module:set_global();

local audit_log_limit = module:get_option_number("audit_log_limit", 10000);
local cleanup_after = module:get_option_string("audit_log_expires_after", "2w");

local attach_ips = module:get_option_boolean("audit_log_ips", true);
local attach_ipv4_prefix = module:get_option_number("audit_log_ipv4_prefix", nil);
local attach_ipv6_prefix = module:get_option_number("audit_log_ipv6_prefix", nil);

local have_geoip, geoip = pcall(require, "geoip.country");
local attach_location = have_geoip and module:get_option_boolean("audit_log_location", true);

local geoip4_country, geoip6_country;
if have_geoip and attach_location then
	geoip4_country = geoip.open(module:get_option_string("geoip_ipv4_country", "/usr/share/GeoIP/GeoIP.dat"));
	geoip6_country = geoip.open(module:get_option_string("geoip_ipv6_country", "/usr/share/GeoIP/GeoIPv6.dat"));
end

local time_now = os.time;
local ip = require "util.ip";
local st = require "util.stanza";
local moduleapi = require "core.moduleapi";

local host_wide_user = "@";

local stores = {};

local function get_store(self, host)
	local store = rawget(self, host);
	if store then
		return store
	end
	store = module:context(host):open_store("audit", "archive");
	rawset(self, host, store);
	return store;
end

setmetatable(stores, { __index = get_store });

local function get_ip_network(ip_addr)
	local _ip = ip.new_ip(ip_addr);
	local proto = _ip.proto;
	local network;
	if proto == "IPv4" and attach_ipv4_prefix then
		network = ip.truncate(_ip, attach_ipv4_prefix).normal.."/"..attach_ipv4_prefix;
	elseif proto == "IPv6" and attach_ipv6_prefix then
		network = ip.truncate(_ip, attach_ipv6_prefix).normal.."/"..attach_ipv6_prefix;
	end
	return network;
end

local function session_extra(session)
	local attr = {
		xmlns = "xmpp:prosody.im/audit",
	};
	if session.id then
		attr.id = session.id;
	end
	if session.type then
		attr.type = session.type;
	end
	local stanza = st.stanza("session", attr);
	if attach_ips and session.ip then
		local remote_ip, network = session.ip;
		if attach_ipv4_prefix or attach_ipv6_prefix then
			network = get_ip_network(remote_ip);
		end
		stanza:text_tag("remote-ip", network or remote_ip);
	end
	if attach_location and session.ip then
		local remote_ip = ip.new(session.ip);
		local geoip_country = ip.proto == "IPv6" and geoip6_country or geoip4_country;
		stanza:tag("location", {
			country = geoip_country:query_by_addr(remote_ip.normal);
		}):up();
	end
	if session.client_id then
		stanza:text_tag("client", session.client_id);
	end
	return stanza
end

local function audit(host, user, source, event_type, extra)
	if not host or host == "*" then
		error("cannot log audit events for global");
	end
	local user_key = user or host_wide_user;

	local attr = {
		["source"] = source,
		["type"] = event_type,
	};
	if user_key ~= host_wide_user then
		attr.user = user_key;
	end
	local stanza = st.stanza("audit-event", attr);
	if extra then
		if extra.session then
			local child = session_extra(extra.session);
			if child then
				stanza:add_child(child);
			end
		end
		if extra.custom then
			for _, child in ipairs(extra.custom) do
				if not st.is_stanza(child) then
					error("all extra.custom items must be stanzas")
				end
				stanza:add_child(child);
			end
		end
	end

	local id, err = stores[host]:append(nil, nil, stanza, extra and extra.timestamp or time_now(), user_key);
	if err then
		module:log("error", "failed to persist audit event: %s", err);
		return
	else
		module:log("debug", "persisted audit event %s as %s", stanza:top_tag(), id);
	end
end

function moduleapi.audit(module, user, event_type, extra)
	audit(module.host, user, "mod_" .. module:get_name(), event_type, extra);
end

function module.command(_arg)
	local arg = require "util.argparse".parse(_arg, { value_params = { "limit", "user" } });
	local host = arg[1];
	if not host then
		print("EE: Please supply the host for which you want to show events");
		return 1;
	elseif not prosody.hosts[host] then
		print("EE: Unknown host: "..host);
		return 1;
	end

	require "core.storagemanager".initialize_host(host);
	local store = stores[host];
	local c = 0;

	local results, err = store:find(nil, {
		with = arg.user;
		limit = arg.limit and tonumber(arg.limit) or nil;
		reverse = true;
	})
	if not results then
		print("EE: Failed to query audit log: "..tostring(err));
		return 1;
	end

	local colspec = {
		{ title = "Date", key = "when", width = 19, mapper = function (when) return os.date("%Y-%m-%d %R:%S", when); end };
		{ title = "Source", key = "source", width = "2p" };
		{ title = "Event", key = "event_type", width = "2p" };
	};

	if arg.show_user ~= false and (not arg.global or arg.show_user) then
		table.insert(colspec, {
			title = "User", key = "username", width = "2p",
			mapper = function (user)
				if user == "@" then return ""; end
				if user:sub(-#host-1, -1) == ("@"..host) then
					return (user:gsub("@.+$", ""));
				end
			end;
		});
	end
	if arg.show_ip ~= false and (not arg.global and attach_ips or arg.show_ip) then
		table.insert(colspec, {
			title = "IP", key = "ip", width = "2p";
		});
	end
	if arg.show_location ~= false and (not arg.global and attach_location or arg.show_location) then
		table.insert(colspec, {
			title = "Location", key = "country", width = 2;
		});
	end

	local row, width = require "util.human.io".table(colspec);

	print(string.rep("-", width));
	print(row());
	print(string.rep("-", width));
	for _, entry, when, user in results do
		c = c + 1;
		print(row({
			when = when;
			source = entry.attr.source;
			event_type = entry.attr.type:gsub("%-", " ");
			username = user;
			ip = entry:get_child_text("remote-ip");
			location = entry:find("location@country");
		}));
	end
	print(string.rep("-", width));
	print(("%d records displayed"):format(c));
end