Module:Webarchive

--[[ ----------------------------------

Lua module implementing the {{webarchive}} template. 

A merger of the functionality of three templates: {{wayback}}, {{webcite}} and {{cite archives}}
 
]]


--[[--------------------------< D E P E N D E N C I E S >------------------------------------------------------
]]

require('strict');
local getArgs = require ('Module:Arguments').getArgs;


--[[--------------------------< F O R W A R D   D E C L A R A T I O N S >--------------------------------------
]]

local categories = {};               -- category names
local config = {};                -- global configuration settings
local digits = {};                -- for i18n; table that translates local-wiki digits to western digits
local err_warn_msgs = {};              -- error and warning messages
local excepted_pages = {};
local month_num = {};               -- for i18n; table that translates local-wiki month names to western digits
local prefixes = {};               -- service provider tail string prefixes
local services = {};               -- archive service provider data from
local s_text = {};                -- table of static text strings used to build final rendering
local uncategorized_namespaces = {};           -- list of namespaces that we should not categorize
local uncategorized_subpages = {};            -- list of subpages that should not be categorized


--[[--------------------------< P A G E   S C O P E   I D E N T I F I E R S >----------------------------------
]]

local non_western_digits;              -- boolean flag set true when data.digits.enable is true
local this_page = mw.title.getCurrentTitle();

local track = {};                -- Associative array to hold tracking categories
local ulx = {};                 -- Associative array to hold template data 


--[[--------------------------< S U B S T I T U T E >----------------------------------------------------------

Populates numbered arguments in a message string using an argument table.

]]

local function substitute (msg, args)
 return args and mw.message.newRawMessage (msg, args):plain() or msg;
end


--[[--------------------------< tableLength >-----------------------

Given a 1-D table, return number of elements

]]

local function tableLength(T)
 local count = 0
 for _ in pairs(T) do count = count + 1 end
 return count
end


--[=[-------------------------< M A K E _ W I K I L I N K >----------------------------------------------------

Makes a wikilink; when both link and display text is provided, returns a wikilink in the form [[L|D]]; if only
link is provided, returns a wikilink in the form [[L]]; if neither are provided or link is omitted, returns an
empty string.

]=]

local function make_wikilink (link, display, no_link)
 if nil == no_link then
  if link and ('' ~= link) then
   if display and ('' ~= display) then
    return table.concat ({'[[', link, '|', display, ']]'});
   else
    return table.concat ({'[[', link, ']]'});
   end
  end
  return display or '';             -- link not set so return the display text

 else                  -- no_link
  if display and ('' ~= display) then          -- if there is display text
   return display;              -- return that
  else
   return link or '';             -- return the target article name or empty string
  end
 end
end


--[[--------------------------< createTracking >-----------------------

Return data in track[] ie. tracking categories

]]

local function createTracking()
 if not excepted_pages[this_page.fullText] then        -- namespace:title/fragment is allowed to be categorized (typically this module's / template's testcases page(s))
  if uncategorized_namespaces[this_page.nsText] then
   return '';               -- this page not to be categorized so return empty string
  end
  for _,v in ipairs (uncategorized_subpages) do       -- cycle through page name patterns
   if this_page.text:match (v) then         -- test page name against each pattern
    return '';              -- this subpage type not to be categorized so return empty string
   end
  end
 end

 local out = {};
 if tableLength(track) > 0 then
  for key, _ in pairs(track) do           -- loop through table
   table.insert (out, make_wikilink (key));       -- and convert category names to links
  end
 end
 return table.concat (out);             -- concat into one big string; empty string if table is empty

end


--[[--------------------------< inlineError >-----------------------

Critical error. Render output completely in red. Add to tracking category.

This function called as the last thing before abandoning this module

]]

local function inlineError (msg, args)
 track[categories.error] = 1
 return table.concat ({
  '<span style="font-size:100%" class="error citation-comment">Error in ', -- open the error message span
  config.tname,               -- insert the local language template name
  ' template: ',
  substitute (msg, args),             -- insert the formatted error message
  '.</span>',                -- close the span
  createTracking()              -- add the category
  })
end


--[[--------------------------< inlineRed >-----------------------

Render a text fragment in red, such as a warning as part of the final output.
Add tracking category.

 ]]

local function inlineRed(msg, trackmsg)
 if trackmsg == "warning" then
  track[categories.warning] = 1;
 elseif trackmsg == "error" then
  track[categories.error] = 1;
 end

 return '<span style="font-size:100%" class="error citation-comment">' .. msg .. '</span>'
end


--[[--------------------------< base62 >-----------------------

Convert base-62 to base-10
Credit: https://de.wikipedia.org/wiki/Modul:Expr 

]]

local function base62( value )
 local r = 1                 -- default return value is input value is malformed

 if value:match ('%W') then             -- value must only be in the set [0-9a-zA-Z]
  return;                 -- nil return when value contains extraneous characters
 end

 local n = #value               -- number of characters in value
 local k = 1
 local c
 r = 0
 for i = n, 1, -1 do               -- loop through all characters in value from ls digit to ms digit
  c = value:byte( i, i )
  if c >= 48 and c <= 57 then            -- character is digit 0-9
   c = c - 48
  elseif c >= 65 and c <= 90 then           -- character is ascii a-z
   c = c - 55
  else                 -- must be ascii A-Z
   c = c - 61
  end
  r = r + c * k               -- accumulate this base62 character's value
  k = k * 62                -- bump for next
 end -- for i

 return r
end 


--[[--------------------------< D E C O D E _ D A T E >--------------------------------------------------------

Given a date string, return it in iso format along with an indicator of the date's format.  Except that month names
must be recognizable as legitimate month names with proper capitalization, and that the date string must match one
of the recognized date formats, no error checking is done here; return nil else

]]

local function decode_date (date_str)
 local patterns = {
  ['dmy'] = {'^(%d%d?) +([^%s%d]+) +(%d%d%d%d)$', 'd', 'm', 'y'},   -- %a does not recognize unicode combining characters used by some languages
  ['mdy'] = {'^([^%s%d]+) (%d%d?), +(%d%d%d%d)$', 'm', 'd', 'y'},
  ['ymd'] = {'^(%d%d%d%d) +([^%s%d]+) (%d%d?)$', 'y', 'm', 'd'},   -- not mos compliant at en.wiki but may be acceptible at other wikis
  };
 
 local t = {};

 if non_western_digits then             -- this wiki uses non-western digits?
  date_str = mw.ustring.gsub (date_str, '%d', digits);     -- convert this wiki's non-western digits to western digits
 end

 if date_str:match ('^%d%d%d%d%-%d%d%-%d%d$') then       -- already an iso format date, return western digits form
  return date_str, 'iso';
 end
 
 for k, v in pairs (patterns) do
  local c1, c2, c3 = mw.ustring.match (date_str, patterns[k][1]);   -- c1 .. c3 are captured but we don't know what they hold
  
  if c1 then                -- set on match
   t = {                -- translate unspecified captures to y, m, and d
    [patterns[k][2]] = c1,           -- fill the table of captures with the captures
    [patterns[k][3]] = c2,           -- take index names from src_pattern table and assign sequential captures
    [patterns[k][4]] = c3,
    };
   if month_num[t.m] then            -- when month not already a number
    t.m = month_num[t.m];           -- replace valid month name with a number
   else
    return nil, 'iso';            -- not a valid date form because month not valid
   end

   return mw.ustring.format ('%.4d-%.2d-%.2d', t.y, t.m, t.d), k;  -- return date in iso format
  end
 end
 return nil, 'iso';               -- date could not be decoded; return nil and default iso date
end

 
--[[--------------------------< makeDate >-----------------------

Given year, month, day numbers, (zero-padded or not) return a full date in df format
where df may be one of:
 mdy, dmy, iso, ymd

on entry, year, month, day are presumed to be correct for the date that they represent; all are required

in this module, makeDate() is sometimes given an iso-format date in year:
 makeDate (2018-09-20, nil, nil, df)
this works because table.concat() sees only one table member

]]

local function makeDate (year, month, day, df)
 local format = {
  ['dmy'] = 'j F Y',
  ['mdy'] = 'F j, Y',
  ['ymd'] = 'Y F j',
  ['iso'] = 'Y-m-d',
  };

 local date = table.concat ({year, month, day}, '-');      -- assemble year-initial numeric-format date (zero padding not required here)

 if non_western_digits then             -- this wiki uses non-western digits?
  date = mw.ustring.gsub (date, '%d', digits);       -- convert this wiki's non-western digits to western digits
 end

 return mw.getContentLanguage():formatDate (format[df], date);
end


--[[--------------------------< I S _ V A L I D _ D A T E >----------------------------------------------------

Returns true if date is after 31 December 1899 (why is 1900 the min year? shouldn't the internet's date-of-birth
be min year?), not after today's date, and represents a valid date (29 February 2017 is not a valid date).  Applies
Gregorian leapyear rules.

all arguments are required

]]

local function is_valid_date (year, month, day)
 local days_in_month = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
 local month_length;
 local y, m, d;
 local today = os.date ('*t');            -- fetch a table of current date parts

 if not year or '' == year or not month or '' == month or not day or '' == day then
  return false;               -- something missing
 end
 
 y = tonumber (year);
 m = tonumber (month);
 d = tonumber (day);

 if 1900 > y or today.year < y or 1 > m or 12 < m then      -- year and month are within bounds TODO: 1900?
  return false;
 end

 if (2==m) then                -- if February
  month_length = 28;              -- then 28 days unless
  if (0==(y%4) and (0~=(y%100) or 0==(y%400))) then      -- is a leap year?
   month_length = 29;             -- if leap year then 29 days in February
  end
 else
  month_length=days_in_month[m];
 end

 if 1 > d or month_length < d then           -- day is within bounds
  return false;
 end
                     -- here when date parts represent a valid date
 return os.time({['year']=y, ['month']=m, ['day']=d, ['hour']=0}) <= os.time(); -- date at midnight must be less than or equal to current date/time
end


--[[--------------------------< decodeWebciteDate >-----------------------

Given a URI-path to Webcite (eg. /67xHmVFWP) return the encoded date in df format

returns date string in df format - webcite date is a unix timestamp encoded as bae62
or the string 'query'

]]

local function decodeWebciteDate(path, df)

 local dt = {};
 local decode;

 dt = mw.text.split(path, "/")

 -- valid URL formats that are not base62

 -- http://www.webcitation.org/query?id=1138911916587475
 -- http://www.webcitation.org/query?url=http..&date=2012-06-01+21:40:03
 -- http://www.webcitation.org/1138911916587475
 -- http://www.webcitation.org/cache/73e53dd1f16cf8c5da298418d2a6e452870cf50e
 -- http://www.webcitation.org/getfile.php?fileid=1c46e791d68e89e12d0c2532cc3cf629b8bc8c8e

 if dt[2]:find ('query', 1, true) or 
  dt[2]:find ('cache', 1, true) or
  dt[2]:find ('getfile', 1, true) or
  tonumber(dt[2]) then
   return 'query';
 end

 decode = base62(dt[2]);              -- base62 string -> exponential number
 if not decode then
  return nil;                -- nil return when dt[2] contains characters not in %w
 end
 dt = os.date('*t', string.format("%d", decode):sub(1,10))     -- exponential number -> text -> first 10 characters (a unix timestamp) -> a table of date parts

 decode = makeDate (dt.year, dt.month, dt.day, 'iso');      -- date comparisons are all done in iso format with western digits
 if non_western_digits then             -- this wiki uses non-western digits?
  decode = mw.ustring.gsub (decode, '%d', digits);      -- convert this wiki's non-western digits to western digits
 end

 return decode;
end


--[[--------------------------< decodeWaybackDate >-----------------------

Given a URI-path to Wayback (eg. /web/20160901010101/http://example.com )
or Library of Congress Web Archives (eg. /all/20160901010101/http://example.com)
or UK Government Web Archive (eg. /ukgwa/20160901010101/http://example.com or /tna/20160901010101/http://example.com)

return the formatted date eg. "September 1, 2016" in df format 
Handle non-digits in snapshot ID such as "re_" and "-" and "*"

returns two values:
 first value is one of these:
  valid date string in df format - wayback date is valid (including the text string 'index' when date is '/*/')
  empty string - wayback date is malformed (less than 8 digits, not a valid date)
  nil - wayback date is '/save/' or otherwise not a number
 
 second return value is an appropriate 'message' may or may not be formatted

]]

local function decodeWaybackDate(path, df)

 local msg, snapdate;

 snapdate = path:gsub ('^/web/', ''):gsub ('^/all/', ''):gsub ('^/ukgwa/', ''):gsub ('^/tna/', ''):gsub ('^/', ''); -- remove leading /web/, /all/, /ukgwa/, /tna/, or /
 snapdate = snapdate:match ('^[^/]+');          -- get timestamp
 if snapdate == "*" then              -- eg. /web/*/http.., etc.
  return 'index';               -- return indicator that this url has an index date
 end

 snapdate = snapdate:gsub ('%a%a_%d?$', ''):gsub ('%-', '');     -- from date, remove any trailing "re_", dashes

 msg = '';
 if snapdate:match ('%*$') then            -- a trailing '*' causes calendar display at archive .org
  snapdate = snapdate:gsub ('%*$', '');         -- remove so not part of length calc later
  msg = inlineRed (err_warn_msgs.ts_cal, 'warning');      -- make a message
 end

 if not tonumber(snapdate) then
  return nil, 'ts_nan';             -- return nil (fatal error flag) and message selector
 end

 local dlen = snapdate:len();
 if dlen < 8 then               -- we need 8 digits TODO: but shouldn't this be testing for 14 digits?
  return '', inlineRed (err_warn_msgs.ts_short, 'error');     -- return empty string and error message
 end

 local year, month, day = snapdate:match ('(%d%d%d%d)(%d%d)(%d%d)');   -- no need for snapdatelong here

 if not is_valid_date (year, month, day) then
  return '', inlineRed (err_warn_msgs.ts_date, 'error');     -- return empty string and error message
 end

 snapdate = table.concat ({year, month, day}, '-');       -- date comparisons are all done in iso format
 if 14 == dlen then
  return snapdate, msg;             -- return date with message if any
 else
  return snapdate, msg .. inlineRed (err_warn_msgs.ts_len, 'warning'); -- return date with warning message(s)
 end
end


--[[--------------------------< decodeArchiveisDate >-----------------------

Given an Archive.is "long link" URI-path (e.g. /2016.08.28-144552/http://example.com)
return the date in df format (e.g. if df = dmy, return 28 August 2016)
Handles "." and "-" in snapshot date, so 2016.08.28-144552 is same as 20160828144552

returns two values:
 first value is one of these:
  valid date string in df format - archive.is date is valid (including the text string 'short link' when url is the short form)
  empty string - wayback date is malformed (not a number, less than 8 digits, not a valid date)
  nil - wayback date is '/save/'
 
 second return value is an appropriate 'message' may or may not be formatted

]]

local function decodeArchiveisDate(path, df)
 local snapdate

 if path:match ('^/%w+$') then            -- short form url path is '/' followed by some number of base 62 digits and nothing else
  return "short link"              -- e.g. http://archive.is/hD1qz
 end

 snapdate = mw.text.split (path, '/')[2]:gsub('[%.%-]', '');     -- get snapshot date, e.g. 2016.08.28-144552; remove periods and hyphens

 local dlen = string.len(snapdate)
 if dlen < 8 then               -- we need 8 digits TODO: but shouldn't this be testing for 14 digits?
  return '', inlineRed (err_warn_msgs.ts_short, 'error');     -- return empty string and error message
 end

 local year, month, day = snapdate:match ('(%d%d%d%d)(%d%d)(%d%d)');   -- no need for snapdatelong here

 if not is_valid_date (year, month, day) then
  return '', inlineRed (err_warn_msgs.ts_date, 'error');     -- return empty string and error message
 end

 snapdate = table.concat ({year, month, day}, '-');       -- date comparisons are all done in iso format
 if 14 == dlen then
  return snapdate;              -- return date
 else
  return snapdate, inlineRed (err_warn_msgs.ts_len, 'warning');   -- return date with warning message
 end
 end


--[[--------------------------< serviceName >-----------------------

Given a domain extracted by mw.uri.new() (eg. web.archive.org) set tail string and service ID

]]

local function serviceName(host, no_link)
 local tracking;
 local index;
 
 host = host:lower():gsub ('^web%.(.+)', '%1'):gsub ('^www%.(.+)', '%1'); -- lowercase, remove web. and www. subdomains

 if services[host] then
  index = host;
 else
  for k, _ in pairs (services) do
   if host:find ('%f[%a]'..k:gsub ('([%.%-])', '%%%1')) then
    index = k;
    break;
   end
  end
 end
 
 if index then
  local out = {''};              -- empty string in [1] so that concatenated result has leading single space
  ulx.url1.service = services[index][4] or 'other';
  tracking = services[index][5] or categories.other;
                    -- build tail string
  if false == services[index][1] then          -- select prefix
   table.insert (out, prefixes.at);
  elseif true == services[index][1] then
   table.insert (out, prefixes.atthe);
  else
   table.insert (out, services[index][1]);
  end
  
  table.insert (out, make_wikilink (services[index][2], services[index][3], no_link)); -- add article wikilink
  if services[index][6] then            -- add tail postfix if it exists
   table.insert (out, services[index][6]);
  end
  
  ulx.url1.tail = table.concat (out, ' ');        -- put it all together; result has leading space character

 else                  -- here when unknown archive
  ulx.url1.service = 'other';
  tracking = categories.unknown;
  ulx.url1.tail = table.concat ({'', prefixes.at, host, inlineRed (err_warn_msgs.unknown_url, error)}, ' ');
 end
 
 track[tracking] = 1
end


--[[--------------------------< parseExtraArgs >-----------------------

Parse numbered arguments starting at 2, such as url2..url10, date2..date10, title2..title10
 For example: {{webarchive |url=.. |url4=.. |url7=..}}
  Three url arguments not in numeric sequence (1..4..7). 
   Function only processes arguments numbered 2 or greater (in this case 4 and 7)
    It creates numeric sequenced table entries like:
    urlx.url2.url = <argument value for url4>
    urlx.url3.url = <argument value for url7>
   Returns the number of URL arguments found numbered 2 or greater (in this case returns "2")

 ]]

local function parseExtraArgs(args)

 local i, j, argurl, argurl2, argdate, argtitle

 j = 2
 for i = 2, config.maxurls do
  argurl = "url" .. i
  if args[argurl] then
   argurl2 = "url" .. j
   ulx[argurl2] = {}
   ulx[argurl2]["url"] = args[argurl]
   argdate = "date" .. i
   if args[argdate] then
    ulx[argurl2]["date"] = args[argdate]
   else
    ulx[argurl2]["date"] = inlineRed (err_warn_msgs.date_miss, 'warning');
   end
 
   argtitle = "title" .. i
   if args[argtitle] then
    ulx[argurl2]["title"] = args[argtitle]
   else
    ulx[argurl2]["title"] = nil
   end
   j = j + 1
  end
 end

 if j == 2 then
  return 0
 else
  return j - 2
 end
end


--[[--------------------------< comma >-----------------------

Given a date string, return "," if it's MDY 

]]

local function comma(date)
 return (date and date:match ('%a+ +%d%d?(,) +%d%d%d%d')) or '';
end


--[[--------------------------< createRendering >-----------------------

Return a rendering of the data in ulx[][]

]]

local function createRendering()

 local displayfield
 local out = {};
 
 local index_date, msg = ulx.url1.date:match ('(index)(.*)');    -- when ulx.url1.date extract 'index' text and message text (if there is a message)
 ulx.url1.date = ulx.url1.date:gsub ('index.*', 'index');     -- remove message

 if 'none' == ulx.url1.format then           -- For {{wayback}}, {{webcite}}
  table.insert (out, '[');            -- open extlink markup
  table.insert (out, ulx.url1.url);          -- add url

  if ulx.url1.title then
   table.insert (out, ' ')            -- the required space
   table.insert (out, ulx.url1.title)         -- the title
   table.insert (out, ']');           -- close extlink markup
   table.insert (out, ulx.url1.tail);         -- tail text
   if ulx.url1.date then
    table.insert (out, '&#32;(');         -- open date text; TODO: why the html entity? replace with regular space?
    table.insert (out, 'index' == ulx.url1.date and s_text.archive or s_text.archived); -- add text
    table.insert (out, ' ');          -- insert a space
    table.insert (out, ulx.url1.date);        -- add date
    table.insert (out, ')');          -- close date text
   end
  else                 -- no title
   if index_date then             -- when url date is 'index' 
    table.insert (out, table.concat ({' ', s_text.Archive_index, ']'})); -- add the index link label
    table.insert (out, msg or '');         -- add date mismatch message when url date is /*/ and |date= has valid date
   else
    table.insert (out, table.concat ({' ', s_text.Archived, '] '})); -- add link label for url has timestamp date (will include mismatch message if there is one)
   end
   if ulx.url1.date then
    if 'index' ~= ulx.url1.date then
     table.insert (out, ulx.url1.date);       -- add date when data is not 'index'
    end
    table.insert (out, comma(ulx.url1.date));      -- add ',' if date format is mdy
    table.insert (out, ulx.url1.tail);        -- add tail text
   else                -- no date
    table.insert (out, ulx.url1.tail);        -- add tail text
   end
  end

  if 0 < ulx.url1.extraurls then           -- For multiple archive URLs
   local tot = ulx.url1.extraurls + 1
   table.insert (out, '.')            -- terminate first url
   table.insert (out, table.concat ({' ', s_text.addlarchives, ': '})); -- add header text

   for i=2, tot do              -- loop through the additionals
    local index = table.concat ({'url', i});      -- make an index
    displayfield = ulx[index]['title'] and 'title' or 'date';  -- choose display text
    table.insert (out, '[');          -- open extlink markup
    table.insert (out, ulx[index]['url']);       -- add the url
    table.insert (out, ' ');          -- the required space
    table.insert (out, ulx[index][displayfield]);     -- add the label
    table.insert (out, ']');          -- close extlink markup
    table.insert (out, i==tot and '.' or ', ');      -- add terminator
   end
  end
  return table.concat (out);            -- make a big string and done

 else                  -- For {{cite archives}}                 
  if 'addlarchives' == ulx.url1.format then        -- Multiple archive services 
   table.insert (out, table.concat ({s_text.addlarchives, ': '}));  -- add header text
  else                 -- Multiple pages from the same archive 
   table.insert (out, table.concat ({s_text.addlpages, ' '}));   -- add header text
   table.insert (out, ulx.url1.date);         -- add date to header text
   table.insert (out, ': ');           -- close header text
  end

  local tot = ulx.url1.extraurls + 1;
  for i=1, tot do               -- loop through the additionals
   local index = table.concat ({'url', i});       -- make an index
   table.insert (out, '[');           -- open extlink markup
   table.insert (out, ulx[index]['url']);        -- add url
   table.insert (out, ' ');           -- add required space

   displayfield = ulx[index]['title'];
   if 'addlarchives' == ulx.url1.format then
    if not displayfield then 
     displayfield = ulx[index]['date']
    end
   else                -- must be addlpages
    if not displayfield then 
     displayfield = table.concat ({s_text.Page, ' ', i});
    end
   end
   table.insert (out, displayfield);         -- add title, date, page label text
   table.insert (out, ']');           -- close extlink markup
   table.insert (out, (i==tot and '.' or ', '));       -- add terminator
  end
  return table.concat (out);            -- make a big string and done
 end
end


--[[--------------------------< P A R A M E T E R _ N A M E _ X L A T E >--------------------------------------

for internaltionalization, translate local-language parameter names to their English equivalents

TODO: return error message if multiple aliases of the same canonical parameter name are found?

returns two tables:
 new_args - holds canonical form parameters and their values either from translation or because the parameter was already in canonical form
 origin - maps canonical-form parameter names to their untranslated (local language) form for error messaging in the local language

unrecognized parameters are ignored

]]

local function parameter_name_xlate (args, params, enum_params)
 local name;                 -- holds modifiable name of the parameter name during evaluation
 local enum;                 -- for enumerated parameters, holds the enumerator during evaluation
 local found = false;              -- flag used to break out of nested for loops
 local new_args = {};              -- a table that holds canonical and translated parameter k/v pairs
 local origin = {};               -- a table that maps original (local language) parameter names to their canonical name for local language error messaging
 local unnamed_params;              -- set true when unsupported positional parameters are detected
 
 for k, v in pairs (args) do             -- loop through all of the arguments in the args table
  name = k;                -- copy of original parameter name

  if 'string' == type (k) then
   if non_western_digits then           -- true when non-western digits supported at this wiki
    name = mw.ustring.gsub (name, '%d', digits);     -- convert this wiki's non-western digits to western digits
   end
   
   enum = name:match ('%d+$');           -- get parameter enumerator if it exists; nil else
   
   if not enum then             -- no enumerator so looking for non-enumnerated parameters
    -- TODO: insert shortcut here? if params[name] then name holds the canonical parameter name; no need to search further
    for pname, aliases in pairs (params) do       -- loop through each parameter the params table
     for _, alias in ipairs (aliases) do       -- loop through each alias in the parameter's aliases table
      if name == alias then
       new_args[pname] = v;        -- create a new entry in the new_args table
       origin [pname] = k;         -- create an entry to make canonical parameter name to original local language parameter name
       found = true;          -- flag so that we can break out of these nested for loops
       break;            -- no need to search the rest of the aliases table for name so go on to the next k, v pair
      end
     end
 
     if found then            -- true when we found an alias that matched name
      found = false;           -- reset the flag
      break;             -- go do next args k/v pair
     end
    end
   else                -- enumerated parameters
    name = name:gsub ('%d$', '#');         -- replace enumeration digits with place holder for table search
    -- TODO: insert shortcut here? if num_params[name] then name holds the canonical parameter name; no need to search further
    for pname, aliases in pairs (enum_params) do     -- loop through each parameter the num_params table
     for _, alias in ipairs (aliases) do       -- loop through each alias in the parameter's aliases table
      if name == alias then
       pname = pname:gsub ('#$', enum);     -- replace the '#' place holder with the actual enumerator
       new_args[pname] = v;        -- create a new entry in the new_args table
       origin [pname] = k;         -- create an entry to make canonical parameter name to original local language parameter name
       found = true;          -- flag so that we can break out of these nested for loops
       break;            -- no need to search the rest of the aliases table for name so go on to the next k, v pair
      end
     end
 
     if found then            -- true when we found an alias that matched name
      found = false;           -- reset the flag
      break;             -- go do next args k/v pair
     end
    end
   end
  else
   unnamed_params = true;            -- flag for unsupported positional parameters
  end
 end                   -- for k, v
 return new_args, origin, unnamed_params;
end


--[[--------------------------< W E B A R C H I V E >----------------------------------------------------------

template entry point

]]

local function webarchive(frame)
 local args = getArgs (frame);

 local data = mw.loadData (table.concat ({         -- make a data module name; sandbox or live
  'Module:Webarchive/data',
  frame:getTitle():find('sandbox', 1, true) and '/sandbox' or ''   -- this instance is ./sandbox then append /sandbox
  }));
 categories = data.categories;            -- fill in the forward declarations
 config = data.config;
 if data.digits.enable then
  digits = data.digits;             -- for i18n; table of digits in the local wiki's language
  non_western_digits = true;            -- use_non_western_digits
 end
 err_warn_msgs = data.err_warn_msgs;
 excepted_pages = data.excepted_pages;
 month_num = data.month_num;             -- for i18n; table of month names in the local wiki's language
 prefixes = data.prefixes;
 services = data.services;
 s_text = data.s_text;
 uncategorized_namespaces = data.uncategorized_namespaces;
 uncategorized_subpages = data.uncategorized_subpages;

 local origin = {};               -- holds a map of English to local language parameter names used in the current template; not currently used
 local unnamed_params;              -- boolean set to true when template call has unnamed parameters
 args, origin, unnamed_params = parameter_name_xlate (args, data.params, data.enum_params); -- translate parameter names in args to English

 local date, format, msg, udate, uri, url;
 local ldf = 'iso';               -- when there is no |date= parameter, render url dates in iso format
 
 if args.url and args.url1 then            -- URL argument (first)
  return inlineError (data.crit_err_msgs.conflicting, {origin.url, origin.url1});
 end
 
 url = args.url or args.url1;
 
 if not url then
  return inlineError (data.crit_err_msgs.empty);
 end
                    -- these iabot bugs perportedly fixed; removing these causes lua script error
--[[                    -- at Template:Webarchive/testcases/Production; resolve that before deleting these tests
 if mw.ustring.find( url, "https://web.http", 1, true ) then     -- track bug - TODO: IAbot bug; not known if the bug has been fixed; deferred
  track[categories.error] = 1;
  return inlineError (data.crit_err_msgs.iabot1);
 end 
 if url == "https://web.archive.org/http:/" then         -- track bug - TODO: IAbot bug; not known if the bug has been fixed; deferred
  track[categories.error] = 1;
  return inlineError (data.crit_err_msgs.iabot2);
 end
]]

 if not (url:lower():find ('^http') or url:find ('^//')) then
  return inlineError (data.crit_err_msgs.invalid_url );
 end

 ulx.url1 = {}
 ulx.url1.url = url

 ulx.url1.extraurls = parseExtraArgs(args)

 local good = false;
 good, uri = pcall (mw.uri.new, ulx.url1.url);        -- get a table of uri parts from this url; protected mode to prevent lua error when ulx.url1.url is malformed
 
 if not good or nil == uri.host then           -- abandon when ulx.url1.url is malformed
  return inlineError (data.crit_err_msgs.invalid_url);
 end
 
 serviceName(uri.host, args.nolink)

 if args.date and args.date1 then           -- Date argument
  return inlineError (data.crit_err_msgs.conflicting, {origin.date, origin.date1});
 end
 
 date = args.date or args.date1;
 date = date and date:gsub (' +', ' ');          -- replace multiple spaces with a single space

 if date and config.verifydates then
  if '*' == date then
   date = 'index';
   ldf = 'iso';              -- set to default format
  elseif 'mdy' == date then
   date = nil;               -- if date extracted from URL,
   ldf = 'mdy';              -- then |date=mdy overrides iso
  elseif 'dmy' == date then
   date = nil;               -- if date extracted from URL,
   ldf = 'dmy';              -- then |date=dmy overrides iso
  elseif 'ymd' == date then
   date = nil;               -- if date extracted from URL,
   ldf = 'ymd';              -- then |date=ymd overrides iso
  else
   date, ldf = decode_date (date);          -- get an iso format date from date and get date's original format
  end
 end

 if 'wayback' == ulx.url1.service or 'locwebarchives' == ulx.url1.service or 'ukgwa' == ulx.url1.service then
  if date then
   if config.verifydates then
    if ldf then
     udate, msg = decodeWaybackDate (uri.path);     -- get the url date in iso format and format of date in |date=; 'index' when wayback url date is *
     if not udate then           -- this is the only 'fatal' error return
      return inlineError (data.crit_err_msgs[msg]);
     end

     if udate ~= date then          -- date comparison using iso format dates
      date = udate;
      msg = table.concat ({
       inlineRed (err_warn_msgs.mismatch, 'warning'),  -- add warning message
       msg,            -- add message if there is one
      });
     end
    end
   end
  else                 -- no |date=
   udate, msg = decodeWaybackDate (uri.path);

   if not udate then             -- this is the only 'fatal' error return
    return inlineError (data.crit_err_msgs[msg]);
   end

   if '' == udate then 
    date = nil;              -- unset
   else
    date = udate;
   end
  end

 elseif 'webcite' == ulx.url1.service then
  if date then
   if config.verifydates then
    if ldf then
     udate = decodeWebciteDate (uri.path);      -- get the url date in iso format
     if 'query' ~= udate then         -- skip if query
      if udate ~= date then         -- date comparison using iso format dates
       date = udate;
       msg = table.concat ({
        inlineRed (err_warn_msgs.mismatch, 'warning'),
        });
      end
     end
    end
   end
  else
   date = decodeWebciteDate( uri.path, "iso" )
   if date == "query" then
    date = nil;              -- unset
    msg = inlineRed (err_warn_msgs.date_miss, 'warning');
   elseif not date then            -- invalid base62 string
    date = inlineRed (err_warn_msgs.date1, 'error');
   end
  end

 elseif 'archiveis' == ulx.url1.service then
  if date then
   if config.verifydates then
    if ldf then
     udate, msg = decodeArchiveisDate (uri.path)     -- get the url date in iso format
     if 'short link' ~= udate then        -- skip if short link
      if udate ~= date then         -- date comparison using iso format dates
       date = udate;
       msg = table.concat ({
        inlineRed (err_warn_msgs.mismatch, 'warning'), -- add warning message
        msg,           -- add message if there is one
       });
      end
     end
    end
   end
  else                 -- no |date=
   udate, msg = decodeArchiveisDate( uri.path, "iso" )
   if udate == "short link" then
    date = nil;              -- unset
    msg = inlineRed (err_warn_msgs.date_miss, 'warning');
   elseif '' == udate then
    date = nil;              -- unset
   else
    date = udate;
   end
  end
  
 else                  -- some other service
  if not date then
   msg = inlineRed (err_warn_msgs.date_miss, 'warning');
  end
 end

 if 'index' == date then
  ulx.url1.date = date .. (msg or '');         -- create index + message (if there is one)
 elseif date then
  ulx.url1.date = makeDate (date, nil, nil, ldf) .. (msg or '');   -- create a date in the wiki's local language + message (if there is one)
 else
  ulx.url1.date = msg;
 end
  
 format = args.format;              -- Format argument 

 if not format then
  format = "none"
 else
  for k, v in pairs (data.format_vals) do         -- |format= accepts two specific values loop through a table of those values
   local found;              -- declare a nil flag
   for _, p in ipairs (v) do           -- loop through local language variants
    if format == p then            -- when |format= value matches 
     format = k;             -- use name from table key
     found = true;            -- declare found so that we can break out of outer for loop
     break;              -- break out of inner for loop
    end
   end
   
   if found then
    break;
   end
  end

  if format == "addlpages" then
   if not ulx.url1.date then
    format = "none"
   end
  elseif format == "addlarchives" then
   format = "addlarchives"
  else
   format = "none"
  end
 end
 ulx.url1.format = format

 if args.title and args.title1 then           -- Title argument
  return inlineError (data.crit_err_msgs.conflicting, {origin.title, origin.title1});
 end

 ulx.url1.title = args.title or args.title1;

 local rend = createRendering()
 if not rend then
  return inlineError (data.crit_err_msgs.unknown);
 end

 return rend .. ((unnamed_params and inlineRed (err_warn_msgs.unnamed_params, 'warning')) or '') .. createTracking();

end


--[[--------------------------< E X P O R T E D   F U N C T I O N S >------------------------------------------
]]

return {webarchive = webarchive};