# Module:Category handler

---
-- --  
-- CATEGORY HANDLER --  
-- --  
-- This module implements the template in Lua, --  
-- with a few improvements: all namespaces and all namespace aliases --  
-- are supported, and namespace names are detected automatically for --  
-- the local wiki. This module requires Module:Namespace detect --  
-- and Module:Yesno to be available on the local wiki. It can be --  
-- configured for different wikis by altering the values in --  
-- Module:Category handler/config, and pages can be blacklisted --  
-- from categorisation by using Module:Category handler/blacklist. --  
-- --  
---

-- Load required modules  
local yesno = require('Module:Yesno')  

-- Lazily load things we don't always need  
local mShared, mappings  

local p = {}  

---
-- Helper functions  
---

local function trimWhitespace(s, removeBlanks)  
if type(s) ~= 'string' then  
return s  
end  
s = s:match('^%s*(.-)%s*$')  
if removeBlanks then  
if s ~= '' then  
return s  
else  
return nil  
end  
else  
return s  
end  
end  

---
-- CategoryHandler class  
---

local CategoryHandler = {}  
CategoryHandler.__index = CategoryHandler  

function CategoryHandler.new(data, args)  
local obj = setmetatable({ _data = data, _args = args }, CategoryHandler)  

-- Set the title object  
do  
local pagename = obj:parameter('demopage')  
local success, titleObj  
if pagename then  
success, titleObj = pcall(mw.title.new, pagename)  
end  
if success and titleObj then  
obj.title = titleObj  
if titleObj == mw.title.getCurrentTitle then  
obj._usesCurrentTitle = true  
end  
else  
obj.title = mw.title.getCurrentTitle  
obj._usesCurrentTitle = true  
end  
end  

-- Set suppression parameter values  
for _, key in ipairs{'nocat', 'categories'} do  
local value = obj:parameter(key)  
value = trimWhitespace(value, true)  
obj['_' .. key] = yesno(value)  
end  
do  
local subpage = obj:parameter('subpage')  
local category2 = obj:parameter('category2')  
if type(subpage) == 'string' then  
subpage = mw.ustring.lower(subpage)  
end  
if type(category2) == 'string' then  
subpage = mw.ustring.lower(category2)  
end  
obj._subpage = trimWhitespace(subpage, true)  
obj._category2 = trimWhitespace(category2) -- don't remove blank values  
end  
return obj  
end  

function CategoryHandler:parameter(key)  
local parameterNames = self._data.parameters[key]  
local pntype = type(parameterNames)  
if pntype == 'string' or pntype == 'number' then  
return self._args[parameterNames]  
elseif pntype == 'table' then  
for _, name in ipairs(parameterNames) do  
local value = self._args[name]  
if value ~= nil then  
return value  
end  
end  
return nil  
else  
error(string.format(  
'invalid config key "%s"',  
tostring(key)  
), 2)  
end  
end  

function CategoryHandler:isSuppressedByArguments  
return  
-- See if a category suppression argument has been set.  
self._nocat == true  
or self._categories == false  
or (  
self._category2  
and self._category2 ~= self._data.category2Yes  
and self._category2 ~= self._data.category2Negative  

-- Check whether we are on a subpage, and see if categories are  
-- suppressed based on our subpage status.  
or self._subpage == self._data.subpageNo and self.title.isSubpage  
or self._subpage == self._data.subpageOnly and not self.title.isSubpage  
end  

function CategoryHandler:shouldSkipBlacklistCheck  
-- Check whether the category suppression arguments indicate we  
-- should skip the blacklist check.  
return self._nocat == false  
or self._categories == true  
or self._category2 == self._data.category2Yes  
end  

function CategoryHandler:matchesBlacklist  
if self._usesCurrentTitle then  
return self._data.currentTitleMatchesBlacklist  
else  
mShared = mShared or require('Module:Category handler/shared')  
return mShared.matchesBlacklist(  
self.title.prefixedText,  
mw.loadData('Module:Category handler/blacklist')  
end  
end  

function CategoryHandler:isSuppressed  
-- Find if categories are suppressed by either the arguments or by  
-- matching the blacklist.  
return self:isSuppressedByArguments  
or not self:shouldSkipBlacklistCheck and self:matchesBlacklist  
end  

function CategoryHandler:getNamespaceParameters  
if self._usesCurrentTitle then  
return self._data.currentTitleNamespaceParameters  
else  
if not mappings then  
mShared = mShared or require('Module:Category handler/shared')  
mappings = mShared.getParamMappings(true) -- gets mappings with mw.loadData  
end  
return mShared.getNamespaceParameters(  
self.title,  
mappings  
end  
end  

function CategoryHandler:namespaceParametersExist  
-- Find whether any namespace parameters have been specified.  
-- We use the order "all" --> namespace params --> "other" as this is what  
-- the old template did.  
if self:parameter('all') then  
return true  
end  
if not mappings then  
mShared = mShared or require('Module:Category handler/shared')  
mappings = mShared.getParamMappings(true) -- gets mappings with mw.loadData  
end  
for ns, params in pairs(mappings) do  
for i, param in ipairs(params) do  
if self._args[param] then  
return true  
end  
end  
end  
if self:parameter('other') then  
return true  
end  
return false  
end  

function CategoryHandler:getCategories  
local params = self:getNamespaceParameters  
local nsCategory  
for i, param in ipairs(params) do  
local value = self._args[param]  
if value ~= nil then  
nsCategory = value  
break  
end  
end  
if nsCategory ~= nil or self:namespaceParametersExist then  
-- Namespace parameters exist - advanced usage.  
if nsCategory == nil then  
nsCategory = self:parameter('other')  
end  
local ret = {self:parameter('all')}  
local numParam = tonumber(nsCategory)  
if numParam and numParam >= 1 and math.floor(numParam) == numParam then  
-- nsCategory is an integer  
ret[#ret + 1] = self._args[numParam]  
else  
ret[#ret + 1] = nsCategory  
end  
if #ret < 1 then  
return nil  
else  
return table.concat(ret)  
end  
elseif self._data.defaultNamespaces[self.title.namespace] then  
-- Namespace parameters don't exist, simple usage.  
return self._args[1]  
end  
return nil  
end  

---
-- Exports  
---

local p = {}  

function p._exportClasses  
-- Used for testing purposes.  
return {  
CategoryHandler = CategoryHandler  
}  
end  

function p._main(args, data)  
data = data or mw.loadData('Module:Category handler/data')  
local handler = CategoryHandler.new(data, args)  
if handler:isSuppressed then  
return nil  
end  
return handler:getCategories  
end  

function p.main(, data)  
data = data or mw.loadData('Module:Category handler/data')  
local args = require('Module:Arguments').getArgs(, {  
wrappers = data.wrappers,  
valueFunc = function (k, v)  
v = trimWhitespace(v)  
if type(k) == 'number' then  
if v ~= '' then  
return v  
else  
return nil  
end  
else  
return v  
end  
end  
})  
return p._main(args, data)  
end  

return p