<?php

namespace App\Http\Controllers;

use App\Models\Book;
use App\Models\Category;
use App\Models\Author;
use Illuminate\Http\Request;
use Illuminate\Support\Str;

class BookController extends Controller
{
    /**
     * Display a listing of the resource.
     */
    public function index(Request $request)
    {
        $query = Book::query()->with(['category', 'authors', 'summary'])->orderByDesc('created_at');

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

        // Category filter (by id or slug)
        if ($cat = $request->get('category')) {
            if (is_numeric($cat)) {
                $query->where('category_id', (int) $cat);
            } else {
                $query->whereHas('category', function ($q) use ($cat) {
                    $q->where('slug', $cat)->orWhere('name', 'like', "%{$cat}%");
                });
            }
        }

        // Author filter (by id, slug, or name)
        if ($author = $request->get('author')) {
            $query->whereHas('authors', function ($q) use ($author) {
                if (is_numeric($author)) {
                    $q->where('authors.id', (int) $author);
                } else {
                    $q->where('authors.slug', $author)
                      ->orWhere('authors.name', 'like', "%{$author}%");
                }
            });
        }

        // Publication date range
        if ($from = $request->get('date_from')) {
            $query->whereDate('publication_date', '>=', $from);
        }
        if ($to = $request->get('date_to')) {
            $query->whereDate('publication_date', '<=', $to);
        }

        $books = $query->paginate(12)->withQueryString();

        // For filter dropdowns
        $categories = Category::orderBy('name')->get();
        $authors = Author::orderBy('name')->get();

        return view('books.index', [
            'books' => $books,
            'categories' => $categories,
            'authors' => $authors,
            'filters' => [
                'q' => $request->get('q'),
                'category' => $request->get('category'),
                'author' => $request->get('author'),
                'date_from' => $request->get('date_from'),
                'date_to' => $request->get('date_to'),
            ],
        ]);
    }

    /**
     * Show the form for creating a new resource.
     */
    public function create()
    {
        $categories = Category::all();
        return view('books.create', compact('categories'));
    }

    /**
     * Store a newly created resource in storage.
     */
    public function store(Request $request)
    {
        $request->validate([
            'title' => 'required|string|max:255',
            'author' => 'required|string|max:255',
            'description' => 'nullable|string',
            'publication_date' => 'nullable|date',
            'cover_image' => 'nullable|string|max:255',
            'category_id' => 'required|exists:categories,id',
        ]);

        // Generate a unique slug for the title
        $baseSlug = Str::slug($request->title);
        $slug = $baseSlug;
        $i = 2;
        while (Book::where('slug', $slug)->exists()) {
            $slug = $baseSlug . '-' . $i;
            $i++;
        }

        $book = Book::create([
            'title' => $request->title,
            'slug' => $slug,
            'author' => $request->author,
            'description' => $request->description,
            'publication_date' => $request->publication_date,
            'cover_image' => $request->cover_image,
            'category_id' => $request->category_id,
        ]);

        // Normalize author: link to authors table via pivot
        if (!empty($request->author)) {
            $name = trim($request->author);
            $slug = Str::slug($name);
            $author = Author::where('slug', $slug)->first();
            if (!$author) {
                $author = Author::where('name', $name)->first();
            }
            if ($author) {
                $author->fill(['name' => $name, 'slug' => $author->slug ?: $slug])->save();
            } else {
                $author = Author::create(['name' => $name, 'slug' => $slug]);
            }
            $book->authors()->sync([$author->id]);
        }

        return redirect()->route('books.index')
            ->with('success', 'Book created successfully.');
    }

    /**
     * Display the specified resource.
     */
    public function show(Book $book)
    {
        $book->load(['summary', 'category', 'authors', 'reviews.user']);
        $avgRating = (float) round($book->reviews()->avg('rating') ?? 0, 1);
        $reviewsCount = (int) $book->reviews()->count();
        $userReview = auth()->check() ? $book->reviews()->where('user_id', auth()->id())->first() : null;

        return view('books.show', [
            'book' => $book,
            'avgRating' => $avgRating,
            'reviewsCount' => $reviewsCount,
            'userReview' => $userReview,
        ]);
    }

    /**
     * Show the form for editing the specified resource.
     */
    public function edit(Book $book)
    {
        $categories = Category::all();
        return view('books.edit', compact('book', 'categories'));
    }

    /**
     * Update the specified resource in storage.
     */
    public function update(Request $request, Book $book)
    {
        $request->validate([
            'title' => 'required|string|max:255',
            'author' => 'required|string|max:255',
            'description' => 'nullable|string',
            'publication_date' => 'nullable|date',
            'cover_image' => 'nullable|string|max:255',
            'category_id' => 'required|exists:categories,id',
        ]);

        // If title changed, compute a unique slug (preserving current slug if still matching)
        $baseSlug = Str::slug($request->title);
        $slug = $baseSlug;
        if ($book->slug !== $baseSlug) {
            $i = 2;
            while (Book::where('slug', $slug)->where('id', '!=', $book->id)->exists()) {
                $slug = $baseSlug . '-' . $i;
                $i++;
            }
        } else {
            // Ensure no collision with other records even if same base
            if (Book::where('slug', $baseSlug)->where('id', '!=', $book->id)->exists()) {
                $i = 2;
                $slug = $baseSlug . '-' . $i;
                while (Book::where('slug', $slug)->where('id', '!=', $book->id)->exists()) {
                    $i++;
                    $slug = $baseSlug . '-' . $i;
                }
            }
        }

        $book->update([
            'title' => $request->title,
            'slug' => $slug,
            'author' => $request->author,
            'description' => $request->description,
            'publication_date' => $request->publication_date,
            'cover_image' => $request->cover_image,
            'category_id' => $request->category_id,
        ]);

        // Normalize author: sync pivot to the single provided author
        if (!empty($request->author)) {
            $name = trim($request->author);
            $slug = Str::slug($name);
            $author = Author::where('slug', $slug)->first();
            if (!$author) {
                $author = Author::where('name', $name)->first();
            }
            if ($author) {
                $author->fill(['name' => $name, 'slug' => $author->slug ?: $slug])->save();
            } else {
                $author = Author::create(['name' => $name, 'slug' => $slug]);
            }
            $book->authors()->sync([$author->id]);
        } else {
            // If author field is cleared, detach all author links
            $book->authors()->detach();
        }

        return redirect()->route('books.index')
            ->with('success', 'Book updated successfully.');
    }

    /**
     * Remove the specified resource from storage.
     */
    public function destroy(Book $book)
    {
        $book->delete();

        return redirect()->route('books.index')
            ->with('success', 'Book deleted successfully.');
    }
}