class RestClient::Request

def self.execute(args)
	new(args).execute
end

def default_headers
	{ :accept => 'application/xml' }
end

def error_message(res)
	"HTTP code #{res.code}: #{res.body}"
end

def execute
	execute_inner
rescue Redirect => e
	@url = e.message
	execute
end

def execute_inner
	uri = parse_url(url)
	transmit uri, net_http_class(method).new(uri.request_uri, make_headers(headers)), payload
end

def initialize(args)
	@method = args[:method] or raise ArgumentError, "must pass :method"
	@url = args[:url] or raise ArgumentError, "must pass :url"
	@headers = args[:headers] || {}
	@payload = process_payload(args[:payload])
	@user = args[:user]
	@password = args[:password]
end

def make_headers(user_headers)
	final = {}
	merged = default_headers.merge(user_headers)
	merged.keys.each do |key|
		final[key.to_s.gsub(/_/, '-').capitalize] = merged[key]
	end
	final
end

def net_http_class(method)
	Object.module_eval "Net::HTTP::#{method.to_s.capitalize}"
end

def parse_url(url)
	url = "http://#{url}" unless url.match(/^http/)
	URI.parse(url)
end

def process_payload(p=nil)
	unless p.is_a?(Hash)
		p
	else
		@headers[:content_type] = 'application/x-www-form-urlencoded'
		p.keys.map { |k| "#{k}=#{URI.escape(p[k].to_s)}" }.join("&")
	end
end

def process_result(res)
	if %w(200 201 202).include? res.code
		res.body
	elsif %w(301 302 303).include? res.code
		raise Redirect, res.header['Location']
	elsif res.code == "401"
		raise Unauthorized
	else
		raise RequestFailed, error_message(res)
	end
end

def setup_credentials(req)
	req.basic_auth(user, password) if user
end

def transmit(uri, req, payload)
	setup_credentials(req)
	Net::HTTP.start(uri.host, uri.port) do |http|
		process_result http.request(req, payload || "")
	end
end