<?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 LmStudioClient implements LlmClientInterface
{
    public function __construct(private readonly AppSettingsService $settings) {}

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

        try {
            $response = Http::connectTimeout(5)
                ->timeout($timeout)
                ->withOptions(['read_timeout' => $timeout])
                ->post($baseUrl.'/v1/embeddings', [
                    'model' => $this->model('embedding', (string) config('services.llm.embedding_model')),
                    'input' => $text,
                ])
                ->throw()
                ->json();
        } catch (Throwable $e) {
            throw $this->mapException($e, 'embedding');
        }

        $embedding = $response['data'][0]['embedding'] ?? [];
        if (! is_array($embedding) || $embedding === []) {
            throw new OllamaUnavailableException('lmstudio', 'embedding', 'No embedding in response');
        }

        return $embedding;
    }

    public function generate(string $prompt, array $options = []): string
    {
        $timeout = $this->timeout();
        $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')),
            'messages' => [
                ['role' => 'user', 'content' => $prompt],
            ],
            'temperature' => 0.1,
        ];

        if ($expectJson) {
            // OpenAI-compatible endpoints vary: some support json_schema/text only.
            $payload['response_format'] = ['type' => 'json_schema'];
        }

        try {
            $response = Http::connectTimeout(5)
                ->timeout($timeout)
                ->withOptions(['read_timeout' => $timeout])
                ->post($baseUrl.'/v1/chat/completions', $payload)
                ->throw()
                ->json();
        } catch (RequestException $e) {
            $body = (string) $e->response->body();
            $isResponseFormatError = str_contains($body, 'response_format.type')
                || str_contains($body, 'json_schema');

            if ($expectJson && $isResponseFormatError) {
                // Fallback retry without response_format for stricter local servers.
                try {
                    $retryPayload = $payload;
                    unset($retryPayload['response_format']);

                    $response = Http::connectTimeout(5)
                        ->timeout($timeout)
                        ->withOptions(['read_timeout' => $timeout])
                        ->post($baseUrl.'/v1/chat/completions', $retryPayload)
                        ->throw()
                        ->json();

                    return (string) ($response['choices'][0]['message']['content'] ?? '');
                } catch (Throwable $retryException) {
                    throw $this->mapException($retryException, 'generation');
                }
            }

            throw $this->mapException($e, 'generation');
        } catch (Throwable $e) {
            throw $this->mapException($e, 'generation');
        }

        return (string) ($response['choices'][0]['message']['content'] ?? '');
    }

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

        return rtrim((string) ($instance['base_url'] ?? $this->settings->get('llm.providers.lmstudio.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.lmstudio.chat_model', $fallback));
        $embeddingModel = (string) ($instance['embedding_model'] ?? $this->settings->get('llm.providers.lmstudio.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('lmstudio', $operation, $e->getMessage(), $e, $snippet);
        }

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