<?php

namespace App\Http\Controllers;

use App\Models\User;
use Carbon\Carbon;

class ExportController extends Controller
{
    public function exportIcs($userId)
    {
        $user = User::with('tasks.event')->findOrFail($userId);

        $lines = [
            'BEGIN:VCALENDAR',
            'VERSION:2.0',
            'PRODID:-//VotreApp//FR',
        ];

        $now = Carbon::now()->utc()->format('Ymd\THis\Z');

        foreach ($user->tasks as $task) {

            // On ignore les tâches sans dates
            if (!$task->start || !$task->end) {
                continue;
            }

            $uid = $task->id . '-' . $user->id . '@votreapp.local';

            $dtstart = Carbon::parse($task->start)->utc()->format('Ymd\THis\Z');
            $dtend   = Carbon::parse($task->end)->utc()->format('Ymd\THis\Z');

            $summary = $this->escapeText($task->name);

            $description = $this->escapeText(
                trim(
                    ($task->description ?? '') .
                    ($task->event ? "\nÉvénement: {$task->event->name}" : '')
                )
            );

            $location = $this->escapeText($task->location ?? '');

            $lines[] = 'BEGIN:VEVENT';
            $lines[] = 'UID:' . $uid;
            $lines[] = 'DTSTAMP:' . $now;
            $lines[] = 'DTSTART:' . $dtstart;
            $lines[] = 'DTEND:' . $dtend;
            $lines[] = 'SUMMARY:' . $summary;
            $lines[] = 'DESCRIPTION:' . $description;
            $lines[] = 'LOCATION:' . $location;
            $lines[] = 'END:VEVENT';
        }

        $lines[] = 'END:VCALENDAR';

        $content = implode("\r\n", $lines) . "\r\n";

        return response($content, 200, [
            'Content-Type' => 'text/calendar; charset=utf-8',
            'Content-Disposition' => 'attachment; filename="agenda_user_' . $user->id . '.ics"',
        ]);
    }

    protected function escapeText($text)
    {
        $text = (string) $text;

        return str_replace(
            ["\\", "\r\n", "\n", "\r", ";", ","],
            ["\\\\", "\\n", "\\n", "\\n", "\\;", "\\,"],
            $text
        );
    }
}