Portmeirion.IdentifyController V3

identify_controller.ex

defp where_clause(query, params) do
  # Get just the credentials params from the full params - can I use a struct for that?
  # Turn that into a key value list
  # Pass to a where_fragment method that matched on list length
  # Return fragment of appropriate size
  allowed_params = ~w(login_id facebook_id device_id prism_id)

  key_values = params
  |> Enum.filter(fn({key, _}) -> Enum.member?(allowed_params, key) end)
  |> Enum.map(fn({key, value}) -> [String.to_existing_atom(key), cast_param(key, value)] end)
  |> Enum.sort # Ensure device_id is always first if present
  |> List.flatten

  where_fragment(query, key_values)
end

defp where_fragment(query, [:device_id, v1]), do: from [u, d] in query, where: fragment("? = ?", d.device_id, ^v1)
defp where_fragment(query, [k1, v1]), do: from u in query, where: fragment("? = ?", field(u, ^k1), ^v1)
defp where_fragment(query, [:device_id, v1, k2, v2]) do
  from [u, d] in query, where: fragment("? = ? OR ? = ?", d.device_id, ^v1, field(u, ^k2), ^v2)
end
defp where_fragment(query, [k1, v1, k2, v2]) do
  from u in query, where: fragment("? = ? OR ? = ?", field(u, ^k1), ^v1, field(u, ^k2), ^v2)
end
defp where_fragment(query, [:device_id, v1, k2, v2, k3, v3]) do
  from [u, d] in query, where: fragment("? = ? OR ? = ? OR ? = ?", d.device_id, ^v1, field(u, ^k2), ^v2, field(u, ^k3), ^v3)
end
defp where_fragment(query, [k1, v1, k2, v2, k3, v3]) do
  from u in query, where: fragment("? = ? OR ? = ? OR ? = ?", field(u, ^k1), ^v1, field(u, ^k2), ^v2, field(u, ^k3), ^v3)
end
defp where_fragment(query, [:device_id, v1, k2, v2, k3, v3, k4, v4]) do
  from [u, d] in query, where: fragment("? = ? OR ? = ? OR ? = ? OR ? = ?", d.device_id, ^v1, field(u, ^k2), ^v2, field(u, ^k3), ^v3, field(u, ^k4), ^v4)
end