defmodule ElixirAiWeb.ChatLive do
  use ElixirAiWeb, :live_view
  require Logger
  import ElixirAiWeb.Spinner
  import ElixirAiWeb.ChatMessage
  import ElixirAiWeb.ChatProviderDisplay
  alias ElixirAi.ChatRunner
  alias ElixirAi.ConversationManager
  import ElixirAi.PubsubTopics

  def mount(%{"name" => name}, _session, socket) do
    case ConversationManager.open_conversation(name) do
      {:ok, _pid} ->
        if connected?(socket) do
          Phoenix.PubSub.subscribe(ElixirAi.PubSub, chat_topic(name))
        end

        conversation = ChatRunner.get_conversation(name)

        {:ok,
         socket
         |> assign(conversation_name: name)
         |> assign(user_input: "")
         |> assign(messages: conversation.messages)
         |> assign(streaming_response: conversation.streaming_response)
         |> assign(background_color: "bg-cyan-950/30")
         |> assign(provider: conversation.provider)
         |> assign(db_error: nil)}

      {:error, :not_found} ->
        {:ok, push_navigate(socket, to: "/")}

      {:error, reason} ->
        Logger.error("Failed to start conversation #{name}: #{inspect(reason)}")

        {:ok,
         socket
         |> assign(conversation_name: name)
         |> assign(user_input: "")
         |> assign(messages: [])
         |> assign(streaming_response: nil)
         |> assign(background_color: "bg-cyan-950/30")
         |> assign(provider: nil)
         |> assign(db_error: Exception.format(:error, reason))}
    end
  end

  def render(assigns) do
    ~H"""
    <div class="flex flex-col h-full  rounded-lg">
      <div class="px-4 py-3 font-semibold flex items-center gap-3">
        <.link navigate={~p"/"} class="text-cyan-700 hover:text-cyan-400 transition-colors">
          ←
        </.link>
        <span class="flex-1">{@conversation_name}</span>
        <.chat_provider_display provider={@provider} />
      </div>
      <%= if @db_error do %>
        <div class="mx-4 mt-2 px-3 py-2 rounded text-sm text-red-400 bg-red-950/40" role="alert">
          Database error: {@db_error}
        </div>
      <% end %>
      <div
        id="chat-messages"
        phx-hook="ScrollBottom"
        class={"flex-1 overflow-y-auto p-4 rounded-lg #{@background_color}"}
      >
        <%= if @messages == [] do %>
          <p class="text-sm text-center mt-4">No messages yet.</p>
        <% end %>
        <%= for msg <- @messages do %>
          <%= cond do %>
            <% msg.role == :user -> %>
              <.user_message content={Map.get(msg, :content) || ""} />
            <% msg.role == :tool -> %>
              <.tool_result_message
                content={Map.get(msg, :content) || ""}
                tool_call_id={Map.get(msg, :tool_call_id) || ""}
              />
            <% true -> %>
              <.assistant_message
                content={Map.get(msg, :content) || ""}
                reasoning_content={Map.get(msg, :reasoning_content)}
                tool_calls={Map.get(msg, :tool_calls) || []}
              />
          <% end %>
        <% end %>
        <%= if @streaming_response do %>
          <.streaming_assistant_message
            content={@streaming_response.content}
            reasoning_content={@streaming_response.reasoning_content}
            tool_calls={@streaming_response.tool_calls}
          />
          <.spinner />
        <% end %>
      </div>
      <form class="p-3 flex gap-2" phx-submit="submit" phx-change="update_user_input">
        <input
          type="text"
          name="user_input"
          value={@user_input}
          class="flex-1 rounded px-3 py-2 text-sm focus:outline-none focus:ring-2"
        />
        <button type="submit" class="px-4 py-2 rounded text-sm border">
          Send
        </button>
      </form>
    </div>
    """
  end

  def handle_event("update_user_input", %{"user_input" => user_input}, socket) do
    {:noreply, assign(socket, user_input: user_input)}
  end

  def handle_event("submit", %{"user_input" => user_input}, socket) when user_input != "" do
    ChatRunner.new_user_message(socket.assigns.conversation_name, user_input)
    {:noreply, assign(socket, user_input: "")}
  end

  def handle_info({:user_chat_message, message}, socket) do
    {:noreply,
     socket
     |> update(:messages, &(&1 ++ [message]))
     |> push_event("scroll_to_bottom", %{})}
  end

  def handle_info(
        {:start_ai_response_stream,
         %{id: _id, reasoning_content: "", content: ""} = starting_response},
        socket
      ) do
    {:noreply, assign(socket, streaming_response: starting_response)}
  end

  # chunk arrived before :start_ai_response_stream — fetch snapshot from runner and apply
  def handle_info(
        {:reasoning_chunk_content, reasoning_content},
        %{assigns: %{streaming_response: nil}} = socket
      ) do
    base = get_snapshot(socket) |> Map.update!(:reasoning_content, &(&1 <> reasoning_content))
    {:noreply, assign(socket, streaming_response: base)}
  end

  def handle_info({:reasoning_chunk_content, reasoning_content}, socket) do
    updated_response = %{
      socket.assigns.streaming_response
      | reasoning_content:
          socket.assigns.streaming_response.reasoning_content <> reasoning_content
    }

    # Update assign (controls toggle button visibility) and stream chunk to hook.
    {:noreply,
     socket
     |> assign(streaming_response: updated_response)
     |> push_event("reasoning_chunk", %{chunk: reasoning_content})}
  end

  def handle_info(
        {:text_chunk_content, text_content},
        %{assigns: %{streaming_response: nil}} = socket
      ) do
    base = get_snapshot(socket) |> Map.update!(:content, &(&1 <> text_content))
    {:noreply, assign(socket, streaming_response: base)}
  end

  def handle_info({:text_chunk_content, text_content}, socket) do
    updated_response = %{
      socket.assigns.streaming_response
      | content: socket.assigns.streaming_response.content <> text_content
    }

    # Update assign (accumulated for final message) and stream chunk to hook.
    {:noreply,
     socket
     |> assign(streaming_response: updated_response)
     |> push_event("md_chunk", %{chunk: text_content})}
  end

  def handle_info(:tool_calls_finished, socket) do
    # Logger.info("Received tool_calls_finished")

    {:noreply,
     socket
     |> assign(streaming_response: nil)}
  end

  def handle_info({:tool_request_message, tool_request_message}, socket) do
    # Logger.info("tool request message: #{inspect(tool_request_message)}")

    {:noreply,
     socket
     |> update(:messages, &(&1 ++ [tool_request_message]))}
  end

  def handle_info({:one_tool_finished, tool_response}, socket) do
    {:noreply,
     socket
     |> update(:messages, &(&1 ++ [tool_response]))}
  end

  def handle_info({:end_ai_response, final_message}, socket) do
    {:noreply,
     socket
     |> update(:messages, &(&1 ++ [final_message]))
     |> assign(streaming_response: nil)}
  end

  def handle_info({:db_error, reason}, socket) do
    {:noreply, assign(socket, db_error: reason)}
  end

  def handle_info({:set_background_color, color}, socket) do
    Logger.info("setting background color to #{color}")
    {:noreply, assign(socket, background_color: color)}
  end

  defp get_snapshot(socket) do
    ChatRunner.get_streaming_response(socket.assigns.conversation_name)
    |> case do
      nil -> %{id: nil, content: "", reasoning_content: "", tool_calls: []}
      snapshot -> snapshot
    end
  end
end