defmodule SyntropyWeb.TasksLive do
  use SyntropyWeb, :live_view

  import SyntropyWeb.RuntimeViewHelpers

  alias Syntropy.{HistoryStore, RecommendationStore, TaskScheduler}

  @history_limit 20

  @impl true
  def mount(_params, _session, socket) do
    if connected?(socket) do
      Phoenix.PubSub.subscribe(Syntropy.PubSub, "lattice:events")
    end

    {:ok,
     assign(socket,
       task_entries: build_task_entries(),
       active_runs: build_active_runs(),
       cancel_error: nil
     )}
  end

  @impl true
  def handle_info({:lattice_event, _event}, socket) do
    {:noreply,
     assign(socket, task_entries: build_task_entries(), active_runs: build_active_runs())}
  end

  @impl true
  def handle_event("cancel_run", %{"id" => run_id}, socket) do
    case TaskScheduler.cancel_run(run_id) do
      {:ok, _cancelled_run} ->
        {:noreply,
         assign(socket,
           cancel_error: nil,
           task_entries: build_task_entries(),
           active_runs: build_active_runs()
         )}

      {:error, reason} ->
        {:noreply,
         assign(socket,
           cancel_error: format_cancel_error(run_id, reason),
           active_runs: build_active_runs()
         )}
    end
  end

  @impl true
  def render(assigns) do
    ~H"""
    <main class="dashboard">
      <section class="dashboard-header glass-panel p-4">
        <div>
          <h1>Task history</h1>
          <p class="body-copy">Active and retained runs with selection evidence.</p>
        </div>
        <nav class="dashboard-nav">
          <.link navigate={~p"/"} class="text-link">Lattice</.link>
          <span> · </span>
          <.link navigate={~p"/history"} class="text-link">History</.link>
          <span> · </span>
          <.link navigate={~p"/operations"} class="text-link">Operations</.link>
        </nav>
      </section>

      <%= if @active_runs != [] or @cancel_error do %>
        <section class="glass-panel detail-panel mt-4">
          <header class="section-heading section-heading--flush">
            <div>
              <h2>Active runs</h2>
            </div>
          </header>

          <%= if @cancel_error do %>
            <p id="cancel-error" class="meta-label text-danger">
              <%= @cancel_error %>
            </p>
          <% end %>

          <ul id="active-runs" class="task-list">
            <%= for run <- @active_runs do %>
              <li id={"active-run-#{run.id}"} class="task-list-item">
                <div class="section-heading section-heading--flush">
                  <div>
                    <p class="task-title"><%= run.id %></p>
                    <p class="meta-copy">
                      node <%= node_id_for(run) %>
                      · <%= run.strategy %> resolved <%= run.resolved_mode %>
                      · <%= length(run.selected_agent_ids) %> agents
                    </p>
                  </div>
                  <div class="flex-row" style="gap: 8px; align-items: center;">
                    <span class="status-chip status-chip--warn"><%= run.status %></span>
                    <button
                      type="button"
                      class="ds-button--destructive"
                      phx-click="cancel_run"
                      phx-value-id={run.id}
                      data-confirm={"Cancel run #{run.id}? In-flight agent calls will be aborted."}
                    >
                      Cancel
                    </button>
                  </div>
                </div>
                <p class="body-copy synthesis-copy"><%= run.prompt %></p>
              </li>
            <% end %>
          </ul>
        </section>
      <% end %>

      <section class="glass-panel detail-panel mt-4">
        <header class="section-heading section-heading--flush">
          <div>
            <h2>Task runs</h2>
          </div>
        </header>
        <%= if @task_entries == [] do %>
          <div class="empty-panel">
            <p id="tasks-empty" class="body-copy">No completed tasks yet.</p>
          </div>
        <% else %>
          <ul id="task-history" class="task-list">
            <%= for entry <- @task_entries do %>
              <li id={"task-#{entry.task.task_id}"} class="task-list-item">
                <div class="section-heading section-heading--flush">
                  <div>
                    <p class="task-title"><%= entry.task.task_id %></p>
                    <p class="meta-copy">
                      node <%= node_id_for(entry.task) %>
                      · <%= entry.task.strategy %> resolved <%= entry.task.resolved_mode %>
                    </p>
                  </div>
                  <span class="status-chip status-chip--muted">
                    <%= length(entry.task.selected_agent_ids) %> agents
                  </span>
                </div>

                <div>
                  <span class="meta-label">Synthesis</span>
                  <p class="body-copy synthesis-copy"><%= entry.task.synthesis %></p>
                </div>

                <div>
                  <span class="meta-label">Selected agents</span>
                  <div class="task-list-meta mt-2">
                    <%= for agent_id <- entry.task.selected_agent_ids do %>
                      <.link
                        navigate={graph_path(entry.snapshot && entry.snapshot.id, agent_id)}
                        class="status-chip status-chip--muted"
                      >
                        <%= agent_id %>
                      </.link>
                    <% end %>
                  </div>
                </div>

                <%= if entry.snapshot || entry.recommendations != [] do %>
                  <div>
                    <span class="meta-label">Evidence</span>
                    <div class="task-list-meta mt-2">
                      <%= if entry.snapshot do %>
                        <.link navigate={~p"/history?snapshot=#{entry.snapshot.id}"} class="status-chip status-chip--ok">
                          <%= entry.snapshot.id %>
                        </.link>
                      <% end %>
                      <%= for recommendation <- entry.recommendations do %>
                        <.link
                          navigate={
                            graph_path(
                              entry.snapshot && entry.snapshot.id,
                              List.first(recommendation.candidate_agent_ids)
                            )
                          }
                          class="status-chip status-chip--warn"
                        >
                          <%= recommendation.id %> · <%= recommendation.status %>
                        </.link>
                      <% end %>
                    </div>
                  </div>
                <% end %>

                <details class="progressive-detail">
                  <summary>Selection trace (<%= length(entry.task.selection_trace) %>)</summary>
                  <div class="trace-table">
                    <%= for trace <- entry.task.selection_trace do %>
                      <div class="trace-row">
                        <strong><%= trace.agent_name %></strong>
                        <span>rank <%= trace.rank %></span>
                        <span>rel <%= format_score(trace.relevance) %></span>
                        <span>pos <%= format_score(trace.position) %></span>
                        <span>cap <%= format_score(trace.capacity) %></span>
                        <span class={if trace.selected, do: "trace-selected", else: "trace-considered"}>
                          <%= format_score(trace.composite) %> <%= if trace.selected, do: "sel", else: "—" %>
                        </span>
                      </div>
                    <% end %>
                  </div>
                </details>
              </li>
            <% end %>
          </ul>
        <% end %>
      </section>
    </main>
    """
  end

  defp build_active_runs do
    TaskScheduler.recent_runs(@history_limit)
    |> Enum.filter(&(&1.status in ["queued", "running"]))
  end

  defp format_cancel_error(run_id, :not_found), do: "Run #{run_id} was not found."

  defp format_cancel_error(run_id, :not_cancellable),
    do: "Run #{run_id} already reached a terminal state."

  defp build_task_entries do
    snapshots = HistoryStore.recent(@history_limit)

    snapshots_by_task_id =
      Map.new(snapshots, fn snapshot ->
        {snapshot.task_id, snapshot}
      end)

    recommendations = RecommendationStore.recent(@history_limit)
    recommendations_by_id = Map.new(recommendations, &{&1.id, &1})

    Enum.map(TaskScheduler.recent(@history_limit), fn task ->
      %{
        task: task,
        snapshot: Map.get(snapshots_by_task_id, task.task_id),
        recommendations:
          task.recommendation_ids
          |> Enum.map(&Map.get(recommendations_by_id, &1))
          |> Enum.reject(&is_nil/1)
      }
    end)
  end

  defp graph_path(snapshot_id, agent_id) do
    params =
      %{}
      |> maybe_put("snapshot", snapshot_id)
      |> maybe_put("agent", agent_id)

    ~p"/?#{params}"
  end

  defp maybe_put(params, _key, nil), do: params
  defp maybe_put(params, key, value), do: Map.put(params, key, value)
end