pgn = require('module:pgn')





local function moveToIndex(move)

	if not move:match('^%d+[dl]$') then return -1 end -- not a move

	local num, color = move:match('(%d+)([dl])')

	return num * 2 + (color == 'd' and 1 or 0)

end



local function indexToMove(index)

	return string.format('%d%s', math.floor( index / 2), index % 2 == 0 and 'l' or 'd')

end

	

function display_game(frame)

	local args = frame:getParent().args

	for k, v in pairs(frame.args) do argsk = v end

	local game = args'pgn'

	if not game then error('must have "pgn" parameter') end

	

	local moves = pgn.pgn2fen(game)

	local template = args'template'

	if not template then error('must have "template" parameter') end

	local tmTable = {}

	

	local hydrate = function(index, comment) 

		local temp = template:gsub('%$fen%$', movesindex])

		temp = temp:gsub('%$comment%$', comment)

		temp = temp:gsub('%$move%$', indexToMove(index))

		table.insert(tmTable,  { index, temp } )

	end

	template = mw.text.unstripNoWiki( template )

	for arg, val in pairs(args) do -- collect boards of the form "12l = comment"

		local index = moveToIndex(arg)

		if index >= 0 then hydrate(index, val) end

	end



	for arg, val in pairs(args) do -- collect boards of the form "| from1 = 7d | to1 = 8l | comments1 = { "comment", "comment" }

		if arg:match('^from%d+$') then

			local hunk = arg:match(('^from(%d+)$'))

			toMove = args'to' .. hunk

			if not toMove then error (string.format('parameter %s exists, but no parameter to%s', arg, hunk)) end

			local fromIndex = moveToIndex(val)

			if fromIndex < 0 then error(string.format('malformed value for parameter %s', arg)) end

			local toIndex = moveToIndex(toMove)

			if toIndex < 0 then error(string.format('malformed value for parameter to%s', hunk)) end

			local comments = {}

			local commentsVal = args'comments' .. hunk or ''

			for comment in commentsVal:gmatch('{([^}]*)}') do table.insert(comments, comment) end

			for index = fromIndex, toIndex do hydrate(index, table.remove(comments, 1) or '') end

		end

	end

	table.sort(tmTable, function(a, b) return a1 < b1 end)

	local res = ''

	for _, item in ipairs(tmTable) do res = res ..  frame:preprocess(item2]) end

	return res

end



return {

	'display game' = display_game

}