require('strict');



--[[--------------------------< E X T R A C T _ F R O M _ T E M P L A T E >------------------------------------



no direct template access



extracts short description text from a named template in the named article when that template is found in article

wiki source



requires three arguments:

	frame: frame object required to preprocess template_name

	article_title: the name of the article to inspect - correct spelling and captialization is required

	template_names_tbl: a single template name (a string) or a table of one or more template names all without

		namespace to be inspected - correct spelling and captialization is required



returns two values:

	on success, returns the short description text and true

	on failure, returns error message and nil



]]



local function extract_from_template (frame, article_title, template_names_tbl)

	local content = mw.title.new (article_title):getContent();					-- read the unparsed article source

	if not content then

		return '<span style="font-size:100%;" class="error">error: no article: ' .. article_title .. '</span>';

	end



	local template_name_pattern;

	local start;

	

	if 'string' == type (template_names_tbl) then								-- when single template name passed in as a string

		template_names_tbl = {template_names_tbl};								-- convert to a table

	end

	

	local templateName

	for _, template_name in ipairs (template_names_tbl) do						-- loop through the name in the table

		template_name_pattern = template_name:gsub ('^%a', string.lower):gsub ('^%a', '%[%1%1%]'):gsub ('%[%a', string.upper);	-- make lua pattern for initial letter upper or lower case: A -> [Aa]

		start = content:find ('{{%s*' .. template_name_pattern);				-- find the start of {{template name ...;

		if start then

			templateName = template_name

			break;																-- found a matching template

		end

	end



	if not start then															-- no templates found: return name of first template in template_names_tbl in error message

		return '<span style="font-size:100%;" class="error">error: no template: ' .. template_names_tbl1 .. ' in: ' .. article_title .. '</span>';

	end



	local text = string.match (content, '%b{}', start);							-- start points to first { of the templateName

	if not text then

		return '<span style="font-size:100%;" class="error">error: failed to extract template: ' .. templateName .. '</span>';

	end



	text = text:gsub ('<ref[^>]->[^<]-</ref>', '');								-- delete references before preprocessing; they do not belong in shortdesc text

	text = text:gsub ('<ref[^>]-/ *>', '');										-- also delete self-closed named references

	text = text:gsub ('{{%s*sfn[^}]-}}', '');									-- delete sfn template which make references using {{#tag:}} parser functions

	text = text:gsub ('{{#tag:ref[^}]-}}', '');									-- and delete these too



	text = frame:preprocess (text):match ('<div[^>]-class="shortdescription.->(.-)</div>');		-- preprocess and extract shortdescription text

	if not text then

		return '<span style="font-size:100%;" class="error">error: no short description text in: ' .. templateName .. ' in '.. article_title .. '</span>';

	end



	return mw.text.trim (text), true;											-- trim whitespace and done

																				-- preprocess the template then apply syntax highlighting

																				-- this will display the preprocessed template; not usable here

																				-- for much other than debugging because syntaxhighlight returns a stripmarker

--	return template_name .. frame:callParserFunction ('#tag:syntaxhighlight', frame:preprocess (text));

end





--[[--------------------------< E X T R A C T _ F R O M _ A R T I C L E >--------------------------------------



no direct template access



extracts short description text from {{short description}} template when that template is found in article wiki

source; searches for both the long name (short description) and the short-name redirect (SHD); if both are present

long name controls; if multiples of the same name are present, the first-found controls.



requires one argument: article_title is the name of the article to be inspected



on success, returns the short description text; error message else



]]



local function extract_from_article (article_title)

	local content = mw.title.new (article_title):getContent();					-- read the unparsed article source

	if not content then

		return '<span style="font-size:100%;" class="error">error: no article: ' .. article_title .. '</span>';

	end



	local text, start;

	

	start = string.find (content, '{{%s*[Ss]hort description') or				-- find the start of {{Short description}} template

		string.find (content, '{{%s*SHD');										-- not full name, try the {{SHD}} redirect



	if not start then

		return '<span style="font-size:100%;" class="error">error: no short description in: ' .. article_title .. '</span>';

	end



	text = content:match ('%b{}', start);										-- get the short description template; start points to first { of the template

	if not text then

		return '<span style="font-size:100%;" class="error">error: failed to extract short description template from ' .. article_title .. '</span>';

	end



	text = text:match ('^[^|}]+|%s*(.+)%s*}}$');								-- strip '{{template name|' and '}}'; trim leading and trailing whitespace

	

	return text and text or '<span style="font-size:100%;" class="error">error: no short description text in: ' .. article_title .. '</span>';

end





--[[--------------------------< E X T R A C T _ S H O R T _ D E S C R I P T I O N >----------------------------



template entry point:

	{{#invoke:extract short description|extract_short_description}}



search for and return text that is used by the {{short description}} template.  {{Short description}}, also {{SHD}}

may be located in article wikisource or embedded in a template (commonly an infobox template).  When neither of

|template= and {{{2|}}} are set, this code will look in the article wiki source; when set, this code look inside the

named template.



This template entry takes two parameters:

	{{{1}}} or |article=: required; name of wiki article from which to extract the short description

	{{{2}}} or |template=; optional; name of template that holds the {{short description}} template



on success, returns the short description text; error message else



]]



local function extract_short_description (frame)

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

	local args = getArgs(frame);

	

	if args1 and args.article then											-- both assigned, fail with an error message

		return '<span style="font-size:100%;" class="error">error: conflicting |{{{1}}} and |article= parameters</span>';

	end

	

	local article_title = args1 or args.article;								-- the required parameter

	

	if not article_title then													-- not supplied, fail with an error message

		return '<span style="font-size:100%;" class="error">error: article title required</span>';

	end

	

	local template_name = args2 or args.template;								-- optional

	

	if template_name then

		local text, _ = extract_from_template (frame, article_title, template_name);	-- ignore second return value

		return text;

	else

		return extract_from_article (article_title);

	end

end





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

]]



return {

	extract_short_description = extract_short_description,

	extract_from_template = extract_from_template,

	extract_from_article = extract_from_article,

	}