<?php

namespace App\Http\Controllers\Admin;

use App\Http\Controllers\Controller;
use App\Models\Article;
use App\Models\ArticleAttachment;
use App\Models\ArticleCategory;
use App\Models\ArticleTag;
use App\Models\AuditLog;
use App\Services\SiteAssetSyncService;
use App\Services\SiteRevalidationService;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Storage;
use Illuminate\Support\Str;

class ArticleController extends Controller
{
    public function __construct()
    {
        $this->middleware('can:view_articles')->only(['index', 'show']);
        $this->middleware('can:create_articles')->only(['create', 'store']);
        $this->middleware('can:edit_articles')->only(['edit', 'update']);
        $this->middleware('can:delete_articles')->only(['destroy']);
        $this->middleware('can:publish_articles')->only(['publish', 'archive']);
    }

    public function index(Request $request)
    {
        $query = Article::with(['creator', 'categories'])
            ->orderByDesc('is_pinned')
            ->orderByDesc('created_at');

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

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

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

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

        $articles = $query->paginate(20);

        $stats = [
            'total' => Article::count(),
            'draft' => Article::draft()->count(),
            'published' => Article::published()->count(),
            'archived' => Article::archived()->count(),
            'pinned' => Article::pinned()->count(),
        ];

        $categories = ArticleCategory::orderBy('sort_order')->get();

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

    public function create()
    {
        $categories = ArticleCategory::orderBy('sort_order')->get();
        $tags = ArticleTag::orderBy('name')->get();

        return view('admin.articles.create', compact('categories', 'tags'));
    }

    public function store(Request $request)
    {
        $validated = $request->validate([
            'title' => 'required|string|max:255',
            'slug' => 'nullable|string|max:255|unique:articles,slug',
            'summary' => 'nullable|string|max:1000',
            'content' => 'required|string',
            'content_type' => 'required|in:blog,notice,document,related_news',
            'access_level' => 'required|in:public,members,board,admin',
            'author_name' => 'nullable|string|max:255',
            'meta_description' => 'nullable|string|max:500',
            'published_at' => 'nullable|date',
            'expires_at' => 'nullable|date|after:published_at',
            'is_pinned' => 'boolean',
            'display_order' => 'nullable|integer',
            'categories' => 'nullable|array',
            'categories.*' => 'exists:article_categories,id',
            'tags_input' => 'nullable|string',
            'featured_image' => 'nullable|image|max:5120',
            'featured_image_alt' => 'nullable|string|max:255',
            'save_action' => 'required|in:draft,publish',
        ]);

        $articleData = [
            'title' => $validated['title'],
            'slug' => $validated['slug'] ?? null,
            'summary' => $validated['summary'] ?? null,
            'content' => $validated['content'],
            'content_type' => $validated['content_type'],
            'access_level' => $validated['access_level'],
            'author_name' => $validated['author_name'] ?? null,
            'meta_description' => $validated['meta_description'] ?? null,
            'status' => $validated['save_action'] === 'publish' ? Article::STATUS_PUBLISHED : Article::STATUS_DRAFT,
            'published_at' => $validated['save_action'] === 'publish' ? ($validated['published_at'] ?? now()) : ($validated['published_at'] ?? null),
            'expires_at' => $validated['expires_at'] ?? null,
            'is_pinned' => $validated['is_pinned'] ?? false,
            'display_order' => $validated['display_order'] ?? 0,
            'created_by_user_id' => auth()->id(),
            'last_updated_by_user_id' => auth()->id(),
            'featured_image_alt' => $validated['featured_image_alt'] ?? null,
        ];

        if ($request->hasFile('featured_image')) {
            $storagePath = $request->file('featured_image')->store('articles/images', 'public');
            $nextPublicPath = SiteAssetSyncService::syncPublicDiskFileToNext($storagePath);

            if ($nextPublicPath) {
                $articleData['featured_image_path'] = $nextPublicPath;
                $articleData['featured_image_storage_path'] = $storagePath;
            } else {
                $articleData['featured_image_path'] = $storagePath;
            }
        }

        $article = Article::create($articleData);

        // Sync categories
        if (! empty($validated['categories'])) {
            $article->categories()->sync($validated['categories']);
        }

        // Handle tags
        if (! empty($validated['tags_input'])) {
            $tagNames = array_filter(array_map('trim', explode(',', $validated['tags_input'])));
            $tagIds = [];
            foreach ($tagNames as $tagName) {
                $tag = ArticleTag::firstOrCreate(
                    ['name' => $tagName],
                    ['slug' => Str::slug($tagName) ?: 'tag-'.time()]
                );
                $tagIds[] = $tag->id;
            }
            $article->tags()->sync($tagIds);
        }

        AuditLog::create([
            'user_id' => auth()->id(),
            'action' => 'article.created',
            'description' => "建立文章：{$article->title} (類型：{$article->getContentTypeLabel()}，狀態：{$article->getStatusLabel()})",
            'ip_address' => request()->ip(),
        ]);

        if ($validated['save_action'] === 'publish') {
            SiteRevalidationService::revalidateArticle($article->slug);
        }

        $message = $validated['save_action'] === 'publish' ? '文章已成功發布' : '文章已儲存為草稿';

        return redirect()
            ->route('admin.articles.show', $article)
            ->with('status', $message);
    }

    public function show(Article $article)
    {
        if (! $article->canBeViewedBy(auth()->user())) {
            abort(403, '您沒有權限查看此文章');
        }

        $article->load(['creator', 'lastUpdatedBy', 'categories', 'tags', 'attachments']);

        return view('admin.articles.show', compact('article'));
    }

    public function edit(Article $article)
    {
        if (! $article->canBeEditedBy(auth()->user())) {
            abort(403, '您沒有權限編輯此文章');
        }

        $article->load(['categories', 'tags', 'attachments']);
        $categories = ArticleCategory::orderBy('sort_order')->get();
        $tags = ArticleTag::orderBy('name')->get();

        return view('admin.articles.edit', compact('article', 'categories', 'tags'));
    }

    public function update(Request $request, Article $article)
    {
        if (! $article->canBeEditedBy(auth()->user())) {
            abort(403, '您沒有權限編輯此文章');
        }

        $validated = $request->validate([
            'title' => 'required|string|max:255',
            'slug' => 'nullable|string|max:255|unique:articles,slug,'.$article->id,
            'summary' => 'nullable|string|max:1000',
            'content' => 'required|string',
            'content_type' => 'required|in:blog,notice,document,related_news',
            'access_level' => 'required|in:public,members,board,admin',
            'author_name' => 'nullable|string|max:255',
            'meta_description' => 'nullable|string|max:500',
            'published_at' => 'nullable|date',
            'expires_at' => 'nullable|date|after:published_at',
            'is_pinned' => 'boolean',
            'display_order' => 'nullable|integer',
            'categories' => 'nullable|array',
            'categories.*' => 'exists:article_categories,id',
            'tags_input' => 'nullable|string',
            'featured_image' => 'nullable|image|max:5120',
            'featured_image_alt' => 'nullable|string|max:255',
            'remove_featured_image' => 'boolean',
        ]);

        $updateData = [
            'title' => $validated['title'],
            'summary' => $validated['summary'] ?? null,
            'content' => $validated['content'],
            'content_type' => $validated['content_type'],
            'access_level' => $validated['access_level'],
            'author_name' => $validated['author_name'] ?? null,
            'meta_description' => $validated['meta_description'] ?? null,
            'published_at' => $validated['published_at'],
            'expires_at' => $validated['expires_at'] ?? null,
            'is_pinned' => $validated['is_pinned'] ?? false,
            'display_order' => $validated['display_order'] ?? 0,
            'last_updated_by_user_id' => auth()->id(),
            'featured_image_alt' => $validated['featured_image_alt'] ?? null,
        ];

        if (! empty($validated['slug']) && $validated['slug'] !== $article->slug) {
            $updateData['slug'] = $validated['slug'];
        }

        if ($request->hasFile('featured_image')) {
            // Remove old copies (best-effort). If we synced to Next.js, the DB path is relative (uploads/...).
            if ($article->featured_image_storage_path) {
                Storage::disk('public')->delete($article->featured_image_storage_path);
            } elseif ($article->featured_image_path && str_starts_with($article->featured_image_path, 'articles/')) {
                Storage::disk('public')->delete($article->featured_image_path);
            }

            SiteAssetSyncService::deleteNextPublicFile($article->featured_image_path);

            $storagePath = $request->file('featured_image')->store('articles/images', 'public');
            $nextPublicPath = SiteAssetSyncService::syncPublicDiskFileToNext($storagePath);

            if ($nextPublicPath) {
                $updateData['featured_image_path'] = $nextPublicPath;
                $updateData['featured_image_storage_path'] = $storagePath;
            } else {
                $updateData['featured_image_path'] = $storagePath;
                $updateData['featured_image_storage_path'] = null;
            }
        } elseif ($request->boolean('remove_featured_image') && $article->featured_image_path) {
            if ($article->featured_image_storage_path) {
                Storage::disk('public')->delete($article->featured_image_storage_path);
            } elseif (str_starts_with($article->featured_image_path, 'articles/')) {
                Storage::disk('public')->delete($article->featured_image_path);
            }

            SiteAssetSyncService::deleteNextPublicFile($article->featured_image_path);
            $updateData['featured_image_path'] = null;
            $updateData['featured_image_storage_path'] = null;
        }

        $article->update($updateData);

        // Sync categories
        $article->categories()->sync($validated['categories'] ?? []);

        // Handle tags
        if (isset($validated['tags_input'])) {
            $tagNames = array_filter(array_map('trim', explode(',', $validated['tags_input'])));
            $tagIds = [];
            foreach ($tagNames as $tagName) {
                $tag = ArticleTag::firstOrCreate(
                    ['name' => $tagName],
                    ['slug' => Str::slug($tagName) ?: 'tag-'.time()]
                );
                $tagIds[] = $tag->id;
            }
            $article->tags()->sync($tagIds);
        } else {
            $article->tags()->sync([]);
        }

        AuditLog::create([
            'user_id' => auth()->id(),
            'action' => 'article.updated',
            'description' => "更新文章：{$article->title}",
            'ip_address' => request()->ip(),
        ]);

        if ($article->isPublished()) {
            SiteRevalidationService::revalidateArticle($article->slug);
        }

        return redirect()
            ->route('admin.articles.show', $article)
            ->with('status', '文章已成功更新');
    }

    public function destroy(Article $article)
    {
        if (! $article->canBeEditedBy(auth()->user())) {
            abort(403, '您沒有權限刪除此文章');
        }

        $title = $article->title;
        $slug = $article->slug;
        $wasPublished = $article->isPublished();
        $article->delete();

        AuditLog::create([
            'user_id' => auth()->id(),
            'action' => 'article.deleted',
            'description' => "刪除文章：{$title}",
            'ip_address' => request()->ip(),
        ]);

        if ($wasPublished) {
            SiteRevalidationService::revalidateArticle($slug);
        }

        return redirect()
            ->route('admin.articles.index')
            ->with('status', '文章已成功刪除');
    }

    public function publish(Article $article)
    {
        if (! auth()->user()->can('publish_articles')) {
            abort(403, '您沒有權限發布文章');
        }

        if (! $article->canBeEditedBy(auth()->user())) {
            abort(403, '您沒有權限發布此文章');
        }

        if ($article->isPublished()) {
            return back()->with('error', '此文章已經發布');
        }

        $article->publish(auth()->user());

        AuditLog::create([
            'user_id' => auth()->id(),
            'action' => 'article.published',
            'description' => "發布文章：{$article->title}",
            'ip_address' => request()->ip(),
        ]);

        SiteRevalidationService::revalidateArticle($article->slug);

        return back()->with('status', '文章已成功發布');
    }

    public function archive(Article $article)
    {
        if (! auth()->user()->can('publish_articles')) {
            abort(403, '您沒有權限歸檔文章');
        }

        if (! $article->canBeEditedBy(auth()->user())) {
            abort(403, '您沒有權限歸檔此文章');
        }

        if ($article->isArchived()) {
            return back()->with('error', '此文章已經歸檔');
        }

        $article->archive(auth()->user());

        AuditLog::create([
            'user_id' => auth()->id(),
            'action' => 'article.archived',
            'description' => "歸檔文章：{$article->title}",
            'ip_address' => request()->ip(),
        ]);

        SiteRevalidationService::revalidateArticle($article->slug);

        return back()->with('status', '文章已成功歸檔');
    }

    public function pin(Request $request, Article $article)
    {
        if (! auth()->user()->can('edit_articles')) {
            abort(403, '您沒有權限置頂文章');
        }

        if (! $article->canBeEditedBy(auth()->user())) {
            abort(403, '您沒有權限置頂此文章');
        }

        $validated = $request->validate([
            'display_order' => 'nullable|integer',
        ]);

        $article->pin($validated['display_order'] ?? 0, auth()->user());

        AuditLog::create([
            'user_id' => auth()->id(),
            'action' => 'article.pinned',
            'description' => "置頂文章：{$article->title}",
            'ip_address' => request()->ip(),
        ]);

        return back()->with('status', '文章已成功置頂');
    }

    public function unpin(Article $article)
    {
        if (! auth()->user()->can('edit_articles')) {
            abort(403, '您沒有權限取消置頂文章');
        }

        if (! $article->canBeEditedBy(auth()->user())) {
            abort(403, '您沒有權限取消置頂此文章');
        }

        $article->unpin(auth()->user());

        AuditLog::create([
            'user_id' => auth()->id(),
            'action' => 'article.unpinned',
            'description' => "取消置頂文章：{$article->title}",
            'ip_address' => request()->ip(),
        ]);

        return back()->with('status', '文章已取消置頂');
    }

    public function uploadAttachment(Request $request, Article $article)
    {
        if (! $article->canBeEditedBy(auth()->user())) {
            abort(403, '您沒有權限上傳附件');
        }

        $validated = $request->validate([
            'attachment' => 'required|file|max:20480',
            'description' => 'nullable|string|max:255',
        ]);

        $file = $request->file('attachment');
        $path = $file->store('articles/attachments', 'public');

        $attachment = $article->attachments()->create([
            'file_path' => $path,
            'original_filename' => $file->getClientOriginalName(),
            'mime_type' => $file->getMimeType(),
            'file_size' => $file->getSize(),
            'description' => $validated['description'] ?? null,
        ]);

        AuditLog::create([
            'user_id' => auth()->id(),
            'action' => 'article.attachment_uploaded',
            'description' => "上傳附件至文章「{$article->title}」：{$attachment->original_filename}",
            'ip_address' => request()->ip(),
        ]);

        return back()->with('status', '附件已成功上傳');
    }

    public function deleteAttachment(Article $article, ArticleAttachment $attachment)
    {
        if (! $article->canBeEditedBy(auth()->user())) {
            abort(403, '您沒有權限刪除附件');
        }

        if ($attachment->article_id !== $article->id) {
            abort(404);
        }

        Storage::disk('public')->delete($attachment->file_path);

        $filename = $attachment->original_filename;
        $attachment->delete();

        AuditLog::create([
            'user_id' => auth()->id(),
            'action' => 'article.attachment_deleted',
            'description' => "刪除文章「{$article->title}」的附件：{$filename}",
            'ip_address' => request()->ip(),
        ]);

        return back()->with('status', '附件已成功刪除');
    }
}