Make PreviewCard records reuseable between statuses (#4642)

* Make PreviewCard records reuseable between statuses

**Warning!** Migration truncates preview_cards tablec

* Allow a wider thumbnail for link preview, display it in horizontal layout (#4648)

* Delete preview cards files before truncating

* Rename old table instead of truncating it

* Add mastodon:maintenance:remove_deprecated_preview_cards

* Ignore deprecated_preview_cards in schema definition

* Fix null behaviour

3 files changed, 28 insertions, 9 deletions

diff --git a/app/models/media_attachment.rb b/app/models/media_attachment.rb
index 1e8c6d00a..d83ca44f1 100644
--- a/app/models/media_attachment.rb
+++ b/app/models/media_attachment.rb
@@ -142,9 +142,11 @@ class MediaAttachment < ApplicationRecord
 
   def populate_meta
     meta = {}
+
     file.queued_for_write.each do |style, file|
       begin
         geo = Paperclip::Geometry.from_file file
+
         meta[style] = {
           width: geo.width.to_i,
           height: geo.height.to_i,
@@ -155,6 +157,7 @@ class MediaAttachment < ApplicationRecord
         meta[style] = {}
       end
     end
+
     meta
   end
 
diff --git a/app/models/preview_card.rb b/app/models/preview_card.rb
index c334c48aa..b7efac354 100644
--- a/app/models/preview_card.rb
+++ b/app/models/preview_card.rb
@@ -4,16 +4,13 @@
 # Table name: preview_cards
 #
 #  id                 :integer          not null, primary key
-#  status_id          :integer
 #  url                :string           default(""), not null
-#  title              :string
-#  description        :string
+#  title              :string           default(""), not null
+#  description        :string           default(""), not null
 #  image_file_name    :string
 #  image_content_type :string
 #  image_file_size    :integer
 #  image_updated_at   :datetime
-#  created_at         :datetime         not null
-#  updated_at         :datetime         not null
 #  type               :integer          default("link"), not null
 #  html               :text             default(""), not null
 #  author_name        :string           default(""), not null
@@ -22,6 +19,8 @@
 #  provider_url       :string           default(""), not null
 #  width              :integer          default(0), not null
 #  height             :integer          default(0), not null
+#  created_at         :datetime         not null
+#  updated_at         :datetime         not null
 #
 
 class PreviewCard < ApplicationRecord
@@ -31,21 +30,37 @@ class PreviewCard < ApplicationRecord
 
   enum type: [:link, :photo, :video, :rich]
 
-  belongs_to :status
+  has_and_belongs_to_many :statuses
 
-  has_attached_file :image, styles: { original: '120x120#' }, convert_options: { all: '-quality 80 -strip' }
+  has_attached_file :image, styles: { original: '280x120>' }, convert_options: { all: '-quality 80 -strip' }
 
   include Attachmentable
   include Remotable
 
-  validates :url, presence: true
+  validates :url, presence: true, uniqueness: true
   validates_attachment_content_type :image, content_type: IMAGE_MIME_TYPES
   validates_attachment_size :image, less_than: 1.megabytes
 
+  before_save :extract_dimensions, if: :link?
+
   def save_with_optional_image!
     save!
   rescue ActiveRecord::RecordInvalid
     self.image = nil
     save!
   end
+
+  private
+
+  def extract_dimensions
+    file = image.queued_for_write[:original]
+
+    return if file.nil?
+
+    geo         = Paperclip::Geometry.from_file(file)
+    self.width  = geo.width.to_i
+    self.height = geo.height.to_i
+  rescue Paperclip::Errors::NotIdentifiedByImageMagickError
+    nil
+  end
 end
diff --git a/app/models/status.rb b/app/models/status.rb
index abd902cd7..f44f79aaf 100644
--- a/app/models/status.rb
+++ b/app/models/status.rb
@@ -47,10 +47,11 @@ class Status < ApplicationRecord
   has_many :replies, foreign_key: 'in_reply_to_id', class_name: 'Status', inverse_of: :thread
   has_many :mentions, dependent: :destroy
   has_many :media_attachments, dependent: :destroy
+
   has_and_belongs_to_many :tags
+  has_and_belongs_to_many :preview_cards
 
   has_one :notification, as: :activity, dependent: :destroy
-  has_one :preview_card, dependent: :destroy
   has_one :stream_entry, as: :activity, inverse_of: :status
 
   validates :uri, uniqueness: true, unless: :local?