<?php
namespace App\Http\Controllers;

use App\Http\Controllers\CategoryPageController;
use App\Http\Controllers\Controller;
use App\Http\Requests\ArtworkIndexRequest;
use App\Models\Artwork;
use App\Models\Category;
use App\Services\Recommendations\SimilarArtworksService;
use Illuminate\Http\RedirectResponse;
use Illuminate\Http\Request;
use Illuminate\View\View;

class ArtworkController extends Controller
{
    /**
     * Browse artworks with optional category filtering.
     * Uses cursor pagination (no offset pagination) and only returns public, approved, not-deleted items.
     */
    public function index(ArtworkIndexRequest $request, ?Category $category = null): View
    {
        $perPage = (int) ($request->get('per_page', 24));

        $query = Artwork::public()->published();

        if ($category) {
            $query->whereHas('categories', function ($q) use ($category) {
                $q->where('categories.id', $category->id);
            });
        }

        if ($request->filled('q')) {
            $q = $request->get('q');
            $query->where(function ($sub) use ($q) {
                $sub->where('title', 'like', '%' . $q . '%')
                    ->orWhere('description', 'like', '%' . $q . '%');
            });
        }

        $sort = $request->get('sort', 'latest');
        if ($sort === 'oldest') {
            $query->orderBy('published_at', 'asc');
        } else {
            $query->orderByDesc('published_at');
        }

        // Important: do NOT eager-load artwork_stats in listings
        $artworks = $query->cursorPaginate($perPage);

        return view('artworks.index', [
            'artworks' => $artworks,
            'category' => $category,
        ]);
    }

    /**
     * Show a single artwork by slug. Resolve the slug manually to avoid implicit
     * route-model binding exceptions when the slug does not correspond to an artwork.
     */
    public function show(Request $request, string $contentTypeSlug, string $categoryPath, $artwork = null)
    {
        // Manually resolve artwork by slug when provided. The route may bind
        // the 'artwork' parameter to an Artwork model or pass the slug string.
        $foundArtwork = null;
        $artworkSlug = null;
        if ($artwork instanceof Artwork) {
            $foundArtwork = $artwork;
            $artworkSlug = $artwork->slug;
        } elseif ($artwork) {
            $artworkSlug = (string) $artwork;
            $foundArtwork = Artwork::where('slug', $artworkSlug)->first();
        }

        // If no artwork was found, treat the request as a category path.
        // The route places the artwork slug in the last segment, so include it
        // when forwarding to CategoryPageController to support arbitrary-depth paths
        if (! $foundArtwork) {
            $combinedPath = $categoryPath;
            if ($artworkSlug) {
                $combinedPath = trim($categoryPath . '/' . $artworkSlug, '/');
            }
            return app(CategoryPageController::class)->show(request(), $contentTypeSlug, $combinedPath);
        }

        if (! $foundArtwork->is_public || ! $foundArtwork->is_approved || $foundArtwork->trashed()) {
            abort(404);
        }

        $foundArtwork->loadMissing(['categories.contentType', 'user']);

        $defaultAlgoVersion = (string) config('recommendations.embedding.algo_version', 'clip-cosine-v1');
        $selectedAlgoVersion = $this->selectAlgoVersionForRequest($request, $defaultAlgoVersion);

        $similarService = app(SimilarArtworksService::class);
        $similarArtworks = $similarService->forArtwork((int) $foundArtwork->id, 12, $selectedAlgoVersion);

        if ($similarArtworks->isEmpty() && $selectedAlgoVersion !== $defaultAlgoVersion) {
            $similarArtworks = $similarService->forArtwork((int) $foundArtwork->id, 12, $defaultAlgoVersion);
            $selectedAlgoVersion = $defaultAlgoVersion;
        }

        $similarArtworks->each(static function (Artwork $item): void {
            $item->loadMissing(['categories.contentType', 'user']);
        });

        $similarItems = $similarArtworks
            ->map(function (Artwork $item): ?array {
                $category = $item->categories->first();
                $contentType = $category?->contentType;

                if (! $category || ! $contentType || empty($item->slug)) {
                    return null;
                }

                return [
                    'id' => (int) $item->id,
                    'title' => (string) $item->title,
                    'author' => (string) optional($item->user)->name,
                    'thumb' => (string) ($item->thumb_url ?? $item->thumb ?? '/gfx/sb_join.jpg'),
                    'thumb_srcset' => (string) ($item->thumb_srcset ?? ''),
                    'url' => route('artworks.show', [
                        'contentTypeSlug' => (string) $contentType->slug,
                        'categoryPath' => (string) $category->slug,
                        'artwork' => (string) $item->slug,
                    ]),
                ];
            })
            ->filter()
            ->values();

        return view('artworks.show', [
            'artwork' => $foundArtwork,
            'similarItems' => $similarItems,
            'similarAlgoVersion' => $selectedAlgoVersion,
        ]);
    }

    private function selectAlgoVersionForRequest(Request $request, string $default): string
    {
        $configured = (array) config('recommendations.ab.algo_versions', []);
        $versions = array_values(array_filter(array_map(static fn ($value): string => trim((string) $value), $configured)));

        if ($versions === []) {
            return $default;
        }

        if (! in_array($default, $versions, true)) {
            array_unshift($versions, $default);
            $versions = array_values(array_unique($versions));
        }

        $forced = trim((string) $request->query('algo_version', ''));
        if ($forced !== '' && in_array($forced, $versions, true)) {
            return $forced;
        }

        if (count($versions) === 1) {
            return $versions[0];
        }

        $visitorKey = $request->user()?->id
            ? 'u:' . (string) $request->user()->id
            : 's:' . (string) $request->session()->getId();

        $bucket = abs(crc32($visitorKey)) % count($versions);

        return $versions[$bucket] ?? $default;
    }
}