-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local indexedbheap = require "util.indexedbheap";

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

local server = require "net.server";

local math_min = math.min

local math_huge = math.huge

local get_time = require "socket".gettime;

local t_insert = table.insert;

local pairs = pairs;

local type = type;

local data = {};

local new_data = {};

module "timer"

local _add_task;

if not server.event then

	function _add_task(delay, callback)

		local current_time = get_time();

		delay = delay + current_time;

		if delay >= current_time then

			t_insert(new_data, {delay, callback});

		else

			local r = callback(current_time);

			if r and type(r) == "number" then

				return _add_task(r, callback);

			end

		end

	end

	server._addtimer(function()

		local current_time = get_time();

		if #new_data > 0 then

			for _, d in pairs(new_data) do

				t_insert(data, d);

			end

			new_data = {};

		end

		local next_time = math_huge;

		for i, d in pairs(data) do

			local t, callback = d[1], d[2];

			if t <= current_time then

				data[i] = nil;

				local r = callback(current_time);

				if type(r) == "number" then

					_add_task(r, callback);

					next_time = math_min(next_time, r);

				end

			else

				next_time = math_min(next_time, t - current_time);

			end

		end

		return next_time;

	end);

else

	local event = server.event;

	local event_base = server.event_base;

	local EVENT_LEAVE = (event.core and event.core.LEAVE) or -1;

	function _add_task(delay, callback)

		local event_handle;

		event_handle = event_base:addevent(nil, 0, function ()

			local ret = callback(get_time());

			if ret then

				return 0, ret;

			elseif event_handle then

				return EVENT_LEAVE;

			end

		end

		, delay);

	end

end

--add_task = _add_task;

local h = indexedbheap.create();

local params = {};

local next_time = nil;

local _id, _callback, _now, _param;

local function _call() return _callback(_now, _id, _param); end

local function _traceback_handler(err) log("error", "Traceback[timer]: %s", traceback(tostring(err), 2)); end

local function _on_timer(now)

	local peek;

	while true do

		peek = h:peek();

		if peek == nil or peek > now then break; end

		local _;

		_, _callback, _id = h:pop();

		_now = now;

		--item(now, id, _param); -- FIXME pcall

		local success, err = xpcall(_call, _traceback_handler);

		if success and type(err) == "number" then

			h:insert(_callback, err + now, _id); -- re-add

		end

	end

	next_time = peek;

	if peek ~= nil then

		return peek - now;

	end

end

function add_task(delay, callback, param)

	local current_time = get_time();

	local event_time = current_time + delay;

	local id = h:insert(callback, event_time);

	params[id] = param;

	if next_time == nil or event_time < next_time then

		next_time = event_time;

		_add_task(next_time - current_time, _on_timer);

	end

	return id;

end

function stop(id)

	params[id] = nil;

	return h:remove(id);

end

function reschedule(id, delay)

	local current_time = get_time();

	local event_time = current_time + delay;

	h:reprioritize(id, delay);

	if next_time == nil or event_time < next_time then

		next_time = event_time;

		_add_task(next_time - current_time, _on_timer);

	end

	return id;

end

return _M;