-- Note: This file is loaded automatically by the engine.

local mt = {
	__index = function(self, k)
		if k ~= "__tostring" then
			error("Tried to access an empty package", 2)
		end
	end,
	__newindex = function()
		error("Tried to access an empty package", 2)
	end,
	__metatable = "empty package",
	__tostring = function() return "{empty package}" end,
}
local empty_pkg = setmetatable({}, mt)

local function resolve_package(pkg_name)
	pkg_name = wesnoth.canonical_path(pkg_name)
	if pkg_name[#pkg_name] == '/' then
		pkg_name = pkg_name:sub(1, -2)
	end
	if wesnoth.have_file(pkg_name) then return pkg_name end
	if pkg_name:sub(-4) ~= ".lua" then
		local test = resolve_package(pkg_name .. ".lua")
		if test then return test end
	end
	if pkg_name:sub(1, 4) ~= "lua/" then
		if wesnoth.have_file("lua/" .. pkg_name) then
			return "lua/" .. pkg_name
		end
	end
	if pkg_name:sub(1, 2) ~= "./" then
		if wesnoth.have_file("./" .. pkg_name) then
			return "./" .. pkg_name
		end
	end
	return nil
end

function wesnoth.require(pkg_name)
	-- First, check if the package is already loaded
	local loaded_name = resolve_package(pkg_name)
	if loaded_name and wesnoth.package[loaded_name] then
		return wesnoth.package[loaded_name]
	end
	if not loaded_name then
		wesnoth.log("err", "Failed to load required package: " .. pkg_name, true)
		return nil
	end

	-- Next, if it's a single file, load the package with dofile
	if wesnoth.have_file(loaded_name, true) then
		local pkg = wesnoth.dofile(loaded_name)
		wesnoth.package[loaded_name] = pkg or empty_pkg
		return pkg
	else -- If it's a directory, load all the files therein
		local files = wesnoth.read_file(loaded_name)
		local pkg = {}
		for i = files.ndirs + 1, #files do
			if files[i]:sub(-4) == ".lua" then
				local subpkg_name = files[i]:sub(1, -5)
				pkg[subpkg_name] = wesnoth.require(loaded_name .. '/' .. files[i])
			end
		end
		wesnoth.package[loaded_name] = pkg
		return pkg
	end
end

return empty_pkg