local p = {}
local mRedirect = require('Module:Redirect')
local disambiguationTemplates = mw.loadData('Module:Disambiguation/templates')

local function capitalize(s)
	-- This function only works on ASCII strings. If your wiki has
	-- disambiguation templates that use Unicode strings, use the commented-out
	-- line instead. Enwiki uses ASCII string manipulation only here to improve
	-- performance.
	return s:sub(1, 1):upper() .. s:sub(2, -1)
	-- return mw.ustring.upper(mw.ustring.sub(1, 1)) .. mw.ustring.sub(2, -1)
end

local function isDisambiguationTemplate(template)
	return disambiguationTemplates[capitalize(template)] or false
end

p.isDisambiguation = function(content)
	-- false if there is no content
	if content == nil then
		return false
	end

	-- redirects are not disambiguation pages
	if mRedirect.getTargetFromText(content) ~= nil then
		return false
	end

	-- check for disambiguation templates in the content
	local templateNames = {}
	for template in string.gmatch(content, "{{%s*([^|}]-)%s*[|}]") do
		if isDisambiguationTemplate(template) then
			return true
		end
	end

	-- check for magic word
	if string.find(content, "__DISAMBIG__", 1, true) ~= nil then
		return true
	end

	return false
end

p._isDisambiguationPage = function(page)
	-- Look "(disambiguation)" in the title
	if string.find(page, "(disambiguation)",0,true) ~= nil then
		return true;
	end
	-- Look for disamiguation template in page content
	local title = mw.title.new(page)
	if not title then return false end
	local content = title:getContent()
	return p.isDisambiguation(content)
end

-- Entry points for templates
p.isDisambiguationPage = function(frame)
	local title = frame.args[1]
	return p._isDisambiguationPage(title) and "yes" or ""
end

return p