defmodule Microwaveprop.Workers.NexradWorkerTest do
  use Microwaveprop.DataCase, async: false
  use Oban.Testing, repo: Microwaveprop.Repo

  alias Microwaveprop.Radio.Contact
  alias Microwaveprop.Weather.NexradClient
  alias Microwaveprop.Weather.NexradObservation
  alias Microwaveprop.Workers.NexradWorker

  # Build a minimal valid indexed-color PNG (20x20, all-zero pixels).
  # The worker's PNG decoder only needs:
  #   - 8-byte signature
  #   - IHDR (width, height, bit_depth=8, color_type=3)
  #   - one or more IDAT chunks (zlib-compressed filtered scanlines)
  #   - IEND
  # CRCs are read but not validated. Pixel value 0 = no echo everywhere, so
  # extract_box returns pixel_count: 0 for every point. That's fine: these
  # tests characterize the worker (filtering, upsert, error handling), not
  # the PNG decoder (covered in NexradClientTest).
  defp minimal_png(width \\ 20, height \\ 20) do
    signature = <<137, 80, 78, 71, 13, 10, 26, 10>>
    ihdr_data = <<width::32, height::32, 8, 3, 0, 0, 0>>
    ihdr_chunk = <<byte_size(ihdr_data)::32, "IHDR", ihdr_data::binary, 0::32>>

    # Each scanline: filter byte (0 = None) + width pixel bytes (all 0).
    raw = for _ <- 1..height, into: <<>>, do: <<0, 0::size(width)-unit(8)>>
    compressed = :zlib.compress(raw)
    idat_chunk = <<byte_size(compressed)::32, "IDAT", compressed::binary, 0::32>>

    iend_chunk = <<0::32, "IEND", 0::32>>

    signature <> ihdr_chunk <> idat_chunk <> iend_chunk
  end

  defp stub_png_success do
    png = minimal_png()

    Req.Test.stub(NexradClient, fn conn ->
      Plug.Conn.send_resp(conn, 200, png)
    end)
  end

  defp insert_contact!(attrs) do
    defaults = %{
      station1: "W5XD",
      station2: "K5TR",
      mode: "CW",
      band: Decimal.new("10000")
    }

    %Contact{}
    |> Contact.changeset(Map.merge(defaults, attrs))
    |> Repo.insert!()
  end

  describe "perform/1" do
    test "fetches one n0q frame and upserts one observation per unique snapped point" do
      stub_png_success()

      # Frame at 14:00 UTC. Two contacts inside the +/-30 min window,
      # at two distinct positions (snapped to 3-decimal precision).
      insert_contact!(%{
        qso_timestamp: ~U[2022-08-20 14:10:00Z],
        pos1: %{"lat" => 32.9, "lon" => -97.0}
      })

      insert_contact!(%{
        qso_timestamp: ~U[2022-08-20 13:45:00Z],
        pos1: %{"lat" => 33.5, "lon" => -96.5}
      })

      args = %{
        "year" => 2022,
        "month" => 8,
        "day" => 20,
        "hour" => 14,
        "minute" => 0
      }

      assert :ok = NexradWorker.perform(%Oban.Job{args: args})

      rows = Repo.all(NexradObservation)
      assert length(rows) == 2

      coords = rows |> Enum.map(&{&1.lat, &1.lon}) |> Enum.sort()
      assert coords == [{32.9, -97.0}, {33.5, -96.5}]

      for row <- rows do
        assert DateTime.compare(row.observed_at, ~U[2022-08-20 14:00:00Z]) == :eq
        assert row.pixel_count == 0
        assert row.mean_reflectivity_dbz == 0.0
        assert row.max_reflectivity_dbz == 0.0
        assert row.texture_variance == 0.0
      end
    end

    test "re-running the same job upserts in place (no duplicates, updated fields persist)" do
      stub_png_success()

      insert_contact!(%{
        qso_timestamp: ~U[2022-08-20 14:00:00Z],
        pos1: %{"lat" => 32.9, "lon" => -97.0}
      })

      args = %{
        "year" => 2022,
        "month" => 8,
        "day" => 20,
        "hour" => 14,
        "minute" => 0
      }

      # First run inserts.
      assert :ok = NexradWorker.perform(%Oban.Job{args: args})
      assert [first] = Repo.all(NexradObservation)

      # Seed a stale value on the existing row so we can prove the
      # second run overwrites it via the ON CONFLICT clause.
      Repo.update_all(NexradObservation, set: [mean_reflectivity_dbz: 42.0, pixel_count: 999])

      # Second run: same (lat, lon, observed_at) => upsert on the unique
      # index, not a duplicate insert.
      assert :ok = NexradWorker.perform(%Oban.Job{args: args})

      assert [second] = Repo.all(NexradObservation)
      # Unique index kept us at one row.
      assert second.id == first.id
      # :replace_all_except [:id, :inserted_at] overwrote the stale values.
      assert second.mean_reflectivity_dbz == 0.0
      assert second.pixel_count == 0
      # inserted_at preserved, updated_at refreshed.
      assert DateTime.compare(second.inserted_at, first.inserted_at) == :eq
    end

    test "skips contacts outside the +/- 30 minute window around the frame timestamp" do
      stub_png_success()

      # Frame at 14:00. Window is [13:30, 14:30].
      # In-window contact:
      insert_contact!(%{
        qso_timestamp: ~U[2022-08-20 14:20:00Z],
        pos1: %{"lat" => 32.9, "lon" => -97.0}
      })

      # Out-of-window (too early):
      insert_contact!(%{
        qso_timestamp: ~U[2022-08-20 13:00:00Z],
        pos1: %{"lat" => 40.0, "lon" => -80.0}
      })

      # Out-of-window (too late):
      insert_contact!(%{
        qso_timestamp: ~U[2022-08-20 15:00:00Z],
        pos1: %{"lat" => 41.0, "lon" => -81.0}
      })

      # In-window but pos1 is nil — the query filters it out.
      insert_contact!(%{
        qso_timestamp: ~U[2022-08-20 14:15:00Z],
        pos1: nil
      })

      args = %{"year" => 2022, "month" => 8, "day" => 20, "hour" => 14, "minute" => 0}

      assert :ok = NexradWorker.perform(%Oban.Job{args: args})

      rows = Repo.all(NexradObservation)
      assert length(rows) == 1
      assert hd(rows).lat == 32.9
      assert hd(rows).lon == -97.0
    end

    test "returns {:error, _} and inserts nothing when upstream returns 404" do
      insert_contact!(%{
        qso_timestamp: ~U[2022-08-20 14:00:00Z],
        pos1: %{"lat" => 32.9, "lon" => -97.0}
      })

      Req.Test.stub(NexradClient, fn conn ->
        Plug.Conn.send_resp(conn, 404, "not found")
      end)

      args = %{"year" => 2022, "month" => 8, "day" => 20, "hour" => 14, "minute" => 0}

      assert {:error, reason} = NexradWorker.perform(%Oban.Job{args: args})
      assert reason =~ "HTTP 404"
      assert Repo.aggregate(NexradObservation, :count, :id) == 0
    end

    test "returns {:error, _} and inserts nothing when the PNG body is garbage" do
      # A 200 response with bytes that fail the PNG signature match. The
      # client's decode_png_to_pixels rescues the MatchError and returns
      # {:error, "PNG decode failed: ..."}; the worker surfaces that.
      insert_contact!(%{
        qso_timestamp: ~U[2022-08-20 14:00:00Z],
        pos1: %{"lat" => 32.9, "lon" => -97.0}
      })

      Req.Test.stub(NexradClient, fn conn ->
        Plug.Conn.send_resp(conn, 200, "not a png")
      end)

      args = %{"year" => 2022, "month" => 8, "day" => 20, "hour" => 14, "minute" => 0}

      assert {:error, reason} = NexradWorker.perform(%Oban.Job{args: args})
      assert reason =~ "PNG decode failed"
      assert Repo.aggregate(NexradObservation, :count, :id) == 0
    end

    test "returns :ok without contacting upstream when no contacts fall in the window" do
      # Stub that fails loudly if touched.
      Req.Test.stub(NexradClient, fn _conn ->
        raise "NexradClient should not be contacted when POI list is empty"
      end)

      args = %{"year" => 2022, "month" => 8, "day" => 20, "hour" => 14, "minute" => 0}

      assert :ok = NexradWorker.perform(%Oban.Job{args: args})
      assert Repo.aggregate(NexradObservation, :count, :id) == 0
    end

    test "defaults the minute arg to 0 when omitted" do
      stub_png_success()

      insert_contact!(%{
        qso_timestamp: ~U[2022-08-20 14:05:00Z],
        pos1: %{"lat" => 32.9, "lon" => -97.0}
      })

      # No "minute" key — the worker Map.gets it with default 0.
      args = %{"year" => 2022, "month" => 8, "day" => 20, "hour" => 14}

      assert :ok = NexradWorker.perform(%Oban.Job{args: args})

      assert [row] = Repo.all(NexradObservation)
      assert DateTime.compare(row.observed_at, ~U[2022-08-20 14:00:00Z]) == :eq
    end

    test "deduplicates points_of_interest when multiple contacts share a snapped coordinate" do
      stub_png_success()

      # Two contacts at coordinates that snap to the same 3-decimal point.
      insert_contact!(%{
        qso_timestamp: ~U[2022-08-20 14:10:00Z],
        pos1: %{"lat" => 32.9001, "lon" => -97.0002}
      })

      insert_contact!(%{
        qso_timestamp: ~U[2022-08-20 14:20:00Z],
        pos1: %{"lat" => 32.9004, "lon" => -97.0001}
      })

      args = %{"year" => 2022, "month" => 8, "day" => 20, "hour" => 14, "minute" => 0}

      assert :ok = NexradWorker.perform(%Oban.Job{args: args})

      # Both snap to (32.900, -97.000) → one row, not two.
      assert [row] = Repo.all(NexradObservation)
      assert row.lat == 32.9
      assert row.lon == -97.0
    end
  end

  describe "unique constraint" do
    test "duplicate enqueues collapse via Oban unique on {year, month, day, hour, minute}" do
      args = %{
        "year" => 2022,
        "month" => 8,
        "day" => 20,
        "hour" => 14,
        "minute" => 0
      }

      Oban.Testing.with_testing_mode(:manual, fn ->
        {:ok, job1} = Oban.insert(NexradWorker.new(args))
        {:ok, job2} = Oban.insert(NexradWorker.new(args))

        # Second insert hits the unique constraint; Oban returns the
        # existing job instead of inserting a new one.
        assert job1.id == job2.id
        assert Repo.aggregate(Oban.Job, :count, :id) == 1
      end)
    end
  end
end