<?php
namespace DayTidy;

use DayTidy\Data\GeneralSettings;
use DateTime;

class DateRange
{
    private GeneralSettings $settings;

    /**
     * @param GeneralSettings|null $settings
     */
    public function __construct(?GeneralSettings $settings = null)
    {
        $this->settings = $settings ?? Config::general();
    }

    /**
     * @param DateTime $start
     * @param DateTime $end
     * @return string
     */
    public function generate(DateTime $start, DateTime $end): string
    {
        // Equivalent Dates
        if ($start->format('YmdHi') === $end->format('YmdHi'))
        {
            return $start->format($this->settings->datetimeFormat());
        }

        // Range Formats
        $range_formats = $this->settings->rangeFormat();

        // Same Hour
        if ($start->format('YmdH') === $end->format('YmdH'))
        {
            $range = $range_formats['hour'] ?? 'F1 j1, G1:i1 - i2';
        }
        // Same Day
        else if ($start->format('Ymd') === $end->format('Ymd'))
        {
            $range = $range_formats['day'] ?? 'F1 j1, G1:i1 - G2:i2';
        }
        // Same Calendar Month
        else if ($start->format('Ym') === $end->format('Ym'))
        {
            $range = $range_formats['month'] ?? 'F1 j1 - j2, G1:i1 - G2:i2';
        }
        // Same Calendar Year
        else if ($start->format('Y') === $end->format('Y'))
        {
            $range = $range_formats['year'] ?? 'F1 j1 - F2 j2, G1:i1 - G2:i2';
        }
        // General Case (spans calendar years)
        else
        {
            $range = $range_formats['other'] ?? 'F1 j1, Y1 G1:i1 - F2 j2, Y2 G2:i2';
        }

        foreach ([1 => $start, 2 => $end] as $key => $date)
        {
            foreach ([
                'Y', 'y', 'X', 'x', 'L', 'o', // Year
                'M', 'm', 'F', 'n', 't', // Month
                'W', // Week
                'd', 'D', 'j', 'l', 'N', 'S', 'w', 'z', // Day
                'a', 'A', 'B', 'g', 'G', 'h', 'H', 'i', 's', // Time
                'e', 'I', 'O', 'P', 'p', 'T', 'Z', // TimeZone
            ] as $f)
            {
                $range = str_replace($f . $key, $date->format($f), $range);
            }
        }

        return $range;
    }
}