DEV: Move discourse-chat to the core repo. (#18776)

As part of this move, we are also renaming `discourse-chat` to `chat`.

plugins/chat/lib/guardian_extensions.rb

@@ -0,0 +1,182 @@
+# frozen_string_literal: true
+
+module Chat::GuardianExtensions
+  def can_moderate_chat?(chatable)
+    case chatable.class.name
+    when "Category"
+      is_staff? || is_category_group_moderator?(chatable)
+    else
+      is_staff?
+    end
+  end
+
+  def can_chat?(user)
+    return false unless user
+
+    user.staff? || user.in_any_groups?(Chat.allowed_group_ids)
+  end
+
+  def can_create_chat_message?
+    !SpamRule::AutoSilence.prevent_posting?(@user)
+  end
+
+  def can_create_direct_message?
+    is_staff? || @user.in_any_groups?(SiteSetting.direct_message_enabled_groups_map)
+  end
+
+  def hidden_tag_names
+    @hidden_tag_names ||= DiscourseTagging.hidden_tag_names(self)
+  end
+
+  def can_create_chat_channel?
+    is_staff?
+  end
+
+  def can_delete_chat_channel?
+    is_staff?
+  end
+
+  # Channel status intentionally has no bearing on whether the channel
+  # name and description can be edited.
+  def can_edit_chat_channel?
+    is_staff?
+  end
+
+  def can_move_chat_messages?(channel)
+    can_moderate_chat?(channel.chatable)
+  end
+
+  def can_create_channel_message?(chat_channel)
+    valid_statuses = is_staff? ? %w[open closed] : ["open"]
+    valid_statuses.include?(chat_channel.status)
+  end
+
+  # This is intentionally identical to can_create_channel_message, we
+  # may want to have different conditions here in future.
+  def can_modify_channel_message?(chat_channel)
+    return chat_channel.open? || chat_channel.closed? if is_staff?
+    chat_channel.open?
+  end
+
+  def can_change_channel_status?(chat_channel, target_status)
+    return false if chat_channel.status.to_sym == target_status.to_sym
+    return false if !is_staff?
+
+    case target_status
+    when :closed
+      chat_channel.open?
+    when :open
+      chat_channel.closed?
+    when :archived
+      chat_channel.read_only?
+    when :read_only
+      chat_channel.closed? || chat_channel.open?
+    else
+      false
+    end
+  end
+
+  def can_rebake_chat_message?(message)
+    return false if !can_modify_channel_message?(message.chat_channel)
+    is_staff? || @user.has_trust_level?(TrustLevel[4])
+  end
+
+  def can_see_chat_channel?(chat_channel)
+    return false unless chat_channel.chatable
+
+    if chat_channel.direct_message_channel?
+      chat_channel.chatable.user_can_access?(@user)
+    elsif chat_channel.category_channel?
+      can_see_category?(chat_channel.chatable)
+    else
+      true
+    end
+  end
+
+  def can_flag_chat_messages?
+    return false if @user.silenced?
+
+    @user.in_any_groups?(SiteSetting.chat_message_flag_allowed_groups_map)
+  end
+
+  def can_flag_in_chat_channel?(chat_channel)
+    return false if !can_modify_channel_message?(chat_channel)
+
+    can_see_chat_channel?(chat_channel)
+  end
+
+  def can_flag_chat_message?(chat_message)
+    return false if !authenticated? || !chat_message || chat_message.trashed? || !chat_message.user
+    return false if chat_message.user.staff? && !SiteSetting.allow_flagging_staff
+    return false if chat_message.user_id == @user.id
+
+    can_flag_chat_messages? && can_flag_in_chat_channel?(chat_message.chat_channel)
+  end
+
+  def can_flag_message_as?(chat_message, flag_type_id, opts)
+    return false if !is_staff? && (opts[:take_action] || opts[:queue_for_review])
+
+    if flag_type_id == ReviewableScore.types[:notify_user]
+      is_warning = ActiveRecord::Type::Boolean.new.deserialize(opts[:is_warning])
+
+      return false if is_warning && !is_staff?
+    end
+
+    true
+  end
+
+  def can_delete_chat?(message, chatable)
+    return false if @user.silenced?
+    return false if !can_modify_channel_message?(message.chat_channel)
+
+    if message.user_id == current_user.id
+      can_delete_own_chats?(chatable)
+    else
+      can_delete_other_chats?(chatable)
+    end
+  end
+
+  def can_delete_own_chats?(chatable)
+    return false if (SiteSetting.max_post_deletions_per_day < 1)
+    return true if can_moderate_chat?(chatable)
+
+    true
+  end
+
+  def can_delete_other_chats?(chatable)
+    return true if can_moderate_chat?(chatable)
+
+    false
+  end
+
+  def can_restore_chat?(message, chatable)
+    return false if !can_modify_channel_message?(message.chat_channel)
+
+    if message.user_id == current_user.id
+      case chatable.class.name
+      when "Category"
+        return can_see_category?(chatable)
+      when "DirectMessageChannel"
+        return true
+      end
+    end
+
+    can_delete_other_chats?(chatable)
+  end
+
+  def can_restore_other_chats?(chatable)
+    can_moderate_chat?(chatable)
+  end
+
+  def can_edit_chat?(message)
+    message.user_id == @user.id && !@user.silenced?
+  end
+
+  def can_react?
+    can_create_chat_message?
+  end
+
+  def can_delete_category?(category)
+    super && !category.category_channel
+  end
+end