Module:CRTTypeList

Documentation for this module may be created at Module:CRTTypeList/doc

-- Module:CRTTypeList
-- Dynamically generates a list of CRT type buttons by querying
-- all unique types from the CRT models category.
-- Uses pagination to work around server-side SMW query limits.

local p = {}

local function trim(s)
	if s == nil then return nil end
	s = tostring(s)
	s = s:gsub('^%s+', ''):gsub('%s+$', '')
	if s == '' then return nil end
	return s
end

local function extractTypesFromResult(queryResult, typesSet, typesList)
	if not queryResult then return end
	
	for cellContent in queryResult:gmatch('<td[^>]*>(.-)</td>') do
		local crtType = trim(cellContent:gsub('<[^>]+>', ''))
		if crtType and crtType ~= '' and not typesSet[crtType] then
			typesSet[crtType] = true
			table.insert(typesList, crtType)
		end
	end
end

function p.list(frame)
	local typesSet = {}
	local typesList = {}
	
	-- Query in batches to work around server-side limits
	local batchSize = 500
	local maxBatches = 20  -- Safety limit: 500 * 20 = 10,000 max pages
	
	for batch = 0, maxBatches - 1 do
		local offset = batch * batchSize
		
		local queryWikitext =
			'{{#ask:\n' ..
			' [[Category:CRT models]]\n' ..
			' |?Has CRT type\n' ..
			' |format=broadtable\n' ..
			' |headers=hide\n' ..
			' |link=none\n' ..
			' |mainlabel=-\n' ..
			' |limit=' .. batchSize .. '\n' ..
			' |offset=' .. offset .. '\n' ..
			' |searchlabel=\n' ..
			'}}'
		
		local queryResult = frame:preprocess(queryWikitext)
		
		extractTypesFromResult(queryResult, typesSet, typesList)
		
		-- Count cells to check if we got a full batch
		local cellCount = 0
		if queryResult then
			for _ in queryResult:gmatch('<td[^>]*>') do
				cellCount = cellCount + 1
			end
		end
		
		-- If we got fewer results than batch size, we're done
		if cellCount < batchSize then
			break
		end
	end
	
	-- Sort alphabetically
	table.sort(typesList)
	
	if #typesList == 0 then
		return '<p><em>No CRT types found.</em></p>'
	end
	
	-- Build the output: render each type using Template:CRT type entry
	local output = {}
	for _, crtType in ipairs(typesList) do
		local templateCall = '{{CRT type entry|type=' .. crtType .. '}}'
		table.insert(output, frame:preprocess(templateCall))
	end
	
	return table.concat(output, '\n')
end

return p