local http = require "util.http";

local jid = require "util.jid";

local json = require "util.json";

local usermanager = require "core.usermanager";

local errors = require "util.error";

local tokens = module:depends("tokenauth");

local function oauth_error(err_name, err_desc)

	return errors.new({

		type = "modify";

		condition = "bad-request";

		code = err_name == "invalid_client" and 401 or 400;

		text = err_desc and (err_name..": "..err_desc) or err_name;

		context = { oauth2_response = { error = err_name, error_description = err_desc } };

	});

end

local function new_access_token(token_jid, scope, ttl)

	local token = tokens.create_jid_token(token_jid, token_jid, scope, ttl);

	return {

		token_type = "bearer";

		access_token = token;

		expires_in = ttl;

		-- TODO: include refresh_token when implemented

	};

end

local grant_type_handlers = {};

function grant_type_handlers.password(params)

	local request_jid = assert(params.username, oauth_error("invalid_request", "missing 'username' (JID)"));

	local request_password = assert(params.password, oauth_error("invalid_request", "missing 'password'"));

	local request_username, request_host, request_resource = jid.prepped_split(request_jid);

		return oauth_error("invalid_scope", "unknown scope requested");

	end

	if not (request_username and request_host) or request_host ~= module.host then

		return oauth_error("invalid_request", "invalid JID");

	end

	if usermanager.test_password(request_username, request_host, request_password) then

		local granted_jid = jid.join(request_username, request_host, request_resource);

		return json.encode(new_access_token(granted_jid, request_host, nil, nil));

	end

	return oauth_error("invalid_grant", "incorrect credentials");

end

if module:get_host_type() == "component" then

	local component_secret = assert(module:get_option_string("component_secret"), "'component_secret' is a required setting when loaded on a Component");

	function grant_type_handlers.password(params)

		local request_jid = assert(params.username, oauth_error("invalid_request", "missing 'username' (JID)"));

		local request_password = assert(params.password, oauth_error("invalid_request", "missing 'password'"));

		local request_username, request_host, request_resource = jid.prepped_split(request_jid);

		if params.scope then

			return oauth_error("invalid_scope", "unknown scope requested");

		end

		if not request_host or request_host ~= module.host then

			return oauth_error("invalid_request", "invalid JID");

		end

		if request_password == component_secret then

			local granted_jid = jid.join(request_username, request_host, request_resource);

			return json.encode(new_access_token(granted_jid, request_host, nil, nil));

		end

		return oauth_error("invalid_grant", "incorrect credentials");

	end

end

function handle_token_grant(event)

	event.response.headers.content_type = "application/json";

	local params = http.formdecode(event.request.body);

	if not params then

		return oauth_error("invalid_request");

	end

	local grant_type = params.grant_type

	local grant_handler = grant_type_handlers[grant_type];

	if not grant_handler then

		return oauth_error("unsupported_grant_type");

	end

	return grant_handler(params);

end

module:depends("http");

module:provides("http", {

	route = {

		["POST /token"] = handle_token_grant;

	};

});

local http_server = require "net.http.server";

module:hook_object_event(http_server, "http-error", function (event)

	local oauth2_response = event.error and event.error.context and event.error.context.oauth2_response;

	if not oauth2_response then

		return;

	end

	event.response.headers.content_type = "application/json";

	event.response.status_code = event.error.code or 400;

	return json.encode(oauth2_response);

end, 5);