local categoryData = require("Module:Storm categories/categories")
local colors = require("Module:Storm categories/colors").colors
local icons = require("Module:Storm categories/icons").icons
local cats = categoryData.cats
local defaultCategory = categoryData.defaultCategory
local p = {}

function p.color(frame)
	return p._color(frame.args[1] or frame:getParent().args[1], false)
end

function p.name(frame)
	return p._name(
		frame.args[1] or frame:getParent().args[1],
		frame.args[2] or frame:getParent().args[2],
		false
	)
end

function p.sortkey(frame)
	return p._sortkey(frame.args[1] or frame:getParent().args[1], false)
end

function p.icon(frame)
	return p._icon(frame.args[1] or frame:getParent().args[1], false)
end

function p.isEqual(frame)
	return p._isEqual(
		frame.args[1] or frame:getParent().args[1],
		frame.args[2] or frame:getParent().args[2]
	) and "yes" or ""
end

function p._normalizeId(category, fallback)
	-- Normalize if normalizable, fall back to default if not.
	return (category ~= nil and string.len(category) ~= 0) and
		string.gsub(string.lower(category), "[^%w]", "") or fallback
end

function p._color(category, nilIfMissing)
	-- This looks confusing, but it's actually nested ternaries (for nil checks)
	local color = p._normalizeId(category, defaultCategory)
		
	return colors[color] or ((cats[color] or (
		nilIfMissing
		and { color = nil }
		or cats[defaultCategory]
	)).color)
end

function p._name(category, basin, nilIfMissing)
	local name_def = (cats[
		p._normalizeId(category, defaultCategory)
	] or (nilIfMissing and { name = nil } or cats[defaultCategory])).name
	return type(name_def) == "table" and 
		(
			name_def[string.lower(basin or "default")]
			or name_def["default"]
			or (not nilIfMissing and error("No default name for basin-based category name.") or nil)
		) 
		or name_def
end

function p._sortkey(category, nilIfMissing)
	-- This looks confusing, but it's actually nested ternaries (for nil checks)
	return (cats[
		p._normalizeId(category, defaultCategory)
	] or (nilIfMissing and { sortkey = nil } or cats[defaultCategory])).sortkey
end

function p._icon(category, nilIfMissing)
	-- This looks confusing, but it's actually nested ternaries (for nil checks)
	local icon = p._normalizeId(category, defaultCategory)
		
	return icons[icon] or (cats[icon] ~= nil and (
		cats[icon].icon or cats["tropicalcyclone"].icon
	) or (not nilIfMissing and cats[defaultCategory].icon) or nil)
end

function p._isEqual(category1, category2)
	-- Checks if two IDs are equal.
	-- An {{#ifeq}} check does not consider aliases. This function compares two
	-- IDs in a way that considers category aliases. This works because alias
	-- assignments are references to the actual table containing the category
	-- info found in the main category table.
	-- 
	-- `false` will be returned if at least one of the categories are nil or
	-- if the category is not defined.
	local _category1 = p._normalizeId(category1)
	local _category2 = p._normalizeId(category2)
	return (_category1 == _category2 and _category1 ~= nil) or
		cats[ _category1 ] == cats[ _category2 ] and
			-- `false` if categories are undefined and not equal.
			cats[ _category1 ] ~= nil
end

function p.demo(frame)
	return require("Module:Storm categories/demo").demo(frame)
end

return p