-- This module performs validation checks for [[WP:DYK]] hooks



local libraryUtil = require('libraryUtil')

local p = {}



local validationPatternGroups = {

	{

		-- Check that hooks start with three periods, followed by an acceptable

		-- follow-on word.

		"^%.%.%. *that",

		"^%.%.%. *about",	

	},

	{

		-- Check that hooks end with a question mark, or another acceptable

		-- phrase.

		[[.%?%]*'*"?$]],

		[[.&#63;</span>%]*'*"?$]],

		"[Yy]ou probably did%.+$",

	}

}



function p._isValidHook(hook)

	-- Whether the given hook is valid.

	-- We use the patterns in the validationPatternGroups table to find whether

	-- a hook is valid or not. Hooks are treated as valid if they match at least

	-- one pattern from each group.

	libraryUtil.checkType("_isValidHook", 1, hook, "string")

	for _, patternGroup in ipairs(validationPatternGroups) do

		local found = false

		for _, pattern in ipairs(patternGroup) do

			if mw.ustring.find(hook, pattern) then

				found = true

				break

			end

		end

		if not found then

			return false

		end

	end

	return true

end



function p.isValidHook(frame)

	local args = frame.args

	local hook = args.hook or args1

	if not hook then

		error("No hook specified")

	end

	hook = hook:match('^%s*(.-)%s*$') -- Trim whitespace

	if p._isValidHook(hook) then

		return "yes"

	else

		return ""

	end

end



return p