From Blaseball Wiki

-- This module contains a number of functions that make use of random numbers. local cfg = {}

-- Configuration

-- Set this to true if your wiki has a traffic rate of less than one edit every two minutes or so. -- This will prevent the same "random" number being generated many times in a row until a new edit is made -- to the wiki. This setting is only relevant if the |same= parameter is set. cfg.lowTraffic = false -- If cfg.lowTraffic is set to true, and the |same= parameter is set, this value is used for the refresh rate of the random seed. -- This is the number of seconds until the seed is changed. Getting this right is tricky. If you set it too high, the same number -- will be returned many times in a row. If you set it too low, you may get different random numbers appearing on the same page, -- particularly for pages that take many seconds to process. cfg.seedRefreshRate = 60

-- End configuration

local p = {} -- For functions available from other Lua modules. local l = {} -- For functions not available from other Lua modules, but that need to be accessed using table keys. local yesno = require('Module:Yesno') local makeList = require('Module:List').makeList

-- Helper functions

local function raiseError(msg)

   -- This helps to generate a wikitext error. It is the calling function's responsibility as to how to include it in the output.
   return mw.ustring.format('Module:Random error: %s.', msg)


-- random number function

local function getBigRandom(l, u)

   -- Gets a random integer between l and u, and is not limited to RAND_MAX.
   local r = 0
   local n = 2^math.random(30) -- Any power of 2.
   local limit = math.ceil(53 / (math.log(n) / math.log(2)))
   for i = 1, limit do
       r = r + math.random(0, n - 1) / (n^i)
   return math.floor(r * (u - l + 1)) + l

end function l.number(args)

   -- Gets a random number.
   first = tonumber(args[1])
   second = tonumber(args[2])
   -- This needs to use if statements as math.random won't accept explicit nil values as arguments.
   if first then
       if second then
           if first > second then -- Second number cannot be less than the first, or it causes an error.
               first, second = second, first
           return getBigRandom(first, second)
           return getBigRandom(1, first)
       return math.random()


-- Date function


   -- This function gets random dates, and takes timestamps as positional arguments.
   -- With no arguments specified, it outputs a random date in the current year.
   -- With two arguments specified, it outputs a random date between the timestamps.
   -- With one argument specified, the date is a random date between the unix epoch (1 Jan 1970) and the timestamp.
   -- The output can be formatted using the "format" argument, which works in the same way as the #time parser function.
   -- The default format is the standard Wikipedia timestamp.
   local lang = mw.language.getContentLanguage()
   local function getDate(format, ts)
       local success, date = pcall(lang.formatDate, lang, format, ts)
       if success then
           return date
   local function getUnixTimestamp(ts)
       local unixts = getDate('U', ts)
       if unixts then
           return tonumber(unixts)
   local t1 = args[1]
   local t2 = args[2]
   -- Find the start timestamp and the end timestamp.
   local startTimestamp, endTimestamp
   if not t1 then
       -- Find the first and last second in the current year.
       local currentYear = tonumber(getDate('Y'))
       local currentYearStartUnix = tonumber(getUnixTimestamp('1 Jan ' .. tostring(currentYear)))
       local currentYearEndUnix = tonumber(getUnixTimestamp('1 Jan ' .. tostring(currentYear + 1))) - 1
       startTimestamp = '@' .. tostring(currentYearStartUnix) -- @ is used to denote Unix timestamps with lang:formatDate.
       endTimestamp = '@' .. tostring(currentYearEndUnix)
   elseif t1 and not t2 then
       startTimestamp = '@0' -- the Unix epoch, 1 January 1970
       endTimestamp = t1
   elseif t1 and t2 then
       startTimestamp = t1
       endTimestamp = t2
   -- Get Unix timestamps and return errors for bad input (or for bugs in the underlying PHP library, of which there are unfortunately a few)
   local startTimestampUnix = getUnixTimestamp(startTimestamp)
   local endTimestampUnix = getUnixTimestamp(endTimestamp)
   if not startTimestampUnix then
       return raiseError('"' .. tostring(startTimestamp) .. '" was not recognised as a valid timestamp')
   elseif not endTimestampUnix then
       return raiseError('"' .. tostring(endTimestamp) .. '" was not recognised as a valid timestamp')
   elseif startTimestampUnix > endTimestampUnix then
       return raiseError('the start date must not be later than the end date (start date: "' .. startTimestamp .. '", end date: "' .. endTimestamp .. '")')
   -- Get a random number between the two Unix timestamps and return it using the specified format.
   local randomTimestamp = getBigRandom(startTimestampUnix, endTimestampUnix)
   local dateFormat = args.format or 'H:i, d F Y (T)'
   local result = getDate(dateFormat, '@' .. tostring(randomTimestamp))
   if result then
       return result
       return raiseError('"' .. dateFormat .. '" is not a valid date format')


-- List functions

local function randomizeArray(t, limit)

   -- Randomizes an array. It works by iterating through the list backwards, each time swapping the entry
   -- "i" with a random entry. Courtesy of Xinhuan at
   -- If the limit parameter is set, the array is shortened to that many elements after being randomized.
   -- The lowest possible value is 0, and the highest possible is the length of the array.
   local len = #t
   for i = len, 2, -1 do
       local r = math.random(i)
       t[i], t[r] = t[r], t[i]
   if limit and limit < len then
       local ret = {}
       for i, v in ipairs(t) do
           if i > limit then
           ret[i] = v
       return ret
       return t

end local function removeBlanks(t)

   -- Removes blank entries from an array so that it can be used with ipairs.
   local ret = {}
   for k, v in pairs(t) do
       if type(k) == 'number' then
           table.insert(ret, k)
   for i, v in ipairs(ret) do
       ret[i] = t[v]
   return ret

end local function makeSeparator(sep)

   if sep == 'space' then
       -- Include an easy way to use spaces as separators.
       return ' '
   elseif sep == 'newline' then
       -- Ditto for newlines
       return '\n'
   elseif type(sep) == 'string' then
       -- If the separator is a recognised MediaWiki separator, use that. Otherwise use the value of sep if it is a string.
       local mwseparators = {'dot', 'pipe', 'comma', 'tpt-languages'}
       for _, mwsep in ipairs(mwseparators) do
           if sep == mwsep then
               return sep .. '-separator' ):plain()
       return sep

end local function makeRandomList(args)

   local list = removeBlanks(args)
   list = randomizeArray(list, tonumber(args.limit))
   return list

end function l.item(args)

   -- Returns a random item from a numbered list.
   local list = removeBlanks(args)
   local len = #list
   if len >= 1 then
       return list[math.random(len)]

end function l.list(args)

   -- Randomizes a list and concatenates the result with a separator.
   local list = makeRandomList(args)
   local sep = makeSeparator(args.sep or args.separator)
   return table.concat(list, sep)

end function l.text_list(args)

   -- Randomizes a list and concatenates the result, text-style. Accepts separator and conjunction arguments.
   local list = makeRandomList(args)
   local sep = makeSeparator(args.sep or args.separator)
   local conj = makeSeparator(args.conj or args.conjunction)
   return mw.text.listToText(list, sep, conj)

end function l.array(args)

   -- Returns a Lua array, randomized. For use from other Lua modules.
   return randomizeArray(args.t, args.limit)


-- HTML list function

function l.html_list(args, listType)

   -- Randomizes a list and turns it into an HTML list. Uses Module:List.
   listType = listType or 'bulleted'
   local listArgs = makeRandomList(args) -- Arguments for Module:List.
   for k, v in pairs(args) do
       if type(k) == 'string' then
           listArgs[k] = v
   return makeList(listType, listArgs)


-- The main function. Called from other Lua modules.

function p.main(funcName, args, listType)

   -- Sets the seed for the random number generator and passes control over to the other functions.
   local same = yesno(args.same)
   if not same then
       -- Generates a different number every time the module is called, even from the same page.
       -- This is because of the variability of os.clock (the time in seconds that the Lua script has been running for).
       math.randomseed( + + os.time() + math.floor(os.clock() * 1000000000))
       if not cfg.lowTraffic then
           -- Make the seed as random as possible without using anything time-based. This means that the same random number
           -- will be generated for the same input from the same page - necessary behaviour for some wikicode templates that
           -- assume bad pseudo-random-number generation.
           local stats =
           local views = stats.views or 0 -- This is not always available, so we need a backup.
           local seed = views + stats.pages + stats.articles + stats.files + stats.edits + stats.users + stats.activeUsers + stats.admins -- Make this as random as possible without using os.time() or os.clock()
           -- Make the random seed change every n seconds, where n is set by cfg.seedRefreshRate.
           -- This is useful for low-traffic wikis where new edits may not happen very often.
           math.randomseed(math.floor(os.time() / cfg.seedRefreshRate))
   if type(args) ~= 'table' then
       error('the second argument to p.main must be a table')
   return l[funcName](args, listType)


-- Process arguments from #invoke

local function makeWrapper(funcName, listType)

   -- This function provides a wrapper for argument-processing from #invoke.
   -- listType is only used with p.html_list, and is nil the rest of the time.
   return function (frame)
       -- If called via #invoke, use the args passed into the invoking template, or the args passed to #invoke if any exist.
       -- Otherwise assume args are being passed directly in from the debug console or from another Lua module.
       local origArgs
       if frame == mw.getCurrentFrame() then
           origArgs = frame:getParent().args
           for k, v in pairs(frame.args) do
               origArgs = frame.args
           origArgs = frame
       -- Trim whitespace and remove blank arguments.
       local args = {}
       for k, v in pairs(origArgs) do
           if type(v) == 'string' then
               v = mw.text.trim(v)
           if v ~=  then
               args[k] = v
       return p.main(funcName, args, listType)

end -- Process arguments for HTML list functions. local htmlListFuncs = {

   bulleted_list           = 'bulleted',
   unbulleted_list         = 'unbulleted',
   horizontal_list         = 'horizontal',
   ordered_list            = 'ordered',
   horizontal_ordered_list = 'horizontal_ordered'

} for funcName, listType in pairs(htmlListFuncs) do

   p[funcName] = makeWrapper('html_list', listType)

end -- Process arguments for other functions. local otherFuncs = {'number', 'date', 'item', 'list', 'text_list'} for _, funcName in ipairs(otherFuncs) do

   p[funcName] = makeWrapper(funcName)

end return p