Module:TwitterSnowflake

local p = {}

local Date = require('Module:Date')._Date

function p.snowflakeToDate(frame)

local format = frame.args.format or "%B %e, %Y"

local epoch = tonumber(frame.args.epoch) or 1288834974

local id_str = frame.args.id_str

if type(id_str) ~= "string" then error("bad argument #1 (expected string, got " .. type(id_str) .. ")", 2) end

if type(format) ~= "string" then error("bad argument #2 (expected string, got " .. type(format) .. ")", 2) end

if type(epoch) ~= "number" then error("bad argument #3 (expected number, got " .. type(epoch) .. ")", 2) end

local hi, lo = 0, 0

local hiexp = 1

local two32 = 2^32

for c in id_str:gmatch(".") do

lo = lo * 10 + c

if lo >= two32 then

hi, lo = hi * 10^hiexp + math.floor(lo / two32), lo % two32

hiexp = 1

else hiexp = hiexp + 1 end

end

hi = hi * 10^(hiexp-1)

local timestamp = math.floor((hi * 1024 + math.floor(lo / 4194304)) / 1000) + epoch

return os.date(format, timestamp)

end

function p.getDate(frame)

-- just pass frame directly to snowflakeToDate, this wraps it but the args are the same plus

if (frame.args.id_str):match("%D") then -- not a number, so return -2

return -2

end

frame.args.format = "%B %e, %Y"

if frame.args.date then

frame.args.date = mw.ustring.gsub(frame.args.date, "(%d%d%d%d)%a", "%1")

end

frame.args.epoch = tonumber(frame.args.epoch) or 1288834974

local epochdate = Date(os.date("%B %e, %Y", frame.args.epoch))

local twitterdate = Date(p.snowflakeToDate(frame))

if twitterdate == epochdate then -- created before epoch, so can't determine the date

return -1

end

local date = Date(frame.args.date) or 0 -- if we error here, then an input of no date causes an error, which is contrary to the entire way {{TwitterSnowflake/datecheck}} works

return date - twitterdate

end

local function abs_datediff(x)

if type(x) == 'number' then return math.abs(x) end

return math.abs(x.age_days)

end

function p.datecheck(frame)

local args = frame.args

if not (args.date and args.id_str) then

error('Must define date and id_str, even if they are blank.')

end

local errors = {

args.error1 or 'Date mismatch of two or more days',

args.error2 or 'No date, and posted before November 4, 2010',

args.error3 or 'Invalid id_str'

}

if mw.title.getCurrentTitle():inNamespace(0) and args.error_cat then

for i = 1, 3 do errors[i] = errors[i] .. '' .. args.error_cat .. '' end

end

if not args.date:match('^%s*$') then -- #if:{{{date|}}}

local testResult = p.getDate{ args = { date = args.date, id_str = args.id_str }}

if testResult == -2 then return errors[3] end

if abs_datediff(testResult) > 1 then return errors[1] end

elseif not args.id_str:match('^%s*$') then

local testResult = p.getDate{ args = { id_str = args.id_str }}

if testResult == -1 then return errors[2] end

if testResult == -2 then return errors[3] end

end

end

return p