#!/opt/lnxall_app/bin/lua

local invoker = require "invoker"
local module = {}

local MIN_HEALTH_PERCENT = 10
local TOP_FLAGS = invoker.OUTPUT + invoker.NOSTDIO + invoker.BUFSIZ + 0x1F0000

function module.checkplat()
	return true
end

function module.category()
	return "系统资源"
end

function module.description()
	return "检查系统资源"
end

function module.detailed()
	return "读取内存信息和 CPU 空闲率, 用于判断系统是否存在内存不足或 CPU 负载过高的问题."
end

function module.suggestion()
	return table.concat({
		"1. 使用 free -h 查看内存总量和可用内存.",
		"2. 使用 top 查看 CPU 空闲率和占用较高的进程.",
		"3. 使用 ps aux --sort=-%mem | head 查看内存占用较高的进程.",
	}, "\n")
end

function module.step()
	local minfo = invoker.readfile("/proc/meminfo", nil, 1024)
	if not minfo then
		return { error = "failed to read /proc/meminfo" }, true
	end

	local mtotal = string.match(minfo, "MemTotal:%s+(%d+)")
	if mtotal then
		mtotal = tonumber(mtotal)
	end
	local mavail = string.match(minfo, "MemAvailable:%s+(%d+)")
	if mavail then
		mavail = tonumber(mavail)
	end

	if type(mtotal) ~= "number" or type(mavail) ~= "number" then
		io.stderr:write("Error, failed to parse /proc/meminfo!\n")
		io.stderr:flush()
		return { error = "failed to parse /proc/meminfo" }, true
	end

	local avail = math.floor(mavail * 100 / mtotal)

	local _, output = invoker.invoke(TOP_FLAGS, "busybox", "top", "-d2", "-n2")
	if type(output) ~= "string" then
		output = ""
	end

	local cpu_idle
	for cpui in string.gmatch(output, "([%d%.]+)%%%s+idle") do
		local idle = tonumber(cpui)
		if idle and idle >= 0 then
			cpu_idle = idle
		end
	end

	local reply = {
		["内存总量      "] = mtotal,
		["可用内存      "] = mavail,
		["可用内存百分比"] = avail,
		["CPU 空闲率    "] = cpu_idle,
	}

	local has_error = avail <= MIN_HEALTH_PERCENT
	if cpu_idle and cpu_idle <= MIN_HEALTH_PERCENT then
		has_error = true
	end

	return reply, has_error
end

return module