<?php

/**
 * Time Utility Collection
 *
 * Licensed under The MIT License
 * Redistribution of these files must retain the above copyright notice.
 *
 * @copyright Copyright 2007-2014, Josh Sherman
 * @license   http://www.opensource.org/licenses/mit-license.html
 * @link      https://github.com/joshtronic/pickles
 * @package   Pickles
 */

namespace Pickles;

/**
 * Time Class
 *
 * Just a simple collection of static functions to accomplish some of the more
 * redundant time and date related manipulation.
 */
class Time
{
    // {{{ Intervals (in seconds)

    /**
     * Minute
     *
     * Seconds in a minute
     *
     * @var integer
     */
    const MINUTE = 60;

    /**
     * Hour
     *
     * Seconds in an hour (minute * 60)
     *
     * @var integer
     */
    const HOUR = 3600;

    /**
     * Day
     *
     * Seconds in a day (hour * 24)
     *
     * @var integer
     */
    const DAY = 86400;

    /**
     * Week
     *
     * Seconds in a week (day * 7)
     *
     * @var integer
     */
    const WEEK = 604800;

    /**
     * Month
     *
     * Seconds in a month (day * 30)
     *
     * @var integer
     */
    const MONTH = 2592000;

    /**
     * Quarter
     *
     * Seconds in a quarter (day * 90)
     *
     * @var integer
     */
    const QUARTER = 7776000;

    /**
     * Year
     *
     * Seconds in a year (day * 365)
     *
     * @var integer
     */
    const YEAR = 31536000;

    /**
     * Decade
     *
     * Seconds in a decade (year * 10)
     *
     * @var integer
     */
    const DECADE = 315360000;

    /**
     * Century
     *
     * Seconds in a decade (decade * 10)
     *
     * @var integer
     */
    const CENTURY = 3153600000;

    // }}}

    /**
     * Age
     *
     * Calculates age based on the passed date.
     *
     * @static
     * @param  string $date birth / inception date
     * @return integer $age number of years old
     * @todo   Wondering if this really should live in the Date class since
     *         it's a Date function. Could flip the aliasing to preserve any
     *         older code.
     */
    public static function age($date)
    {
        if (!preg_match('/\d{4}-\d{2}-\d{2}/', $date))
        {
            $date = date('Y-m-d', strtotime($date));
        }

        list($year, $month, $day) = explode('-', $date, 3);

        $age = date('Y') - $year;

        if (date('md') < $month . $day)
        {
            $age--;
        }

        return $age;
    }

    /**
     * Ago
     *
     * Generates a relative time (e.g. X minutes ago).
     *
     * @static
     * @param  mixed $time timestamp to calculate from
     * @return string relative time
     */
    public static function ago($time)
    {
        $current = strtotime(Time::timestamp());
        $time    = preg_match('/^\d+$/', $time) ? $time : strtotime($time);

        if ($current == $time)
        {
            $time_ago = 'just now';
        }
        else
        {
            if ($current > $time)
            {
                $difference = $current - $time;
                $suffix     = ' ago';
            }
            else
            {
                $difference = $time - $current;
                $suffix     = ' from now';
            }

            // Less than 1 minute ago (seconds ago)
            if ($difference < 60)
            {
                $time_ago = 'seconds';
            }
            // Less than 1 hour ago (minutes ago)
            elseif ($difference < Time::HOUR)
            {
                $minutes = round($difference / 60);

                if ($minutes == 60)
                {
                    $time_ago = 'an hour';
                }
                else
                {
                    $time_ago = ($minutes == 1 ? 'a' : $minutes) . ' minute' . ($minutes != 1 ? 's' : '');
                }
            }
            // Less than 1 day ago (hours ago)
            elseif ($difference < Time::DAY)
            {
                $hours = round($difference / Time::HOUR);

                if ($hours == 24)
                {
                    $time_ago = 'a day';
                }
                else
                {
                    $time_ago = ($hours == 1 ? 'an' : $hours) . ' hour' . ($hours != 1 ? 's' : '');
                }
            }
            // Less than 1 week ago (days ago)
            elseif ($difference < Time::WEEK)
            {
                $days = round($difference / Time::DAY);

                if ($days == 7)
                {
                    $time_ago = 'a week';
                }
                else
                {
                    $time_ago = ($days == 1 ? 'a' : $days) . ' day' . ($days != 1 ? 's' : '');
                }
            }
            // Less than 1 month ago (weeks ago)
            elseif ($difference < Time::MONTH)
            {
                $weeks = round($difference / Time::WEEK);

                if ($weeks == 4)
                {
                    $time_ago = 'a month';
                }
                else
                {
                    $time_ago = ($weeks == 1 ? 'a' : $weeks) . ' week' . ($weeks != 1 ? 's' : '');
                }
            }
            // Less than 1 year ago (months ago)
            elseif ($difference < Time::YEAR)
            {
                $months = round($difference / Time::MONTH);

                if ($months == 12)
                {
                    $time_ago = 'a year';
                }
                else
                {
                    $time_ago = ($months == 1 ? 'a' : $months) . ' month' . ($months != 1 ? 's' : '');
                }
            }
            // Over 1 year ago (years ago)
            else
            {
                $years    = round($difference / Time::YEAR);
                $time_ago = ($years == 1 ? 'a' : $years) . ' year' . ($years != 1 ? 's' : '');
            }

            $time_ago .= $suffix;
        }

        return $time_ago;
    }

    /**
     * Timestamp
     *
     * Current Universal Time in the specified format.
     *
     * @static
     * @param  string $format format of the timestamp
     * @return string $timestamp formatted timestamp
     */
    public static function timestamp($format = 'Y-m-d H:i:s')
    {
        return gmdate($format);
    }
}