-- This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
-- This file is based on Lua 5.x tests -- https://github.com/lua/lua/tree/master/testes
print "testing datetime library"

local function checkerr (msg, f, ...)
  local stat, err = pcall(f, ...)
  assert(not stat and string.find(err, msg, 1, true))
end

assert(os.date("") == "")
assert(os.date("!") == "")
local x = string.rep("a", 10000)
assert(os.date(x) == x)
local t = os.time()
D = os.date("*t", t)
assert(os.date(string.rep("%d", 1000), t) ==
       string.rep(os.date("%d", t), 1000))
assert(os.date(string.rep("%", 200)) == string.rep("%", 100))
assert(os.date("", -1) == nil)

assert(os.time({ year = 1969, month = 12, day = 31, hour = 23, min = 59, sec = 59}) == nil) -- just before start
assert(os.time({ year = 1970, month = 1, day = 1, hour = 0, min = 0, sec = 0}) == 0) -- start
assert(os.time({ year = 3000, month = 12, day = 31, hour = 23, min = 59, sec = 59}) == 32535215999) -- just before Windows max range
assert(os.time({ year = 1970, month = 1, day = 1, hour = 0, min = 0, sec = -1}) == nil) -- going before using time fields

local function checkDateTable (t)
  local D = os.date("!*t", t)
  assert(os.time(D) == t)
  local DC = os.date("!%Y %m %d %H %M %S %w %j"):split(" ")
  assert(D.year == tonumber(DC[1]))
  assert(D.month == tonumber(DC[2]))
  assert(D.day == tonumber(DC[3]))
  assert(D.hour == tonumber(DC[4]))
  assert(D.min == tonumber(DC[5]))
  assert(D.sec == tonumber(DC[6]))
  assert(D.wday == tonumber(DC[7]) + 1)
  assert(D.yday == tonumber(DC[8]))
end

checkDateTable(os.time())

checkerr("invalid conversion specifier", os.date, "%9")
checkerr("invalid conversion specifier", os.date, "%O")
checkerr("invalid conversion specifier", os.date, "%E")
checkerr("invalid conversion specifier", os.date, "%Ea")

checkerr("missing", os.time, {hour = 12})   -- missing date

do
  local D = os.date("*t")
  local t = os.time(D)
  if D.isdst == nil then
    print("no daylight saving information")
  else
    assert(type(D.isdst) == 'boolean')
  end
  D.isdst = nil
  local t1 = os.time(D)
  assert(t == t1)   -- if isdst is absent uses correct default
end

local D = os.date("*t")
t = os.time(D)
D.year = D.year-1;
local t1 = os.time(D)
-- allow for leap years
assert(math.abs(os.difftime(t,t1)/(24*3600) - 365) < 2)

-- should not take more than 1 second to execute these two lines
t = os.time()
t1 = os.time(os.date("!*t"))
local diff = os.difftime(t1,t)
assert(0 <= diff and diff <= 1)
diff = os.difftime(t,t1)
assert(-1 <= diff and diff <= 0)

local t1 = os.time{year=2000, month=10, day=1, hour=23, min=12}
local t2 = os.time{year=2000, month=10, day=1, hour=23, min=10, sec=19}
assert(os.difftime(t1,t2) == 60*2-19)

assert(os.time({ year = 1970, day = 1, month = 1, hour = 0}) == 0)

return 'OK'