I'm here trying to make a scenario, where I visit a juice shop to ask the juice seller to provide juice until a certain date, by providing him a certain amount he will provide me juice service until by balance will over.

$rate = 30;  //rate of per juice glass
$total_amt = 200; //amt that provide to the seller at start of the service
$start_date = "19-08-2022"; //date of starting the service

$cost = $rate * 7; //rate * days
if($cost <= $total_amt){
    echo "Remainder:".$total_amt - $cost; //Money that seller give back to buyer
} else {
 echo "you need to pay extra:".$cost - $total_amt; //money need to pay exta for glass
}

Demo

I'm unable to figure out, how can I calculate the number of glass that comes inside $200 based upon the service start date and the next due date.

Example:

In $200 amount, the buyer will get 6 glass with returing balance $20, because If the buyer service start date is 19-08-2022 then the due date is 25-08-2022 (19 6 = 25)

So, the output needs to be like:

Number of glass in $200 is: 6
returning balance : $20
next due date: 25-08-2022

CodePudding user response：

Calculation of the due date:

• GIVEN a start date (as in your example)
• GIVEN the interval (as in your example)

You can easily calculate the according target date via:

• Initiate a DateTime object, with your given start date, according to your specified format:

DateTime::createFromFormat("d-m-Y", "19-08-2022")

• Create your DateInterval. Given an amount of days, for example two days, the according string you need to pass would need to be: P2D:

new DateInterval('P2D')

• Now you just need to add your DateInterval onto your DateTime via the add method, and you get your resulting DateTime object:

var_dump( DateTime::createFromFormat("d-m-Y", "19-08-2022")->add(new DateInterval('P2D')) );

Calculation of the amount of glasses that can be afforded:

If one class costs $glass_price, and you have a total amount of $money_available, you can simply calculate the amount of glasses you can afford via:

floor($money_available / $glass_price)

Calculation of the remaining amount:

And for the returning balance, you would do:

$money_available % $glass_price

CodePudding user response：

Thanks, @DevelJoe for providing the way to calculate the next due date

$rate = 30;
$total_amt = 200;
$start_date = "19-08-2022";

$days  = floor($total_amt / $rate); // provide number of days 
$glasses = $days; //each day means 1 glass 
$cost = $rate * $days; //calculating the per day cost with days
$due_date = DateTime::createFromFormat("d-m-Y", $start_date)->add(new DateInterval('P'.$days.'D'));
if($cost <= $total_amt){
    $bal = $total_amt % $cost;
    var_dump(array("glasses"=>$glasses, "buyer_bal"=> $bal, "due_date"=>$due_date->format('d-m-Y')));
} else {
   $bal = $cost % $total_amt;
   var_dump(array("glasses"=>$glasses, "buyer_bal"=> $bal, "due_date"=>$due_date->format('d-m-Y')));
}

Output

 array(3) {
  ["glasses"]=>
  float(6)  //<-----------Glasses
  ["returing_bal"]=>
  int(20)  //<------------Return Balance
  ["due_date"]=>
  object(DateTime)#1 (3) {
    ["date"]=>
    string(26) "2022-08-25 14:09:02.000000"  //<----Next due date
    ["timezone_type"]=>
    int(3)
    ["timezone"]=>
    string(16) "Europe/Amsterdam"
  }
}