Recently Updated: ignore price-refresh payloads

lib/pulse/portfolio_worker.ex

@@ -67,10 +67,21 @@ defmodule Pulse.PortfolioWorker do
     # LiveView templates already guard for it.
     stats = payload["stats"]
 
-    # On store restore the payload includes the original updated_at so a server
-    # restart doesn't make every portfolio look freshly active. Otherwise stamp
-    # with now.
-    updated_at = payload["__updated_at"] || DateTime.utc_now()
+    # `updated_at` should reflect when the user *materially* changed their
+    # portfolio — adding/removing stocks or editing qty/avg_price — not every
+    # NATS payload (Quantic also fires one on each periodic stock-price
+    # refresh, which would otherwise make every dashboard look freshly active
+    # at the same time). The restore path passes `__updated_at` to bypass
+    # this check and preserve the historical timestamp.
+    override = payload["__updated_at"]
+    materially_changed = holdings_signature(holdings) != holdings_signature(state.holdings)
+
+    updated_at =
+      cond do
+        override != nil -> override
+        materially_changed -> DateTime.utc_now()
+        true -> state.updated_at
+      end
 
     new_state = %{
       state
@@ -148,4 +159,14 @@ defmodule Pulse.PortfolioWorker do
   # plain math.
   defp holding_value_in_usd(%{"value_in_usd" => value}) when is_number(value), do: value
   defp holding_value_in_usd(h), do: holding_value(h)
+
+  # Deterministic fingerprint of what the user controls (symbol set, quantities,
+  # cost basis). Excludes price-derived fields so a stock-refresh payload that
+  # only updates `price` / `value_in_base` / `value_in_usd` doesn't register
+  # as a material change.
+  defp holdings_signature(holdings) do
+    holdings
+    |> Enum.map(fn h -> {h["symbol"], h["quantity"], h["avg_price"]} end)
+    |> Enum.sort()
+  end
 end

test/pulse/portfolio_worker_test.exs

@@ -198,4 +198,80 @@ defmodule Pulse.PortfolioWorkerTest do
     portfolio = Pulse.PortfolioWorker.get_portfolio("test-nostats")
     assert portfolio.stats == nil
   end
+
+  describe "updated_at material-change detection" do
+    setup do
+      {:ok, _pid} = Pulse.PortfolioSupervisor.start_worker("test-mc")
+
+      Pulse.PortfolioWorker.update_holdings("test-mc", %{
+        "holdings" => [
+          %{"symbol" => "AAPL", "quantity" => 10, "avg_price" => 150.0, "price" => 150.0}
+        ]
+      })
+
+      Process.sleep(50)
+      initial = Pulse.PortfolioWorker.get_portfolio("test-mc").updated_at
+      assert %DateTime{} = initial
+
+      [initial_updated_at: initial]
+    end
+
+    test "price-only payloads do NOT bump updated_at", %{initial_updated_at: initial} do
+      Process.sleep(20)
+
+      Pulse.PortfolioWorker.update_holdings("test-mc", %{
+        "holdings" => [
+          %{"symbol" => "AAPL", "quantity" => 10, "avg_price" => 150.0, "price" => 165.0}
+        ]
+      })
+
+      Process.sleep(50)
+      portfolio = Pulse.PortfolioWorker.get_portfolio("test-mc")
+      assert portfolio.updated_at == initial
+    end
+
+    test "adding a holding bumps updated_at", %{initial_updated_at: initial} do
+      Process.sleep(20)
+
+      Pulse.PortfolioWorker.update_holdings("test-mc", %{
+        "holdings" => [
+          %{"symbol" => "AAPL", "quantity" => 10, "avg_price" => 150.0, "price" => 150.0},
+          %{"symbol" => "MSFT", "quantity" => 5, "avg_price" => 300.0, "price" => 300.0}
+        ]
+      })
+
+      Process.sleep(50)
+      portfolio = Pulse.PortfolioWorker.get_portfolio("test-mc")
+      assert DateTime.compare(portfolio.updated_at, initial) == :gt
+    end
+
+    test "editing quantity bumps updated_at", %{initial_updated_at: initial} do
+      Process.sleep(20)
+
+      Pulse.PortfolioWorker.update_holdings("test-mc", %{
+        "holdings" => [
+          %{"symbol" => "AAPL", "quantity" => 15, "avg_price" => 150.0, "price" => 150.0}
+        ]
+      })
+
+      Process.sleep(50)
+      portfolio = Pulse.PortfolioWorker.get_portfolio("test-mc")
+      assert DateTime.compare(portfolio.updated_at, initial) == :gt
+    end
+
+    test "__updated_at override (restore path) preserves the historical timestamp" do
+      preserved = ~U[2026-01-01 12:00:00Z]
+
+      Pulse.PortfolioWorker.update_holdings("test-mc", %{
+        "holdings" => [
+          %{"symbol" => "AAPL", "quantity" => 99, "avg_price" => 999.0, "price" => 200.0}
+        ],
+        "__updated_at" => preserved
+      })
+
+      Process.sleep(50)
+      portfolio = Pulse.PortfolioWorker.get_portfolio("test-mc")
+      assert portfolio.updated_at == preserved
+    end
+  end
 end