<?php

declare(strict_types=1);

namespace Steuerkram\Services;

/**
 * Einheitlicher LLM-Client für lokales Ollama und OpenAI-kompatible Remote-APIs.
 *
 * Provider-Erkennung (Reihenfolge):
 *  1. OLLAMA_URL in Umgebungsvariablen → Ollama-Modus
 *  2. LLM_API_URL + LLM_API_KEY in Umgebungsvariablen → OpenAI-kompatibler Modus
 *  3. Auto-Discovery: HEAD-Request auf http://localhost:11434 → Ollama-Modus
 *  4. Kein Provider gefunden → isAvailable() = false
 */
class LlmService
{
    private ?string $mode        = null;  // 'ollama' | 'openai' | null
    private string  $url         = '';
    private string  $model       = '';
    private string  $visionModel = '';
    private ?string $apiKey      = null;

    public function __construct()
    {
        $this->detect();
    }

    public function isAvailable(): bool
    {
        return $this->mode !== null;
    }

    public function isVisionAvailable(): bool
    {
        return $this->mode === 'ollama';
    }

    public function getProviderLabel(): ?string
    {
        return match($this->mode) {
            'ollama' => 'Ollama (' . $this->url . ')',
            'openai' => 'Remote-API (' . $this->url . ')',
            default  => null,
        };
    }

    public function generate(string $prompt): string
    {
        return match($this->mode) {
            'ollama' => $this->callOllama($prompt),
            'openai' => $this->callOpenAi($prompt),
            default  => '',
        };
    }

    /**
     * Sendet Bilder (base64-kodiert) zusammen mit einem Prompt an das Vision-Modell.
     * Nur im Ollama-Modus verfügbar. Gibt '' zurück wenn Vision nicht verfügbar.
     *
     * @param string   $prompt
     * @param string[] $base64Images  Array von base64-kodierten Bildern (JPEG/PNG)
     */
    public function generateVision(string $prompt, array $base64Images): string
    {
        if ($this->mode !== 'ollama' || empty($base64Images)) return '';

        $payload = [
            'model'   => $this->visionModel,
            'messages' => [[
                'role'    => 'user',
                'content' => $prompt,
                'images'  => $base64Images,
            ]],
            'stream'  => false,
            'options' => ['temperature' => 0.1],
        ];

        $ch = curl_init($this->url . '/api/chat');
        curl_setopt_array($ch, [
            CURLOPT_POST           => true,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_TIMEOUT        => 300,
            CURLOPT_HTTPHEADER     => ['Content-Type: application/json'],
            CURLOPT_POSTFIELDS     => json_encode($payload),
        ]);
        $response = curl_exec($ch);
        $err      = curl_error($ch);
        curl_close($ch);

        if ($err || !$response) return '';
        $data = json_decode($response, true);
        return $data['message']['content'] ?? '';
    }

    /**
     * Prüft ohne Timeout-Kosten, ob der Provider überhaupt erreichbar ist.
     * Nur für Diagnosezwecke (Einstellungsseite) – nicht im normalen Request-Pfad nutzen.
     */
    public function isReachable(): bool
    {
        if ($this->mode === null) return false;
        if ($this->mode === 'ollama') return $this->probeOllama($this->url);
        return true; // OpenAI-Modus: kein schneller Probe verfügbar
    }

    private function detect(): void
    {
        $ollamaUrl = getenv('OLLAMA_URL') ?: ($_ENV['OLLAMA_URL'] ?? '');
        $apiUrl    = getenv('LLM_API_URL') ?: ($_ENV['LLM_API_URL'] ?? '');
        $apiKey    = getenv('LLM_API_KEY') ?: ($_ENV['LLM_API_KEY'] ?? '');

        if ($ollamaUrl !== '') {
            $this->mode        = 'ollama';
            $this->url         = rtrim($ollamaUrl, '/');
            $this->model       = getenv('OLLAMA_MODEL') ?: ($_ENV['OLLAMA_MODEL'] ?? 'llama3.2');
            $this->visionModel = getenv('VISION_MODEL') ?: ($_ENV['VISION_MODEL'] ?? 'qwen2.5vl:latest');
            return;
        }

        if ($apiUrl !== '' && $apiKey !== '') {
            $this->mode   = 'openai';
            $this->url    = rtrim($apiUrl, '/');
            $this->model  = getenv('LLM_MODEL') ?: ($_ENV['LLM_MODEL'] ?? 'gpt-4o-mini');
            $this->apiKey = $apiKey;
            return;
        }

        // Auto-Discovery: lokales Ollama auf Port 11434
        if ($this->probeOllama('http://localhost:11434')) {
            $this->mode  = 'ollama';
            $this->url   = 'http://localhost:11434';
            $this->model = 'llama3.2';
        }
    }

    private function probeOllama(string $baseUrl): bool
    {
        $ch = curl_init($baseUrl . '/api/tags');
        curl_setopt_array($ch, [
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_TIMEOUT        => 2,
            CURLOPT_CONNECTTIMEOUT => 2,
            CURLOPT_NOBODY         => false,
        ]);
        curl_exec($ch);
        $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        $err  = curl_errno($ch);
        curl_close($ch);
        return $err === 0 && $code >= 200 && $code < 300;
    }

    private function callOllama(string $prompt): string
    {
        $payload = [
            'model'  => $this->model,
            'prompt' => $prompt,
            'stream' => false,
        ];

        $endpoint = $this->url . '/api/generate';
        $ch = curl_init($endpoint);
        curl_setopt_array($ch, [
            CURLOPT_POST           => true,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_TIMEOUT        => 300,
            CURLOPT_HTTPHEADER     => ['Content-Type: application/json'],
            CURLOPT_POSTFIELDS     => json_encode($payload),
        ]);
        $response = curl_exec($ch);
        $err      = curl_error($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);

        if ($err) {
            error_log("[Steuerkram] LlmService::callOllama() cURL-Fehler auf {$endpoint}: {$err}");
            return '';
        }
        if (!$response) {
            error_log("[Steuerkram] LlmService::callOllama() leere Antwort von {$endpoint} (HTTP {$httpCode})");
            return '';
        }
        return json_decode($response, true)['response'] ?? '';
    }

    private function callOpenAi(string $prompt): string
    {
        $payload = [
            'model'    => $this->model,
            'messages' => [['role' => 'user', 'content' => $prompt]],
        ];

        $ch = curl_init($this->url . '/chat/completions');
        curl_setopt_array($ch, [
            CURLOPT_POST           => true,
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_TIMEOUT        => 300,
            CURLOPT_HTTPHEADER     => [
                'Content-Type: application/json',
                'Authorization: Bearer ' . $this->apiKey,
            ],
            CURLOPT_POSTFIELDS     => json_encode($payload),
        ]);
        $response = curl_exec($ch);
        $err      = curl_error($ch);
        curl_close($ch);

        if ($err || !$response) return '';
        $data = json_decode($response, true);
        return $data['choices'][0]['message']['content'] ?? '';
    }
}