<?php

namespace App\Http\Controllers\Admin;

use App\Http\Controllers\Controller;
use App\Models\Subject;
use App\Models\UserInterest;
use App\Models\UserSubject;
use App\Services\AIService;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;
use Illuminate\View\View;

/**
 * Manages user interests and AI-generated subject suggestions.
 */
class InterestController extends Controller
{
    /**
     * Display the user's interests and AI suggestions.
     */
    public function index(): View
    {
        /** @var \App\Models\User $user */
        $user = Auth::user();

        $interests = $user->userInterests()->orderByDesc('created_at')->get();
        $suggestions = session('suggestions', []);

        return view('admin.interests.index', compact('interests', 'suggestions'));
    }

    /**
     * Store a new user interest.
     */
    public function store(Request $request): RedirectResponse
    {
        $validated = $request->validate([
            'interest' => ['required', 'string', 'max:255'],
        ]);

        /** @var \App\Models\User $user */
        $user = Auth::user();

        $user->userInterests()->create([
            'interest' => $validated['interest'],
        ]);

        return back()->with('success', __('Interest added successfully.'));
    }

    /**
     * Remove the specified user interest.
     */
    public function destroy(UserInterest $userInterest): RedirectResponse
    {
        $this->authorize('delete', $userInterest);

        $userInterest->delete();

        return back()->with('success', __('Interest removed successfully.'));
    }

    /**
     * Generate AI subject suggestions based on user interests.
     */
    public function generateSuggestions(Request $request): RedirectResponse
    {
        /** @var \App\Models\User $user */
        $user = Auth::user();

        $interests = $user->userInterests()->pluck('interest')->toArray();

        if (empty($interests)) {
            return back()->with('error', __('Add at least one interest before generating suggestions.'));
        }

        $interestsList = implode(', ', $interests);

        $prompt = "Com base nos interesses do usuário: {$interestsList}. Sugira de 3 a 5 temas de assuntos de aprendizado que seriam relevantes para este usuário. Para cada tema, forneça: 1) name (formato: 'Aprendizado e Treinamento de [Tema]'), 2) description (máximo 1000 caracteres), 3) introduction (máximo 5000 caracteres). Retorne APENAS um array JSON válido (sem texto adicional, sem markdown, sem code blocks) com objetos contendo esses campos. Todo o conteúdo deve estar em Português do Brasil.";

        /** @var \App\Services\AIService $ai */
        $ai = app(AIService::class);
        $result = $ai->generateInsight('Sugestões de assuntos', $prompt, ['language' => 'pt_BR']);

        if (!$result['success']) {
            return back()->with('error', __('Failed to generate suggestions: :error', ['error' => $result['error'] ?? __('Unknown error')]));
        }

        $suggestions = $this->extractJsonFromAiResponse($result['content']);

        if (!$suggestions || !is_array($suggestions)) {
            return back()->with('error', __('Failed to parse AI suggestions. Please try again.'));
        }

        return back()->with('suggestions', $suggestions)->with('success', __('Suggestions generated successfully.'));
    }

    /**
     * Create a subject automatically from a suggestion.
     */
    public function createSubjectFromSuggestion(Request $request): RedirectResponse
    {
        $request->validate([
            'name' => ['required', 'string', 'max:255'],
            'description' => ['nullable', 'string', 'max:1000'],
            'introduction' => ['nullable', 'string', 'max:5000'],
        ]);

        $existing = Subject::where('name', $request->name)->first();

        if ($existing) {
            return back()->with('error', __('A subject with this name already exists.'));
        }

        $subject = Subject::create([
            'user_id' => Auth::id(),
            'name' => $request->name,
            'description' => $request->description,
            'introduction' => $request->introduction,
            'is_system' => false,
            'is_active' => true,
        ]);

        UserSubject::firstOrCreate(
            [
                'user_id' => Auth::id(),
                'subject_id' => $subject->id,
            ],
            [
                'frequency' => 'daily',
                'preferred_times' => ['09:00'],
                'insight_language' => Auth::user()->locale ?? 'en',
                'delivery_channels' => ['dashboard'],
                'is_active' => true,
            ]
        );

        return back()->with('success', __('Subject created successfully.'));
    }

    /**
     * Extract JSON from AI response, handling code blocks and plain text.
     */
    private function extractJsonFromAiResponse(string $content): ?array
    {
        $content = trim($content);

        if (str_starts_with($content, '```')) {
            $content = preg_replace('/^```(?:json)?\s*/', '', $content);
            $content = preg_replace('/\s*```$/', '', $content);
        }

        $data = json_decode($content, true);

        if (json_last_error() === JSON_ERROR_NONE && is_array($data)) {
            return $data;
        }

        if (preg_match('/\[.*\]/s', $content, $matches)) {
            $data = json_decode($matches[0], true);
            if (json_last_error() === JSON_ERROR_NONE && is_array($data)) {
                return $data;
            }
        }

        return null;
    }
}