describe("Timetable library", function()
	local timetable = require "luatz.timetable"

	local function native_normalise(year, month, day)
		return os.date("*t",os.time {
			year = year;
			month = month;
			day = day;
		})
	end

	it("#is_leap is correct", function()
		assert.same(false, timetable.is_leap(1))
		assert.same(false, timetable.is_leap(3))
		assert.same(true , timetable.is_leap(4))
		assert.same(true , timetable.is_leap(2000))
		assert.same(true , timetable.is_leap(2004))
		assert.same(true , timetable.is_leap(2012))
		assert.same(false, timetable.is_leap(2013))
		assert.same(false, timetable.is_leap(2014))
		assert.same(false, timetable.is_leap(2100))
		assert.same(true , timetable.is_leap(2400))
	end)

	it("#normalise gets #wday (day of week) correct", function()

		local function assert_same_wday(year, month, day)
			return assert.are.same(
				native_normalise(year, month, day).wday,
				timetable.new(year, month, day):normalise().wday
			)
		end

		assert_same_wday(2013, 7, 23)
		assert_same_wday(2013, 7, 24)
		assert_same_wday(2013, 7, 25)
		assert_same_wday(2013, 7, 26)
		assert_same_wday(2013, 7, 27)
		assert_same_wday(2013, 7, 28)
		assert_same_wday(2013, 7, 29)
		assert_same_wday(2014, 1, 1)
		assert_same_wday(2014, 1, 6)
		assert_same_wday(2016, 2, 28)
		assert_same_wday(2016, 2, 29)
		assert_same_wday(2016, 3, 1)
	end)

	local function native_timestamp(year, month, day)
		return assert(tonumber(assert(io.popen(
						string.format('date -u -d "%d-%d-%d" +%%s', year, month, day)
					)):read "*l"))
	end

	it("#timestamp creation is valid", function()
		for y=1950,2013 do
			for m=1,12 do
				assert.same(native_timestamp(y,m,1), timetable.timestamp(y,m,1,0,0,0))
			end
		end
	end)

	it("#normalise handles out of range days in a year", function()
		assert.same({2014,1,1,0,0,0}, {timetable.normalise(2013,1,366,0,0,0)})
		assert.same({2014,2,4,0,0,0}, {timetable.normalise(2013,1,400,0,0,0)})
		assert.same({2017,2,3,0,0,0}, {timetable.normalise(2016,1,400,0,0,0)})
		assert.same({2016,3,5,0,0,0}, {timetable.normalise(2015,1,430,0,0,0)})
		assert.same({2017,3,5,0,0,0}, {timetable.normalise(2016,1,430,0,0,0)})
		assert.same({2027,5,18,0,0,0}, {timetable.normalise(2000,1,10000,0,0,0)})
		assert.same({29379,1,25,0,0,0}, {timetable.normalise(2000,1,10000000,0,0,0)})
	end)

	it("#normalise handles out of range days in a #month", function()
		assert.same({2012,12,1,0,0,0}, {timetable.normalise(2013,0,1,0,0,0)})
		assert.same({2016,6,1,0,0,0}, {timetable.normalise(2013,42,1,0,0,0)})

		-- Correct behaviour around leap days
		assert.same({2012,3,23,0,0,0}, {timetable.normalise(2012,2,52,0,0,0)})
		assert.same({2013,3,24,0,0,0}, {timetable.normalise(2013,2,52,0,0,0)})

		assert.same({2012,2,27,0,0,0}, {timetable.normalise(2012,3,-2,0,0,0)})
		assert.same({2013,2,26,0,0,0}, {timetable.normalise(2013,3,-2,0,0,0)})

		-- Also when more fields are out of range
		assert.same({2016,7,22,0,0,0}, {timetable.normalise(2013,42,52,0,0,0)})
		assert.same({2016,7,24,2,0,0}, {timetable.normalise(2013,42,52,50,0,0)})
	end)

	it("#normalise handles fractional #month", function()
		assert.same({2015,2,15,0,0,0}, {timetable.normalise(2014,14.5,1,0,0,0)})
		assert.same({2016,2,15,12,0,0}, {timetable.normalise(2015,14.5,1,0,0,0)}) -- leap year, so hours is 12
		assert.same({2017,2,15,0,0,0}, {timetable.normalise(2016,14.5,1,0,0,0)})
	end)

	it("#normalise handles negative carry (issue #10)", function()
		assert.same({1970,01,01,00,59,00}, {timetable.normalise(1970,01,01,01,00,-60)})
		assert.same({1970,01,01,00,58,58}, {timetable.normalise(1970,01,01,01,00,-62)})
		assert.same({1969,12,31,23,55,58}, {timetable.normalise(1970,01,01,01,-63,-62)})
		assert.same({2017,02,3,0,0,0}, {timetable.normalise(2017,02,13,0,-14400,0)})
	end)

	it("#normalise handles negative day carry (issue #13)", function()
		assert.same({2016,11,30,00,00,00}, {timetable.normalise(2016,12,0,0,0,0)})
		assert.same({2017,11,30,00,00,00}, {timetable.normalise(2017,12,0,0,0,0)})
		assert.same({2018,11,30,00,00,00}, {timetable.normalise(2018,12,0,0,0,0)})

		assert.same({2017,2,13,0,0,0}, {timetable.normalise(2017,3,-15,0,0,0)})
		assert.same({2016,10,1,0,0,0}, {timetable.normalise(2017,3,-150,0,0,0)})
		assert.same({2013,1,20,0,0,0}, {timetable.normalise(2017,3,-1500,0,0,0)})
		assert.same({1976,2,4,0,0,0}, {timetable.normalise(2017,3,-15000,0,0,0)})
		assert.same({1606,6,23,0,0,0}, {timetable.normalise(2017,3,-150000,0,0,0)})
	end)

	local function round_trip_add(t, field, x)
		local before = t:clone()
		t[field]=t[field]+x;
		t:normalise();
		t[field]=t[field]-x;
		t:normalise();
		assert.same(0, t-before)
	end
	it("#normalise round trips", function()
		round_trip_add(timetable.new(2000,2,28,0,0,0), "month", 0.5)
		round_trip_add(timetable.new(2014,8,28,19,23,0), "month", 0.4)
		round_trip_add(timetable.new(2014,14.5,28,0,0,0), "month", 0.4)
	end)

	it("#rfc_3339 works with fractional milliseconds", function()
		-- on lua 5.3 this used to throw an error due to milliseconds not being an integer
		timetable.new_from_timestamp(1415141759.999911111):rfc_3339()
	end)

	it("#rfc_3339 doesn't round seconds up to 60 (issue #4)", function()
		assert.same("2014-11-04T22:55:59.999", timetable.new_from_timestamp(1415141759.999911111):rfc_3339())
		assert.same("1970-01-01T00:00:59.999", timetable.new_from_timestamp(59.9999999):rfc_3339())
		assert.same("1969-12-31T23:59:59.999", timetable.new_from_timestamp(-0.001):rfc_3339())
		assert.same("1969-12-31T23:59:00.000", timetable.new_from_timestamp(-59.9999999):rfc_3339())
	end)
end)