<?php

declare(strict_types=1);

namespace App\Filament\Pages;

use App\Support\EditorialCalendar as Calendar;
use BackedEnum;
use Carbon\CarbonImmutable;
use Filament\Pages\Page as FilamentPage;
use Filament\Support\Icons\Heroicon;
use Illuminate\Contracts\Support\Htmlable;
use Illuminate\Support\Facades\Auth;
use Livewire\Attributes\Url;
use UnitEnum;

/**
 * A month at a glance: what goes live, what comes off, which calls open and
 * close. The dates were always there, one form at a time; this is them side
 * by side, which is where a clash or an empty fortnight shows.
 */
class EditorialCalendar extends FilamentPage
{
    protected string $view = 'filament.pages.editorial-calendar';

    protected static string|BackedEnum|null $navigationIcon = Heroicon::OutlinedCalendarDays;

    protected static ?int $navigationSort = 5;

    /**
     * `2026-10`. In the address, so a month can be linked to.
     */
    #[Url]
    public string $month = '';

    public function mount(): void
    {
        if (! preg_match('/^\d{4}-\d{2}$/', $this->month)) {
            $this->month = now()->format('Y-m');
        }
    }

    public static function canAccess(): bool
    {
        return Auth::user()?->can('panel.access') ?? false;
    }

    public static function getNavigationGroup(): string|UnitEnum|null
    {
        return __('panel.groups.content');
    }

    public static function getNavigationLabel(): string
    {
        return __('panel.calendar.title');
    }

    public function getTitle(): string|Htmlable
    {
        return __('panel.calendar.title');
    }

    public function previous(): void
    {
        $this->month = $this->first()->subMonth()->format('Y-m');
    }

    public function next(): void
    {
        $this->month = $this->first()->addMonth()->format('Y-m');
    }

    public function today(): void
    {
        $this->month = now()->format('Y-m');
    }

    public function first(): CarbonImmutable
    {
        return CarbonImmutable::createFromFormat('Y-m-d', $this->month.'-01')->startOfDay();
    }

    public function label(): string
    {
        return ucfirst($this->first()->locale(app()->getLocale())->isoFormat('MMMM YYYY'));
    }

    /**
     * Whole weeks, Monday first, covering the month.
     *
     * @return array<int, array<int, array{date: CarbonImmutable, inMonth: bool, isToday: bool, events: array<int, array<string, mixed>>}>>
     */
    public function weeks(): array
    {
        $start = $this->first()->startOfWeek(CarbonImmutable::MONDAY);
        $end = $this->first()->endOfMonth()->endOfWeek(CarbonImmutable::SUNDAY);

        $events = Calendar::between($start, $end, Auth::user())->groupBy('date');

        $weeks = [];

        for ($day = $start; $day->lte($end); $day = $day->addDay()) {
            $weeks[intdiv((int) $start->diffInDays($day), 7)][] = [
                'date' => $day,
                'inMonth' => $day->month === $this->first()->month,
                'isToday' => $day->isToday(),
                'events' => ($events[$day->toDateString()] ?? collect())->all(),
            ];
        }

        return $weeks;
    }

    /**
     * @return array<int, string>
     */
    public function weekdays(): array
    {
        $monday = CarbonImmutable::now()->locale(app()->getLocale())->startOfWeek(CarbonImmutable::MONDAY);

        return array_map(fn (int $i) => $monday->addDays($i)->isoFormat('ddd'), range(0, 6));
    }
}