DEV: refactor flag message (#24604)

- Uses a chat service: `Chat::FlatMessage`
- Moves logic inside chat api controllers
- Create a javascript chat api helper: `chatApi.flagMessage(...)`

plugins/chat/spec/services/chat/flag_message_spec.rb

@@ -0,0 +1,107 @@
+# frozen_string_literal: true
+
+RSpec.describe Chat::FlagMessage do
+  describe described_class::Contract, type: :model do
+    subject(:contract) { described_class.new }
+
+    it { is_expected.to validate_presence_of(:channel_id) }
+    it { is_expected.to validate_presence_of(:message_id) }
+    it do
+      is_expected.to validate_inclusion_of(:flag_type_id).in_array(ReviewableScore.types.values)
+    end
+  end
+
+  describe ".call" do
+    subject(:result) { described_class.call(params) }
+
+    fab!(:current_user) { Fabricate(:user) }
+    fab!(:channel_1) { Fabricate(:chat_channel) }
+    fab!(:message_1) { Fabricate(:chat_message, chat_channel: channel_1) }
+
+    let(:guardian) { Guardian.new(current_user) }
+    let(:channel_id) { channel_1.id }
+    let(:message_id) { message_1.id }
+    let(:flag_type_id) { ReviewableScore.types.values.first }
+    let(:message) { nil }
+    let(:is_warning) { nil }
+    let(:take_action) { nil }
+
+    before { SiteSetting.direct_message_enabled_groups = Group::AUTO_GROUPS[:everyone] }
+
+    let(:params) do
+      {
+        guardian: guardian,
+        channel_id: channel_id,
+        message_id:,
+        flag_type_id: flag_type_id,
+        message: message,
+        is_warning: is_warning,
+        take_action: take_action,
+      }
+    end
+
+    context "when all steps pass" do
+      fab!(:current_user) { Fabricate(:admin) }
+
+      it "flags the message" do
+        expect { result }.to change { Reviewable.count }.by(1)
+
+        reviewable = Reviewable.last
+        expect(reviewable.target_type).to eq("ChatMessage")
+        expect(reviewable.created_by_id).to eq(current_user.id)
+        expect(reviewable.target_created_by_id).to eq(message_1.user.id)
+        expect(reviewable.target_id).to eq(message_1.id)
+        expect(reviewable.payload).to eq("message_cooked" => message_1.cooked)
+      end
+    end
+
+    context "when channel is not found" do
+      before { params[:channel_id] = -999 }
+
+      it { is_expected.to fail_to_find_a_model(:message) }
+    end
+
+    context "when user is silenced" do
+      before { UserSilencer.new(current_user).silence }
+
+      it { is_expected.to fail_a_policy(:can_flag_message_in_channel) }
+    end
+
+    context "when channel is in read only mode" do
+      before { channel_1.update!(status: Chat::Channel.statuses[:read_only]) }
+
+      it { is_expected.to fail_a_policy(:can_flag_message_in_channel) }
+    end
+
+    context "when flagging staff message is not allowed" do
+      before { SiteSetting.allow_flagging_staff = false }
+
+      fab!(:message_1) do
+        Fabricate(:chat_message, chat_channel: channel_1, user: Fabricate(:admin))
+      end
+
+      it { is_expected.to fail_a_policy(:can_flag_message_in_channel) }
+    end
+
+    context "when flagging its own message" do
+      fab!(:message_1) { Fabricate(:chat_message, chat_channel: channel_1, user: current_user) }
+
+      before { UserSilencer.new(current_user).silence }
+
+      it { is_expected.to fail_a_policy(:can_flag_message_in_channel) }
+    end
+
+    context "when message is not found" do
+      before { params[:message_id] = -999 }
+
+      it { is_expected.to fail_to_find_a_model(:message) }
+    end
+
+    context "when user doesn't have access to channel" do
+      fab!(:channel_1) { Fabricate(:private_category_channel, group: Fabricate(:group)) }
+      fab!(:message_1) { Fabricate(:chat_message, chat_channel: channel_1) }
+
+      it { is_expected.to fail_a_policy(:can_flag_message_in_channel) }
+    end
+  end
+end