index.php

<?php

require __DIR__ . '/vendor/autoload.php';

use Phpfastcache\Helper\Psr16Adapter;

$defaultDriver = 'Files';
$Psr16Adapter = new Psr16Adapter($defaultDriver);

// Get the JSON contents
$json = file_get_contents('php://input');

// decode the json data
$data = json_decode($json, true);

$sessionID = $data['sessionID'];
$userID = $data['userID'];
$newSession = $data['newSession'];
$msisdn = $data['msisdn'];
$userData = $data['userData'];
$network = $data['network'];

if ($newSession) {
    $message = "Welcome to Arkesel Voting Portal. Please vote for your favourite service from Arkesel" .
        "\n1. SMS" .
        "\n2. Voice" .
        "\n3. Email" .
        "\n4. USSD" .
        "\n5. Payments";
    $continueSession = true;

    // Keep track of the USSD state of the user and their session
    $currentState = [
        'sessionID' => $sessionID,
        'msisdn' => $msisdn,
        'userData' => $userData,
        'network'   => $network,
        'newSession' => $newSession,
        'message' => $message,
        'level' => 1,
        'page' => 1,
    ];

    $userResponseTracker = $Psr16Adapter->get($sessionID);

    !$userResponseTracker
        ? $userResponseTracker = [$currentState]
        : $userResponseTracker[] = $currentState;

    $Psr16Adapter->set($sessionID, $userResponseTracker);

    http_response_code(200);

    // treat this as json
    header('Content-Type: application/json');

    echo json_encode([
        'sessionID' => $sessionID,
        'msisdn' => $msisdn,
        'userID' => $userID,
        'continueSession' => $continueSession,
        'message' => $message,
    ]);
    exit();
}


$userResponseTracker = $Psr16Adapter->get($sessionID) ?? [];

if (!(count($userResponseTracker) > 0)) {
    http_response_code(200);

    echo json_encode([
        'sessionID' => $sessionID,
        'msisdn' => $msisdn,
        'userID' => $userID,
        'continueSession' => false,
        'message' => 'Error! Please dial code again!',
    ]);
    exit();
}

$lastResponse = $userResponseTracker[count($userResponseTracker) - 1];

$message = "Bad Option";
$continueSession = false;

if ($lastResponse['level'] === 1) {
    if (in_array($userData, ["2", "3", "4", "5"])) {

        $message = "Thank you for voting!";
        $continueSession = false;
    } else if ($userData === '1') {
        $message = "For SMS which of the features do you like best?" .
            "\n1. From File" .
            "\n2. Quick SMS" .
            "\n\n #. Next Page";

        $continueSession = true;

        $currentState = [
            'sessionID' => $sessionID,
            'msisdn' => $msisdn,
            'userData' => $userData,
            'network'   => $network,
            'newSession' => $newSession,
            'message' => $message,
            'level' => 2,
            'page' => 1,
        ];

        $userResponseTracker[] = $currentState;
        $Psr16Adapter->set($sessionID, $userResponseTracker);
    }
} else if ($lastResponse['level'] === 2) {
    if ($lastResponse['page'] === 1 && $userData === '#') {
        $message = "For SMS which of the features do you like best?" .
            "\n3. Bulk SMS" .
            "\n\n*. Go Back" .
            "\n#. Next Page";

        $continueSession = true;

        $currentState = [
            'sessionID' => $sessionID,
            'msisdn' => $msisdn,
            'userData' => $userData,
            'network'   => $network,
            'newSession' => $newSession,
            'message' => $message,
            'level' => 2,
            'page' => 2,
        ];

        $userResponseTracker[] = $currentState;
        $Psr16Adapter->set($sessionID, $userResponseTracker);
    } else if ($lastResponse['page'] === 2 && $userData === '#') {
        // Useful Resources
        $message = "For SMS which of the features do you like best?" .
            "\n4. SMS To Contacts" .
            "\n\n*. Go Back";

        $continueSession = true;

        $currentState = [
            'sessionID' => $sessionID,
            'msisdn' => $msisdn,
            'userData' => $userData,
            'network'   => $network,
            'newSession' => $newSession,
            'message' => $message,
            'level' => 2,
            'page' => 3,
        ];

        $userResponseTracker[] = $currentState;
        $Psr16Adapter->set($sessionID, $userResponseTracker);
    } else if ($lastResponse['page'] === 3 && $userData === '*') {
        $message = "For SMS which of the features do you like best?" .
            "\n3. Bulk SMS" .
            "\n\n*. Go Back" .
            "\n#. Next Page";

        $continueSession = true;

        $currentState = [
            'sessionID' => $sessionID,
            'msisdn' => $msisdn,
            'userData' => $userData,
            'network'   => $network,
            'newSession' => $newSession,
            'message' => $message,
            'level' => 2,
            'page' => 2,
        ];

        $userResponseTracker[] = $currentState;
        $Psr16Adapter->set($sessionID, $userResponseTracker);
    } else if ($lastResponse['page'] === 2 && $userData === '*') {
        $message = "For SMS which of the features do you like best?" .
            "\n1. From File" .
            "\n2. Quick SMS" .
            "\n\n #. Next Page";

        $continueSession = true;
        $currentState = [
            'sessionID' => $sessionID,
            'msisdn' => $msisdn,
            'userData' => $userData,
            'network'   => $network,
            'newSession' => $newSession,
            'message' => $message,
            'level' => 2,
            'page' => 1,
        ];

        $userResponseTracker[] = $currentState;
        $Psr16Adapter->set($sessionID, $userResponseTracker);
    } else if (in_array($userData, ["1", "2", "3", "4"])) {
        $message = "Thank you for voting!";
        $continueSession = false;
    } else {
        $message = "Bad choice!";
        $continueSession = false;
    }
}

http_response_code(200);

// treat this as json
header('Content-Type: application/json');

echo json_encode([
    'sessionID' => $sessionID,
    'msisdn' => $msisdn,
    'userID' => $userID,
    'continueSession' => $continueSession,
    'message' => $message,
]);