wanderer/test/integration/map/map_pool_crash_integration_test.exs

defmodule WandererApp.Map.MapPoolCrashIntegrationTest do
  @moduledoc """
  Integration tests for MapPool crash recovery.

  These tests verify end-to-end crash recovery behavior including:
  - MapPool GenServer crashes and restarts
  - State recovery from ETS
  - Registry and cache consistency after recovery
  - Telemetry events during recovery
  - Multi-pool scenarios

  Note: Many tests are skipped as they require full map infrastructure
  (database, Server.Impl, map data, etc.) to be set up.
  """

  use WandererApp.IntegrationCase, async: false

  import Mox

  setup :verify_on_exit!

  alias WandererApp.Map.{MapPool, MapPoolDynamicSupervisor, MapPoolState}

  @cache :map_pool_cache
  @registry :map_pool_registry
  @unique_registry :unique_map_pool_registry
  @ets_table :map_pool_state_table

  setup do
    # Clean up any existing test data
    cleanup_test_data()

    # Check if required infrastructure is running
    supervisor_running? = Process.whereis(MapPoolDynamicSupervisor) != nil

    ets_exists? =
      try do
        :ets.info(@ets_table) != :undefined
      rescue
        _ -> false
      end

    on_exit(fn ->
      cleanup_test_data()
    end)

    {:ok, supervisor_running: supervisor_running?, ets_exists: ets_exists?}
  end

  defp cleanup_test_data do
    # Clean up test caches
    WandererApp.Cache.delete("started_maps")
    Cachex.clear(@cache)

    # Clean up ETS entries
    if :ets.whereis(@ets_table) != :undefined do
      :ets.match_delete(@ets_table, {:"$1", :"$2", :"$3"})
    end
  end

  defp find_pool_pid(uuid) do
    pool_name = Module.concat(MapPool, uuid)

    case Registry.lookup(@unique_registry, pool_name) do
      [{pid, _value}] -> {:ok, pid}
      [] -> {:error, :not_found}
    end
  end

  describe "End-to-end crash recovery" do
    @tag :skip
    @tag :integration
    test "MapPool recovers all maps after abnormal crash" do
      # This test would:
      # 1. Start a MapPool with test maps via MapPoolDynamicSupervisor
      # 2. Verify maps are running and state is in ETS
      # 3. Simulate crash using GenServer.call(pool_pid, :error)
      # 4. Wait for supervisor to restart the pool
      # 5. Verify all maps are recovered
      # 6. Verify Registry, Cache, and ETS are consistent

      # Requires:
      # - Test map data in database
      # - Server.Impl.start_map to work with test data
      # - Full supervision tree running

      :ok
    end

    @tag :skip
    @tag :integration
    test "MapPool preserves ETS state on abnormal termination" do
      # This test would:
      # 1. Start a MapPool with maps
      # 2. Force crash
      # 3. Verify ETS state is preserved (not deleted)
      # 4. Verify new pool instance recovers from ETS

      :ok
    end

    @tag :skip
    @tag :integration
    test "MapPool cleans ETS state on graceful shutdown" do
      # This test would:
      # 1. Start a MapPool with maps
      # 2. Gracefully stop the pool (GenServer.cast(pool_pid, :stop))
      # 3. Verify ETS state is deleted
      # 4. Verify new pool starts with empty state

      :ok
    end
  end

  describe "Multi-pool crash scenarios" do
    @tag :skip
    @tag :integration
    test "multiple pools crash and recover independently" do
      # This test would:
      # 1. Start multiple MapPool instances with different maps
      # 2. Crash one pool
      # 3. Verify only that pool recovers, others unaffected
      # 4. Verify no cross-pool state corruption

      :ok
    end

    @tag :skip
    @tag :integration
    test "concurrent pool crashes don't corrupt recovery state" do
      # This test would:
      # 1. Start multiple pools
      # 2. Crash multiple pools simultaneously
      # 3. Verify all pools recover correctly
      # 4. Verify no ETS corruption or race conditions

      :ok
    end
  end

  describe "State consistency after recovery" do
    @tag :skip
    @tag :integration
    test "Registry state matches recovered state" do
      # This test would verify that after recovery:
      # - unique_registry has correct map_ids for pool UUID
      # - map_pool_registry has correct pool UUID entry
      # - All map_ids in Registry match ETS state

      :ok
    end

    @tag :skip
    @tag :integration
    test "Cache state matches recovered state" do
      # This test would verify that after recovery:
      # - map_pool_cache has correct map_id -> uuid mappings
      # - started_maps cache includes all recovered maps
      # - No orphaned cache entries

      :ok
    end

    @tag :skip
    @tag :integration
    test "Map servers are actually running after recovery" do
      # This test would:
      # 1. Recover maps from crash
      # 2. Verify each map's GenServer is actually running
      # 3. Verify maps respond to requests
      # 4. Verify map state is correct

      :ok
    end
  end

  describe "Recovery failure handling" do
    @tag :skip
    @tag :integration
    test "recovery continues when individual map fails to start" do
      # This test would:
      # 1. Save state with maps [1, 2, 3] to ETS
      # 2. Delete map 2 from database
      # 3. Trigger recovery
      # 4. Verify maps 1 and 3 recover successfully
      # 5. Verify map 2 failure is logged and telemetry emitted
      # 6. Verify pool continues with maps [1, 3]

      :ok
    end

    @tag :skip
    @tag :integration
    test "recovery handles maps already running in different pool" do
      # This test would simulate a race condition where:
      # 1. Pool A crashes with map X
      # 2. Before recovery, map X is started in Pool B
      # 3. Pool A tries to recover map X
      # 4. Verify conflict is detected and handled gracefully

      :ok
    end

    @tag :skip
    @tag :integration
    test "recovery handles corrupted ETS state" do
      # This test would:
      # 1. Manually corrupt ETS state (invalid map IDs, wrong types, etc.)
      # 2. Trigger recovery
      # 3. Verify pool handles corruption gracefully
      # 4. Verify telemetry emitted for failures
      # 5. Verify pool continues with valid maps only

      :ok
    end
  end

  describe "Telemetry during recovery" do
    test "telemetry events emitted in correct order", %{ets_exists: ets_exists?} do
      if ets_exists? do
        test_pid = self()
        events = []

        # Attach handlers for all recovery events
        :telemetry.attach_many(
          "test-recovery-events",
          [
            [:wanderer_app, :map_pool, :recovery, :start],
            [:wanderer_app, :map_pool, :recovery, :complete],
            [:wanderer_app, :map_pool, :recovery, :map_failed]
          ],
          fn event, measurements, metadata, _config ->
            send(test_pid, {:telemetry_event, event, measurements, metadata})
          end,
          nil
        )

        uuid = "test-pool-#{:rand.uniform(1_000_000)}"

        # Simulate recovery sequence
        # 1. Start event
        :telemetry.execute(
          [:wanderer_app, :map_pool, :recovery, :start],
          %{recovered_map_count: 3, total_map_count: 3},
          %{pool_uuid: uuid}
        )

        # 2. Complete event (in real recovery, this comes after all maps start)
        :telemetry.execute(
          [:wanderer_app, :map_pool, :recovery, :complete],
          %{recovered_count: 3, failed_count: 0, duration_ms: 100},
          %{pool_uuid: uuid}
        )

        # Verify we received both events
        assert_receive {:telemetry_event, [:wanderer_app, :map_pool, :recovery, :start], _, _},
                       500

        assert_receive {:telemetry_event, [:wanderer_app, :map_pool, :recovery, :complete], _, _},
                       500

        :telemetry.detach("test-recovery-events")
      else
        :ok
      end
    end

    @tag :skip
    @tag :integration
    test "telemetry includes accurate recovery statistics" do
      # This test would verify that:
      # - recovered_map_count matches actual recovered maps
      # - failed_count matches actual failed maps
      # - duration_ms is accurate
      # - All metadata is correct

      :ok
    end
  end

  describe "Interaction with Reconciler" do
    @tag :skip
    @tag :integration
    test "Reconciler doesn't interfere with crash recovery" do
      # This test would:
      # 1. Crash a pool with maps
      # 2. Trigger both recovery and reconciliation
      # 3. Verify they don't conflict
      # 4. Verify final state is consistent

      :ok
    end

    @tag :skip
    @tag :integration
    test "Reconciler detects failed recovery" do
      # This test would:
      # 1. Crash a pool with map X
      # 2. Make recovery fail for map X
      # 3. Run reconciler
      # 4. Verify reconciler detects and potentially fixes the issue

      :ok
    end
  end

  describe "Edge cases" do
    @tag :skip
    @tag :integration
    test "recovery during pool at capacity" do
      # This test would:
      # 1. Create pool with 19 maps
      # 2. Crash pool while adding 20th map
      # 3. Verify recovery handles capacity limit
      # 4. Verify all maps start or overflow is handled

      :ok
    end

    @tag :skip
    @tag :integration
    test "recovery with empty map list" do
      # This test would:
      # 1. Crash pool with empty map_ids
      # 2. Verify recovery completes successfully
      # 3. Verify pool starts with no maps

      :ok
    end

    @tag :skip
    @tag :integration
    test "multiple crashes in quick succession" do
      # This test would:
      # 1. Crash pool
      # 2. Immediately crash again during recovery
      # 3. Verify supervisor's max_restarts is respected
      # 4. Verify state remains consistent

      :ok
    end
  end

  describe "Performance under load" do
    @tag :slow
    @tag :skip
    @tag :integration
    test "recovery completes within 2 seconds for 20 maps" do
      # This test would:
      # 1. Create pool with 20 maps (pool limit)
      # 2. Crash pool
      # 3. Measure time to full recovery
      # 4. Assert recovery < 2 seconds

      :ok
    end

    @tag :slow
    @tag :skip
    @tag :integration
    test "recovery doesn't block other pools" do
      # This test would:
      # 1. Start multiple pools
      # 2. Crash one pool with many maps
      # 3. Verify other pools continue to operate normally during recovery
      # 4. Measure performance impact on healthy pools

      :ok
    end
  end

  describe "Supervisor interaction" do
    test "ETS table survives individual pool crash", %{ets_exists: ets_exists?} do
      if ets_exists? do
        # Verify ETS table is owned by supervisor, not individual pools
        table_info = :ets.info(@ets_table)
        owner_pid = Keyword.get(table_info, :owner)

        # Owner should be alive and be the supervisor or a system process
        assert Process.alive?(owner_pid)

        # Verify we can still access the table
        uuid = "test-pool-#{:rand.uniform(1_000_000)}"
        MapPoolState.save_pool_state(uuid, [1, 2, 3])
        assert {:ok, [1, 2, 3]} = MapPoolState.get_pool_state(uuid)
      else
        :ok
      end
    end

    @tag :skip
    @tag :integration
    test "supervisor restarts pool after crash" do
      # This test would:
      # 1. Start a pool via DynamicSupervisor
      # 2. Crash the pool
      # 3. Verify supervisor restarts it
      # 4. Verify new PID is different from old PID
      # 5. Verify pool is functional after restart

      :ok
    end
  end

  describe "Database consistency" do
    @tag :skip
    @tag :integration
    test "recovered maps load latest state from database" do
      # This test would:
      # 1. Start maps with initial state
      # 2. Modify map state in database
      # 3. Crash pool
      # 4. Verify recovered maps have latest database state

      :ok
    end

    @tag :skip
    @tag :integration
    test "recovery uses MapState for map configuration" do
      # This test would:
      # 1. Verify recovery calls WandererApp.Map.get_map_state!/1
      # 2. Verify state comes from database MapState table
      # 3. Verify maps start with correct configuration

      :ok
    end
  end

  describe "Real-world scenarios" do
    @tag :skip
    @tag :integration
    test "recovery after OOM crash" do
      # This test would simulate recovery after out-of-memory crash:
      # 1. Start pool with maps
      # 2. Simulate OOM condition
      # 3. Verify recovery completes successfully
      # 4. Verify no memory leaks after recovery

      :ok
    end

    @tag :skip
    @tag :integration
    test "recovery after network partition" do
      # This test would simulate recovery after network issues:
      # 1. Start maps with external dependencies
      # 2. Simulate network partition
      # 3. Crash pool
      # 4. Verify recovery handles network errors gracefully

      :ok
    end

    @tag :skip
    @tag :integration
    test "recovery preserves user sessions" do
      # This test would:
      # 1. Start maps with active user sessions
      # 2. Crash pool
      # 3. Verify users can continue after recovery
      # 4. Verify presence tracking works after recovery

      :ok
    end
  end
end