defmodule Ash.Type.Decimal do
@constraints [
max: [
type: {:custom, __MODULE__, :decimal, []},
doc: "Enforces a maximum on the value"
],
min: [
type: {:custom, __MODULE__, :decimal, []},
doc: "Enforces a minimum on the value"
]
]
@moduledoc """
Represents a decimal.
A builtin type that can be referenced via `:decimal`
### Constraints
#{Ash.OptionsHelpers.docs(@constraints)}
"""
use Ash.Type
@impl true
def generator(constraints) do
StreamData.float(Keyword.take(constraints, [:min, :max]))
|> StreamData.map(&Decimal.from_float/1)
end
@impl true
def storage_type, do: :decimal
@impl true
def constraints, do: @constraints
@doc false
def decimal(value) do
case cast_input(value, []) do
{:ok, decimal} ->
{:ok, decimal}
:error ->
{:error, "cannot be casted to decimal"}
end
end
@impl true
def apply_constraints(nil, _), do: :ok
def apply_constraints(value, constraints) do
errors =
Enum.reduce(constraints, [], fn
{:max, max}, errors ->
if Decimal.compare(value, max) == :gt do
[[message: "must be less than or equal to %{max}", max: max] | errors]
else
errors
end
{:min, min}, errors ->
if Decimal.compare(value, min) == :lt do
[[message: "must be more than or equal to %{min}", min: min] | errors]
else
errors
end
end)
case errors do
[] -> :ok
errors -> {:error, errors}
end
end
@impl true
def cast_input(value, _) when is_binary(value) do
case Decimal.parse(value) do
{decimal, ""} ->
{:ok, decimal}
_ ->
:error
end
end
@impl true
def cast_input(value, _) do
Ecto.Type.cast(:decimal, value)
end
@impl true
def cast_stored(value, _) when is_binary(value) do
case Decimal.parse(value) do
{decimal, ""} ->
{:ok, decimal}
_ ->
:error
end
end
@impl true
def cast_stored(nil, _), do: {:ok, nil}
def cast_stored(value, _) do
Ecto.Type.load(:decimal, value)
end
@impl true
@spec dump_to_native(any, any) :: :error | {:ok, any}
def dump_to_native(nil, _), do: {:ok, nil}
def dump_to_native(value, _) do
Ecto.Type.dump(:decimal, value)
end
end