<?php

namespace App\Helpers;

class CalendarHelper
{
    /**
     * Parse a date string (may be Jalali) and return a Gregorian date string.
     * If the calendar preference is 'jalali', try to convert from Jalali format.
     */
    public static function parseDate(?string $date): ?string
    {
        if (empty($date)) {
            return null;
        }

        // If it's already a valid Gregorian date (Y-m-d), return as-is
        if (preg_match('/^\d{4}-\d{2}-\d{2}$/', $date)) {
            return $date;
        }

        // Try to parse as Jalali date (Y/m/d or Y-m-d with Jalali year)
        $calendar = session('calendar', auth()->user()?->preferred_calendar ?? 'jalali');

        if ($calendar === 'jalali' && class_exists(\Morilog\Jalali\Jalalian::class)) {
            try {
                // Try Jalali format: 1404/03/15 or 1404-03-15
                $normalized = str_replace('/', '-', $date);
                $parts = explode('-', $normalized);

                if (count($parts) === 3) {
                    $jYear = (int) $parts[0];
                    $jMonth = (int) $parts[1];
                    $jDay = (int) $parts[2];

                    // If year looks like a Jalali year (> 1300), convert
                    if ($jYear > 1300 && $jYear < 1600) {
                        $gregorian = \Morilog\Jalali\Jalalian::fromDateTime(
                            \Morilog\Jalali\CalendarUtils::toGregorian($jYear, $jMonth, $jDay)
                        );

                        return $gregorian->format('Y-m-d');
                    }
                }
            } catch (\Exception $e) {
                // Fall through to Carbon parse
            }
        }

        // Fallback: try Carbon parse
        try {
            return \Carbon\Carbon::parse($date)->format('Y-m-d');
        } catch (\Exception $e) {
            return $date;
        }
    }

    /**
     * Format a date based on the user's calendar preference.
     */
    public static function formatDate(?string $date, string $calendar = 'jalali', string $format = 'Y/m/d'): string
    {
        return JalaliHelper::formatDateForDisplay($date, $calendar, $format);
    }

    /**
     * Get the month name for a given month number.
     */
    public static function getMonthName(int $month, string $calendar = 'jalali'): string
    {
        if ($calendar === 'jalali') {
            return JalaliHelper::jalaliMonthName($month);
        }

        $months = [
            1  => 'January',
            2  => 'February',
            3  => 'March',
            4  => 'April',
            5  => 'May',
            6  => 'June',
            7  => 'July',
            8  => 'August',
            9  => 'September',
            10 => 'October',
            11 => 'November',
            12 => 'December',
        ];

        return $months[$month] ?? '';
    }

    /**
     * Get the day (of week) name.
     */
    public static function getDayName(int $dayOfWeek, string $calendar = 'jalali'): string
    {
        if ($calendar === 'jalali') {
            return JalaliHelper::jalaliDayName($dayOfWeek);
        }

        $days = [
            0 => 'Sunday',
            1 => 'Monday',
            2 => 'Tuesday',
            3 => 'Wednesday',
            4 => 'Thursday',
            5 => 'Friday',
            6 => 'Saturday',
        ];

        return $days[$dayOfWeek] ?? '';
    }

    /**
     * Get the current date formatted based on the calendar preference.
     */
    public static function getCurrentDate(string $calendar = 'jalali', string $format = 'Y/m/d'): string
    {
        return self::formatDate(now()->format('Y-m-d'), $calendar, $format);
    }

    /**
     * Get the query date range for a given month and year.
     */
    public static function getQueryRangeForMonth(int $year, int $month, string $calendar = 'jalali'): array
    {
        if ($calendar === 'jalali') {
            return JalaliHelper::getQueryRangeForJalaliMonth($year, $month);
        }

        // Gregorian range
        $start = \Carbon\Carbon::create($year, $month, 1)->startOfDay();
        $end = \Carbon\Carbon::create($year, $month, 1)->endOfMonth()->endOfDay();

        return [$start, $end];
    }
}