<?php

namespace App\Http\Controllers;

use App\Models\Document;
use App\Models\DocumentCategory;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Storage;

class PublicDocumentController extends Controller
{
    /**
     * Display the document library (public + member access)
     */
    public function index(Request $request)
    {
        $query = Document::with(['category', 'currentVersion'])
            ->where('status', 'active');

        // Filter based on user's access level
        $user = auth()->user();
        if (!$user) {
            // Only public documents for guests
            $query->where('access_level', 'public');
        } elseif (!$user->is_admin && !$user->hasRole('admin')) {
            // Members can see public + members-only
            $query->whereIn('access_level', ['public', 'members']);
        }
        // Admins can see all documents

        // Filter by category
        if ($request->filled('category')) {
            $query->where('document_category_id', $request->category);
        }

        // Search
        if ($request->filled('search')) {
            $search = $request->search;
            $query->where(function($q) use ($search) {
                $q->where('title', 'like', "%{$search}%")
                  ->orWhere('description', 'like', "%{$search}%");
            });
        }

        $documents = $query->orderBy('created_at', 'desc')->paginate(20);

        // Get categories with document counts (based on user's access)
        $categories = DocumentCategory::withCount([
            'activeDocuments' => function($query) use ($user) {
                if (!$user) {
                    $query->where('access_level', 'public');
                } elseif (!$user->is_admin && !$user->hasRole('admin')) {
                    $query->whereIn('access_level', ['public', 'members']);
                }
            }
        ])->orderBy('sort_order')->get();

        return view('documents.index', compact('documents', 'categories'));
    }

    /**
     * Show a document via its public UUID
     */
    public function show(string $uuid)
    {
        $document = Document::where('public_uuid', $uuid)
            ->where('status', 'active')
            ->with(['category', 'currentVersion', 'versions.uploadedBy'])
            ->firstOrFail();

        // Check access permission
        $user = auth()->user();
        if (!$document->canBeViewedBy($user)) {
            if (!$user) {
                return redirect()->route('login')->with('error', '請先登入以檢視此文件');
            }
            abort(403, '您沒有權限檢視此文件');
        }

        // Log access
        $document->logAccess('view', $user);

        return view('documents.show', compact('document'));
    }

    /**
     * Download the current version of a document
     */
    public function download(string $uuid)
    {
        $document = Document::where('public_uuid', $uuid)
            ->where('status', 'active')
            ->firstOrFail();

        // Check access permission
        $user = auth()->user();
        if (!$document->canBeViewedBy($user)) {
            if (!$user) {
                return redirect()->route('login')->with('error', '請先登入以下載此文件');
            }
            abort(403, '您沒有權限下載此文件');
        }

        $currentVersion = $document->currentVersion;
        if (!$currentVersion || !$currentVersion->fileExists()) {
            abort(404, '檔案不存在');
        }

        // Log access
        $document->logAccess('download', $user);

        return Storage::disk('private')->download(
            $currentVersion->file_path,
            $currentVersion->original_filename
        );
    }

    /**
     * Download a specific version (if user has access)
     */
    public function downloadVersion(string $uuid, int $versionId)
    {
        $document = Document::where('public_uuid', $uuid)
            ->where('status', 'active')
            ->firstOrFail();

        // Check access permission
        $user = auth()->user();
        if (!$document->canBeViewedBy($user)) {
            abort(403, '您沒有權限下載此文件');
        }

        $version = $document->versions()->findOrFail($versionId);

        if (!$version->fileExists()) {
            abort(404, '檔案不存在');
        }

        // Log access
        $document->logAccess('download', $user);

        return Storage::disk('private')->download(
            $version->file_path,
            $version->original_filename
        );
    }

    /**
     * Generate and download QR code for document
     */
    public function downloadQRCode(string $uuid)
    {
        // Check if QR code feature is enabled
        $settings = app(\App\Services\SettingsService::class);
        if (!$settings->isFeatureEnabled('qr_codes')) {
            abort(404, 'QR Code 功能未啟用');
        }

        // Check user permission
        $user = auth()->user();
        if ($user && !$user->can('use_qr_codes')) {
            abort(403, '您沒有使用 QR Code 功能的權限');
        }

        $document = Document::where('public_uuid', $uuid)->firstOrFail();

        // Check document access
        if (!$document->canBeViewedBy($user)) {
            abort(403);
        }

        // Use default size from system settings
        $qrCode = $document->generateQRCodePNG();

        return response($qrCode, 200)
            ->header('Content-Type', 'image/png')
            ->header('Content-Disposition', 'attachment; filename="qrcode-' . $document->id . '.png"');
    }
}