Module:Main page

---

local p = {}
local h = {}

-- merge args from frame and frame:getParent()
function h.mergeArgs(frame)
	local inputArgs = {}
	
	for k, v in pairs(frame.args) do
		v = mw.text.trim(tostring(v))
		if v ~= '' then
			inputArgs[k] = v
		end
	end
	
	for k, v in pairs(frame:getParent().args) do
		v = mw.text.trim(v)
		if v ~= '' then
			inputArgs[k] = v
		end
	end
	
	return inputArgs
end

--------------------------------------------------------------------

function p.main(frame)

	local args = h.mergeArgs(frame)
	
	-- use the rootpage parameter if given, otherwise use the current page name
	local rootpage = args['rootpage'] or mw.title.getCurrentTitle().fullText
		
	local layouts = {'desktop', 'tablet', 'mobile'}
	
	for _,layout in pairs(layouts) do
		-- collapse consecutive line breaks and spaces, then trim
		-- we need to check for permutations of " \n" because trim can't clean that up if it's in the middle of the string
		args[layout] = mw.text.trim(args[layout]):gsub("\n\n+", "\n"):gsub("  +", " "):gsub(" \n", "\n"):gsub("\n ", "\n")
		
		-- check if columns are consistent in this layout
		local warn = false
		local last_column_count = 0
		local current_column_count = 0
		for _,row in pairs(mw.text.split(mw.text.trim(args[layout]), '\n')) do
			current_column_count = #mw.text.split(row, '%s') --count elements in this row
			if last_column_count == 0 then
				last_column_count = current_column_count
			elseif last_column_count ~= current_column_count then
				warn = true
			end
		end
		if warn then
			mw.addWarning( 'ERROR: the ' .. layout .. ' layout does not have a consistent number of columns in each row. This will result in all the boxes merging into one.')
		end
	end
	
	-- parse the arguments into CSS variables that contain legal syntax for grid-template-areas
	local desktop_var = "--main-page-layout--desktop: '" .. string.gsub(args['desktop'], '\n', "' '") .. "';"
	local tablet_var =  "--main-page-layout--tablet: '"  .. string.gsub(args['tablet' ], '\n', "' '") .. "';"
	local mobile_var =  "--main-page-layout--mobile: '"  .. string.gsub(args['mobile' ], '\n', "' '") .. "';"
	
	-- grid-template-columns overrides
	local desktop_cols = mw.text.trim(string.gsub(args['desktop-columns'] or '', ';', ''))
	local  tablet_cols = mw.text.trim(string.gsub(args[ 'tablet-columns'] or '', ';', ''))
	local  mobile_cols = mw.text.trim(string.gsub(args[ 'mobile-columns'] or '', ';', ''))
	
	-- set the variables used by grid-template-columns
	if desktop_cols ~= '' then
		desktop_var = desktop_var .. '--main-page-layout-columns--desktop: '.. desktop_cols ..';'
	end
	if tablet_cols ~= '' then
		tablet_var = tablet_var .. '--main-page-layout-columns--tablet: '.. tablet_cols ..';'
	end
	if mobile_cols ~= '' then
		mobile_var = mobile_var .. '--main-page-layout-columns--mobile: '.. mobile_cols ..';'
	end

	local boxes = {} -- list of all boxes as a simple list, used to set the order of appearance
	local seen_boxes = {} -- list of all boxes as a k:v pair, used to filter out duplicates
	local boxes_in_layout = {} -- list of layouts, then list of all boxes in that layout
	local missing_boxes = {} -- list of layouts, then list of boxes that are *not* included in that layout
	
	-- add every box referenced in the layout rules once
	function parse_layout(layout)
		for _,name in pairs(mw.text.split(mw.text.trim(args[layout]), '%s')) do
			if not seen_boxes[name] then
				boxes[#boxes+1] = name -- table with numerical keys for set html order
				seen_boxes[name] = true
			end
			boxes_in_layout[layout][name] = true
		end
	end
	
	-- loop through the layouts the first time to set up the box lists
	for _,layout in pairs(layouts) do
		boxes_in_layout[layout] = {}
		missing_boxes[layout] = {}
		parse_layout(layout)
	end
	
	-- then loop through the layouts a second time because we need to compare those completed lists to check for missing boxes
	for _,layout in pairs(layouts) do
		for _,name in pairs(boxes) do
			if boxes_in_layout[layout][name] ~= true then
				mw.addWarning( 'WARNING: the \"' .. name .. '\" box is missing in the ' .. layout .. ' layout. If this is intentional, you can ignore this warning.')
				missing_boxes[layout][name] = true	
			end
		end
	end
	
	-- start our mp-container wrapper, and add our variables from earlier as inline styles to declare them
	-- the rootpage is added to the dataset so it's easily accessible by mp-edit-links.js and it doesn't need to make its own API call
	local output = mw.html.create()
	local container = output:tag('div'):attr('id', 'mp-container'):cssText(desktop_var .. tablet_var .. mobile_var):attr('data-rootpage', rootpage)
	
	-- loop through boxes and add the relevant main page subpages into the output
	for _,box in pairs(boxes) do
		mw.ext.VariablesLua.vardefine('imp-variable-id', box) -- using a vardefine lets us pass this directly to the template without going through the user-facing box
		
		local pre_vardefine = ''
		for _,layout in pairs(layouts) do
			pre_vardefine = pre_vardefine .. (missing_boxes[layout][box] and '0' or '1') .. ','
		end
		-- formatted as a psuedo-bitmask to reduce variable usage, "<display-on-destop>, <display-on-tablet>, <display-on-mobile>," each value is 0 or 1 (trailing comma is insignificant)
		-- expected to be used with #explode in the template receiving the variable
		mw.ext.VariablesLua.vardefine('imp-variable-display-box', pre_vardefine)
		
		if mw.title.new(rootpage .. '/' .. box).exists then
			container:wikitext(frame:expandTemplate{ title = ':' .. rootpage .. '/' .. box})
		else
			container:wikitext(frame:expandTemplate{ title = 'Main page box/missing', args = { box, rootpage = rootpage}}) -- See [[Template:Main page box/missing]]
		end
	end
	
	return output
end

return p