defmodule ExAzureKeyVault.Url do
  @moduledoc """
  Internal module for getting Azure Key Vault URL.
  """
  alias __MODULE__

  @enforce_keys [:secret_name, :vault_name]
  defstruct(
    secret_name: nil,
    vault_name: nil
  )

  @type t :: %__MODULE__{
          secret_name: String.t(),
          vault_name: String.t()
        }

  @doc """
  Creates `%ExAzureKeyVault.Url{}` struct with vault name.

  ## Examples

      iex(1)> ExAzureKeyVault.Url.new("my-secret", "my-vault")
      %ExAzureKeyVault.Url{secret_name: "my-secret", vault_name: "my-vault"}

  """
  @spec new(String.t() | nil, String.t()) :: Url.t()
  def new(secret_name, vault_name) do
    %Url{secret_name: secret_name, vault_name: vault_name}
  end

  @doc """
  Returns Azure Key Vault URL for secret management.

  ## Examples

  Passing secret version.

      iex(1)> ExAzureKeyVault.Url.new("my-secret", "my-vault") |> ExAzureKeyVault.Url.get_url("7ea98ee699b1...", "2016-10-01")
      "https://my-vault.vault.azure.net/secrets/my-secret/7ea98ee699b1...?api-version=2016-10-01"

  Ignoring secret version.

      iex(1)> ExAzureKeyVault.Url.new("my-secret", "my-vault") |> ExAzureKeyVault.Url.get_url(nil, "2016-10-01")
      "https://my-vault.vault.azure.net/secrets/my-secret?api-version=2016-10-01"

  """
  @spec get_url(Url.t(), String.t() | nil, String.t()) :: String.t()
  def get_url(%Url{} = params, version \\ nil, api_version) do
    base_url = base_secret_url(params.vault_name, params.secret_name)
    api_version_string = get_api_version_string(api_version)

    if !is_nil(version) && version != "" do
      base_url <> "/#{version}" <> api_version_string
    else
      base_url <> api_version_string
    end
  end

  @doc """
  Returns Azure Key Vault URL for get secrets.

  ## Examples

  Passing a maximum number of 10 results in a page.

      iex(1)> ExAzureKeyVault.Url.new("my-secret", "my-vault") |> ExAzureKeyVault.Url.get_secrets_url(10, "2016-10-01")
      "https://my-vault.vault.azure.net/secrets?api-version=2016-10-01&maxresults=10"

  Ignoring maximum number of results.

      iex(1)> ExAzureKeyVault.Url.new("my-secret", "my-vault") |> ExAzureKeyVault.Url.get_secrets_url(nil, "2016-10-01")
      "https://my-vault.vault.azure.net/secrets?api-version=2016-10-01"

  """
  @spec get_secrets_url(Url.t(), integer | nil, String.t()) :: String.t()
  def get_secrets_url(%Url{} = params, max_results \\ nil, api_version) do
    base_url = base_secrets_url(params.vault_name)
    api_version_string = get_api_version_string(api_version)

    if !is_nil(max_results) && max_results != "" do
      base_url <> api_version_string <> "&maxresults=#{max_results}"
    else
      base_url <> api_version_string
    end
  end

  @doc """
  Returns body for secret creation.

  ## Examples

      iex(1)> ExAzureKeyVault.Url.get_body("my-secret")
      "{\\"value\\":\\"my-secret\\"}"

  """
  @spec get_body(String.t()) :: String.t()
  def get_body(secret_value) do
    Jason.encode!(%{value: secret_value})
  end

  @spec base_secret_url(String.t(), String.t()) :: String.t()
  defp base_secret_url(vault_name, secret_name) do
    base_url(vault_name) <> "/secrets/#{secret_name}"
  end

  @spec base_secrets_url(String.t()) :: String.t()
  defp base_secrets_url(vault_name) do
    base_url(vault_name) <> "/secrets"
  end

  @spec base_url(String.t()) :: String.t()
  defp base_url(vault_name) do
    "https://#{vault_name}.vault.azure.net"
  end

  @spec get_api_version_string(String.t()) :: String.t()
  defp get_api_version_string(api_version) do
    "?api-version=#{api_version}"
  end
end