time-factory

//if the request is not far 60 minute from the lastSpan

var Milli = {
    second: 1000,
    minute:60000,
    hour: 3600000,
    day: 86400000,
    month: 2592000000,
    year: 31104000000
}

//cb accepts unite
function throughTime(t, v, cb){
    var k;
    switch(t) {
            case 'second':
            case 'seconds':
                k = cb(v, Milli.second);
                break;
            case 'minute':
            case 'minutes':
                k = cb(v,Milli.minute);
                break;
            case 'hour':
            case 'hours':
                k = cb(v,Milli.hour);
                break;
            case 'day':
            case 'days':
                k = cb(v,Milli.day);
                break;
            case 'month':
            case 'months':
                k = cb(v,Milli.month);
                break;
            case 'year':
            case 'years':
                k = cb(v,Milli.year);
                break;
            default:
                return false;
   }
   return k;
}

module.exports = {
    
    //return different in x-format
    //dif('days', dateObj1, dateObj2); 
    difIn: function(t, d1, d2){
        
        d1 = Date.parse(d1);
        d2 = Date.parse(d2);

        var dif = d1-d2;
        if(dif<0)dif*=-1; 

        dif = throughTime(t, dif, function(dif, unit){
            return dif/unit;
        })

        return dif.toFixed(3);

    },

    //v : verb -> add/remove
    //n : number -> 1/2/3
    //t : time -> 'minutes/hours/day'
    //d : date -> dateObject
    //add or remove (v) specific number (n)  of (t = minutes/hours/days) to date (d = dateObject)
    cal: function(v, n, t, d){
        var c = 0;

        c = throughTime(t, n, function(n, unit){
            return n*unit;
        });

        // console.log(`${v} ${n} ${t} to ${d}`);
        // console.log(`${n} ${t} to milliseconds = ${c}`);

        switch(v) {
            case 'add':
                d.setTime(d.getTime() + c); 
                break;
            case 'remove':
                d.setTime(d.getTime() - c); 
                break;
            default:
                return false;
        }

        return d; 
    },
    //convert date to (t = minutes/hours/days)
    to: function(t, d){
        var n = Date.parse(d);
        return throughTime(t, n, function(n, unit){
            return n*unit;
        });
    }
}