defmodule Microwaveprop.Propagation.GridTaskEnqueuerTest do
  use Microwaveprop.DataCase, async: true

  import Ecto.Query

  alias Microwaveprop.Propagation.GridTaskEnqueuer
  alias Microwaveprop.Repo

  test "seeds one row per fh=1..18" do
    run_time = ~U[2026-04-19 15:00:00Z]
    assert {:ok, 18} = GridTaskEnqueuer.seed(run_time)

    rows =
      Repo.all(
        from(g in "grid_tasks",
          where: g.run_time == ^run_time,
          select: %{forecast_hour: g.forecast_hour, status: g.status, valid_time: g.valid_time}
        )
      )

    assert length(rows) == 18
    assert rows |> Enum.map(& &1.forecast_hour) |> Enum.sort() == Enum.to_list(1..18)
    assert Enum.all?(rows, &(&1.status == "queued"))

    # Raw schemaless selects return NaiveDateTime; compare against the
    # equivalent naive form.
    expected_naive = DateTime.to_naive(run_time)

    Enum.each(rows, fn r ->
      expected = NaiveDateTime.add(expected_naive, r.forecast_hour * 3600, :second)
      assert NaiveDateTime.compare(r.valid_time, expected) == :eq
    end)
  end

  test "is idempotent: reseeding the same run_time inserts nothing" do
    run_time = ~U[2026-04-19 16:00:00Z]
    assert {:ok, 18} = GridTaskEnqueuer.seed(run_time)
    assert {:ok, 0} = GridTaskEnqueuer.seed(run_time)

    count = Repo.one(from(g in "grid_tasks", where: g.run_time == ^run_time, select: count()))

    assert count == 18
  end

  test "never emits a row for fh=0 — Elixir keeps that chain step" do
    run_time = ~U[2026-04-19 17:00:00Z]
    assert {:ok, 18} = GridTaskEnqueuer.seed(run_time)

    f0_count = Repo.one(from(g in "grid_tasks", where: g.run_time == ^run_time and g.forecast_hour == 0, select: count()))

    assert f0_count == 0
  end

  describe "reclaim_stale_running/1" do
    test "flips stale-running rows back to queued and clears claimed_at" do
      now = DateTime.truncate(DateTime.utc_now(), :second)
      stale = DateTime.add(now, -30 * 60, :second)

      insert_task(%{
        run_time: ~U[2026-04-19 20:00:00Z],
        forecast_hour: 5,
        valid_time: ~U[2026-04-20 01:00:00Z],
        status: "running",
        attempt: 1,
        claimed_at: stale
      })

      assert %{requeued: 1, failed: 0} = GridTaskEnqueuer.reclaim_stale_running()

      row =
        Repo.one!(
          from(t in "grid_tasks",
            where: t.run_time == ^~U[2026-04-19 20:00:00Z] and t.forecast_hour == 5,
            select: %{status: t.status, claimed_at: t.claimed_at, attempt: t.attempt}
          )
        )

      assert row.status == "queued"
      assert is_nil(row.claimed_at)
      # attempt is NOT incremented — claim_next does that on re-claim.
      assert row.attempt == 1
    end

    test "leaves recently-claimed running rows untouched" do
      now = DateTime.truncate(DateTime.utc_now(), :second)
      fresh = DateTime.add(now, -60, :second)

      insert_task(%{
        run_time: ~U[2026-04-19 21:00:00Z],
        forecast_hour: 6,
        valid_time: ~U[2026-04-20 03:00:00Z],
        status: "running",
        attempt: 1,
        claimed_at: fresh
      })

      assert %{requeued: 0, failed: 0} = GridTaskEnqueuer.reclaim_stale_running()

      row =
        Repo.one!(
          from(t in "grid_tasks",
            where: t.run_time == ^~U[2026-04-19 21:00:00Z] and t.forecast_hour == 6,
            select: %{status: t.status}
          )
        )

      assert row.status == "running"
    end

    test "flips stale rows past max attempts to failed" do
      now = DateTime.truncate(DateTime.utc_now(), :second)
      stale = DateTime.add(now, -30 * 60, :second)

      insert_task(%{
        run_time: ~U[2026-04-19 22:00:00Z],
        forecast_hour: 7,
        valid_time: ~U[2026-04-20 05:00:00Z],
        status: "running",
        attempt: 5,
        claimed_at: stale
      })

      assert %{requeued: 0, failed: 1} = GridTaskEnqueuer.reclaim_stale_running()

      row =
        Repo.one!(
          from(t in "grid_tasks",
            where: t.run_time == ^~U[2026-04-19 22:00:00Z] and t.forecast_hour == 7,
            select: %{status: t.status, error: t.error, claimed_at: t.claimed_at}
          )
        )

      assert row.status == "failed"
      assert is_nil(row.claimed_at)
      assert row.error =~ "reclaim"
    end

    test "does not touch queued or done rows even if claimed_at is ancient" do
      now = DateTime.truncate(DateTime.utc_now(), :second)
      stale = DateTime.add(now, -30 * 60, :second)

      insert_task(%{
        run_time: ~U[2026-04-19 23:00:00Z],
        forecast_hour: 8,
        valid_time: ~U[2026-04-20 07:00:00Z],
        status: "done",
        attempt: 1,
        claimed_at: stale,
        completed_at: stale
      })

      assert %{requeued: 0, failed: 0} = GridTaskEnqueuer.reclaim_stale_running()
    end
  end

  defp insert_task(attrs) do
    now = DateTime.truncate(DateTime.utc_now(), :microsecond)

    row =
      Map.merge(
        %{
          id: Ecto.UUID.bingenerate(),
          status: "queued",
          attempt: 0,
          kind: "forecast",
          claimed_at: nil,
          completed_at: nil,
          error: nil,
          inserted_at: now,
          updated_at: now
        },
        attrs
      )

    {1, _} = Repo.insert_all("grid_tasks", [row])
  end
end