module Phlex::Helpers

def __append_token__(tokens, token)
	case token
		when nil then nil
		when String then tokens << token
		when Symbol then tokens << token.name
		when Array then tokens.concat(token)
		else raise ArgumentError,
			"Conditional classes must be Symbols, Strings, or Arrays of Symbols or Strings."
	end
end

def classes(*tokens, **conditional_tokens)
	tokens = self.tokens(*tokens, **conditional_tokens)
	if tokens.empty?
		{}
	else
		{ class: tokens }
	end
end

def mix(*args)
	args.each_with_object({}) do |object, result|
		result.merge!(object) do |_key, old, new|
			next new if old.nil?
			case new
			when Hash
				old.is_a?(Hash) ? mix(old, new) : new
			when Array
				case old
				when Array then old + new
				when Set then old.to_a + new
				when Hash then new
				else
					[old] + new
				end
			when Set
				case old
				when Set then old + new
				when Array then old + new.to_a
				when Hash then new
				else
					new + [old]
				end
			when String
				old.is_a?(String) ? "#{old} #{new}" : old + old.class[new]
			when nil
				old
			else
				new
			end
		end
		result.transform_keys! do |key|
			key.end_with?("!") ? key.name.chop.to_sym : key
		end
	end
end

def tokens(*tokens, **conditional_tokens)
	conditional_tokens.each do |condition, token|
		truthy = case condition
			when Symbol then send(condition)
			when Proc then condition.call
			else raise ArgumentError, "The class condition must be a Symbol or a Proc."
		end
		if truthy
			case token
				when Hash then __append_token__(tokens, token[:then])
				else __append_token__(tokens, token)
			end
		else
			case token
				when Hash then __append_token__(tokens, token[:else])
			end
		end
	end
	tokens = tokens.select(&:itself).join(" ")
	tokens.strip!
	tokens.gsub!(/\s+/, " ")
	tokens
end