<?php

namespace App\Console\Commands;

use App\Models\Certificate;
use App\Models\User;
use App\Notifications\CertificateExpiredNotification;
use App\Notifications\CertificateExpiringNotification;
use Illuminate\Console\Command;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Support\Carbon;

class SendCertificateReminders extends Command
{
    protected $signature = 'app:send-certificate-reminders';

    protected $description = 'Notify users about certificates that are approaching or reaching their expiry date';

    public function handle(): int
    {
        $today = Carbon::today();

        $advanceCount = $this->sendAdvanceReminders($today);
        $urgentCount = $this->sendExpiryReminders($today);

        $this->info("Sent {$advanceCount} advance reminder(s) and {$urgentCount} expiry reminder(s).");

        return self::SUCCESS;
    }

    /**
     * Part 1: for each user, notify about certificates expiring exactly on
     * their personal "months before" threshold.
     */
    private function sendAdvanceReminders(Carbon $today): int
    {
        $sent = 0;

        User::query()
            ->whereHas('certificates')
            ->with('certificates')
            ->chunkById(100, function ($users) use ($today, &$sent) {
                foreach ($users as $user) {
                    $targetDate = $today->copy()->addMonths($user->reminder_months_before);

                    $certificates = $user->certificates()
                        ->whereDate('expires_at', $targetDate)
                        ->tap($this->notRemindedToday($today))
                        ->get();

                    foreach ($certificates as $certificate) {
                        $user->notify(new CertificateExpiringNotification($certificate));
                        $certificate->forceFill(['last_reminded_at' => now()])->save();
                        $sent++;
                    }
                }
            });

        return $sent;
    }

    /**
     * Part 2: notify about certificates expiring today (across all users).
     */
    private function sendExpiryReminders(Carbon $today): int
    {
        $sent = 0;

        Certificate::query()
            ->whereDate('expires_at', $today)
            ->tap($this->notRemindedToday($today))
            ->with('user')
            ->chunkById(100, function ($certificates) use (&$sent) {
                foreach ($certificates as $certificate) {
                    $certificate->user?->notify(new CertificateExpiredNotification($certificate));
                    $certificate->forceFill(['last_reminded_at' => now()])->save();
                    $sent++;
                }
            });

        return $sent;
    }

    /**
     * Skip certificates already reminded today, so a re-run (or a missed day
     * followed by a catch-up run) never double-sends.
     */
    private function notRemindedToday(Carbon $today): callable
    {
        return function (Builder $query) use ($today) {
            $query->where(function (Builder $query) use ($today) {
                $query->whereNull('last_reminded_at')
                    ->orWhereDate('last_reminded_at', '<', $today);
            });
        };
    }
}