        }
        catch (error) {
            callback (null, "Not found\n\n");
        }
    },

    getUser: (username, callback) => {
        try {
            callback (users[username], null);
        }
        catch (error) {
            callback (null, "Not found\n\n");
        }
    },

    updateUser: (payload, callback) => {
        payload = JSON.parse (payload);
        callback ("OK\n\n", null);
    },

    deleteUser: (username, callback) => {
        try {
            delete users[username];
            persistData ();
            callback ("OK\n\n", null);
        }
        catch (error) {
            callback (null, "Error\n\n");
        }
    }
}