defmodule Plaid.Utils do
  @moduledoc """
  Utility functions.
  """

  @doc """
  Handles Plaid response and maps to the correct data structure.
  """
  @spec handle_resp({:ok, HTTPoison.Response.t()} | {:error, HTTPoison.Error.t()}, atom) ::
          {:ok, any} | {:error, Plaid.Error.t() | HTTPoison.Error.t()}
  def handle_resp({:ok, %HTTPoison.Response{status_code: code} = resp}, schema)
      when code in 200..201 do
    {:ok, map_body(resp.body, schema)}
  end

  def handle_resp({:ok, %HTTPoison.Response{} = resp}, _schema) do
    {:error, Poison.Decode.decode(resp.body, as: %Plaid.Error{})}
  end

  def handle_resp({:error, %HTTPoison.Error{} = error}, _schema) do
    {:error, error}
  end

  defp map_body(body, :categories) do
    Poison.Decode.decode(body,
      as: %Plaid.Categories{
        categories: [
          %Plaid.Categories.Category{}
        ]
      }
    )
  end

  defp map_body(body, :institutions) do
    Poison.Decode.decode(body,
      as: %Plaid.Institutions{
        institutions: [
          %Plaid.Institutions.Institution{
            credentials: [%Plaid.Institutions.Institution.Credentials{}]
          }
        ]
      }
    )
  end

  defp map_body(%{"institution" => institution} = body, :institution) do
    new_body = body |> Map.take(["request_id"]) |> Map.merge(institution)

    Poison.Decode.decode(new_body,
      as: %Plaid.Institutions.Institution{
        credentials: [%Plaid.Institutions.Institution.Credentials{}]
      }
    )
  end

  defp map_body(body, :transactions) do
    Poison.Decode.decode(body,
      as: %Plaid.Transactions{
        accounts: [
          %Plaid.Accounts.Account{
            balances: %Plaid.Accounts.Account.Balance{}
          }
        ],
        transactions: [
          %Plaid.Transactions.Transaction{
            location: %Plaid.Transactions.Transaction.Location{},
            payment_meta: %Plaid.Transactions.Transaction.PaymentMeta{}
          }
        ],
        item: %Plaid.Item{}
      }
    )
  end

  defp map_body(body, :accounts) do
    Poison.Decode.decode(body,
      as: %Plaid.Accounts{
        accounts: [
          %Plaid.Accounts.Account{balances: %Plaid.Accounts.Account.Balance{}}
        ],
        item: %Plaid.Item{}
      }
    )
  end

  defp map_body(body, :auth) do
    Poison.Decode.decode(body,
      as: %Plaid.Auth{
        numbers: %Plaid.Auth.Numbers{
          ach: [%Plaid.Auth.Numbers.ACH{}]
        },
        item: %Plaid.Item{},
        accounts: [
          %Plaid.Accounts.Account{
            balances: %Plaid.Accounts.Account.Balance{}
          }
        ]
      }
    )
  end

  defp map_body(%{"item" => item} = body, :item) do
    new_body = body |> Map.take(["request_id"]) |> Map.merge(item)
    Poison.Decode.decode(new_body, as: %Plaid.Item{})
  end

  defp map_body(%{"new_access_token" => _} = body, :item) do
    body
    |> Map.take(["new_access_token", "request_id"])
    |> Enum.reduce(%{}, fn {k, v}, acc ->
      Map.put(acc, String.to_atom(k), v)
    end)
  end

  defp map_body(%{"access_token" => _} = body, :item) do
    body
    |> Map.take(["access_token", "item_id", "request_id"])
    |> Enum.reduce(%{}, fn {k, v}, acc ->
      Map.put(acc, String.to_atom(k), v)
    end)
  end

  defp map_body(%{"public_token" => _} = body, :item) do
    body
    |> Map.take(["public_token", "expiration", "request_id"])
    |> Enum.reduce(%{}, fn {k, v}, acc ->
      Map.put(acc, String.to_atom(k), v)
    end)
  end

  defp map_body(%{"deleted" => _} = body, :item) do
    body
    |> Map.take(["deleted", "request_id"])
    |> Enum.reduce(%{}, fn {k, v}, acc ->
      Map.put(acc, String.to_atom(k), v)
    end)
  end

  defp map_body(%{"processor_token" => _} = body, :item) do
    body
    |> Map.take(["processor_token", "request_id"])
    |> Enum.reduce(%{}, fn {k, v}, acc ->
      Map.put(acc, String.to_atom(k), v)
    end)
  end
end