<?php

/**
 * class that provides methods to convert human readable time / interval length
 * expressions into other formats
 *
 * @author markus
 * $Id: HumanReadableTime.php 92 2010-03-10 11:43:15Z markus $
 */

require_once(LIBRARY_PATH . '/date/exception.HumanReadableTimeException.php');

class HumanReadableTime {
    /**
     * normalize an HRT string, convert from HRT to seconds and then convert back to
     * HRT
     * @param string $hrt
     * @param string $maxunit
     * @return string
     */
    public static function NormalizeHRT($hrt, $maxunit = 'w') {
        return self::Seconds2HR(self::HR2Seconds($hrt), $maxunit);
    }

    /**
     * convert string / interger which contains an interval length to
     * human readable format (1w2d7h)
     *
     * if $maxunit is set, it defines the biggest unit in output (i.e. $maxunit = 'h' will
     * allow only hms)
     *
     * @param string|integer $seconds
     * @param string $maxunit
     * @return string
     */
    public static function Seconds2HR($seconds, $maxunit = 'w') {
        $maxunit = trim(strtolower($maxunit));
        $allowed = array('w' => 0, 'd' => 0, 'h' => 0, 'm' => 0, 's' => 0);
        if (!in_array($maxunit, array_keys($allowed), true))
            throw new HumanReadableTimeException('illegal value for maxunit: "' . $maxunit . '"');
        foreach ($allowed as $key => $value) {
            if ($maxunit == $key)
                break;
            unset($allowed[$key]);
        }

        $seconds = intval($seconds);
        $hrt = '';
        foreach ($allowed as $key => $value) {
            switch ($key) {
                case 'w':
                    $tmp = intval($seconds / (7*86400));
                    if ($tmp > 0)
                        $seconds %= (7*86400);
                    $allowed[$key] += $tmp;
                    break;
                case 'd':
                    $tmp = intval($seconds / (86400));
                    if ($tmp > 0)
                        $seconds %= (86400);
                    $allowed[$key] += $tmp;
                    break;
                case 'h':
                    $tmp = intval($seconds / (3600));
                    if ($tmp > 0)
                        $seconds %= (3600);
                    $allowed[$key] += $tmp;
                    break;
                case 'm':
                    $tmp = intval($seconds / (60));
                    if ($tmp > 0)
                        $seconds %= (60);
                    $allowed[$key] += $tmp;
                    break;
                case 's':
                    $allowed[$key] += $seconds;
                    break;
            }
        }

        $hrt = '';
        foreach ($allowed as $key => $value) {
            if ($value > 0)
                $hrt .= sprintf('%d%s', $value, $key);
        }
        return $hrt;
    }

    /**
     * parse a string of 3h2m7s and return the number of seconds as integer
     * add "s" to the end of the number if $addsecond is set to true
     * @param string $hr
     * @param boolean $addsecond
     * @return integer|string
     */
    public static function HR2Seconds($hr, $addsecond = false) {
        $hr = trim($hr);
        if ($hr == '') {
            if ($addsecond === true)
                return '0s';
            else
                return 0;
        }

        $hr = strtolower($hr);

        $matches = array();
        if (preg_match_all('/([0-9]*)([wdhms])/', $hr, $matches, PREG_SET_ORDER) > 0) {
            $interval = 0;
            for ($i = 0; $i < count($matches); $i++) {
                switch ($matches[$i][2]) {
                    case 'w':
                        $interval += $matches[$i][1] * 7 * 86400;
                        break;
                    case 'd':
                        $interval += $matches[$i][1] * 86400;
                        break;
                    case 'h':
                        $interval += $matches[$i][1] * 3600;
                        break;
                    case 'm':
                        $interval += $matches[$i][1] * 60;
                        break;
                    case 's':
                        $interval += $matches[$i][1];
                        break;
                }
            }
            if ($addsecond === true)
                return sprintf('%ds', $interval);
            else
                return $interval;
        }

        if ($addsecond === true)
            return '0s';
        else
            return 0;
    }
}