sfp_api_laravel_diarista/app/Services/GeminiService.php

<?php

namespace App\Services;

use App\Enums\UserTypeEnum;
use GuzzleHttp\Client;
use GuzzleHttp\Exception\GuzzleException;
use Illuminate\Support\Facades\Log;

class GeminiService
{
    private const API_URL = 'https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent';

    private Client $client;

    public function __construct()
    {
        $this->client = new Client(['timeout' => 30]);
    }

    public function sendMessage(string $message, UserTypeEnum $userType, array $history = []): string
    {
        $apiKey = config('services.gemini.api_key');
        $contents = $this->buildContents($history, $message);

        $payload = [
            'systemInstruction' => [
                'parts' => [['text' => $this->loadContext($userType)]],
            ],
            'contents' => $contents,
            'generationConfig' => [
                'temperature'     => 0.4,
                'maxOutputTokens' => 512,
            ],
        ];

        try {
            $response = $this->client->post(self::API_URL . '?key=' . $apiKey, [
                'json' => $payload,
            ]);

            $data = json_decode($response->getBody()->getContents(), true);

            return $data['candidates'][0]['content']['parts'][0]['text']
                ?? __('chatbot.error_response');
        } catch (GuzzleException $e) {
            Log::error('Gemini API error', ['error' => $e->getMessage()]);

            return __('chatbot.error_response');
        }
    }

    private function buildContents(array $history, string $newMessage): array
    {
        $contents = [];

        foreach ($history as $entry) {
            $role = $entry['role'] === 'model' ? 'model' : 'user';
            $contents[] = [
                'role'  => $role,
                'parts' => [['text' => $entry['text']]],
            ];
        }

        $contents[] = [
            'role'  => 'user',
            'parts' => [['text' => $newMessage]],
        ];

        return $contents;
    }

    private function loadContext(UserTypeEnum $userType): string
    {
        $restrictionsFile = resource_path('chatbot/restricoes.md');
        $restrictions     = file_exists($restrictionsFile) ? file_get_contents($restrictionsFile) : '';

        $contextFile = match ($userType) {
            UserTypeEnum::CLIENT   => resource_path('chatbot/context_cliente.txt'),
            UserTypeEnum::PROVIDER => resource_path('chatbot/context_prestador.txt'),
            default                => resource_path('chatbot/context_cliente.txt'),
        };

        $context = file_exists($contextFile) ? file_get_contents($contextFile) : '';

        return $restrictions . "\n\n" . $context;
    }
}