From 3155d0ee40d51a000400f52d0c882669c41b559d Mon Sep 17 00:00:00 2001
From: miteruzo <miteruzo@naver.com>
Date: Sun, 8 Mar 2026 18:05:38 +0900
Subject: [PATCH] =?UTF-8?q?#68=20=E3=81=BE=E3=81=A5=E3=81=AF=20NOT=20?=
 =?UTF-8?q?=E3=81=AB=E5=AF=BE=E5=BF=9C?=
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---
 backend/app/controllers/posts_controller.rb | 40 ++++++++++++++++-----
 backend/app/controllers/tags_controller.rb  |  3 +-
 2 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/backend/app/controllers/posts_controller.rb b/backend/app/controllers/posts_controller.rb
index f9f68f5..75b380b 100644
--- a/backend/app/controllers/posts_controller.rb
+++ b/backend/app/controllers/posts_controller.rb
@@ -84,7 +84,7 @@ class PostsController < ApplicationController
     title = params[:title].presence
     url = params[:url]
     thumbnail = params[:thumbnail]
-    tag_names = params[:tags].to_s.split(' ')
+    tag_names = params[:tags].to_s.split
     original_created_from = params[:original_created_from]
     original_created_before = params[:original_created_before]
 
@@ -125,7 +125,7 @@ class PostsController < ApplicationController
     return head :forbidden unless current_user.gte_member?
 
     title = params[:title].presence
-    tag_names = params[:tags].to_s.split(' ')
+    tag_names = params[:tags].to_s.split
     original_created_from = params[:original_created_from]
     original_created_before = params[:original_created_before]
 
@@ -192,7 +192,7 @@ class PostsController < ApplicationController
   private
 
   def filtered_posts
-    tag_names = params[:tags].to_s.split(' ')
+    tag_names = params[:tags].to_s.split
     match_type = params[:match]
     if tag_names.present?
       filter_posts_by_tags(tag_names, match_type)
@@ -202,19 +202,41 @@ class PostsController < ApplicationController
   end
 
   def filter_posts_by_tags tag_names, match_type
-    tag_names = TagName.canonicalise(tag_names)
+    literals = tag_names.map do |raw_name|
+      { name: TagName.canonicalise(raw_name.sub(/\Anot:/i, '')).first,
+        negative: raw_name.downcase.start_with?('not:') }
+    end
 
-    posts = Post.joins(tags: :tag_name)
+    return Post.all if literals.empty?
 
     if match_type == 'any'
-      posts.where(tag_names: { name: tag_names }).distinct
+      literals.reduce(Post.none) do |posts, literal|
+        posts.or(tag_literal_relation(literal[:name], negative: literal[:negative]))
+      end
+    else
+      literals.reduce(Post.all) do |posts, literal|
+        ids = tagged_post_ids_for(literal[:name])
+        if literal[:negative]
+          posts.where.not(id: ids)
+        else
+          posts.where(id: ids)
+        end
+      end
+    end
+  end
+
+  def tag_literal_relation name, negative:
+    ids = tagged_post_ids_for(name)
+    if negative
+      Post.where.not(id: ids)
     else
-      posts.where(tag_names: { name: tag_names })
-           .group('posts.id')
-           .having('COUNT(DISTINCT tag_names.id) = ?', tag_names.uniq.size)
+      Post.where(id: ids)
     end
   end
 
+  def tagged_post_ids_for(name) =
+      Post.joins(tags: :tag_name).where(tag_names: { name: }).select(:id)
+
   def sync_post_tags! post, desired_tags
     desired_tags.each do |t|
       t.save! if t.new_record?
diff --git a/backend/app/controllers/tags_controller.rb b/backend/app/controllers/tags_controller.rb
index bf4c821..b97fcaa 100644
--- a/backend/app/controllers/tags_controller.rb
+++ b/backend/app/controllers/tags_controller.rb
@@ -17,8 +17,7 @@ class TagsController < ApplicationController
   end
 
   def autocomplete
-    q = params[:q].to_s.strip
-    return render json: [] if q.blank?
+    q = params[:q].to_s.strip.sub(/\Anot:/i, '')
 
     with_nico = bool?(:nico, default: true)
     present_only = bool?(:present, default: true)