Transform the time in a string representation [problem at: https://www.hackerrank.com/challenges/the-time-in-words]

time_to_string.php

<?php

function getTime($hour, $minute)
{
    $hour = (int) $hour;
    $minute = (int) $minute;

    // start time again
    if ($hour == 12 && $minute > 30) {
        $hour = 0;
    }

    $numbers = [
        1 => 'one',
        2 => 'two',
        3 => 'three',
        4 => 'four',
        5 => 'five',
        6 => 'six',
        7 => 'seven',
        8 => 'eight',
        9 => 'nine',
        10 => 'ten',
        11 => 'eleven',
        12 => 'twelve',
        13 => 'thirteen',
        14 => 'fourteen',
        16 => 'sixteen',
        17 => 'seventeen',
        18 => 'eighteen',
        19 => 'nineteen',
        20 => 'twenty',
        21 => 'twenty one',
        22 => 'twenty two',
        23 => 'twenty three',
        24 => 'twenty four',
        25 => 'twenty five',
        26 => 'twenty six',
        27 => 'twenty seven',
        28 => 'twenty eight',
        29 => 'twenty nine'
    ];

    $defaultMinuteRanges = [
        0 => [
            'format' => '%s o\' clock',
            'increaseHour' => false
        ],
        15 => [
            'format' => 'quarter past %s',
            'increaseHour' => false
        ],
        30 => [
            'format' => 'half past %s',
            'increaseHour' => false
        ],
        45 => [
            'format' => 'quarter to %s',
            'increaseHour' => true
        ]
    ];

    // check in default range
    if (isset($defaultMinuteRanges[$minute])) {
        $range = $defaultMinuteRanges[$minute];

        return !$range['increaseHour']
            ? sprintf($range['format'], $numbers[$hour])
            : sprintf($range['format'], $numbers[$hour + 1]);
    }

    // dynamically proccess the time
    $increaseHours = false;

    // past time
    if ($minute < 30) {
        $format = $minute == 1 ? '%s minute past %s' : '%s minutes past %s';
    }
    else {
        // to time
        $minute = 60 - $minute;
        $format = $minute == 1 ? '%s minute to %s' : '%s minutes to %s';
        $increaseHours = true;
    }

    return !$increaseHours
        ? sprintf($format, $numbers[$minute], $numbers[$hour])
        : sprintf($format, $numbers[$minute], $numbers[$hour + 1]);
}

// tests
$testCases = [
    [
        'h' => '4',
        'm' => '15',
        'expect' => 'quarter past four'
    ],
    [
        'h' => '12',
        'm' => '59',
        'expect' => 'one minute to one'
    ],
    [
        'h' => '12',
        'm' => '02',
        'expect' => 'two minutes past twelve'
    ],
    [
        'h' => '12',
        'm' => '01',
        'expect' => 'one minute past twelve'
    ],
    [
        'h' => '12',
        'm' => '45',
        'expect' => 'quarter to one'
    ],
    [
        'h' => '12',
        'm' => '30',
        'expect' => 'half past twelve'
    ],
    [
        'h' => '5',
        'm' => '59',
        'expect' => 'one minute to six'
    ],
    [
        'h' => '5',
        'm' => '28',
        'expect' => 'twenty eight minutes past five'
    ],
    [
        'h' => '5',
        'm' => '47',
        'expect' => 'thirteen minutes to six'
    ],
    [
        'h' => '5',
        'm' => '45',
        'expect' => 'quarter to six'
    ],
    [
        'h' => '5',
        'm' => '40',
        'expect' => 'twenty minutes to six'
    ],
    [
        'h' => '5',
        'm' => '30',
        'expect' => 'half past five'
    ],
    [
        'h' => '5',
        'm' => '10',
        'expect' => 'ten minutes past five'
    ],
    [
        'h' => '5',
        'm' => '01',
        'expect' => 'one minute past five'
    ],
    [
        'h' => '5',
        'm' => '00',
        'expect' => 'five o\' clock'
    ]
];

foreach ($testCases as $time) {
    $result = getTime($time['h'], $time['m']);

    if ($time['expect'] == $result) {
        echo '<span style="color:green">passed:</span> ' . $time['expect'] . ' == ' . $result;
    }
    else {
        echo '<span style="color:red">failed:</span> ' . $time['expect'] . ' <>' . $result;
    }

    echo '<br />';
}