# AUTO-GENERATED FILE - DO NOT EDIT
# This file was automatically generated by the XDK build tool.
# Any manual changes will be overwritten on the next generation.
defmodule Xdk do
  @moduledoc """
  Auto-generated X API client.

  Uses Finch for HTTP transport and supports bearer token authentication.
  """

  @version "0.1.0"

  defstruct [
    :base_url,
    :finch,
    :auth,
    :headers,
    :request_opts
  ]

  @type auth ::
          nil | {:bearer, String.t()} | {:oauth2, map()} | {:oauth1, OAuther.Credentials.t()}

  @type t :: %__MODULE__{
          base_url: String.t(),
          finch: atom() | nil,
          auth: auth(),
          headers: [{String.t(), String.t()}],
          request_opts: keyword()
        }

  @spec new(keyword()) :: t()
  def new(opts \\ []) do
    defaults = Application.get_env(:xdk, :default_config, [])
    opts = Keyword.merge(defaults, opts)

    %__MODULE__{
      base_url: Keyword.get(opts, :base_url, "https://api.x.com"),
      finch: Keyword.get(opts, :finch),
      auth: resolve_auth(opts),
      headers: Keyword.get(opts, :headers, []),
      request_opts: Keyword.get(opts, :request_opts, [])
    }
  end

  @doc """
  Returns a child spec for a Finch pool suitable for the X API.

  Add to your supervision tree:

      children = [
        Xdk.child_spec(name: MyApp.XFinch),
        ...
      ]

  Then: `Xdk.new(finch: MyApp.XFinch, auth: {:bearer, token})`
  """
  @spec child_spec(keyword()) :: Supervisor.child_spec()
  def child_spec(opts) do
    name = Keyword.fetch!(opts, :name)
    pool_opts = Keyword.get(opts, :pools, %{})
    Finch.child_spec(name: name, pools: pool_opts)
  end

  @spec request(t(), atom(), String.t(), keyword()) ::
          {:ok, term()} | {:error, Xdk.Errors.error()}
  def request(%__MODULE__{} = client, method, path, opts \\ []) do
    params = Keyword.get(opts, :params, %{})
    query = Keyword.get(opts, :query, [])
    json = Keyword.get(opts, :json)
    raw_body = Keyword.get(opts, :body)

    url = client.base_url <> interpolate_path(path, params)

    url =
      case query do
        [] -> url
        _ -> url <> "?" <> Xdk.Query.encode(query)
      end

    headers = build_headers(client, method, url, opts)

    {encoded_body, headers} =
      cond do
        json != nil ->
          case Jason.encode(json) do
            {:ok, bin} -> {bin, [{"content-type", "application/json"} | headers]}
            {:error, err} -> throw({:encode_error, err})
          end

        raw_body != nil ->
          {raw_body, headers}

        true ->
          {nil, headers}
      end

    finch = require_finch!(client)

    method
    |> Finch.build(url, headers, encoded_body)
    |> Finch.request(finch, client.request_opts)
    |> handle_response()
  catch
    {:encode_error, err} ->
      {:error, Xdk.Errors.DecodeError.exception(error: err, raw_body: nil)}
  end

  @doc false
  def require_finch!(%__MODULE__{finch: nil}) do
    raise ArgumentError, """
    Xdk requires a Finch pool name.

    Start Finch in your application supervision tree:

        children = [
          {Finch, name: MyApp.Finch}
        ]

    Then create a client:

        client = Xdk.new(finch: MyApp.Finch, auth: {:bearer, token})

    Or set a default via application config:

        config :xdk, :default_config, finch: MyApp.Finch
    """
  end

  def require_finch!(%__MODULE__{finch: finch}), do: finch

  @doc false
  def build_finch_request(%__MODULE__{} = client, method, path, opts) do
    params = Keyword.get(opts, :params, %{})
    query = Keyword.get(opts, :query, [])

    url = client.base_url <> interpolate_path(path, params)

    url =
      case query do
        [] -> url
        _ -> url <> "?" <> Xdk.Query.encode(query)
      end

    headers = build_headers(client, method, url, opts)

    Finch.build(method, url, headers)
  end

  defp interpolate_path(path, params) do
    Enum.reduce(params, path, fn {k, v}, acc ->
      String.replace(acc, "{#{k}}", URI.encode_www_form(to_string(v)))
    end)
  end

  defp resolve_auth(opts) do
    case Keyword.get(opts, :auth) do
      nil ->
        case Keyword.get(opts, :bearer) do
          nil -> nil
          token -> {:bearer, token}
        end

      auth ->
        auth
    end
  end

  defp build_headers(%__MODULE__{} = client, method, url, opts) do
    per_request_auth = Keyword.get(opts, :auth, client.auth)

    [{"user-agent", "xdk-elixir/#{@version}"}]
    |> Kernel.++(client.headers)
    |> Kernel.++(Keyword.get(opts, :headers, []))
    |> Kernel.++(auth_headers(per_request_auth, method, url))
  end

  defp auth_headers(nil, _method, _url), do: []
  defp auth_headers({:bearer, token}, _method, _url), do: [{"authorization", "Bearer #{token}"}]

  defp auth_headers({:oauth2, %{access_token: token}}, _method, _url),
    do: [{"authorization", "Bearer #{token}"}]

  defp auth_headers({:oauth1, credentials}, method, url) do
    {uri, query_string} =
      case String.split(url, "?", parts: 2) do
        [base] -> {base, ""}
        [base, qs] -> {base, qs}
      end

    query_params =
      query_string
      |> URI.decode_query()
      |> Enum.to_list()

    signed_params = OAuther.sign(to_string(method), uri, query_params, credentials)
    {header, _params} = OAuther.header(signed_params)
    [header]
  end

  defp handle_response({:ok, %Finch.Response{status: 429, headers: headers, body: body}}) do
    decoded = try_decode_body(body, headers)
    {limit, remaining, reset, retry_after} = parse_rate_limit_headers(headers)

    {:error,
     Xdk.Errors.RateLimitError.exception(
       status: 429,
       body: decoded,
       headers: headers,
       limit: limit,
       remaining: remaining,
       reset: reset,
       retry_after_ms: retry_after
     )}
  end

  defp handle_response({:ok, %Finch.Response{status: status, body: body, headers: headers}})
       when status in 200..299 do
    case try_decode_body(body, headers) do
      {:ok, decoded} -> {:ok, decoded}
      {:error, err} -> {:error, Xdk.Errors.DecodeError.exception(error: err, raw_body: body)}
    end
  end

  defp handle_response({:ok, %Finch.Response{status: status, body: body, headers: headers}}) do
    decoded =
      case try_decode_body(body, headers) do
        {:ok, d} -> d
        _ -> body
      end

    {:error, Xdk.Errors.ApiError.exception(status: status, body: decoded, headers: headers)}
  end

  defp handle_response({:error, reason}) do
    {:error, Xdk.Errors.TransportError.exception(reason: reason)}
  end

  defp try_decode_body("", _), do: {:ok, nil}
  defp try_decode_body(nil, _), do: {:ok, nil}

  defp try_decode_body(body, headers) do
    content_type =
      Enum.find_value(headers, "", fn
        {k, v} when k in ["content-type", "Content-Type"] -> v
        _ -> nil
      end)

    if String.contains?(content_type, "application/json") do
      Jason.decode(body)
    else
      {:ok, body}
    end
  end

  defp parse_rate_limit_headers(headers) do
    get = fn name ->
      Enum.find_value(headers, fn
        {k, v} when k == name -> v
        _ -> nil
      end)
    end

    limit = parse_int(get.("x-rate-limit-limit"))
    remaining = parse_int(get.("x-rate-limit-remaining"))
    reset = parse_int(get.("x-rate-limit-reset"))

    retry_after =
      case reset do
        nil -> nil
        unix -> max(0, (unix - System.system_time(:second)) * 1000)
      end

    {limit, remaining, reset, retry_after}
  end

  defp parse_int(nil), do: nil

  defp parse_int(s) when is_binary(s) do
    case Integer.parse(s) do
      {n, _} -> n
      :error -> nil
    end
  end
end