Add `RelationshipsController`

app/controllers/relationships_controller.rb

@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+class RelationshipsController < ApplicationController
+  include TurboStreamable
+
+  before_action :authenticate_user!
+
+  turbo_stream_actions :create, :destroy
+
+  def create
+    UseCase::Relationship::Create.call(
+      source_user: current_user,
+      target_user: ::User.find_by!(screen_name: params[:screen_name]),
+      type:        params[:type]
+    )
+
+    respond_to do |format|
+      format.turbo_stream do
+        render turbo_stream: [
+          turbo_stream.replace("#{params[:type]}-#{params[:screen_name]}", partial: "relationships/destroy", locals: { type: params[:type], screen_name: params[:screen_name] }),
+          render_toast(t(".#{params[:type]}.success"))
+        ]
+      end
+
+      format.html { redirect_back(fallback_location: user_path(username: params[:screen_name])) }
+    end
+  end
+
+  def destroy
+    UseCase::Relationship::Destroy.call(
+      source_user: current_user,
+      target_user: ::User.find_by!(screen_name: params[:screen_name]),
+      type:        params[:type]
+    )
+
+    respond_to do |format|
+      format.turbo_stream do
+        render turbo_stream: [
+          turbo_stream.replace("#{params[:type]}-#{params[:screen_name]}", partial: "relationships/create", locals: { type: params[:type], screen_name: params[:screen_name] }),
+          render_toast(t(".#{params[:type]}.success"))
+        ]
+      end
+
+      format.html { redirect_back(fallback_location: user_path(username: params[:screen_name])) }
+    end
+  end
+end

app/views/relationships/_create.html.haml

@@ -0,0 +1,13 @@
+- if type == "follow"
+  = button_to relationships_path(screen_name:, type:), form: { id: "#{type}-#{screen_name}" }, class: "btn btn-primary", form_class: "d-grid" do
+    = t("voc.follow")
+
+- if type == "block"
+  = button_to relationships_path(screen_name:, type:), form: { id: "#{type}-#{screen_name}" }, class: "dropdown-item" do
+    %i.fa.fa-minus-circle.fa-fw
+    = t("voc.block")
+
+- if type == "mute"
+  = button_to relationships_path(screen_name:, type:), form: { id: "#{type}-#{screen_name}" }, class: "dropdown-item" do
+    %i.fa.fa-volume-off.fa-fw
+    = t("voc.mute")

app/views/relationships/_destroy.html.haml

@@ -0,0 +1,13 @@
+- if type == "follow"
+  = button_to relationships_path(screen_name:, type:), method: :delete, form: { id: "#{type}-#{screen_name}" }, class: "btn btn-primary", form_class: "d-grid" do
+    = t("voc.unfollow")
+
+- if type == "block"
+  = button_to relationships_path(screen_name:, type:), method: :delete, form: { id: "#{type}-#{screen_name}" }, class: "dropdown-item" do
+    %i.fa.fa-minus-circle.fa-fw
+    = t("voc.unblock")
+
+- if type == "mute"
+  = button_to relationships_path(screen_name:, type:), method: :delete, form: { id: "#{type}-#{screen_name}" }, class: "dropdown-item" do
+    %i.fa.fa-volume-off.fa-fw
+    = t("voc.unmute")

config/routes.rb

@@ -147,6 +147,7 @@ Rails.application.routes.draw do
   get "/inbox", to: "inbox#show", as: :inbox
 
   resource :subscriptions, controller: :subscriptions, only: %i[create destroy]
+  resource :relationships, only: %i[create destroy]
 
   get "/user/:username", to: "user#show"
   get "/@:username", to: "user#show", as: :user