<?php

namespace App\Services;

use Illuminate\Support\Facades\Http;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Str;
use Illuminate\Support\Facades\Storage;

class AiBlogService
{
    protected $geminiKey;
    protected $unsplashKey;

    public function __construct()
    {
        $this->geminiKey = config('services.gemini.key', env('GEMINI_API_KEY'));
        $this->unsplashKey = config('services.unsplash.access_key', env('UNSPLASH_ACCESS_KEY'));
    }

    /**
     * Generate blog content using Gemini API
     */
    public function generateContent(string $topic, ?string $context = null): array
    {
        $prompt = $this->buildPrompt($topic, $context);

        // Debug logging
        $keyStatus = empty($this->geminiKey) ? 'MISSING' : 'PRESENT (' . substr($this->geminiKey, 0, 5) . '...)';
        Log::info("Gemini Service: Key status: $keyStatus");

        try {
            $response = Http::withoutVerifying()
                ->retry(3, 10000, function ($exception, $request) {
                    if ($exception instanceof \Illuminate\Http\Client\RequestException && $exception->response->status() === 429) {
                        return false;
                    }
                    return true;
                })
                ->withHeaders(['Content-Type' => 'application/json'])
                ->post("https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash:generateContent?key={$this->geminiKey}", [
                    'contents' => [
                        [
                            'parts' => [
                                ['text' => $prompt]
                            ]
                        ]
                    ],
                    'generationConfig' => [
                        'temperature' => 0.7,
                        'topK' => 40,
                        'topP' => 0.95,
                        'maxOutputTokens' => 8192,
                        'responseMimeType' => 'application/json',
                    ]
                ]);

            if ($response->failed()) {
                Log::error('Gemini API Error Status: ' . $response->status());
                Log::error('Gemini API Error Body: ' . $response->body());
                throw new \Exception('Gemini API request failed: ' . $response->body());
            }

            $data = $response->json();
            
            if (!isset($data['candidates'][0]['content']['parts'][0]['text'])) {
                Log::error('Gemini API Invalid Response: ' . json_encode($data));
                throw new \Exception('Invalid response from Gemini API.');
            }

            $jsonContent = $data['candidates'][0]['content']['parts'][0]['text'];
            
            // Clean markdown json blocks if present
            $jsonContent = str_replace(['```json', '```'], '', $jsonContent);
            
            return json_decode($jsonContent, true);

        } catch (\Exception $e) {
            Log::error('AI Blog Generation Exception: ' . $e->getMessage());
            throw $e;
        }
    }

    /**
     * Build the prompt for Gemini
     */
    private function buildPrompt(string $topic, ?string $context = null): string
    {
        $contextStr = $context ? "Additional Context: {$context}" : "";
        
        return <<<EOT
You are an expert content writer for "Trunçgil Teknoloji", a leading technology company specializing in web software, mobile apps, IoT, and digital transformation.
Write a comprehensive, SEO-friendly blog post about the topic: "{$topic}".
{$contextStr}

**IMPORTANT**: All content in the JSON response (title, content, excerpt, meta_data) MUST BE IN TURKISH language. Only the `image_prompt` should be in English.

Requirements:
1.  **Format**: Return ONLY a valid JSON object. No markdown formatting outside the JSON structure.
2.  **Language**: Turkish (Türkçe).
3.  **Tone**: Professional, authoritative, yet accessible. Enthusiastic about technology.
4.  **Brand Integration**: Naturally mention "Trunçgil Teknoloji" at least 2-3 times. Position Trunçgil Teknoloji as a solution provider or expert in this field. Use phrases like "Trunçgil Teknoloji olarak biz...", "Deneyimli ekibimizle...", etc.
5.  **Structure**:
    *   `title`: Catchy, SEO-optimized title (Max 60 chars) - IN TURKISH.
    *   `meta_title`: SEO Meta Title - IN TURKISH.
    *   `meta_description`: SEO Meta Description (Max 160 chars) - IN TURKISH.
    *   `content`: Full HTML blog post content. 
        *   Use <h2> and <h3> tags for headings.
        *   Use <p> for paragraphs.
        *   Include a bulleted list (<ul>/<li>) if appropriate.
        *   Do NOT use <h1> or <html>/<body> tags.
        *   Ensure the content is informative and valuable (min 600 words).
        *   ALL CONTENT MUST BE TURKISH.
    *   `excerpt`: A short summary (1-2 sentences) - IN TURKISH.
    *   `tags`: Array of 5-8 relevant tags (Turkish).
    *   `image_prompt`: A creative English prompt to generate a cover image for this article using an AI image generator.

JSON Schema:
{
    "title": "string",
    "meta_title": "string",
    "meta_description": "string",
    "content": "html_string",
    "excerpt": "string",
    "tags": ["string"],
    "image_prompt": "string"
}
EOT;
    }

    /**
     * Fetch and save a cover image
     */
    public function fetchAndSaveImage(string $keyword, string $imagePrompt): ?string
    {
        $imageUrl = null;

        // 1. Try Unsplash if key exists
        if ($this->unsplashKey) {
            try {
                $response = Http::withoutVerifying()->get('https://api.unsplash.com/search/photos', [
                    'query' => $keyword,
                    'orientation' => 'landscape',
                    'per_page' => 1,
                    'client_id' => $this->unsplashKey
                ]);

                if ($response->successful() && !empty($response['results'])) {
                    $imageUrl = $response['results'][0]['urls']['regular'];
                }
            } catch (\Exception $e) {
                Log::warning('Unsplash API failed: ' . $e->getMessage());
            }
        }

        // 2. Fallback to Pollinations AI (using the generated prompt)
        if (!$imageUrl) {
            // Encode the prompt
            $encodedPrompt = urlencode($imagePrompt . " high quality, technological, photorealistic, 4k");
            $imageUrl = "https://image.pollinations.ai/prompt/{$encodedPrompt}";
        }

        if (!$imageUrl) {
            return null;
        }

        // Download and Save
        try {
            $imageContent = Http::withoutVerifying()->get($imageUrl)->body();
            $filename = 'blog/ai-generated-' . Str::slug($keyword) . '-' . time() . '.jpg';
            
            Storage::disk('public')->put($filename, $imageContent);
            
            return $filename;
        } catch (\Exception $e) {
            Log::error('Image download failed: ' . $e->getMessage());
            return null;
        }
    }
}