<?php

namespace App\Http\Controllers\Admin;

use App\Http\Controllers\Controller;
use App\Http\Requests\Admin\SplitChunkRequest;
use App\Http\Requests\Admin\UpdateChunkRequest;
use App\Models\Document;
use App\Models\DocumentChunk;
use App\Models\DocumentVersion;
use App\Services\Document\ChunkEditingService;
use App\Services\Document\ChunkSplitService;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\View\View;
use InvalidArgumentException;
use RuntimeException;

/**
 * ChunkReviewController
 *
 * Menguruskan UI dan operasi Chunk Review & Editing:
 *   - index()      → Senarai chunk per versi (enhanced list dengan status filter)
 *   - show()       → Detail satu chunk + preview 3 teks + form edit
 *   - update()     → Simpan final_text yang diedit
 *   - exclude()    → Kecualikan chunk dari indexing
 *   - include()    → Kembalikan chunk ke indexing
 *   - reindex()    → Trigger reindex manual
 *   - splitForm()  → Form split chunk
 *   - doSplit()    → Jalankan split
 *
 * NOTA: Hanya admin yang boleh akses (dikuatkuasakan di routes via 'role:admin').
 */
class ChunkReviewController extends Controller
{
    public function __construct(
        private readonly ChunkEditingService $editor,
        private readonly ChunkSplitService   $splitter,
    ) {}

    // =========================================================================
    // LIST VIEW
    // =========================================================================

    /**
     * Senarai chunk untuk satu versi dokumen.
     * Menggantikan DocumentController::chunks().
     *
     * Route: GET /admin/documents/{document}/versions/{version}/chunks
     */
    public function index(Document $document, DocumentVersion $version): View
    {
        abort_if($version->document_id !== $document->id, 404);

        $statusFilter = request('status');

        $query = $version->chunks()
            ->with(['editor', 'parentChunk', 'childChunks'])
            ->withCount('audits')
            ->orderBy('chunk_index');

        if ($statusFilter) {
            $query->where('chunk_status', $statusFilter);
        }

        $chunks = $query->paginate(20)->withQueryString();

        // Bilangan chunk mengikut status untuk filter pills
        $statusCounts = $version->chunks()
            ->selectRaw('chunk_status, count(*) as total')
            ->groupBy('chunk_status')
            ->pluck('total', 'chunk_status')
            ->toArray();

        $allStatuses = DocumentChunk::STATUS_PENDING === 'pending'
            ? [
                DocumentChunk::STATUS_PENDING,
                DocumentChunk::STATUS_INDEXED,
                DocumentChunk::STATUS_NEEDS_REVIEW,
                DocumentChunk::STATUS_NEEDS_REINDEX,
                DocumentChunk::STATUS_EXCLUDED,
                DocumentChunk::STATUS_SUPERSEDED,
                DocumentChunk::STATUS_FAILED_EMBEDDING,
            ]
            : [];

        return view('admin.documents.chunks', compact(
            'document',
            'version',
            'chunks',
            'statusCounts',
            'statusFilter'
        ));
    }

    // =========================================================================
    // DETAIL + EDIT VIEW
    // =========================================================================

    /**
     * Detail satu chunk: preview raw/cleaned/final text + form edit + audit trail.
     *
     * Route: GET /admin/chunks/{chunk}
     */
    public function show(DocumentChunk $chunk): View
    {
        $chunk->load([
            'document.category',
            'documentVersion',
            'editor',
            'parentChunk',
            'childChunks.editor',
            'audits' => fn($q) => $q->with('user')->limit(10),
        ]);

        return view('admin.chunks.show', compact('chunk'));
    }

    /**
     * Simpan perubahan final_text.
     *
     * Route: PATCH /admin/chunks/{chunk}
     */
    public function update(UpdateChunkRequest $request, DocumentChunk $chunk): RedirectResponse
    {
        try {
            $this->editor->editFinalText(
                $chunk,
                $request->validated('final_text'),
                $request->validated('notes')
            );

            return redirect()
                ->route('admin.chunks.show', $chunk)
                ->with('success', 'final_text berjaya disimpan. Reindex sedang diantrikan dalam queue.');
        } catch (RuntimeException $e) {
            return back()->withInput()->with('error', $e->getMessage());
        }
    }

    // =========================================================================
    // EXCLUDE / INCLUDE
    // =========================================================================

    /**
     * Kecualikan chunk dari indexing.
     *
     * Route: POST /admin/chunks/{chunk}/exclude
     */
    public function exclude(Request $request, DocumentChunk $chunk): RedirectResponse
    {
        $request->validate(['notes' => ['nullable', 'string', 'max:500']]);

        try {
            $this->editor->excludeChunk($chunk, $request->input('notes'));

            return back()->with(
                'success',
                "Chunk #{$chunk->chunk_index} berjaya dikecualikan dari indexing."
            );
        } catch (RuntimeException $e) {
            return back()->with('error', $e->getMessage());
        }
    }

    /**
     * Kembalikan chunk ke indexing.
     *
     * Route: POST /admin/chunks/{chunk}/include
     */
    public function include(Request $request, DocumentChunk $chunk): RedirectResponse
    {
        $request->validate(['notes' => ['nullable', 'string', 'max:500']]);

        try {
            $this->editor->includeChunk($chunk, $request->input('notes'));

            return back()->with(
                'success',
                "Chunk #{$chunk->chunk_index} berjaya dikembalikan ke indexing."
            );
        } catch (RuntimeException $e) {
            return back()->with('error', $e->getMessage());
        }
    }

    // =========================================================================
    // REINDEX
    // =========================================================================

    /**
     * Trigger reindex manual untuk satu chunk.
     *
     * Route: POST /admin/chunks/{chunk}/reindex
     */
    public function reindex(Request $request, DocumentChunk $chunk): RedirectResponse
    {
        $request->validate(['notes' => ['nullable', 'string', 'max:500']]);

        try {
            $this->editor->triggerReindex($chunk, $request->input('notes'));

            return back()->with(
                'success',
                "Chunk #{$chunk->chunk_index} sedang diantrikan untuk reindex."
            );
        } catch (RuntimeException $e) {
            return back()->with('error', $e->getMessage());
        }
    }

    // =========================================================================
    // SPLIT
    // =========================================================================

    /**
     * Form split chunk.
     *
     * Route: GET /admin/chunks/{chunk}/split
     */
    public function splitForm(DocumentChunk $chunk): View
    {
        if ($chunk->isSuperseded()) {
            abort(403, 'Chunk yang telah digantikan tidak boleh di-split semula.');
        }

        if ($chunk->chunk_status === DocumentChunk::STATUS_EXCLUDED) {
            abort(403, 'Chunk yang dikecualikan tidak boleh di-split. Include semula dahulu.');
        }

        $chunk->load(['document', 'documentVersion', 'childChunks']);

        return view('admin.chunks.split', compact('chunk'));
    }

    /**
     * Jalankan split chunk.
     *
     * Route: POST /admin/chunks/{chunk}/split
     */
    public function doSplit(SplitChunkRequest $request, DocumentChunk $chunk): RedirectResponse
    {
        if ($chunk->isSuperseded()) {
            return back()->with('error', 'Chunk yang telah digantikan tidak boleh di-split.');
        }

        try {
            $children = $this->splitter->split(
                $chunk,
                $request->validated('segments'),
                $request->validated('notes')
            );

            return redirect()
                ->route('admin.documents.chunks', [
                    'document' => $chunk->document_id,
                    'version'  => $chunk->document_version_id,
                ])
                ->with(
                    'success',
                    "Chunk #{$chunk->chunk_index} berjaya di-split kepada "
                    . count($children)
                    . " chunk baharu. Reindex sedang dijalankan dalam queue."
                );
        } catch (InvalidArgumentException $e) {
            return back()->withInput()->with('error', $e->getMessage());
        } catch (RuntimeException $e) {
            return back()->withInput()->with('error', $e->getMessage());
        }
    }
}