<?php

namespace App\Services;

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

class OpenRouterService
{
    public function generateInsight(string $subject, string $userMessage, array $context = []): array
    {
        $apiKey = config("services.openrouter.api_key");
        $model = config("services.openrouter.model", "google/gemini-2.0-flash-exp:free");

        // Get language preference from context or default to English
        $language = $context['language'] ?? 'en';
        unset($context['language']);

        // Map language codes to full names
        $languageNames = [
            'pt_BR' => 'Brazilian Portuguese',
            'en' => 'English',
            'es' => 'Spanish',
        ];
        $languageName = $languageNames[$language] ?? 'English';

        if (!$apiKey) {
            return [
                "success" => false,
                "error" => "OpenRouter API key not configured",
            ];
        }

        try {
            $systemPrompt = "You are an expert learning assistant for the subject: {$subject}. "
                . "Provide insightful, educational content. Be concise and practical.\n\n"
                . "CRITICAL LANGUAGE INSTRUCTION - You MUST follow this exactly:\n"
                . "Your entire response MUST be written ONLY in {$languageName} ({$language}).\n"
                . "Do NOT use any other language. Do NOT include English translations or explanations.\n"
                . "If the subject is a language course (like English), you may use that language as examples,\n"
                . "but all instructions, explanations, and tips MUST be in {$languageName}.\n"
                . "This is mandatory. Start your response directly with the tip in {$languageName}.";

            // Append language instruction to user message as well
            $userMessageWithLanguage = "[IMPORTANTE: Responda EXCLUSIVAMENTE em {$languageName}. "
                . "NÃO use inglês. NÃO traduza. NÃO misture idiomas. "
                . "Toda a resposta deve ser APENAS em {$languageName}.]\n\n"
                . $userMessage;

            $messages = [
                ["role" => "system", "content" => $systemPrompt],
                ["role" => "user", "content" => $userMessageWithLanguage],
            ];

            // Add context if provided
            if (!empty($context)) {
                $contextStr = "Context information:\n";
                foreach ($context as $key => $value) {
                    $contextStr .= "- {$key}: {$value}\n";
                }
                array_unshift($messages, ["role" => "system", "content" => $contextStr]);
            }

            $response = Http::withHeaders([
                "Authorization" => "Bearer " . $apiKey,
                "Content-Type" => "application/json",
                "HTTP-Referer" => config("app.url"),
                "X-Title" => config("app.name"),
            ])->timeout(120)->post("https://openrouter.ai/api/v1/chat/completions", [
                "model" => $model,
                "messages" => $messages,
            ]);

            $data = $response->json();

            if (!$data || !isset($data["choices"][0]["message"])) {
                $errorMsg = $data["error"]["message"] ?? "Unknown API error";
                Log::error("OpenRouter API error response", [
                    "response" => $data,
                    "subject" => $subject,
                ]);
                return [
                    "success" => false,
                    "error" => $errorMsg,
                ];
            }

            $message = $data["choices"][0]["message"];
            $content = $message["content"] ?? $message["reasoning"] ?? null;

            if ($content) {
                return [
                    "success" => true,
                    "content" => $content,
                    "input_tokens" => $data["usage"]["prompt_tokens"] ?? 0,
                    "output_tokens" => $data["usage"]["completion_tokens"] ?? 0,
                ];
            }

            Log::error("OpenRouter API: Empty response content", [
                "response" => $data,
                "subject" => $subject,
            ]);

            return [
                "success" => false,
                "error" => "The AI model returned an empty response. Please try again.",
            ];
        } catch (\Exception $e) {
            Log::error("OpenRouter API error: " . $e->getMessage());
            return [
                "success" => false,
                "error" => $e->getMessage(),
            ];
        }
    }
}