Module:Excerpt

-- Module:Excerpt implements the Excerpt template
-- Documentation and master version: https://en.wikipedia.org/wiki/Module:Excerpt
-- Authors: User:Sophivorus, User:Certes, User:Aidan9382 & others
-- License: CC-BY-SA-3.0

local Transcluder = require( 'Module:Transcluder' )

local yesno = require( 'Module:Yesno' )

local ok, config = pcall( require, 'Module:Excerpt/config' )
if not ok then config = {} end

local p = {}

-- Helper function to get arguments
local args
local function getArg( key, default )
 local value = args[ key ]
 if value and mw.text.trim( value ) ~= '' then
  return value
 end
 return default
end

-- Helper function to handle errors
local function getError( message, value )
 if type( message ) == 'string' then
  message = Transcluder.getError( message, value )
 end
 if config.categories and config.categories.errors and mw.title.getCurrentTitle().isContentPage then
  message:node( '[[Category:' .. config.categories.errors .. ']]' )
 end
 return message
end

-- Helper function to get localized messages
local function getMessage( key )
 local ok, TNT = pcall( require, 'Module:TNT' )
 if not ok then return key end
 return TNT.format( 'I18n/Module:Excerpt.tab', key )
end

-- Main entry point for templates
function p.main( frame )
 args = Transcluder.parseArgs( frame )

 -- Make sure the requested page exists
 local page = getArg( 1 )
 if not page or page == '{{{1}}}' then return getError( 'no-page' ) end
 local title = mw.title.new(page)
 if not title then return getError( 'invalid-title', page ) end
 if title.isRedirect then title = title.redirectTarget end
 if not title.exists then return getError( 'page-not-found', page ) end
 page = title.prefixedText

 -- Set variables from the template parameters
 local section = getArg( 2, mw.ustring.match( getArg( 1 ), '[^#]+#(.+)' ) )
 local hat = yesno( getArg( 'hat', true ) )
 local edit = yesno( getArg( 'edit', true ) )
 local this = getArg( 'this' )
 local only = getArg( 'only' )
 local files = getArg( 'files', getArg( 'file', ( only == 'file' and 1 ) ) )
 local lists = getArg( 'lists', getArg( 'list', ( only == 'list' and 1 ) ) )
 local tables = getArg( 'tables', getArg( 'table', ( only == 'table' and 1 ) ) )
 local templates = getArg( 'templates', getArg( 'template', ( only == 'template' and 1 ) ) )
 local paragraphs = getArg( 'paragraphs', getArg( 'paragraph', ( only == 'paragraph' and 1 ) ) )
 local references = getArg( 'references' )
 local subsections = not yesno( getArg( 'subsections' ) )
 local noLinks = not yesno( getArg( 'links', true ) )
 local noBold = not yesno( getArg( 'bold' ) )
 local onlyFreeFiles = yesno( getArg( 'onlyfreefiles', true ) )
 local briefDates = yesno( getArg( 'briefdates', false ) )
 local inline = yesno( getArg( 'inline' ) )
 local quote = yesno( getArg( 'quote' ) )
 local more = yesno( getArg( 'more' ) )
 local class = getArg( 'class' )
 local displaytitle = getArg( 'displaytitle' ) or page

 -- Build the hatnote
 if hat and not inline then
  if this then
   hat = this
  elseif quote then
   hat = getMessage( 'this' )
  elseif only then
   hat = getMessage( only )
  else
   hat = getMessage( 'section' )
  end
  hat = hat .. ' ' .. getMessage( 'excerpt' ) .. ' '
  if section then
   hat = hat .. '[[:' .. page .. '#' .. mw.uri.anchorEncode( section ) .. '|' .. displaytitle
    .. ' § ' .. mw.ustring.gsub( section, '%[%[([^]|]+)|?[^]]*%]%]', '%1' ) .. ']].' -- remove nested links
  else
   hat = hat .. '[[:' .. page .. '|' .. displaytitle .. ']].'
  end
  if edit then
   hat = hat .. '<span class="mw-editsection-like plainlinks"><span class="mw-editsection-bracket">[</span>['
   hat = hat .. title:fullUrl( 'action=edit' ) .. ' ' .. mw.message.new( 'editsection' ):plain()
   hat = hat .. ']<span class="mw-editsection-bracket">]</span></span>'
  end
  if config.hat then
   hat = config.hat .. hat .. '}}'
   hat = frame:preprocess( hat )
  else
   hat = mw.html.create( 'div' ):addClass( 'dablink excerpt-hat' ):wikitext( hat )
  end
 else
  hat = nil
 end

 -- Build the "Read more" link
 if more and not inline then
  more = "'''[[" .. page .. '#' .. ( section or '' ) .. "|" .. getMessage( 'more' ) .. "]]'''"
  more = mw.html.create( 'div' ):addClass( 'noprint excerpt-more' ):wikitext( more )
 else
  more = nil
 end

 -- Build the options for Module:Transcluder out of the template parameters and the desired defaults
 local options = {
  files = files,
  lists = lists,
  tables = tables,
  paragraphs = paragraphs,
  sections = subsections,
  categories = 0,
  references = references,
  only = only and mw.text.trim( only, 's' ) .. 's',
  noLinks = noLinks,
  noBold = noBold,
  noSelfLinks = true,
  noNonFreeFiles = onlyFreeFiles,
  noBehaviorSwitches = true,
  fixReferences = true,
  linkBold = true,
 }

 -- Get the excerpt itself
 local title = page .. '#' .. ( section or '' )
 local ok, excerpt = pcall( Transcluder.get, title, options )
 if not ok then return getError( excerpt ) end
 if mw.text.trim( excerpt ) == '' and not only then
  if section then return getError( 'section-empty', section ) else return getError( 'lead-empty' ) end
 end

 -- Fix birth and death dates, but only in the first paragraph
 if briefDates then
  local startpos = 1 -- skip initial templates
  local s
  local e = 0
  repeat
   startpos = e + 1
   s, e = mw.ustring.find( excerpt, "%s*%b{}%s*", startpos )
  until not s or s > startpos
  s, e = mw.ustring.find( excerpt, "%b()", startpos ) -- get (...), which may be (year–year)
  if s and s < startpos + 100 then -- look only near the start
   local year1, conjunction, year2 = mw.ustring.match( mw.ustring.sub( excerpt, s, e ), '(%d%d%d+)(.-)(%d%d%d+)' )
   if year1 and year2 and (mw.ustring.match( conjunction, '[%-–—]' ) or mw.ustring.match( conjunction, '{{%s*[sS]nd%s*}}' )) then
    local y1 = tonumber(year1)
    local y2 = tonumber(year2)
    if y2 > y1 and y2 < y1 + 125 and y1 <= tonumber( os.date( "%Y" )) then
     excerpt = mw.ustring.sub( excerpt, 1, s ) .. year1 .. "–" .. year2 .. mw.ustring.sub( excerpt, e )
    end
   end
  end
 end

 -- If no file was found, try to get one from the infobox
 local fileNamespaces = Transcluder.getNamespaces( 'File' )
 if ( ( only == 'file' or only == 'files' ) or ( not only and ( files ~= '0' or not files ) ) ) and -- caller asked for files
  not Transcluder.matchAny( excerpt, '%[%[', fileNamespaces, ':' ) and -- and there are no files in Transcluder's output
  config.captions -- and we have the config option required to try finding files in templates
 then
  -- We cannot distinguish the infobox from the other templates so we search them all
  local infobox = Transcluder.getTemplates( excerpt );
  infobox = table.concat( infobox )
  local parameters = Transcluder.getParameters( infobox )
  local file, captions, caption
  for _, pair in pairs( config.captions ) do
   file = pair[1]
   file = parameters[file]
   if file and Transcluder.matchAny( file, '^.*%.', { '[Jj][Pp][Ee]?[Gg]', '[Pp][Nn][Gg]', '[Gg][Ii][Ff]', '[Ss][Vv][Gg]' }, '.*' ) then
    file = mw.ustring.match( file, '%[?%[?.-:([^{|]+)%]?%]?' ) or file -- [[File:Example.jpg{{!}}upright=1.5]] to Example.jpg
    captions = pair[2]
    for _, p in pairs( captions ) do
     if parameters[ p ] then caption = parameters[ p ] break end
    end
    excerpt = '[[File:' .. file .. '|thumb|' .. ( caption or '' ) .. ']]' .. excerpt
    if ( onlyFreeFiles ) then
     excerpt = Transcluder.removeNonFreeFiles( excerpt )
    end
    break
   end
  end
 end

 -- Unlike other elements, templates are filtered here
 -- because we had to search the infoboxes for files
 local trash
 if only and ( only == 'template' or only == 'templates' ) then
  trash, excerpt = Transcluder.getTemplates( excerpt, templates );
 else -- Remove blacklisted templates
  local blacklist = config.blacklist and table.concat( config.blacklist, ',' ) or ''
  if templates then
   if string.sub( templates, 1, 1 ) == '-' then --Unwanted templates. Append to blacklist
    blacklist = templates .. ',' .. blacklist
   else --Wanted templates. Replaces blacklist and acts as whitelist
    blacklist = templates
   end
  else
   blacklist = '-' .. blacklist
  end
  trash, excerpt = Transcluder.getTemplates( excerpt, blacklist );
 end

 -- Remove extra line breaks but leave one before and after so the parser interprets lists, tables, etc. correctly
 excerpt = mw.text.trim( excerpt )
 excerpt = string.gsub( excerpt, '\n\n\n+', '\n\n' )
 excerpt = '\n' .. excerpt .. '\n'

 -- Remove nested categories
 excerpt = frame:preprocess( excerpt )
 local categories, excerpt = Transcluder.getCategories( excerpt, options.categories )

 -- Add tracking categories
 if config.categories then
  local contentCategory = config.categories.content
  if contentCategory and mw.title.getCurrentTitle().isContentPage then
   excerpt = excerpt .. '[[Category:' .. contentCategory .. ']]'
  end
  local namespaceCategory = config.categories[ mw.title.getCurrentTitle().namespace ]
  if namespaceCategory then
   excerpt = excerpt .. '[[Category:' .. namespaceCategory .. ']]'
  end
 end

 -- Load the styles
 local styles
 if config.styles then
  styles = frame:extensionTag( 'templatestyles', '', { src = config.styles } )
 end

 -- Combine and return the elements
 if inline then
  return mw.text.trim( excerpt )
 end
 local tag = 'div'
 if quote then
  tag = 'blockquote'
 end
 excerpt = mw.html.create( 'div' ):addClass( 'excerpt' ):wikitext( excerpt )
 local block = mw.html.create( tag ):addClass( 'excerpt-block' ):addClass( class )
 return block:node( styles ):node( hat ):node( excerpt ):node( more )
end

-- Entry points for backwards compatibility
function p.lead( frame ) return p.main( frame ) end
function p.excerpt( frame ) return p.main( frame ) end

return p