#include <http/proxy_address.hpp>
#include <base/assert.hpp>
#include <base/types.hpp>

namespace base::http {

	asio::ip::address GetProxyAddress(asio::ip::address fallback, beast::http::request<beast::http::string_body>& req) {
#ifdef BASE_HTTP_REVERSE_PROXY_SUPPORT
		auto forwarded_for = req[
	#ifndef BASE_HTTP_CLOUDFLARE
		"X-Forwarded-For"
	#else
		"CF-Connecting-IP"
	#endif
		];

		if(forwarded_for == "") {
			// if no header was provided, just return that hop
			return fallback;
		} else {
			bsys::error_code ec;
			asio::ip::address ip;

			// X-Forwarded-For is a tokenized list, where the first element is always the client hop.
			// We only need to worry about the client hop.

			if(forwarded_for.find(',') != beast::string_view::npos) {
				ip = asio::ip::make_address(std::string_view(forwarded_for.data(), forwarded_for.find(',')), ec);
			} else {
				ip = asio::ip::make_address(std::string_view(forwarded_for.data(), forwarded_for.length()), ec);
			}

			// The X-Forwarded-For header is not controlled by user input (and should *not* be, with a properly written proxy server),
			// so if this CHECK fires, you're probably in a bad enough situation not worth continuing anyways.
			BASE_CHECK(!ec, "Invalid IP address in proxy IP header. Header: \"{}\"",
						   std::string_view(forwarded_for.data(), forwarded_for.length()));
			return ip;
		}
#else
		return fallback;
#endif
	}

} // namespace base::http