defmodule Tipo do

	@doc """
	Returns an item indicating the type of the given value

	## Examples

	iex> Tipo.typeof(34)
	:number

	iex> Tipo.typeof(self())
	:pid
	"""
	def typeof(value) do
		typeof_atom(value)
	end

	# boolean type checkers
	def nil?(v), do: is_nil(v)
	def number?(v), do: is_number(v)
	def integer?(v), do: is_integer(v)
	def float?(v), do: is_float(v)
	def bitstring?(v), do: is_bitstring(v)
	def atom?(v), do: is_atom(v)
	def function?(v), do: is_function(v)
	def boolean?(v), do: is_boolean(v)
	def binary?(v), do: is_binary(v)
	def list?(v), do: is_list(v)
	def map?(v), do: is_map(v)
	def tuple?(v), do: is_tuple(v)
	def pid?(v), do: is_pid(v)
	def port?(v), do: is_port(v)
	def reference?(v), do: is_reference(v)

	# keywords: lists of two element tuples of the form {atom(), any()}
	def keyword?(v), do: Keyword.keyword?(v)

	def regex?(v)
	def regex?(%Regex{}), do: true
	def regex?(_), do: false


	def module?(v) do
		try do
			:erlang.get_module_info(v)
			true
		rescue
			ArgumentError -> false
		end
	end

	def struct?(v) do
		if is_map(v) do
			ret = try do
				v.__struct__ # attempt to access hidden key
				true
			rescue KeyError -> false
			end
			ret
		else
			false
		end
	end

	# valid or printable binaries are `strings
	def string?(v) do
		is_binary(v) and (String.printable?(v) or String.valid?(v))
	end


	defp typeof_atom(v) do
		cond do
			is_nil(v) 		-> nil
			is_number(v) 	-> :number
			regex?(v) 		-> :regex 			# must come before atom
			module?(v) 		-> :module
			is_boolean(v) 	-> :boolean 	# must come before atom b/c booleans are atoms
			is_atom(v) 		-> :atom
			string?(v) 		-> :string
			is_binary(v) 	-> :binary
			is_bitstring(v) -> :bitstring
			is_function(v) 	-> :function


			keyword?(v) 	-> :keyword 		# must come before tuple and list, catches all tuples that match the keyword spec
			is_list(v) 		-> :list
			is_tuple(v) 	-> :tuple
			struct?(v) 		-> :struct
			is_map(v) 		-> :map

			is_pid(v) 		-> :pid
			is_port(v) 		-> :port
			is_reference(v) -> :reference

			true -> :non_primitive
		end
	end
end