Add streaming chat

Gemfile

@@ -57,6 +57,7 @@ gem "intercom-rails"
 gem "plaid"
 gem "rotp", "~> 6.3"
 gem "rqrcode", "~> 2.2"
+gem "ruby-openai"
 
 group :development, :test do
   gem "debug", platforms: %i[mri windows]

Gemfile.lock

@@ -167,6 +167,7 @@ GEM
     erubi (1.13.1)
     et-orbi (1.2.11)
       tzinfo
+    event_stream_parser (1.0.0)
     faker (3.5.1)
       i18n (>= 1.8.11, < 2)
     faraday (2.12.2)
@@ -441,6 +442,10 @@ GEM
       sorbet-runtime (>= 0.5.10782)
     ruby-lsp-rails (0.4.0)
       ruby-lsp (>= 0.23.0, < 0.24.0)
+    ruby-openai (7.4.0)
+      event_stream_parser (>= 0.3.0, < 2.0.0)
+      faraday (>= 1)
+      faraday-multipart (>= 1)
     ruby-progressbar (1.13.0)
     ruby-vips (2.2.3)
       ffi (~> 1.12)
@@ -576,6 +581,7 @@ DEPENDENCIES
   rqrcode (~> 2.2)
   rubocop-rails-omakase
   ruby-lsp-rails
+  ruby-openai
   selenium-webdriver
   sentry-rails
   sentry-ruby

app/controllers/chats_controller.rb

@@ -0,0 +1,17 @@
+class ChatsController < ApplicationController
+  def index
+    Current.user.update!(current_chat: nil)
+    @chats = Current.user.chats.ordered
+  end
+
+  def create
+    @chat = Current.user.chats.create_with_defaults!
+
+    redirect_to chat_path(@chat)
+  end
+
+  def show
+    @chat = Current.user.chats.find(params[:id])
+    Current.user.update!(current_chat: @chat)
+  end
+end

app/controllers/messages_controller.rb

@@ -0,0 +1,23 @@
+class MessagesController < ApplicationController
+  before_action :set_chat
+
+  def create
+    @message = @chat.messages.create!(message_params.merge(role: "user"))
+
+    AiResponseJob.perform_later(@message)
+
+    respond_to do |format|
+      format.turbo_stream
+      format.html { redirect_to chat_path(@chat) }
+    end
+  end
+
+  private
+    def set_chat
+      @chat = Current.user.chats.find(params[:chat_id])
+    end
+
+    def message_params
+      params.require(:message).permit(:content)
+    end
+end

app/javascript/controllers/chat_controller.js

@@ -0,0 +1,32 @@
+import { Controller } from "@hotwired/stimulus";
+
+// Connects to data-controller="chat-scroll"
+export default class extends Controller {
+  static targets = ["form", "messages"];
+
+  connect() {
+    this.scrollToBottom();
+
+    this.observer = new MutationObserver(() => {
+      this.scrollToBottom();
+      this.clearInput();
+    });
+
+    this.observer.observe(this.messagesTarget, {
+      childList: true,
+      subtree: true,
+    });
+  }
+
+  disconnect() {
+    this.observer.disconnect();
+  }
+
+  scrollToBottom() {
+    this.messagesTarget.scrollTop = this.messagesTarget.scrollHeight;
+  }
+
+  clearInput() {
+    this.formTarget.querySelector("textarea").value = "";
+  }
+}

app/jobs/ai_response_job.rb

@@ -0,0 +1,7 @@
+class AiResponseJob < ApplicationJob
+  queue_as :default
+
+  def perform(message)
+    message.chat.generate_next_ai_response
+  end
+end

app/models/chat.rb

@@ -0,0 +1,61 @@
+class Chat < ApplicationRecord
+  belongs_to :user
+  has_many :messages, dependent: :destroy
+  has_one :user_current_chat, class_name: "User", foreign_key: :current_chat_id, dependent: :nullify
+
+  validates :title, presence: true
+
+  scope :ordered, -> { order(created_at: :desc) }
+
+  class << self
+    def create_with_defaults!
+      create!(
+        title: "New chat #{Time.current.strftime("%Y-%m-%d %H:%M:%S")}",
+        messages: [
+          Message.new(
+            role: "system",
+            content: "You are a helpful personal finance assistant.",
+          )
+        ]
+      )
+    end
+  end
+
+  def generate_next_ai_response
+    if messages.conversation.ordered.last&.role == "assistant"
+      Rails.logger.info("Skipping response because last message was an assistant message")
+      return
+    end
+
+    openai.chat(
+      parameters: {
+        model: "gpt-4o-mini",
+        stream: streamer,
+        n: 1,
+        messages: messages.conversation.order(:created_at).map do |message|
+          {
+            role: message.role,
+            content: message.content
+          }
+        end
+      }
+    )
+  end
+
+  private
+    def openai
+      OpenAI::Client.new(access_token: ENV["OPENAI_ACCESS_TOKEN"])
+    end
+
+    def streamer
+      message = messages.create!(
+        role: "assistant",
+        content: ""
+      )
+
+      proc do |chunk, _bytesize|
+        new_content = chunk.dig("choices", 0, "delta", "content")
+        message.update(content: message.content + new_content) if new_content
+      end
+    end
+end

app/models/message.rb

@@ -0,0 +1,33 @@
+class Message < ApplicationRecord
+  belongs_to :chat
+
+  enum :role, { user: "user", assistant: "assistant", system: "system" }
+
+  validates :content, presence: true, allow_blank: true
+  validates :role, presence: true
+
+  scope :conversation, -> { where(debug_mode: false, role: [ :user, :assistant ]) }
+  scope :ordered, -> { order(created_at: :asc) }
+
+  after_create_commit :broadcast_to_chat
+  after_update_commit :broadcast_update_to_chat
+
+  private
+    def broadcast_to_chat
+      broadcast_append_to(
+        chat,
+        partial: "messages/message",
+        locals: { message: self },
+        target: "chat_#{chat.id}_messages"
+      )
+    end
+
+    def broadcast_update_to_chat
+      broadcast_update_to(
+        chat,
+        partial: "messages/message",
+        locals: { message: self },
+        target: "message_#{self.id}"
+      )
+    end
+end

app/models/user.rb

@@ -1,10 +1,12 @@
 class User < ApplicationRecord
   has_secure_password
 
+  belongs_to :current_chat, class_name: "Chat", optional: true
   belongs_to :family
   has_many :sessions, dependent: :destroy
   has_many :impersonator_support_sessions, class_name: "ImpersonationSession", foreign_key: :impersonator_id, dependent: :destroy
   has_many :impersonated_support_sessions, class_name: "ImpersonationSession", foreign_key: :impersonated_id, dependent: :destroy
+  has_many :chats, dependent: :destroy
   accepts_nested_attributes_for :family, update_only: true
 
   validates :email, presence: true, uniqueness: true, format: { with: URI::MailTo::EMAIL_REGEXP }

app/views/chats/_chat.html.erb

@@ -0,0 +1,3 @@
+<%= link_to chat_path(chat) do %>
+  <%= chat.title %>
+<% end %>

app/views/chats/_chat_nav.html.erb

@@ -0,0 +1,6 @@
+<div>
+  <p>Chat nav</p>
+
+  <%= button_to "New chat", chats_path, method: :post, class: "btn btn-primary", data: { turbo_frame: "chat_content" } %>
+  <%= link_to "All chats", chats_path, data: { turbo_frame: "chat_content" } %>
+</div>

app/views/chats/index.html.erb

@@ -0,0 +1,9 @@
+<%= turbo_frame_tag "chat_content" do %>
+  <% if @chats.empty? %>
+    <p>No chats</p>
+  <% else %>
+    <div class="flex flex-col gap-2">
+      <%= render @chats %>
+    </div>
+  <% end %>
+<% end %>

app/views/chats/show.html.erb

@@ -0,0 +1,17 @@
+<%= turbo_frame_tag "chat_content" do %>
+  <div class="flex flex-col gap-4 justify-between h-full" data-controller="chat">
+    <div class="grow overflow-y-auto" data-chat-target="messages">
+      <h2 class="text-2xl font-bold mb-6"><%= @chat.title %></h2>
+
+      <%= turbo_stream_from @chat %>
+
+      <div id="<%= dom_id(@chat) %>_messages" class="space-y-6 py-8">
+        <%= render @chat.messages.conversation.ordered %>
+      </div>
+    </div>
+
+    <div data-chat-target="form">
+      <%= render "messages/form", chat: @chat %>
+    </div>
+  </div>
+<% end %>

app/views/layouts/application.html.erb

@@ -57,5 +57,23 @@
         <%= yield %>
       <% end %>
     <% end %>
+
+    <%= tag.div class: class_names("py-4 shrink-0 flex flex-col justify-between gap-6 h-full transition-all duration-300 w-[375px]") do %>
+      <div class="bg-white p-4">
+        <%= render "chats/chat_nav" %>
+      </div>
+
+      <div id="chat-content" class="grow p-4 bg-white overflow-y-auto" data-turbo-permanent>
+        <% if Current.user.current_chat.present? %>
+          <%= turbo_frame_tag "chat_content", src: chat_path(Current.user.current_chat), loading: "lazy" do %>
+            <p>Loading chat...</p>
+          <% end %>
+        <% else %>
+          <%= turbo_frame_tag "chat_content", src: chats_path, loading: "lazy" do %>
+            <p>Loading chats...</p>
+          <% end %>
+        <% end %>
+      </div>
+    <% end %>
   </div>
 <% end %>

app/views/messages/_form.html.erb

@@ -0,0 +1,6 @@
+<%# locals: (chat:) %>
+
+<%= styled_form_with model: chat.messages.build, url: chat_messages_path(chat), method: :post, class: "space-y-4" do |f| %>
+  <%= f.text_area :content, size: "50x5" %>
+  <%= f.submit "Send message" %>
+<% end %>

app/views/messages/_message.html.erb

@@ -0,0 +1,6 @@
+<div id="<%= dom_id(message) %>">
+  <p class="text-sm text-gray-500">
+    role: <%= message.role %>
+  </p>
+  <p class="text-primary whitespace-pre-wrap"><%= message.content %></p>
+</div>

config/routes.rb

@@ -22,6 +22,10 @@ Rails.application.routes.draw do
     delete :reset, on: :member
   end
 
+  resources :chats, only: %i[index show create destroy] do
+    resources :messages, only: %i[create]
+  end
+
   resource :onboarding, only: :show do
     collection do
       get :profile

db/migrate/20250312152948_create_chats.rb

@@ -0,0 +1,10 @@
+class CreateChats < ActiveRecord::Migration[7.2]
+  def change
+    create_table :chats, id: :uuid do |t|
+      t.timestamps
+
+      t.references :user, null: false, foreign_key: true, type: :uuid
+      t.string :title, null: false
+    end
+  end
+end

db/migrate/20250312153208_create_messages.rb

@@ -0,0 +1,12 @@
+class CreateMessages < ActiveRecord::Migration[7.2]
+  def change
+    create_table :messages, id: :uuid do |t|
+      t.timestamps
+
+      t.references :chat, null: false, foreign_key: true, type: :uuid
+      t.string :role, null: false
+      t.text :content, null: false
+      t.boolean :debug_mode, default: false, null: false
+    end
+  end
+end

db/migrate/20250312160915_user_latest_chat.rb

@@ -0,0 +1,5 @@
+class UserLatestChat < ActiveRecord::Migration[7.2]
+  def change
+    add_reference :users, :current_chat, foreign_key: { to_table: :chats }, null: true, type: :uuid
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.2].define(version: 2025_03_04_140435) do
+ActiveRecord::Schema[7.2].define(version: 2025_03_12_160915) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "pgcrypto"
   enable_extension "plpgsql"
@@ -196,6 +196,14 @@ ActiveRecord::Schema[7.2].define(version: 2025_03_04_140435) do
     t.index ["family_id"], name: "index_categories_on_family_id"
   end
 
+  create_table "chats", id: :uuid, default: -> { "gen_random_uuid()" }, force: :cascade do |t|
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.uuid "user_id", null: false
+    t.string "title", null: false
+    t.index ["user_id"], name: "index_chats_on_user_id"
+  end
+
   create_table "credit_cards", id: :uuid, default: -> { "gen_random_uuid()" }, force: :cascade do |t|
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
@@ -481,6 +489,16 @@ ActiveRecord::Schema[7.2].define(version: 2025_03_04_140435) do
     t.index ["family_id"], name: "index_merchants_on_family_id"
   end
 
+  create_table "messages", id: :uuid, default: -> { "gen_random_uuid()" }, force: :cascade do |t|
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.uuid "chat_id", null: false
+    t.string "role", null: false
+    t.text "content", null: false
+    t.boolean "debug_mode", default: false, null: false
+    t.index ["chat_id"], name: "index_messages_on_chat_id"
+  end
+
   create_table "other_assets", id: :uuid, default: -> { "gen_random_uuid()" }, force: :cascade do |t|
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
@@ -676,6 +694,8 @@ ActiveRecord::Schema[7.2].define(version: 2025_03_04_140435) do
     t.string "otp_backup_codes", default: [], array: true
     t.boolean "show_sidebar", default: true
     t.string "default_period", default: "last_30_days", null: false
+    t.uuid "current_chat_id"
+    t.index ["current_chat_id"], name: "index_users_on_current_chat_id"
     t.index ["email"], name: "index_users_on_email", unique: true
     t.index ["family_id"], name: "index_users_on_family_id"
     t.index ["otp_secret"], name: "index_users_on_otp_secret", unique: true, where: "(otp_secret IS NOT NULL)"
@@ -708,6 +728,7 @@ ActiveRecord::Schema[7.2].define(version: 2025_03_04_140435) do
   add_foreign_key "budget_categories", "categories"
   add_foreign_key "budgets", "families"
   add_foreign_key "categories", "families"
+  add_foreign_key "chats", "users"
   add_foreign_key "impersonation_session_logs", "impersonation_sessions"
   add_foreign_key "impersonation_sessions", "users", column: "impersonated_id"
   add_foreign_key "impersonation_sessions", "users", column: "impersonator_id"
@@ -716,6 +737,7 @@ ActiveRecord::Schema[7.2].define(version: 2025_03_04_140435) do
   add_foreign_key "invitations", "families"
   add_foreign_key "invitations", "users", column: "inviter_id"
   add_foreign_key "merchants", "families"
+  add_foreign_key "messages", "chats"
   add_foreign_key "plaid_accounts", "plaid_items"
   add_foreign_key "plaid_items", "families"
   add_foreign_key "rejected_transfers", "account_transactions", column: "inflow_transaction_id"
@@ -727,5 +749,6 @@ ActiveRecord::Schema[7.2].define(version: 2025_03_04_140435) do
   add_foreign_key "tags", "families"
   add_foreign_key "transfers", "account_transactions", column: "inflow_transaction_id", on_delete: :cascade
   add_foreign_key "transfers", "account_transactions", column: "outflow_transaction_id", on_delete: :cascade
+  add_foreign_key "users", "chats", column: "current_chat_id"
   add_foreign_key "users", "families"
 end

test/fixtures/chats.yml

@@ -0,0 +1,11 @@
+# Read about fixtures at https://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+
+# This model initially had no columns defined. If you add columns to the
+# model remove the "{}" from the fixture names and add the columns immediately
+# below each fixture, per the syntax in the comments below
+#
+one: {}
+# column: value
+#
+two: {}
+# column: value

test/fixtures/messages.yml

@@ -0,0 +1,11 @@
+# Read about fixtures at https://api.rubyonrails.org/classes/ActiveRecord/FixtureSet.html
+
+# This model initially had no columns defined. If you add columns to the
+# model remove the "{}" from the fixture names and add the columns immediately
+# below each fixture, per the syntax in the comments below
+#
+one: {}
+# column: value
+#
+two: {}
+# column: value

test/jobs/ai_response_job_test.rb

@@ -0,0 +1,7 @@
+require "test_helper"
+
+class AiResponseJobTest < ActiveJob::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end

test/models/chat_test.rb

@@ -0,0 +1,7 @@
+require "test_helper"
+
+class ChatTest < ActiveSupport::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end

test/models/message_test.rb

@@ -0,0 +1,7 @@
+require "test_helper"
+
+class MessageTest < ActiveSupport::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end