local array = require"util.array";

local st = require"util.stanza";

local tos_version = assert(module:get_option("tos_version"), "tos_version must be set")

local status_storage;

if prosody.process_type == "prosody" or prosody.shutdown then

	status_storage = module:open_store("tos_status", "keyval")

end

local documents = array{};

local function validate_doc(doc)

	if not doc.title or not doc.sources or #doc.sources < 1 then

		return false, "document needs to have a title and at least one source"

	end

	for _, source in ipairs(doc.sources) do

		if not source.url or not source.type then

			return false, "document " .. doc.title .. " has a source without url or type"

		end

	end

	return true, doc

end

for _, doc in ipairs(assert(module:get_option("tos_documents"), "tos_documents option is required")) do

	local ok, doc_or_err = validate_doc(doc)

	if not ok then

		error("invalid TOS document: "..doc_or_err)

	end

	documents:push(doc);

end

local function send_tos_push(session)

	local to = session.username .. "@" .. session.host .. "/" .. session.resource;

	local push = st.message({

		type = "headline",

		to = to,

	}, "In order to continue to use the service, you have to accept the current version of the Terms of Service.");

	local tos = push:tag("tos-push", { xmlns = "urn:xmpp:tos:0" }):tag("tos", { version = tos_version });

	for _, doc in ipairs(documents) do

		local doc_tag = tos:tag("document"):text_tag("title", doc.title);

		for _, source in ipairs(doc.sources) do

			doc_tag:tag("source", { url = source.url,  type = source.type }):up();

		end

		doc_tag:up();

	end

	tos:up():up();

	module:send(push);

end

local function check_tos(event)

	local user = event.origin.username

	assert(user)

	local tos_status = status_storage:get(user)

	if tos_status and tos_status.version and tos_status.version == tos_version then

		module:log("debug", "user %s has signed the current tos", user);

		return

	end

	module:log("debug", "user %s has not signed the current tos, sending tos push", user);

	send_tos_push(event.origin)

end

local function handle_accept_tos_iq(event)

	local user = event.origin.username;

	assert(user);

	local accept = event.stanza.tags[1];

	local version = accept.attr["version"];

	module:log("debug", "user %s has accepted ToS version %s", user, version);

	if version ~= tos_version then

		local reply = st.error_reply(event.stanza, "modify", "not-allowed", "Only the most recent version of the ToS can be accepted");

		module:log("debug", "%s is not the most recent version (%s), rejecting", version, tos_version);

		event.origin.send(reply);

		return true;

	end

	status_storage:set(user, { version = tos_version });

	local reply = st.reply(event.stanza);

	event.origin.send(reply);

	return true;

end

module:hook("presence/initial", check_tos, -100);

module:hook("iq-set/bare/urn:xmpp:tos:0:accept", handle_accept_tos_iq);