refactor: extract AbstractLlmPredictionProvider for shared boilerplate

Anthropic, Gemini, and OpenAi providers each repeated: API-key gate,
chronological price-list building, response validation
(direction/confidence/reasoning), TrendDirection::tryFrom, confidence
cap at 85, and the top-level try/catch + Log::error.

Now in AbstractLlmPredictionProvider:
- LLM_MAX_CONFIDENCE constant
- buildPriceList(Collection) helper
- buildPrediction(input, ?source) — handles direction validation,
  confidence cap, model construction
- defaultPrompt(priceList) — shared by Gemini and OpenAi
- Default predict() flow (apiKey + callProvider + buildPrediction +
  try/catch). Gemini and OpenAi only implement apiKey() and
  callProvider(). Anthropic overrides predict() because of its
  multi-phase web-search + forced-tool flow but reuses the helpers.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/Services/LlmPrediction/GeminiPredictionProvider.php

@@ -2,110 +2,59 @@
 
 namespace App\Services\LlmPrediction;
 
-use App\Enums\PredictionSource;
-use App\Enums\TrendDirection;
-use App\Models\BrentPrice;
-use App\Models\PricePrediction;
-use App\Services\ApiLogger;
-use Illuminate\Support\Collection;
 use Illuminate\Support\Facades\Http;
 use Illuminate\Support\Facades\Log;
-use Throwable;
 
-class GeminiPredictionProvider implements OilPredictionProvider
+class GeminiPredictionProvider extends AbstractLlmPredictionProvider
 {
-    private const int LLM_MAX_CONFIDENCE = 85;
-
-    public function __construct(
-        private readonly ApiLogger $apiLogger,
-    ) {}
-
-    public function predict(Collection $prices): ?PricePrediction
+    protected function apiKey(): ?string
     {
-        if (! config('services.gemini.api_key')) {
-            return null;
-        }
-
-        $priceList = $prices->sortBy('date')
-            ->map(fn (BrentPrice $p) => $p->date->toDateString().': $'.$p->price_usd)
-            ->implode("\n");
+        return config('services.gemini.api_key');
+    }
 
+    protected function callProvider(string $apiKey, string $priceList): ?array
+    {
         $model = config('services.gemini.model', 'gemini-2.0-flash');
         $url = "https://generativelanguage.googleapis.com/v1beta/models/{$model}:generateContent";
 
-        try {
-            $response = $this->apiLogger->send('gemini', 'POST', $url, fn () => Http::timeout(15)
-                ->withQueryParameters(['key' => config('services.gemini.api_key')])
-                ->post($url, [
-                    'contents' => [[
-                        'parts' => [['text' => $this->prompt($priceList)]],
-                    ]],
-                    'generationConfig' => [
-                        'responseMimeType' => 'application/json',
-                        'responseSchema' => [
-                            'type' => 'OBJECT',
-                            'properties' => [
-                                'direction' => [
-                                    'type' => 'STRING',
-                                    'enum' => ['rising', 'falling', 'flat'],
-                                ],
-                                'confidence' => ['type' => 'INTEGER'],
-                                'reasoning' => ['type' => 'STRING'],
+        $response = $this->apiLogger->send('gemini', 'POST', $url, fn () => Http::timeout(15)
+            ->withQueryParameters(['key' => $apiKey])
+            ->post($url, [
+                'contents' => [[
+                    'parts' => [['text' => $this->defaultPrompt($priceList)]],
+                ]],
+                'generationConfig' => [
+                    'responseMimeType' => 'application/json',
+                    'responseSchema' => [
+                        'type' => 'OBJECT',
+                        'properties' => [
+                            'direction' => [
+                                'type' => 'STRING',
+                                'enum' => ['rising', 'falling', 'flat'],
                             ],
-                            'required' => ['direction', 'confidence', 'reasoning'],
+                            'confidence' => ['type' => 'INTEGER'],
+                            'reasoning' => ['type' => 'STRING'],
                         ],
+                        'required' => ['direction', 'confidence', 'reasoning'],
                     ],
-                ]));
+                ],
+            ]));
 
-            if (! $response->successful()) {
-                Log::error('GeminiPredictionProvider: request failed', ['status' => $response->status()]);
-
-                return null;
-            }
-
-            $text = $response->json('candidates.0.content.parts.0.text') ?? '';
-            $data = json_decode($text, true);
-
-            if (! isset($data['direction'], $data['confidence'], $data['reasoning'])) {
-                Log::error('GeminiPredictionProvider: unexpected response format', ['text' => $text]);
-
-                return null;
-            }
-
-            $direction = TrendDirection::tryFrom($data['direction']);
-
-            if ($direction === null) {
-                Log::error('GeminiPredictionProvider: invalid direction', ['direction' => $data['direction']]);
-
-                return null;
-            }
-
-            return new PricePrediction([
-                'predicted_for' => now()->toDateString(),
-                'source' => PredictionSource::Llm,
-                'direction' => $direction,
-                'confidence' => min((int) $data['confidence'], self::LLM_MAX_CONFIDENCE),
-                'reasoning' => $data['reasoning'],
-                'generated_at' => now(),
-            ]);
-        } catch (Throwable $e) {
-            Log::error('GeminiPredictionProvider: predict failed', ['error' => $e->getMessage()]);
+        if (! $response->successful()) {
+            Log::error(self::class.': request failed', ['status' => $response->status()]);
 
             return null;
         }
-    }
 
-    private function prompt(string $priceList): string
-    {
-        return <<<PROMPT
-            You are analyzing Brent crude oil price data for a UK fuel price alert service.
-            Predict the short-term direction over the next 3–5 days.
+        $text = $response->json('candidates.0.content.parts.0.text') ?? '';
+        $data = json_decode($text, true);
 
-            Recent Brent crude prices (USD/barrel):
-            {$priceList}
+        if (! isset($data['direction'], $data['confidence'], $data['reasoning'])) {
+            Log::error(self::class.': unexpected response format', ['text' => $text]);
 
-            Respond with direction (rising, falling, or flat), a confidence score (0–85),
-            and a one-sentence reasoning.
-            PROMPT;
+            return null;
+        }
+
+        return $data;
     }
 }