feat(#129): add iCal response parser

app/Services/Plugin/Parsers/IcalResponseParser.php

@@ -0,0 +1,111 @@
+<?php
+
+namespace App\Services\Plugin\Parsers;
+
+use Carbon\Carbon;
+use DateTimeInterface;
+use Exception;
+use Illuminate\Http\Client\Response;
+use Illuminate\Support\Facades\Log;
+use om\IcalParser;
+
+class IcalResponseParser implements ResponseParser
+{
+    public function __construct(
+        private readonly IcalParser $parser = new IcalParser(),
+    ) {}
+
+    public function parse(Response $response): ?array
+    {
+        $contentType = $response->header('Content-Type');
+        $body = $response->body();
+
+        if (! $this->isIcalResponse($contentType, $body)) {
+            return null;
+        }
+
+        try {
+            $this->parser->parseString($body);
+
+            $events = $this->parser->getEvents()->sorted()->getArrayCopy();
+            $windowStart = now()->subDays(7);
+            $windowEnd = now()->addDays(30);
+
+            $filteredEvents = array_values(array_filter($events, function (array $event) use ($windowStart, $windowEnd): bool {
+                $startDate = $this->asCarbon($event['DTSTART'] ?? null);
+
+                if (!$startDate instanceof \Carbon\Carbon) {
+                    return false;
+                }
+
+                return $startDate->between($windowStart, $windowEnd, true);
+            }));
+
+            $normalizedEvents = array_map($this->normalizeIcalEvent(...), $filteredEvents);
+
+            return ['ical' => $normalizedEvents];
+        } catch (Exception $exception) {
+            Log::warning('Failed to parse iCal response: '.$exception->getMessage());
+
+            return ['error' => 'Failed to parse iCal response'];
+        }
+    }
+
+    private function isIcalResponse(?string $contentType, string $body): bool
+    {
+        $normalizedContentType = $contentType ? mb_strtolower($contentType) : '';
+
+        if ($normalizedContentType && str_contains($normalizedContentType, 'text/calendar')) {
+            return true;
+        }
+
+        return str_contains($body, 'BEGIN:VCALENDAR');
+    }
+
+    private function asCarbon(DateTimeInterface|string|null $value): ?Carbon
+    {
+        if ($value instanceof Carbon) {
+            return $value;
+        }
+
+        if ($value instanceof DateTimeInterface) {
+            return Carbon::instance($value);
+        }
+
+        if (is_string($value) && $value !== '') {
+            try {
+                return Carbon::parse($value);
+            } catch (Exception $exception) {
+                Log::warning('Failed to parse date value: '.$exception->getMessage());
+
+                return null;
+            }
+        }
+
+        return null;
+    }
+
+    private function normalizeIcalEvent(array $event): array
+    {
+        $normalized = [];
+
+        foreach ($event as $key => $value) {
+            $normalized[$key] = $this->normalizeIcalValue($value);
+        }
+
+        return $normalized;
+    }
+
+    private function normalizeIcalValue(mixed $value): mixed
+    {
+        if ($value instanceof DateTimeInterface) {
+            return Carbon::instance($value)->toAtomString();
+        }
+
+        if (is_array($value)) {
+            return array_map($this->normalizeIcalValue(...), $value);
+        }
+
+        return $value;
+    }
+}