local it = require "util.iterators";

local log = require "util.logger".init("stats");

local has_pposix, pposix = pcall(require, "util.pposix");

local human;

do

	local tostring = tostring;

	local s_format = string.format;

	local m_floor = math.floor;

	local m_max = math.max;

	local prefixes = "kMGTPEZY";

	local multiplier = 1024;

	function human(num)

		num = tonumber(num) or 0;

		local m = 0;

		while num >= multiplier and m < #prefixes do

			num = num / multiplier;

			m = m + 1;

		end

		return s_format("%0."..m_max(0,3-#tostring(m_floor(num))).."f%sB",

		num, m > 0 and (prefixes:sub(m,m) .. "i") or "");

	end

end

local last_cpu_wall, last_cpu_clock;

local get_time = require "socket".gettime;

local active_sessions, active_jids = {}, {};

local stats = {

	total_users = {

		get = function () return it.count(it.keys(bare_sessions)); end

	};

	total_c2s = {

		get = function () return it.count(it.keys(full_sessions)); end

	};

	total_s2sin = {

		get = function () local i = 0; for conn,sess in next,s2s_sessions do if sess.direction == "incoming" then i = i + 1 end end return i end

	};

	total_s2sout = {

		get = function () local i = 0; for conn,sess in next,s2s_sessions do if sess.direction == "outgoing" then i = i + 1 end end return i end

	};

	total_s2s = {

		get = function () return it.count(it.keys(s2s_sessions)); end

	};

	total_component = {

		get = function ()

			local count = 0;

			for host, host_session in pairs(hosts) do

				if host_session.type == "component" then

					local c = host_session.modules.component;

					if c and c.connected then -- 0.9 only

						count = count + 1;

					end

				end

			end

			return count;

		end

	};

	up_since = {

		get = function () return prosody.start_time; end;

		tostring = function (up_since)

			return tostring(os.time()-up_since).."s";

		end;

	};

	memory_lua = {

		get = function () return math.ceil(collectgarbage("count")*1024); end;

		tostring = human;

	};

	time = {

		tostring = function () return os.date("%T"); end;

	};

	cpu = {

		get = function ()

			local new_wall, new_clock = get_time(), os.clock();

			local pc = 0;

			if last_cpu_wall then

				pc = 100/((new_wall-last_cpu_wall)/(new_clock-last_cpu_clock));

			end

			last_cpu_wall, last_cpu_clock = new_wall, new_clock;

			return math.ceil(pc);

		end;

		tostring = "%s%%";

	};

};

if has_pposix and pposix.meminfo then

	stats.memory_allocated = {

		get = function () return math.ceil(pposix.meminfo().allocated); end;

		tostring = human;

	}

	stats.memory_used = {

		get = function () return math.ceil(pposix.meminfo().used); end;

		tostring = human;

	}

	stats.memory_unused = {

		get = function () return math.ceil(pposix.meminfo().unused); end;

		tostring = human;

	}

	stats.memory_returnable = {

		get = function () return math.ceil(pposix.meminfo().returnable); end;

		tostring = human;

	}

end

local pagesize = 4096;

stats.memory_total = {

	get = function ()

		local statm, err = io.open"/proc/self/statm";

		if statm then

			local total = statm:read"*n";

			statm:close();

			return total * pagesize;

		else

			module:log("debug", err);

		end

	end;

	tostring = human;

};

stats.memory_rss = {

	get = function ()

		local statm, err = io.open"/proc/self/statm";

		if statm then

			statm:read"*n"; -- Total size, ignore

			local rss = statm:read"*n";

			statm:close();

			return rss * pagesize;

		else

			module:log("debug", err);

		end

	end;

	tostring = human;

};

local add_statistics_filter; -- forward decl

if prosody and prosody.arg then -- ensures we aren't in prosodyctl

	setmetatable(active_sessions, {

		__index = function ( t, k )

			local v = {

				bytes_in = 0, bytes_out = 0;

				stanzas_in = {

					message = 0, presence = 0, iq = 0;

				};

				stanzas_out = {

					message = 0, presence = 0, iq = 0;

				};

			}

			rawset(t, k, v);

			return v;

		end

	});

	local filters = require "util.filters";

	local function handle_stanza_in(stanza, session)

		local s = active_sessions[session].stanzas_in;

		local n = s[stanza.name];

		if n then

			s[stanza.name] = n + 1;

		end

		return stanza;

	end

	local function handle_stanza_out(stanza, session)

		local s = active_sessions[session].stanzas_out;

		local n = s[stanza.name];

		if n then

			s[stanza.name] = n + 1;

		end

		return stanza;

	end

	local function handle_bytes_in(bytes, session)

		local s = active_sessions[session];

		s.bytes_in = s.bytes_in + #bytes;

		return bytes;

	end

	local function handle_bytes_out(bytes, session)

		local s = active_sessions[session];

		s.bytes_out = s.bytes_out + #bytes;

		return bytes;

	end

	function add_statistics_filter(session)

		filters.add_filter(session, "stanzas/in", handle_stanza_in);

		filters.add_filter(session, "stanzas/out", handle_stanza_out);

		filters.add_filter(session, "bytes/in", handle_bytes_in);

		filters.add_filter(session, "bytes/out", handle_bytes_out);

	end

end

return {

	stats = stats;

	active_sessions = active_sessions;

	filter_hook = add_statistics_filter;

};