soft_bank

defmodule SoftBank.Amount do
  @moduledoc """
  An Amount represents the individual debit or credit for a given account and is
  part of a balanced entry.
  """

  use Ecto.Schema

  import Ecto.Changeset
  import Ecto.Query, only: [from: 1, from: 2]
  alias SoftBank.Entry
  alias SoftBank.Account


  schema "softbank_amounts" do
    field :amount, SoftBank.Note.Ecto.Type
    field :type, :string
    field :currency, :string

    belongs_to :entry, Entry
    belongs_to :account, Account

    timestamps
  end

  @params ~w(amount type)a
  @required_fields ~w()a

  @amount_types ["credit", "debit"]

  @doc """
  Creates an amount changeset associated with a `SoftBank.Entry` and `SoftBank.Account`.
  A type ("credit" or "debit"), as well as, an amount greater than 0 must be specified.
  """
  def changeset(model, params \\ %{}) do
    model
    |> cast(params, @params)
    |> Ecto.Changeset.assoc_constraint([:entry, :account])
    |> validate_required([:amount, :type])
    |> validate_number(:amount, greater_than_or_equal_to: 0)
    |> validate_inclusion(:type, @amount_types)
  end

  @doc false
  def for_entry(query, entry) do
    from c in query,
    join: p in assoc(c, :entry),
    where: p.id == ^entry.id
  end

  @doc false
  def for_account(query, account) do
    from c in query,
    join: p in assoc(c, :account),
    where: p.id == ^account.id
  end

  @doc false
  def sum_type(query, type) do
    from c in query,
    where: c.type == ^type,
    select: sum(c.amount)
  end

  @doc false
  def dated(query, %{from_date: from_date, to_date: to_date}) do
    from c in query,
    join: p in assoc(c, :entry),
    where: p.date >= ^from_date,
    where: p.date <= ^to_date
  end

  @doc false
  def dated(query, %{from_date: from_date}) do
    from c in query,
    join: p in assoc(c, :entry),
    where: p.date >= ^from_date
  end

  @doc false
  def dated(query, %{to_date: to_date}) do
    from c in query,
    join: p in assoc(c, :entry),
    where: p.date <= ^to_date
  end

  def note(amount) do
    currency = Application.get_env(:soft_bank, :default_currency)
    if currency do
      new(amount, currency)
    else
      raise ArgumentError, "to use Amount.new/1 you must set a default currency in your application config."
    end
  end

  def new(int, currency) do

  end

#  def note(int, currency) when is_integer(int),
#      do: %SoftBank.Note{amount: int, currency: Currency.to_atom(currency)}

end