9 files changed, 154 insertions, 10 deletions
diff --git a/app/controllers/api/v1/statuses/publishing_controller.rb b/app/controllers/api/v1/statuses/publishing_controller.rb
index 5124b1009..97c052e22 100644
--- a/app/controllers/api/v1/statuses/publishing_controller.rb
+++ b/app/controllers/api/v1/statuses/publishing_controller.rb
@@ -8,14 +8,7 @@ class Api::V1::Statuses::PublishingController < Api::BaseController
   before_action :set_status
 
   def create
-    @status.update!(published: true)
-
-    LinkCrawlWorker.perform_in(rand(1..30).seconds, @status.id) unless @status.spoiler_text?
-    DistributionWorker.perform_async(@status.id)
-    ActivityPub::DistributionWorker.perform_async(@status.id) if @status.local? && !@status.local_only?
-
-    mentions = @status.active_mentions.includes(:account).where(id: @new_mention_ids, accounts: { domain: nil })
-    mentions.each { |mention| LocalNotificationWorker.perform_async(mention.account.id, mention.id, mention.class.name) }
+    PublishStatusService.new.call(@status)
 
     render json: @status,
            serializer: (@status.is_a?(ScheduledStatus) ? REST::ScheduledStatusSerializer : REST::StatusSerializer),
diff --git a/app/lib/command_tag/commands.rb b/app/lib/command_tag/commands.rb
new file mode 100644
index 000000000..0248e6e99
--- /dev/null
+++ b/app/lib/command_tag/commands.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+module CommandTag::Commands
+  def self.included(base)
+    CommandTag::Commands.constants.map(&CommandTag::Commands.method(:const_get)).grep(Module) do |mod|
+      base.include(mod)
+    end
+  end
+end
diff --git a/app/lib/command_tag/commands/hello_world.rb b/app/lib/command_tag/commands/hello_world.rb
new file mode 100644
index 000000000..4cf17685e
--- /dev/null
+++ b/app/lib/command_tag/commands/hello_world.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+module CommandTag::Commands::HelloWorld
+  def handle_hello_world_at_start
+    @text << "\nHello, world!"
+  end
+end
diff --git a/app/lib/command_tag/commands/status_tools.rb b/app/lib/command_tag/commands/status_tools.rb
new file mode 100644
index 000000000..3c6d7137e
--- /dev/null
+++ b/app/lib/command_tag/commands/status_tools.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module CommandTag::Commands::StatusTools
+  def handle_publish_once_at_end
+    return unless author_of_parent? && !@parent.published?
+
+    PublishStatusService.new.call(@parent)
+  end
+
+  def handle_edit_once_before_save
+    return unless author_of_parent?
+
+    params = @parent.slice(*UpdateStatusService::ALLOWED_ATTRIBUTES).with_indifferent_access.compact
+    params[:text] = @text
+    UpdateStatusService.new.call(@parent, params)
+    destroy_status!
+  end
+end
diff --git a/app/lib/command_tag/processor.rb b/app/lib/command_tag/processor.rb
new file mode 100644
index 000000000..b122b9e8d
--- /dev/null
+++ b/app/lib/command_tag/processor.rb
@@ -0,0 +1,79 @@
+# frozen_string_literal: true
+
+class CommandTag::Processor
+  include CommandTag::Commands
+
+  STATEMENT_RE = /^\s*#!\s*([^\n]+ (?:start|begin|do)$.*)\n\s*#!\s*(?:end|stop|done)\s*$|^\s*#!\s*(.*?)\s*$/im.freeze
+  STATEMENT_STRIP_RE = /^\s*#!\s*(?:[^\n]+ (?:start|begin|do)$.*)\n\s*#!\s*(?:end|stop|done)\s*$\n?|^\s*#!\s*(?:.*?)\s*$\n?/im.freeze
+
+  def initialize(account, status)
+    @account      = account
+    @status       = status
+    @parent       = status.thread
+    @run_once     = Set[]
+    @vars         = {}
+    @text         = status.text.gsub("\r\n", "\n").gsub("\n\r", "\n").gsub("\r", "\n")
+
+    return unless @account.present? && @account.local? && @status.present?
+  end
+
+  def process!
+    @statements = parse_statements
+    @text = @text.gsub(STATEMENT_STRIP_RE, '').split("\n")
+
+    %w(at_start once_at_start).each { |suffix| execute_statements(suffix) }
+    @text = @text.join("\n").rstrip
+    %w(before_save once_before_save).each { |suffix| execute_statements(suffix) }
+
+    if @text.blank?
+      %w(when_blank once_when_blank).each { |suffix| execute_statements(suffix) }
+
+      unless (@status.published? && !@status.edited.zero?) || @text.present?
+        %w(before_destroy once_before_destroy).each { |suffix| execute_statements(suffix) }
+        @status.destroy
+        %w(after_destroy once_after_destroy).each { |suffix| execute_statements(suffix) }
+      end
+    elsif @status.destroyed?
+      %w(after_destroy once_after_destroy).each { |suffix| execute_statements(suffix) }
+    elsif @status.update(text: @text)
+      %w(after_save once_after_save).each { |suffix| execute_statements(suffix) }
+    else
+      %w(after_save_fail once_after_save_fail).each { |suffix| execute_statements(suffix) }
+    end
+
+    %w(at_end once_at_end).each { |suffix| execute_statements(suffix) }
+  end
+
+  private
+
+  def parse_statements
+    @text.scan(STATEMENT_RE).flatten.map do |statement|
+      next if statement.blank? || statement[0]&.strip.blank?
+
+      statement = statement.scan(/^(.*) (?:start|begin|do)$(.*)|'([^']*)'|"([^"]*)"|(\S+)/im).flatten.compact
+      statement[0] = statement[0].strip.tr('- ', '_').downcase
+      statement
+    end.compact
+  end
+
+  def execute_statements(suffix)
+    @statements.each do |statement|
+      name = "handle_#{statement[0]}_#{suffix}"
+      is_run_once = suffix.start_with?('once_')
+      public_send(name, *statement[1..-1]) if respond_to?(name) && !(is_run_once && @run_once.include?(name))
+      @run_once << name if is_run_once
+    end
+  end
+
+  def author_of_status?
+    @account.id == @status.account_id
+  end
+
+  def author_of_parent?
+    @account.id == @parent&.account_id
+  end
+
+  def destroy_status!
+    @status.destroy unless @status.destroyed?
+  end
+end
diff --git a/app/services/post_status_service.rb b/app/services/post_status_service.rb
index 5ddc1aeeb..132e91907 100644
--- a/app/services/post_status_service.rb
+++ b/app/services/post_status_service.rb
@@ -88,6 +88,7 @@ class PostStatusService < BaseService
       @status = @account.statuses.create!(status_attributes)
     end
 
+    process_command_tags_service.call(@account, @status)
     process_hashtags_service.call(@status, nil, @tag_names)
     process_mentions_service.call(@status, mentions: @mentions, deliver: @options[:publish])
   end
@@ -148,6 +149,10 @@ class PostStatusService < BaseService
     ProcessHashtagsService.new
   end
 
+  def process_command_tags_service
+    ProcessCommandTagsService.new
+  end
+
   def scheduled?
     @scheduled_at.present?
   end
@@ -178,8 +183,10 @@ class PostStatusService < BaseService
 
   def bump_potential_friendship!
     return if !@status.reply? || @account.id == @status.in_reply_to_account_id
+
     ActivityTracker.increment('activity:interactions')
     return if @account.following?(@status.in_reply_to_account_id)
+
     PotentialFriendshipTracker.record(@account.id, @status.in_reply_to_account_id, :reply)
   end
 
diff --git a/app/services/process_command_tags_service.rb b/app/services/process_command_tags_service.rb
new file mode 100644
index 000000000..2d8180673
--- /dev/null
+++ b/app/services/process_command_tags_service.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class ProcessCommandTagsService < BaseService
+  def call(account, status, raise_if_no_output: true)
+    CommandTag::Processor.new(account, status).process!
+    raise Mastodon::LengthValidationError, 'Processed command tags yielded no output.' if raise_if_no_output && status.destroyed?
+
+    status
+  end
+end
diff --git a/app/services/publish_status_service.rb b/app/services/publish_status_service.rb
new file mode 100644
index 000000000..737186a17
--- /dev/null
+++ b/app/services/publish_status_service.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+class PublishStatusService < BaseService
+  def call(status)
+    return if status.published?
+
+    status.update!(published: true)
+
+    ProcessMentionsService.new.call(status)
+
+    LinkCrawlWorker.perform_in(rand(1..30).seconds, status.id) unless status.spoiler_text?
+    DistributionWorker.perform_async(status.id)
+    ActivityPub::DistributionWorker.perform_async(status.id) if status.local? && !status.local_only?
+
+    return if !status.reply? || status.account.id == status.in_reply_to_account_id
+
+    ActivityTracker.increment('activity:interactions')
+
+    return if status.account.following?(status.in_reply_to_account_id)
+
+    PotentialFriendshipTracker.record(status.account.id, status.in_reply_to_account_id, :reply)
+  end
+end
diff --git a/app/services/update_status_service.rb b/app/services/update_status_service.rb
index 440b99ce7..795e43d01 100644
--- a/app/services/update_status_service.rb
+++ b/app/services/update_status_service.rb
@@ -13,7 +13,6 @@ class UpdateStatusService < BaseService
     media_attachments
     media_attachment_ids
     application
-    rate_limit
   ).freeze
 
   # Updates the content of an existing status.
@@ -21,7 +20,7 @@ class UpdateStatusService < BaseService
   # @param [Hash] params The attributes of the new status.
   # @param [Enumerable] mentions Additional mentions added to the status.
   # @param [Enumerable] tags New tags for the status to belong to (implicit tags are preserved).
-  def call(status, params, mentions, tags)
+  def call(status, params, mentions = nil, tags = nil)
     raise ActiveRecord::RecordNotFound if status.blank? || status.discarded? || status.destroyed?
     return status if params.blank?
 
@@ -47,6 +46,7 @@ class UpdateStatusService < BaseService
 
     ApplicationRecord.transaction do
       @status.update!(@params)
+      ProcessCommandTagsService.new.call(@account, @status) if @account.local?
       detach_deleted_tags
       attach_updated_tags
     end