paysafe

defmodule Paysafe.Config do
  @moduledoc """
  Configuration for the Paysafe client.

  ## Options

    * `:username` - (required) API username from the Paysafe Business Portal.
    * `:password` - (required) API password from the Paysafe Business Portal.
    * `:environment` - `:test` or `:production`. Defaults to `:test`.
    * `:account_id` - Default account ID for requests. Can be overridden per-call.
    * `:base_url_override` - Override the computed base URL entirely. Primarily
      intended for testing (pointing at a local mock server) or routing through
      a corporate proxy. When set, this replaces the `:environment`-derived
      base URL for every API (Payments, Scheduler, Applications, etc).
    * `:http_options` - Options passed directly to `Req`. Defaults to `[]`.
    * `:timeout` - Request timeout in milliseconds. Defaults to `30_000`.
    * `:recv_timeout` - Receive timeout in milliseconds. Defaults to `30_000`.
    * `:max_retries` - Maximum number of retries on transient failures. Defaults to `3`.
    * `:retry_delay` - Base delay in ms between retries (exponential backoff). Defaults to `500`.
    * `:rate_limit` - `{scale_ms, limit}` tuple for token bucket rate limiting. Defaults to `{1_000, 100}`.
    * `:telemetry_prefix` - Telemetry event prefix. Defaults to `[:paysafe]`.

  ## Example

      config :paysafe,
        username: "1001062690",
        password: "B-qa2-0-...",
        environment: :test,
        account_id: "1009688230"

  """

  @base_urls %{
    test: "https://api.test.paysafe.com",
    production: "https://api.paysafe.com"
  }

  @payments_path "/paymenthub/v1"
  @scheduler_path "/subscriptionsplans/v1"
  @applications_path "/merchant/v1"
  @customer_vault_path "/customervault/v1"
  @fx_rates_path "/fxrates/v1"
  @direct_debit_path "/directdebit/v1"
  @cards_path "/cardpayments/v1"
  @bank_account_validator_path "/bankaccountvalidator/v1"
  @customer_identification_path "/customeridentification/v1"

  @schema NimbleOptions.new!(
            username: [
              type: :string,
              required: true,
              doc: "API username from the Paysafe Business Portal."
            ],
            password: [
              type: :string,
              required: true,
              doc: "API password from the Paysafe Business Portal."
            ],
            environment: [
              type: {:in, [:test, :production]},
              default: :test,
              doc: "The environment to connect to."
            ],
            account_id: [
              type: {:or, [:string, nil]},
              default: nil,
              doc: "Default account ID. Can be overridden per-call."
            ],
            base_url_override: [
              type: {:or, [:string, nil]},
              default: nil,
              doc: "Override the computed base URL entirely (testing/proxy use cases)."
            ],
            timeout: [
              type: :pos_integer,
              default: 30_000,
              doc: "Request timeout in milliseconds."
            ],
            recv_timeout: [
              type: :pos_integer,
              default: 30_000,
              doc: "Receive timeout in milliseconds."
            ],
            max_retries: [
              type: :non_neg_integer,
              default: 3,
              doc: "Maximum number of retries on transient failures."
            ],
            retry_delay: [
              type: :pos_integer,
              default: 500,
              doc: "Base delay in ms between retries (exponential backoff)."
            ],
            rate_limit: [
              type: {:tuple, [:pos_integer, :pos_integer]},
              default: {1_000, 100},
              doc: "{scale_ms, limit} for token bucket rate limiting."
            ],
            telemetry_prefix: [
              type: {:list, :atom},
              default: [:paysafe],
              doc: "Telemetry event prefix."
            ],
            http_options: [
              type: :keyword_list,
              default: [],
              doc: "Extra options passed to Req."
            ]
          )

  @type t :: %__MODULE__{
          username: String.t(),
          password: String.t(),
          environment: :test | :production,
          account_id: String.t() | nil,
          base_url_override: String.t() | nil,
          timeout: pos_integer(),
          recv_timeout: pos_integer(),
          max_retries: non_neg_integer(),
          retry_delay: pos_integer(),
          rate_limit: {pos_integer(), pos_integer()},
          telemetry_prefix: [atom()],
          http_options: keyword()
        }

  defstruct [
    :username,
    :password,
    :account_id,
    :base_url_override,
    environment: :test,
    timeout: 30_000,
    recv_timeout: 30_000,
    max_retries: 3,
    retry_delay: 500,
    rate_limit: {1_000, 100},
    telemetry_prefix: [:paysafe],
    http_options: []
  ]

  @doc """
  Build and validate a `Config` struct from a keyword list or map.

  Raises `NimbleOptions.ValidationError` on invalid input.
  """
  @spec new!(keyword() | map()) :: t()
  def new!(opts) when is_map(opts), do: opts |> Map.to_list() |> new!()

  def new!(opts) do
    validated = NimbleOptions.validate!(opts, @schema)
    struct!(__MODULE__, validated)
  end

  @doc """
  Load config from the application environment and merge with any overrides.
  """
  @spec from_env!(keyword()) :: t()
  def from_env!(overrides \\ []) do
    env_opts = Application.get_all_env(:paysafe)
    Keyword.merge(env_opts, overrides) |> new!()
  end

  @doc """
  Returns the full base URL for the configured environment, or
  `base_url_override` if set.
  """
  @spec base_url(t()) :: String.t()
  def base_url(%__MODULE__{base_url_override: override}) when is_binary(override), do: override
  def base_url(%__MODULE__{environment: env}), do: Map.fetch!(@base_urls, env)

  @doc """
  Returns the Payments API base URL.
  """
  @spec payments_url(t()) :: String.t()
  def payments_url(config), do: base_url(config) <> @payments_path

  @doc """
  Returns the Payment Scheduler API base URL.
  """
  @spec scheduler_url(t()) :: String.t()
  def scheduler_url(config), do: base_url(config) <> @scheduler_path

  @doc """
  Returns the Applications (Onboarding) API base URL.
  """
  @spec applications_url(t()) :: String.t()
  def applications_url(config), do: base_url(config) <> @applications_path

  @doc """
  Returns the Customer Vault API base URL.
  """
  @spec customer_vault_url(t()) :: String.t()
  def customer_vault_url(config), do: base_url(config) <> @customer_vault_path

  @doc """
  Returns the FX Rates API base URL.
  """
  @spec fx_rates_url(t()) :: String.t()
  def fx_rates_url(config), do: base_url(config) <> @fx_rates_path

  @doc """
  Returns the Direct Debit API base URL.
  """
  @spec direct_debit_url(t()) :: String.t()
  def direct_debit_url(config), do: base_url(config) <> @direct_debit_path

  @doc """
  Returns the Cards API base URL.
  """
  @spec cards_url(t()) :: String.t()
  def cards_url(config), do: base_url(config) <> @cards_path

  @doc """
  Returns the Bank Account Validator API base URL (also used by the Interac
  Verification Service, which lives under `/verifiedme` on the same base).
  """
  @spec bank_account_validator_url(t()) :: String.t()
  def bank_account_validator_url(config), do: base_url(config) <> @bank_account_validator_path

  @doc """
  Returns the Customer Identification (KYC) API base URL.
  """
  @spec customer_identification_url(t()) :: String.t()
  def customer_identification_url(config), do: base_url(config) <> @customer_identification_path

  @doc """
  Computes the Base64-encoded Basic Auth header value.
  """
  @spec auth_header(t()) :: String.t()
  def auth_header(%__MODULE__{username: u, password: p}) do
    "Basic " <> Base.encode64("#{u}:#{p}")
  end

  @doc """
  Returns the NimbleOptions schema for external inspection.
  """
  @spec schema() :: NimbleOptions.t()
  def schema, do: @schema
end