local st = require "util.stanza";

local json = require "util.json";

local filters = { --[[ TODO what's useful? ]] };

local render = require "util.interpolation".new("%b{}", tostring, filters);

local uuid_generate = require "util.uuid".generate;

-- TODO alertmanager supports inclusion of HTTP auth and OAuth, worth looking

-- into for using instead of request IP

module:depends("http");

local pubsub_service = module:depends("pubsub").service;

local error_mapping = {

	["forbidden"] = 403;

	["item-not-found"] = 404;

	["internal-server-error"] = 500;

	["conflict"] = 409;

};

local function publish_payload(node, actor, item_id, payload)

	local post_item = st.stanza("item", { xmlns = "http://jabber.org/protocol/pubsub", id = item_id, })

		:add_child(payload);

	local ok, err = pubsub_service:publish(node, actor, item_id, post_item);

	module:log("debug", ":publish(%q, true, %q, %s) -> %q", node, item_id, payload:top_tag(), err or "");

	if not ok then

		return error_mapping[err] or 500;

	end

	return 202;

end

local node_template = module:get_option_string("alertmanager_node_template", "{path?alerts}");

function handle_POST(event, path)

	local request = event.request;

	local payload = json.decode(event.request.body);

	if type(payload) ~= "table" then return 400; end

	if payload.version ~= "4" then return 501; end

	for _, alert in ipairs(payload.alerts) do

		local item = st.stanza("alerts", {xmlns = "urn:uuid:e3bec775-c607-4e9b-9a3f-94de1316d861:v4", status=alert.status});

		for k, v in pairs(alert.annotations) do

			item:text_tag("annotation", v, { name=k });

		end

		for k, v in pairs(alert.labels) do

			item:text_tag("label", v, { name=k });

		end

		item:tag("starts", { at = alert.startsAt}):up();

		if alert.endsAt and alert.status == "resolved" then

			item:tag("ends", { at = alert.endsAt }):up();

		end

		if alert.generatorURL then

			item:tag("link", { href=alert.generatorURL }):up();

		end

		local node = render(node_template, {alert = alert, path = path, payload = payload, request = request});

		local ret = publish_payload(node, request.ip, uuid_generate(), item);

		if ret ~= 202 then

			return ret

		end

	end

	return 202;

end

local template = module:get_option_string("alertmanager_body_template", [[

*ALARM!*

Status: {status}

Starts at: {startsAt}{endsAt&

Ends at: {endsAt}}

Labels: {labels%

  {idx}: {item}}

Annotations: {annotations%

  {idx}: {item}}

]]);

module:hook("pubsub-summary/urn:uuid:e3bec775-c607-4e9b-9a3f-94de1316d861:v4", function(event)

	local payload = event.payload;

	local data = {

		status = payload.attr.status,

		firing = "firing" == payload.attr.status,

		resolved = "resolved" == payload.attr.status,

		annotations = {},

		labels = {},

		endsAt = payload:find("ends/@at"),

		startsAt = payload:find("starts/@at"),

	};

	for label in payload:childtags("label") do

		data.labels[tostring(label.attr.name)] = label:get_text();

	end

	for annotation in payload:childtags("annotation") do

		data.annotations[tostring(annotation.attr.name)] = annotation:get_text();

	end

	return render(template, data);

end);

module:provides("http", {

	route = {

		["POST /*"] = handle_POST;

		["POST"] = handle_POST;

	};

});