defmodule Microwaveprop.Repo.Migrations.CreateBeaconMeasurements do
  use Ecto.Migration

  def change do
    create table(:beacon_measurements, primary_key: false) do
      add :id, :binary_id, primary_key: true

      add :beacon_id, references(:beacons, type: :binary_id, on_delete: :delete_all), null: false

      add :monitor_id, references(:beacon_monitors, type: :binary_id, on_delete: :delete_all),
        null: false

      add :measured_at, :utc_datetime, null: false
      add :frequency_hz, :bigint, null: false
      add :integration_s, :integer, null: false
      add :passband_hz, :float, null: false
      add :gain_db, :float, null: false

      add :noise_floor_dbfs, :float, null: false
      add :signal_peak_dbfs, :float, null: false
      add :signal_avg_dbfs, :float, null: false
      add :snr_peak_db, :float, null: false
      add :snr_avg_db, :float, null: false
      add :signal_active_fraction, :float, null: false

      add :propmonitor_version, :string, null: false

      timestamps(type: :utc_datetime)
    end

    # Time-series query patterns: latest-N for one monitor, latest-N for one
    # beacon, and joint monitor+beacon trends.
    create index(:beacon_measurements, [:monitor_id, "measured_at DESC"])
    create index(:beacon_measurements, [:beacon_id, "measured_at DESC"])

    # Idempotency: the client retries on 5xx with the same `measured_at`. A
    # given monitor cannot legitimately produce two distinct measurements for
    # the same beacon at the same start-of-window timestamp.
    create unique_index(:beacon_measurements, [:monitor_id, :beacon_id, :measured_at],
             name: :beacon_measurements_monitor_beacon_measured_at_idx
           )
  end
end