-- original code made by Bzed and published on http://awesome.naquadah.org/wiki/Calendar_widget
-- modified by Marc Dequènes (Duck) <Duck@DuckCorp.org> (2009-12-29), under the same licence,
-- and with the following changes:
--   + transformed to module
--   + the current day formating is customizable
-- modified by Jörg Thalheim (Mic92) <jthalheim@gmail.com> (2011), under the same licence,
-- and with the following changes:
--   + use tooltip instead of naughty.notify
--   + rename it to cal
--   + lua52 compliant module
--
-- 1. require it in your rc.lua
--	require("cal")
-- 2. attach the calendar to a widget of your choice (ex mytextclock)
--	cal.register(mytextclock)
--    If you don't like the default current day formating you can change it as following
--	cal.register(mytextclock, "<b>%s</b>") -- now the current day is bold instead of underlined
--
-- # How to Use #
-- Just hover with your mouse over the widget, you register and the calendar popup.
-- On clicking or by using the mouse wheel the displayed month changes.
-- Pressing Shift + Mouse click change the year.

local string = {format = string.format}
local os = {date = os.date, time = os.time}
local awful = require("awful")

local cal = {}

local tooltip
local state = {}
local current_day_format = '<span color="#1793D1"><u>%s</u></span>'

local function display_month(month,year,weekStart)
	local t,wkSt=os.time{year=year, month=month+1, day=0},weekStart or 1
	local d=os.date("*t", t)
	local mthDays,stDay=d.day, (d.wday - d.day - wkSt + 1) % 7

	local lines = "    "

	for x=0,6 do
		lines = lines .. os.date("%a ", os.time{year=2006, month=1, day=x + wkSt})
	end

	lines = lines .. "\n" .. os.date(" %V", os.time{year=year, month=month, day=1})

	local writeLine = 1
	while writeLine < (stDay + 1) do
		lines = lines .. "    "
		writeLine = writeLine + 1
	end

    for d=1,mthDays do
        local x = tostring(d)
        local t = os.time{year=year, month=month, day=d}
        if writeLine == 8 then
            writeLine = 1
            lines = lines .. "\n" .. os.date(" %V", t)
        end
        if os.date("%Y-%m-%d") == os.date("%Y-%m-%d", t) then
            x = string.format(current_day_format, d)
        end
        if d < 10 then
            x = " " .. x
        end
        lines = lines .. "  " .. x
        writeLine = writeLine + 1
    end

    if stDay + mthDays < 36 then
            lines = lines .. "\n"
    end
    if stDay + mthDays < 29 then
            lines = lines .. "\n"
    end
    local header = os.date("\n %B %Y\n", os.time{year=year, month=month, day=1})

	return header .. "\n" .. lines
end

local function switch_month(delta)
	state[1] = state[1] + (delta or 1)
	local text = string.format('<span color="white" font_desc="monospace">%s</span>', display_month(state[1], state[2], 2))
	tooltip:set_markup(text)
end


function cal.register(mywidget, custom_current_day_format)
	if custom_current_day_format then current_day_format = custom_current_day_format end

	if not tooltip then
		tooltip = awful.tooltip({})
        function tooltip:update()
            local month, year = os.date('%m'), os.date('%Y')
            state = {month, year}
            tooltip:set_markup(string.format('<span color="white" font_desc="monospace">%s</span>', display_month(month, year, 2)))
        end
        tooltip:update()
	end
	tooltip:add_to_object(mywidget)

	mywidget:connect_signal("mouse::enter",tooltip.update)

	mywidget:buttons(awful.util.table.join(
	awful.button({ }, 1, function()
		switch_month(-1)
	end),
	awful.button({ }, 3, function()
		switch_month(1)
	end),
	awful.button({ }, 4, function()
		switch_month(-1)
	end),
	awful.button({ }, 5, function()
		switch_month(1)
	end),
	awful.button({ 'Shift' }, 1, function()
		switch_month(-12)
	end),
	awful.button({ 'Shift' }, 3, function()
		switch_month(12)
	end),
	awful.button({ 'Shift' }, 4, function()
		switch_month(-12)
	end),
	awful.button({ 'Shift' }, 5, function()
		switch_month(12)
	end)))
end

return cal