local json = require "prosody.util.json";

local _ENV = nil;

local function oauthbearer(self, message)

	if not message then

		return "failure", "malformed-request";

	end

	if message == "\001" then

		return "failure", "not-authorized";

	end

	-- gs2-header kvsep *kvpair kvsep

	local gs2_header, kvpairs = message:match("^(n,[^,]*,)\001(.+)\001$");

	if not gs2_header then

		return "failure", "malformed-request";

	end

	local gs2_authzid = gs2_header:match("^[^,]*,a=([^,]*),$");

	-- key "=" value kvsep

	local auth_header;

	for k, v in kvpairs:gmatch("([a-zA-Z]+)=([\033-\126 \009\r\n]*)\001") do

		if k == "auth" then

			auth_header = v;

			break;

		end

	end

	if not auth_header then

		return "failure", "malformed-request";

	end

	local token = auth_header:match("^Bearer (.+)$");

	local username, state, token_info = self.profile.oauthbearer(self, token, self.realm, gs2_authzid);

	if state == false then

		return "failure", "account-disabled";

	elseif state == nil or not username then

		-- For token-level errors, RFC 7628 demands use of a JSON-encoded

		-- challenge response upon failure. We relay additional info from

		-- the auth backend if available.

		return "challenge", json.encode({

			status = token_info and token_info.status or "invalid_token";

			scope = token_info and token_info.scope or nil;

			["openid-configuration"] = token_info and token_info.oidc_discovery_url or nil;

		});

	end

	self.username = username;

	self.token_info = token_info;

	return "success";

end

local function init(registerMechanism)

	registerMechanism("OAUTHBEARER", {"oauthbearer"}, oauthbearer);

end

return {

	init = init;

}