facebook

defmodule Facebook.Graph do
	require Logger

	alias Facebook.Config

	@moduledoc """
	HTTP Wrapper for the Graph API using hackney.
	"""

	@doc """
	Start the API
	"""
	@spec start_link :: :ok
	def start_link do
		:ignore
	end

	@type path :: String.t
	@type response :: {:json, HashDict.t} | {:body, String.t}
	@type options :: list
	@type params :: list
	@type method :: :get | :post | :put | :head
	@type url :: String.t
	@type payload :: binary

	@doc """
	HTTP GET using a path
	"""
	@spec get(path) :: response
	def get(path) do
		get(path, [], [])
	end

	@doc """
	HTTP GET using path and params
	"""
	@spec get(path, params) :: response
	def get(path, params) do
		get(path, params, [])
	end

	@doc """
	HTTP GET using path, params and options
	"""
	@spec get(path, params, options) :: response
	def get(path, params, options) do
		url = :hackney_url.make_url(Config.graph_url, path, params)
		request(:get, url, options)
	end

	@spec request(method, url, options) :: response
	defp request(method, url, options) do
		request(method, url, <<>>, options)
	end

	@spec request(method, url, payload, options) :: response
	defp request(method, url, payload, options) do
		headers = []
		Logger.info fn ->
			"[#{method}] #{url} #{inspect headers} #{inspect payload}"
		end
		case :hackney.request(method, url, headers, payload, options) do
			{:ok, _status_code, _headers, client_ref} ->
				{:ok, body} = :hackney.body(client_ref)
				Logger.info fn ->
					"body: #{inspect body}"
				end
				case JSON.decode(body) do
					{:ok, data} ->
						{:json, data}
					_ ->
						{:body, body}
				end
			error ->
				Logger.error fn ->
					"error: #{inspect error}"
				end
				error
		end
	end
end