# Module:Delink

-- This module de-links most wikitext.  

require("strict")  

local p = {}  

local getArgs  

local function delinkReversePipeTrick(s)  
if s:match("^%[%[|.*[|\n]") then -- Check for newlines or multiple pipes.  
return s  
end  
return s:match("%[%[|(.*)%]%]")  

end  

local function delinkPipeTrick(s)  
-- We need to deal with colons, brackets, and commas, per .  
-- First, remove the text before the first colon, if any.  
if s:match(":") then  
s = s:match("%[%[.-:(.*)|%]%]")  
-- If there are no colons, grab all of the text apart from the square brackets and the pipe.  
else  
s = s:match("%[%[(.*)|%]%]")  
end  

-- Next up, brackets and commas.  
if s:match("%(.-%)$") then -- Brackets trump commas.  
s = s:match("(.-) ?%(.-%)$")  
elseif s:match(",") then -- If there are no brackets, display only the text before the first comma.  
s = s:match("(.-),.*$")  
end  
return s  
end  

-- Return wikilink target |wikilinks=target  
local function getDelinkedTarget(s)  
local result = s  
-- Deal with the reverse pipe trick.  
if result:match("%[%[|") then  
return delinkReversePipeTrick(result)  
end  

result = mw.uri.decode(result, "PATH") -- decode percent-encoded entities. Leave underscores and plus signs.  
result = mw.text.decode(result, true) -- decode HTML entities.  

-- Check for bad titles. To do this we need to find the  
-- title area of the link, i.e. the part before any pipes.  
local target_area  
if result:match("|") then -- Find if we're dealing with a piped link.  
target_area = result:match("^%[%[(.-)|.*%]%]")  
else  
target_area = result:match("^%[%[(.-)%]%]")  
end  

-- Check for bad characters.  
if mw.ustring.match(target_area, "[%[%]<>{}%%%c\n]") and mw.ustring.match(target_area, "[%[%]<>{}%%%c\n]") ~= "?" then  
return s  
end  

return target_area  
end  

local function getDelinkedLabel(s)  
local result = s  
-- Deal with the reverse pipe trick.  
if result:match("%[%[|") then  
return delinkReversePipeTrick(result)  
end  

result = mw.uri.decode(result, "PATH") -- decode percent-encoded entities. Leave underscores and plus signs.  
result = mw.text.decode(result, true) -- decode HTML entities.  

-- Check for bad titles. To do this we need to find the  
-- title area of the link, i.e. the part before any pipes.  
local target_area  
if result:match("|") then -- Find if we're dealing with a piped link.  
target_area = result:match("^%[%[(.-)|.*%]%]")  
else  
target_area = result:match("^%[%[(.-)%]%]")  
end  

-- Check for bad characters.  
if mw.ustring.match(target_area, "[%[%]<>{}%%%c\n]") and mw.ustring.match(target_area, "[%[%]<>{}%%%c\n]") ~= "?" then  
return s  
end  

-- Check for categories, interwikis, and files.  
local colon_prefix = result:match("%[%[(.-):.*%]%]") or "" -- Get the text before the first colon.  
local ns = mw.site.namespaces[colon_prefix] -- see if this is a known namespace  
if mw.language.isKnownLanguageTag(colon_prefix) or (ns and (ns.canonicalName == "File" or ns.canonicalName == "Category")) then  
return ""  
end  

-- Remove the colon if the link is using the .  
if result:match("%[%[:") then  
result = "[[" .. result:match("%[%[:(.*%]%])")  
end  

-- Deal with links using the .  
if mw.ustring.match(result, "^%[%[[^|]*|%]%]") then  
return delinkPipeTrick(result)  
end  

-- Find the display area of the wikilink  
if result:match("|") then -- Find if we're dealing with a piped link.  
result = result:match("^%[%[.-|(.+)%]%]")  
-- Remove new lines from the display of multiline piped links,  
-- where the pipe is before the first new line.  
result = result:gsub("\n", "")  
else  
result = result:match("^%[%[(.-)%]%]")  
end  

return result  
end  

local function delinkURL(s)  
-- Assume we have already delinked internal wikilinks, and that  
-- we have been passed some text between two square brackets [foo].  

-- If the text contains a line break it is not formatted as a URL, regardless of other content.  
if s:match("\n") then  
return s  
end  

-- Check if the text has a valid URL prefix and at least one valid URL character.  
local valid_url_prefixes = {"//", "http://", "https://", "ftp://", "gopher://", "mailto:", "news:", "irc://"}  
local url_prefix  
for _ ,v in ipairs(valid_url_prefixes) do  
if mw.ustring.match(s, '^%[' .. v ..'[^"%s].*%]' ) then  
url_prefix = v  
break  
end  
end  

-- Get display text  
if not url_prefix then  
return s  
end  
s = s:match("^%[" .. url_prefix .. "(.*)%]") -- Grab all of the text after the URL prefix and before the final square bracket.  
s = s:match('^.-(["<> ].*)') or "" -- Grab all of the text after the first URL separator character ("<> ).  
s = mw.ustring.match(s, "^%s*(%S.*)$") or "" -- If the separating character was a space, trim it off.  

local s_decoded = mw.text.decode(s, true)  
if mw.ustring.match(s_decoded, "%c") then  
return s  
end  

return s_decoded  

end  

local function delinkLinkClass(text, pattern, delinkFunction)  
if type(text) ~= "string" then  
error("Attempt to de-link non-string input.", 2)  
end  
if type(pattern) ~= "string" or mw.ustring.sub(pattern, 1, 1) ~= "^" then  
error('Invalid pattern detected. Patterns must begin with "^".', 2)  
end  
-- Iterate over the text string, and replace any matched text. using the  
-- delink function. We need to iterate character by character rather  
-- than just use gsub, otherwise nested links aren't detected properly.  
local result = ""  
while text ~= "" do  
-- Replace text using one iteration of gsub.  
text = mw.ustring.gsub(text, pattern, delinkFunction, 1)  
-- Append the -most character to the result string.  
result = result .. mw.ustring.sub(text, 1, 1)  
text = mw.ustring.sub(text, 2, -1)  
end  
return result  
end  

function p._delink(args)  
local text = args[1] or ""  
if args.refs == "yes" then  
-- Remove any representing ref tags. In most situations  
-- this is not a good idea - only use it if you know what you are doing!  
text = mw.ustring.gsub(text, "UNIQ%w*%-ref%-%d*%-QINU", "")  
end  
if args.comments ~= "no" then  
text = text:gsub("<!%-%-.-%-%->", "") -- Remove html comments.  
end  

if args.wikilinks ~= "no" and args.wikilinks ~= "target" then  
-- De-link wikilinks and return the label portion of the wikilink.  
text = delinkLinkClass(text, "^%[%[.-%]%]", getDelinkedLabel)  
elseif args.wikilinks == "target" then  
-- De-link wikilinks and return the target portions of the wikilink.  
text = delinkLinkClass(text, "^%[%[.-%]%]", getDelinkedTarget)  
end  
if args.urls ~= "no" then  
text = delinkLinkClass(text, "^%[.-%]", delinkURL) -- De-link URLs.  
end  
if args.whitespace ~= "no" then  
-- Replace single new lines with a single space, but leave double new lines  
-- and new lines only containing spaces or tabs before a second new line.  
text = mw.ustring.gsub(text, "([^\n \t][ \t]*)\n([ \t]*[^\n \t])", "%1 %2")  
text = text:gsub("[ \t]+", " ") -- Remove extra tabs and spaces.  
end  
return text  
end  

function p.delink  
if not getArgs then  
getArgs = require('Module:Arguments').getArgs  
end  
return p._delink(getArgs(, {wrappers = 'Template:Delink'}))  
end  

return p