defmodule Meta.Billing.Partner do
  alias Meta.Accounts.User
  alias Meta.Billing.Partner
  alias Meta.Odoo
  alias Meta.Repo

  import Ecto.Changeset
  use Ecto.Schema

  @address_fields [:display_name, :street, :city, :zip]

  # Note: Odoo stores partner's country under 'country_id'. We do not support
  # editing it at the moment.

  embedded_schema do
    field :name, :string
    field :display_name, :string
    field :email, :string
    field :street, :string
    field :city, :string
    field :zip, :string
    field :country, :string
  end

  def changeset(%Partner{} = partner, attrs) do
    partner |> cast(attrs, @address_fields)
  end

  def apply(changeset) do
    # Check if changeset is valid.
    state = changeset |> Ecto.Changeset.apply_action(:update)
    case state do
      {:ok, partner} ->
        changes = partner
                  |> Map.from_struct
                  |> Enum.filter(fn {k,_v} -> k in @address_fields end)
                  |> Enum.map(fn {k, v} -> {to_string(k), v} end)
                  |> Enum.into(%{})

        # Propagate to Odoo
        Odoo.query([
          "res.partner",
          "write",
          [[partner.id], changes]
        ])
      {:error, _} -> state
    end
  end

  def get(id) do
    fields = ["id", "name", "email", "country_id", "display_name"] ++ @address_fields
    result = Odoo.query([
      "res.partner",
      "search_read",
      [[["id", "=", id]]],
      %{"fields" => fields}
    ])

    format_fields = fn p ->
      case p do
        {k, false} when k in @address_fields -> {k, ""}
        {:country_id, false} -> {:country, ""}
        {:country_id, [_id, str]} -> {:country, str}
        _ -> p
      end
    end

    case result do
      {:ok, [raw]} ->
        args = raw
               |> Enum.map(fn {k, v} -> {String.to_atom(k), v} end)
               |> Enum.map(format_fields)
        struct(Partner, args)
      _ -> nil
    end
  end

  def create(name, email) do
    Odoo.query([
      "res.partner",
      "create",
      [%{"name" => name, "email" => email}]
    ])
  end

  def get_or_create(%User{} = user) do
    case user.partner_id do
      nil ->
        {:ok, id} = create(user.username, user.email)
        {:ok, updated} = user |> change(%{partner_id: id}) |> Repo.update()
        get_or_create(updated)
      id -> get(id)
    end
  end
end