require('Module:No globals');

--[[--------------------------< A R G S _ D E F A U L T >------------------------------------------------------

a table to specify initial values.

]]

local args_default = {
	bracket_left = '',
	bracket_right = '',
	bracket_year_left = '',
	bracket_year_right = '',
	postscript = '',
	page = '',
	pages = '',
	location = '',
	page_sep = ", p.&nbsp;",
	pages_sep = ", pp.&nbsp;",
	ref = '',
	};


--[[--------------------------< I S _ Y E A R >----------------------------------------------------------------

evaluates param to see if it is one of these forms with or without lowercase letter disambiguator:
	YYYY
	n.d.
	nd	
	c. YYYY
	YYYY–YYYY	(separator is endash)
	YYYY–YY		(separator is endash)

return true when param has a recognized form; false else

]]

local function is_year (param)
	return mw.ustring.match (param, '^%d%d%d%d?%l?$') or
		mw.ustring.match (param, '^n%.d%.%l?$') or
		mw.ustring.match (param, '^nd%l?$') or
		mw.ustring.match (param, '^c%. %d%d%d%d?%l?$') or
		mw.ustring.match (param, '^%d%d%d%d–%d%d%d%d%l?$') or
		mw.ustring.match (param, '^%d%d%d%d–%d%d%l?$');
end


--[[--------------------------< C O R E >----------------------------------------------------------------------

returns an anchor link (CITEREF) formed from one to four author names, year, and insource location (|p=, |pp=, loc=)

]]

local function core( args )
	local result;

	if args.P5 ~= '' then
		if is_year (args.P5) then
			result = table.concat ({args.P1, ' et al. ', args.bracket_year_left, args.P5, args.bracket_year_right});
		else
			args.P5 = '';														-- when P5 not a year don't include in anchor
			result = table.concat ({args.P1, ' et al.'});						-- and don't render it
		end

	elseif args.P4 ~= '' then
		if is_year (args.P4) then
			result = table.concat ({args.P1, ', ', args.P2, ' &amp; ', args.P3, ' ', args.bracket_year_left, args.P4, args.bracket_year_right});	-- three names and a year
		else
			result = table.concat ({args.P1, ' et al.'});						-- four names
		end

	elseif args.P3 ~= '' then
		if is_year (args.P3) then
			result = table.concat ({args.P1, ' &amp; ', args.P2, ' ', args.bracket_year_left, args.P3, args.bracket_year_right});	-- two names and a year
		else
			result = table.concat ({args.P1, ', ', args.P2, ' ', ' &amp; ', args.P3});	-- three names
		end
			
	elseif args.P2 ~= '' then
		if is_year (args.P2) then
			result = table.concat ({args.P1, ' ', args.bracket_year_left, args.P2, args.bracket_year_right});	-- one name and year
		else
			result = table.concat ({args.P1, ' &amp; ', args.P2});				-- two names
		end
		
	else
		result = args.P1;														-- one name
	end
																				-- when author-date result ends with a dot (typically when the last positional parameter holds 'n.d.')
																				-- and when no in-source location (no |p=, |pp=, or |loc=)
																				-- and when the first or only character in args.postscript is a dot
																				-- remove the author-date result trailing dot
																				-- the author-date result trailing dot will be replaced later with the content of args.postscript (usually a dot)
	if ('.' == result:sub(-1)) and ('.' == args.postscript:sub(1)) and ('' == args.page) and ('' == args.pages) and ('' == args.location) then
		result = result:gsub ('%.$', '');
	end
	
	if args.ref ~= 'none' then
		if args.ref ~= '' then
			result = table.concat ({'[[#', mw.uri.anchorEncode (args.ref), '|', result, ']]'});
		else
			result = table.concat ({'[[#CITEREF', mw.uri.anchorEncode (table.concat ({args.P1, args.P2, args.P3, args.P4, args.P5})), '|', result, ']]'});
		end
	end

	if args.page ~= '' then
		result = table.concat ({result, args.page_sep, args.page});
	elseif args.pages ~= ''then
		result = table.concat ({result, args.pages_sep, args.pages});
	end      

	if args.location ~= '' then
		result = table.concat ({result, ', ', args.location});
	end

	result = table.concat ({args.bracket_left, result, args.bracket_right, args.postscript}):gsub ('%s+', ' ');		-- strip redundant spaces
	return result;
end


--[[--------------------------< A R G S  _ F E T C H >---------------------------------------------------------

Because all of the templates share a common set of parameters, a single common function to fetch those parameters
from frame and parent frame.

]]

local function args_fetch (frame, ps)
	local args = args_default;													-- create a copy of the default table
	local pframe = frame:getParent();											-- point to the template's parameter table

	for k, v in pairs (frame.args) do											-- override defaults with values provided in the #invoke: if any
		args[k] = v;	   
	end
	
	args.postscript = pframe.args.postscript or pframe.args.ps or ps;
	if 'none' == args.postscript then
		args.postscript = '';
	end
	args.page = pframe.args.p or pframe.args.page or '';
	args.pages = pframe.args.pp or pframe.args.pages or '';
	args.location = pframe.args.loc or '';
	args.ref = pframe.args.ref or pframe.args.Ref or '';
	
	for i, v in ipairs ({'P1', 'P2', 'P3', 'P4', 'P5'}) do						-- loop through the five positional parameters and trim if set else empty string
		args[v] = (pframe.args[i] and mw.text.trim (pframe.args[i])) or '';
	end

	return args;
end


--[[--------------------------< H A R V A R D _ C I T A T I O N >----------------------------------------------

common entry point for:
	{{harvard citation}} aka {{harv}}
	{{Harvard citation no brackets}} aka {{harvnb}}
	{{harvcol}}
	{{harvcolnb}}
	{{harvcoltxt}}
	{{Harvard citation text}} aka {{harvtxt}}
	{{Harvp}}

Distinguishing features (brackets and page separators) are specified in this module's {{#invoke}} in the respective templates.

]]

local function harvard_citation (frame)
	local args = args_fetch (frame, '');										-- get the template and invoke parameters; default postscript is empty string

	return core (args);
end


--[[--------------------------< S T R I P _ U R L >------------------------------------------------------------

used by sfn() and sfnm().  This function fixes an issue with reference tooltip gadget where the tooltip is not displayed
when an insource locator (|p=, |pp=, |loc=) has an external wikilink that contains a # character

strip uri-reserved characters from urls in |p=, |pp-, and |loc= parameters  The researved characters are:
	!#$&'()*+,/:;=?@[]
	
]]

local function strip_url (pages)
local escaped_uri;
	if not pages or ('' == pages) then
		return pages;
	end
	
	for uri in pages:gmatch ('%[(%a[%w%+%.%-]*://%S+)') do						-- for each external link get the uri
		escaped_uri = uri:gsub ("([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1" );		-- save a copy with lua pattern characters escaped
		uri = uri:gsub ("[!#%$&'%(%)%*%+,/:;=%?@%[%]%.%%]", '');				-- remove reserved characters and '%' because '%20' (space character) is a lua 'invalid capture index'
		pages = pages:gsub (escaped_uri, uri, 1);								-- replace original uri with the stripped version
	end
	
	return pages;
end


--[[--------------------------< S F N >------------------------------------------------------------------------

entry point for {{sfn}} and {{sfnp}}

]]

local function sfn (frame)
	local args = args_fetch (frame, '.');										-- get the template and invoke parameters; default postscript is a dot

	local result = core (args);													-- go make a CITEREF anchor
	
																				-- put it all together and then strip redundant spaces
	local name = table.concat ({'FOOTNOTE', args.P1, args.P2, args.P3, args.P4, args.P5, strip_url (args.page), strip_url (args.pages), strip_url (args.location)}):gsub ('%s+', ' ');

	return frame:extensionTag ({name='ref', args={name=name}, content=result});	

	
end


--[[--------------------------< S F N M >----------------------------------------------------------------------

common entry point for {{sfnm}} and {{sfnmp}}

Distinguishing features (brackets) are specified in this module's {{#invoke}} in the respective templates.

]]

local function sfnm (frame)
	local args = args_default;													-- create a copy of the default table
	local pframe = frame:getParent();											-- point to the template's parameter table
	
	local n = 1;																-- index of source; this is the 'n' in na1, ny, etc
	local first_pnum = 1;														-- first of a pair of positional parameters
	local second_pnum = 2;														-- second of a pair of positional parameters

	local last_ps = 0;															-- index of the last source with |nps= set
	local last_index = 0;														-- index of the last source; these used to determine which of |ps= or |nps= will terminate the whole rendering

	local out = {};																-- table to hold rendered sources
	local footnote = {'FOOTNOTE'};												-- all author, date, insource location stuff becomes part of the reference's footnote id; added as we go

	for k, v in pairs (frame.args) do											-- override defaults with values provided in the #invoke: if any
		args[k] = v;	   
	end
	
	while true do
		if not pframe.args[table.concat ({n, 'a1'})] and not pframe.args[first_pnum] then
			break;																-- no na1 or matching positional parameter so done
		end
		
		if pframe.args[table.concat ({n, 'a1'})] then							-- does this source use named parameters?
			for _, v in ipairs ({'P1', 'P2', 'P3', 'P4', 'P5'}) do				-- initialize for this source
				args[v] = '';
			end

			for i, v in ipairs ({'P1', 'P2', 'P3', 'P4', 'P5'}) do				-- extract author and year parameters for this source
				args[v] = pframe.args[table.concat ({n, 'a', i})] or '';		-- attempt to assign author name
				if '' == args[v] then											-- when there wasn't an author name
					args[v] = pframe.args[table.concat ({n, 'y'})] or '';		-- attempt to assign year
					break;														-- done with author/date for this source
				end
			end

		else																	-- this source uses positional parameters
			args.P1 = mw.text.trim (pframe.args[first_pnum]);					-- yes, only one author supported
			args.P2 = (pframe.args[second_pnum] and mw.text.trim (pframe.args[second_pnum])) or '';	-- when positional author, year must also be positional

			for _, v in ipairs ({'P3', 'P4', 'P5'}) do							-- blank the rest of these for this source
				args[v] = '';
			end

			first_pnum = first_pnum + 2;										-- source must use positional author and positional year
			second_pnum = first_pnum + 1;										-- bump these for possible next positional source
		end
		
		args.postscript = pframe.args[table.concat ({n, 'ps'})] or '';
		if 'none' == args.postscript then										-- this for compatibility with other footnote templates; does nothing
			args.postscript = '';
		end

		args.ref = pframe.args[table.concat ({n, 'ref'})] or '';				-- alternate reference for this source

		args.page = pframe.args[table.concat ({n, 'p'})] or '';					-- insource locations for this source
		args.pages = pframe.args[table.concat ({n, 'pp'})] or '';
		args.location = pframe.args[table.concat ({n, 'loc'})] or '';

		table.insert (out, core (args));										-- save the rendering of this source
		
		for k, v in ipairs ({'P1', 'P2', 'P3', 'P4', 'P5'}) do					-- create the FOOTNOTE id
			if '' ~= args[v] then
				table.insert (footnote, args[v]);
			end
		end
		for k, v in ipairs ({'page', 'pages', 'location'}) do					-- these done separately so that we can strip uri-reserved characters from extlinked page numbers 
			if '' ~= args[v] then
				table.insert (footnote, strip_url (args[v]))
			end
		end
		
		last_index = n;															-- flags used to select terminal postscript from nps or from end_ps
		if '' ~= args.postscript then							
			last_ps = n;
		end
		
		n = n+1;																-- bump for the next one
	end
	
	local name = table.concat (footnote):gsub ('%s+', ' ');						-- put the footnote together and strip redundant space
	
	args.end_ps = pframe.args.postscript or pframe.args.ps or '.';				-- this is the postscript for the whole not for the individual sources
	if 'none' == args.end_ps then												-- not an original sfnm parameter value; added for compatibility with other footnote templates
		args.end_ps = '';
	end

	local result = table.concat ({table.concat (out, '; '), (last_index == last_ps) and '' or  args.end_ps});
	return frame:extensionTag ({name='ref', args={name=name}, content=result});
end


--[[--------------------------< E X P O R T   T A B L E >------------------------------------------------------
]]

return {
	harvard_citation = harvard_citation,
	sfn = sfn,
	sfnm = sfnm,
	};