-- 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('<strong class="error error-module-random">ข้อผิดพลาดใน[[มอดูล:Random]]: %s.</strong>', msg) end  -------------------------------------------------------------------------------------- -- 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)  end  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  end  return getBigRandom(first, second)  else  return getBigRandom(1, first)  end  else  return math.random()  end end  -------------------------------------------------------------------------------------- -- Date function --------------------------------------------------------------------------------------  function l.date(args)  -- 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  end  end   local function getUnixTimestamp(ts)  local unixts = getDate('U', ts)  if unixts then  return tonumber(unixts)  end  end   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  end   -- 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) .. '" ไม่ใช่ตราเวลาที่ถูกต้อง')  elseif not endTimestampUnix then  return raiseError('"' .. tostring(endTimestamp) .. '" ไม่ใช่ตราเวลาที่ถูกต้อง')  elseif startTimestampUnix > endTimestampUnix then  return raiseError('วันเวลาเริ่มต้นต้องไม่ใช่เวลาหลังเวลาสิ้นสุด (วันเวลาเริ่มต้น: "' .. startTimestamp .. '" วันเวลาสิ้นสุด: "' .. endTimestamp .. '")')  end   -- 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  else  return raiseError('"' .. dateFormat .. '" ไม่ใช่รูปแบบวันเวลาที่ถูกต้อง')  end end  -------------------------------------------------------------------------------------- -- 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 http://forums.wowace.com/showthread.php?p=279756  -- 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]  end  if limit and limit < len then  local ret = {}  for i, v in ipairs(t) do  if i > limit then  break  end  ret[i] = v  end  return ret  else  return t  end 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)  end  end  table.sort(ret)  for i, v in ipairs(ret) do  ret[i] = t[v]  end  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 mw.message.new( sep .. '-separator' ):plain()  end  end  return sep  end 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 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) end  -------------------------------------------------------------------------------------- -- 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  end  end  return makeList(listType, listArgs) end  -------------------------------------------------------------------------------------- -- 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(mw.site.stats.edits + mw.site.stats.pages + os.time() + math.floor(os.clock() * 1000000000))  else  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 = mw.site.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()  math.randomseed(seed)  else  -- 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))  end  end  if type(args) ~= 'table' then  error('อาร์กิวเมนต์ที่สองของ p.main ควรเป็น table')  end  return l[funcName](args, listType) end  -------------------------------------------------------------------------------------- -- 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  break  end  else  origArgs = frame  end  -- 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)  end  if v ~= '' then  args[k] = v  end  end  return p.main(funcName, args, listType)  end 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