<?php
/*
   Author: Eric Mutua
*/

// Reads the variables sent via POST
$sessionId   = $_POST["sessionId"];
$serviceCode = $_POST["serviceCode"];
$phoneNumber = $_POST["phoneNumber"];
$text        = $_POST["text"];

// Global Variables
$till_num = "";
$pin = "";
$amount = "";
$price = 0;
$N = 0;

// first response which the user gets
if($text == ""){
    $response = "CON Please select a commodity to purchase:\n87 --> back to payment\n";
    $response .= "1. WetWipes @ Ksh20\n";
    $response .= "2. Always @ Ksh30\n";
    $response .= "3. Kortex @ Ksh40\n";
    $response .= "4. SunnyGirl @ Ksh10\n";
    if($text == "87"){
        payment();
    }
}
elseif ($text != ""){
 switch ($text) {
     case 1:
        $price = 20;
        $N = 12;
        payment();
        confirmTrasnaction();
        checkTransactionValidity();
        header('Content-type: text/plain');
        echo $response;
        break;

     case 2:
        $price = 30;
        $N = 8;
        payment();
        confirmTrasnaction();
        checkTransactionValidity();
        header('Content-type: text/plain');
        echo $response;
     break;

     case 3:
       $price = 40;
       $N = 11;
       payment();
       confirmTrasnaction();
       checkTransactionValidity();
       header('Content-type: text/plain');
       echo $response;
     break;

     case 4:
       $price = 10;
       $N = 7;
        payment();
        confirmTrasnaction();
        checkTransactionValidity();
        header('Content-type: text/plain');
        echo $response;
     break;

     default:
      header('Content-type: text/plain');
      $response = "END Invalid Input";
      echo $response;
      exit(0);
      break;
 }
}
// Extract data and count from $text (user Response)
function getResponseParameters($user_response){
    $response_params = array();
    $response_params['count'] = count(explode('*', $user_response));
    $response_params['data'] = explode('*', $user_response);
    return $response_params;
}

function payment(){

    // Fetch Business till Number
    $response = "CON Enter the Till Number:\n";

    if(getResponseParameters($text)['count'] == 2){
        $till_num = getResponseParameters($text)['data'][1];
    }

    // Fetch user mpesa pin
    $response = "CON Enter Mpesa pin:\n";

    if(getResponseParameters($text)['count'] == 3){
        $pin = getResponseParameters($text)['data'][2];

    }

    // Fetch the amount
    if(getResponseParameters($text)['count'] == 4){
        $response = "CON Enter the amount: \n 0 --> Items Menu\n";

        if(getResponseParameters($text)['data'][3] != 0){
            $amount = getResponseParameters($text)['data'][3];
        }else{

           //Send the user back to Item menu
           $text = "";
        }

    }


   return $response;
}

function confirmTrasnaction(){
    $response = "CON If you wish to cancel the transaction enter any character, ";
    $response .= "Otherwise no input means proceed with transaction:\n";
    $response .= "Ksh $price will be debited to account $till_num\n";
    sleep(3);
    if(getResponseParameters($text)['data'][4] != NULL){
        $response = "END Transaction Canceled";
        exit(0);
    }
    return $response;
}

function checkTransactionValidity(){
    if($amount == $price){
      // Send $N and amount payed to VMC server (127.77.110.254:5600)
      $response = "END Transaction succesfull\n";
      $response .= "Please pick the goods at the dispensing unit Thank you for transacting with YZ-Me int\n";
    }
    elseif ($amount < $price){
      // Change is not expected in Mpesa
      $response = "END Unable to proceed with transaction because of Insufficient funds\n";
      //Send the user back to Item menu
    }
    return $response;
}

?>