defmodule Statestores.Adapters.PostgresSnapshotAdapter do
  @moduledoc """
  Implements the behavior defined in `Statestores.Adapters.SnapshotBehaviour` for Postgres databases.
  """
  use Statestores.Adapters.SnapshotBehaviour

  use Ecto.Repo,
    otp_app: :spawn_statestores,
    adapter: Ecto.Adapters.Postgres

  alias Statestores.Schemas.{Snapshot, HistoricalSnapshot}

  def get_by_key(id), do: get_by(Snapshot, id: id)

  def get_by_key_and_revision(id, revision) do
    query = """
    SELECT *
      FROM historical_snapshots
     WHERE actor_id = #{id}
       AND revision = #{revision}
     ORDER BY inserted_at DESC, updated_at DESC
    """

    %Postgrex.Result{rows: rows} =
      Ecto.Adapters.SQL.query!(Statestores.Adapters.PostgresSnapshotAdapter, query)

    List.first(rows)
    |> to_snapshot(:historical)
    |> case do
      nil -> get_by_key(id)
      response -> response
    end
  end

  def get_all_snapshots_by_key(id) do
    query = "SELECT * FROM historical_snapshots WHERE actor_id = #{id}"

    %Postgrex.Result{rows: rows} =
      Ecto.Adapters.SQL.query!(Statestores.Adapters.PostgresSnapshotAdapter, query)

    rows
    |> Enum.map(&to_snapshot(&1, :historical))
  end

  def get_snapshots_by_interval(id, time_start, time_end) do
    query = """
    SELECT *
      FROM historical_snapshots
     WHERE actor_id = #{id}
       AND valid_from <= '#{time_end}'
       AND valid_to >= '#{time_start}'
     ORDER BY inserted_at ASC, updated_at ASC
    """

    %Postgrex.Result{rows: rows} =
      Ecto.Adapters.SQL.query!(Statestores.Adapters.PostgresSnapshotAdapter, query)

    rows
    |> Enum.map(&to_snapshot(:historical, &1))
  end

  def save(%Snapshot{} = actual_snapshot) do
    %Snapshot{}
    |> Snapshot.changeset(%{
      id: actual_snapshot.id,
      actor: actual_snapshot.actor,
      system: actual_snapshot.system,
      status: actual_snapshot.status,
      node: actual_snapshot.node,
      revision: actual_snapshot.revision || 0,
      tags: actual_snapshot.tags,
      data_type: actual_snapshot.data_type,
      data: actual_snapshot.data
    })
    |> insert_or_update(
      on_conflict: [
        set: [
          actor: actual_snapshot.actor,
          system: actual_snapshot.system,
          status: actual_snapshot.status,
          node: actual_snapshot.node,
          revision: (actual_snapshot.revision || 0) + 1,
          tags: actual_snapshot.tags,
          data_type: actual_snapshot.data_type,
          data: actual_snapshot.data,
          updated_at: DateTime.utc_now()
        ]
      ],
      conflict_target: [:id]
    )
  end

  def default_port, do: "5432"

  defp to_snapshot(row, :current) do
    data = Statestores.Vault.decrypt!(Enum.at(row, 8))

    %Snapshot{
      id: Enum.at(row, 0),
      actor: Enum.at(row, 1),
      system: Enum.at(row, 2),
      status: Enum.at(row, 3),
      node: Enum.at(row, 4),
      revision: Enum.at(row, 5),
      tags: Enum.at(row, 6),
      data_type: Enum.at(row, 7),
      data: data,
      inserted_at: Enum.at(row, 9),
      updated_at: Enum.at(row, 10)
    }
  end

  defp to_snapshot(row, :historical) do
    data = Statestores.Vault.decrypt!(Enum.at(row, 9))

    %Snapshot{
      id: Enum.at(row, 1),
      actor: Enum.at(row, 2),
      system: Enum.at(row, 3),
      status: Enum.at(row, 4),
      node: Enum.at(row, 5),
      revision: Enum.at(row, 6),
      tags: Enum.at(row, 7),
      data_type: Enum.at(row, 8),
      data: data,
      inserted_at: Enum.at(row, 12),
      updated_at: Enum.at(row, 13)
    }
  end
end