<?php

namespace App\Http\Controllers\Admin;

use App\Actions\Document\CreateDocumentAction;
use App\Actions\Document\UploadNewVersionAction;
use App\Http\Controllers\Controller;
use App\Http\Requests\Admin\StoreDocumentRequest;
use App\Jobs\ReindexDocumentJob;
use App\Models\Category;
use App\Models\Document;
use App\Models\DocumentVersion;
use App\Services\KnowledgeBase\AuditService;
use App\Services\KnowledgeBase\IngestionService;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Storage;
use Illuminate\View\View;
use RuntimeException;

class DocumentController extends Controller
{
    public function __construct(
        private readonly AuditService $auditService,
        private readonly IngestionService $ingestionService,
    ) {}

    public function index(Request $request): View
    {
        $query = Document::with(['category', 'currentVersion'])
            ->withCount('versions');

        if ($request->filled('category_id')) {
            $query->where('category_id', $request->category_id);
        }

        if ($request->filled('status')) {
            $query->where('status', $request->status);
        }

        if ($request->filled('search')) {
            $query->where('title', 'like', '%' . $request->search . '%');
        }

        $documents  = $query->latest()->paginate(15)->withQueryString();
        $categories = Category::active()->ordered()->get();

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

    public function create(): View
    {
        $categories = Category::active()->ordered()->get();
        return view('admin.documents.create', compact('categories'));
    }

    public function store(StoreDocumentRequest $request, CreateDocumentAction $action): RedirectResponse
    {
        try {
            $document = $action->execute(
                $request->validated(),
                $request->file('file')
            );

            return redirect()
                ->route('admin.documents.show', $document)
                ->with('success', "Dokumen '{$document->title}' berjaya diupload dan sedang diproses.");
        } catch (RuntimeException $e) {
            return back()
                ->withInput()
                ->with('error', $e->getMessage());
        }
    }

    public function show(Document $document): View
    {
        $document->load([
            'category',
            'versions.uploader',
            'currentVersion.chunks' => fn($q) => $q->limit(20),
        ]);

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

    public function edit(Document $document): View
    {
        $categories = Category::active()->ordered()->get();
        return view('admin.documents.edit', compact('document', 'categories'));
    }

    public function update(Request $request, Document $document): RedirectResponse
    {
        $validated = $request->validate([
            'title'          => ['required', 'string', 'max:255'],
            'description'    => ['nullable', 'string', 'max:1000'],
            'category_id'    => ['required', 'exists:categories,id'],
            'effective_date' => ['nullable', 'date'],
            'expiry_date'    => ['nullable', 'date'],
            'tags'           => ['nullable', 'array'],
            'language'       => ['nullable', 'in:ms,en'],
        ]);

        $validated['updated_by'] = auth()->id();
        $document->update($validated);

        return redirect()
            ->route('admin.documents.show', $document)
            ->with('success', 'Maklumat dokumen berjaya dikemaskini.');
    }

    /**
     * Upload versi baru untuk dokumen yang sedia ada.
     */
    public function uploadVersion(
        Request $request,
        Document $document,
        UploadNewVersionAction $action
    ): RedirectResponse {
        $request->validate([
            'file'         => ['required', 'file', 'mimes:pdf', 'max:' . config('knowledgebase.upload.max_file_size', 20480)],
            'change_notes' => ['nullable', 'string', 'max:500'],
        ]);

        try {
            $action->execute($document, $request->file('file'), $request->only('change_notes'));

            return redirect()
                ->route('admin.documents.show', $document)
                ->with('success', 'Versi baru berjaya diupload dan sedang diproses.');
        } catch (RuntimeException $e) {
            return back()->with('error', $e->getMessage());
        }
    }

    /**
     * Toggle status aktif/tidak aktif dokumen.
     * Apabila dinyahaktifkan, chunk dalam Qdrant juga dimatikan.
     */
    public function toggleStatus(Document $document): RedirectResponse
    {
        $newStatus = !$document->is_active;

        if ($newStatus) {
            // Aktifkan — versi semasa mesti sudah indexed
            $currentVersion = $document->currentVersion;
            if (!$currentVersion || !$currentVersion->isProcessed()) {
                return back()->with('error',
                    'Dokumen tidak boleh diaktifkan kerana pemprosesan belum selesai.'
                );
            }

            $document->update([
                'is_active' => true,
                'status'    => Document::STATUS_ACTIVE,
            ]);

            $this->auditService->documentActivated($document);
        } else {
            // Deactivate — matikan juga dalam Qdrant
            $document->update([
                'is_active' => false,
                'status'    => Document::STATUS_INACTIVE,
            ]);

            if ($currentVersion = $document->currentVersion) {
                $this->ingestionService->deactivateVersionInQdrant($currentVersion);
            }

            $this->auditService->documentDeactivated($document);
        }

        $status = $newStatus ? 'diaktifkan' : 'dinyahaktifkan';

        return back()->with('success', "Dokumen '{$document->title}' telah {$status}.");
    }

    /**
     * Trigger reindex untuk versi tertentu.
     */
    public function reindex(Document $document): RedirectResponse
    {
        $currentVersion = $document->currentVersion;

        if (!$currentVersion) {
            return back()->with('error', 'Tiada versi semasa untuk diindeks semula.');
        }

        ReindexDocumentJob::dispatch($currentVersion->id);

        $this->auditService->documentReindexed($document, $currentVersion);

        return back()->with('success', 'Reindeks telah dimulakan. Sila semak semula sebentar lagi.');
    }

    /**
     * Download PDF asal.
     */
    public function download(Document $document, DocumentVersion $version)
    {
        abort_if($version->document_id !== $document->id, 404);

        $disk = config('knowledgebase.upload.storage_disk', 'local');

        if (!Storage::disk($disk)->exists($version->stored_path)) {
            abort(404, 'Fail tidak dijumpai.');
        }

        return Storage::disk($disk)->download(
            $version->stored_path,
            $version->original_filename
        );
    }
}