<?php

namespace App\Services\Llm;

use App\Exceptions\OllamaUnavailableException;
use App\Services\AppSettingsService;
use Illuminate\Http\Client\RequestException;
use Illuminate\Support\Facades\Http;
use Throwable;

class OllamaClient implements LlmClientInterface
{
    public function __construct(private readonly AppSettingsService $settings) {}

    public function embed(string $text): array
    {
        $baseUrl = $this->baseUrl();

        try {
            $response = Http::timeout($this->timeout())
                ->post($baseUrl.'/api/embeddings', [
                    'model' => $this->model('embedding', (string) config('services.llm.embedding_model', 'nomic-embed-text')),
                    'prompt' => $text,
                ])
                ->throw()
                ->json();
        } catch (Throwable $e) {
            throw $this->mapException($e, 'embedding');
        }

        $embedding = $response['embedding'] ?? [];
        if (! is_array($embedding) || $embedding === []) {
            throw new OllamaUnavailableException('ollama', 'embedding', 'No embedding in response');
        }

        return $embedding;
    }

    public function generate(string $prompt, array $options = []): string
    {
        $baseUrl = $this->baseUrl();
        $expectJson = (bool) ($options['expect_json'] ?? false);
        $task = (string) ($options['task'] ?? 'chat');

        $payload = [
            'model' => $this->model($task, (string) config('services.llm.chat_model', 'llama3')),
            'prompt' => $prompt,
            'stream' => false,
        ];

        if ($expectJson) {
            $payload['format'] = 'json';
        }

        try {
            $response = Http::timeout($this->timeout())
                ->post($baseUrl.'/api/generate', $payload)
                ->throw()
                ->json();
        } catch (Throwable $e) {
            throw $this->mapException($e, 'generation');
        }

        return (string) ($response['response'] ?? '');
    }

    private function baseUrl(): string
    {
        $instance = $this->settings->activeProviderInstance();

        return rtrim((string) ($instance['base_url'] ?? $this->settings->get('llm.providers.ollama.base_url', (string) config('services.llm.base_url'))), '/');
    }

    private function timeout(): int
    {
        return (int) $this->settings->get('llm.timeout', (string) config('services.llm.timeout', 30));
    }

    private function model(string $task, string $fallback): string
    {
        $instance = $this->settings->activeProviderInstance();
        $chatModel = (string) ($instance['chat_model'] ?? $this->settings->get('llm.providers.ollama.chat_model', $fallback));
        $embeddingModel = (string) ($instance['embedding_model'] ?? $this->settings->get('llm.providers.ollama.embedding_model', $fallback));

        if ($task === 'chat') {
            return $chatModel;
        }

        $configured = trim((string) $this->settings->get('llm.models.'.$task, ''));
        if ($configured !== '') {
            return $configured;
        }

        return $task === 'embedding' ? $embeddingModel : $chatModel;
    }

    private function mapException(Throwable $e, string $operation): OllamaUnavailableException
    {
        if ($e instanceof RequestException) {
            $body = $e->response?->body();
            $snippet = $body ? mb_substr($body, 0, 280) : null;

            return new OllamaUnavailableException('ollama', $operation, $e->getMessage(), $e, $snippet);
        }

        return new OllamaUnavailableException('ollama', $operation, $e->getMessage(), $e);
    }
}