require 'remon/metrics/system'
defcheck "system" do

  opts ({
    cpu_warning: 85,
    cpu_critical: 95,

    iowait_warning: 30,
    iowait_critical: 70,

    load_warning: 3,
    load_critical: 8,

    memory_warning: 0.85,
    memory_critical: 0.95
  })

  def init
    @sys = Metrics::System.new
  end

  def run
    [*cpu_and_iowait, loadavg, memory, uptime]
  end

  def cpu_and_iowait
    old_cpu = @old_cpu
    new_cpu = @sys.cpu_stat

    if not new_cpu
      return e 'cpu', :unknown, nil, "/proc/stat doesn't include a CPU line"
    end
    @old_cpu = new_cpu
    return nil if not old_cpu
    used, iowait = @sys.cpu_usage(old_cpu, new_cpu)
    [cpu_event(used), iowait_event(iowait)]
  end

  def loadavg
    metric = @sys.loadavg_normalized
    event({
      service: "load",
      metric: metric,
      description: "1-minute load average/core is #{metric}",
      state: service_state("load", metric)
    })
  end

  def memory
    metric = @sys.memory
    description = "#{(metric * 100).round(2)}% used\n\n#{`ps -eo pmem,pid,comm | sort -nrb -k1 | head -10`.chomp}"

    event({
      service: "memory",
      metric: metric,
      description: description,
      state: service_state("memory", metric)
    })
  end

  def uptime
    up_seconds = @sys.uptime
    metric = (up_seconds/24/3600).round(2)
    @ips ||= Sysinfo.ips.join(", ")
    description = <<~HEREDOC
      ip: "#{@ips}"
      instance_type: "#{Sysinfo.instance_type}"
    HEREDOC

    event({
      service: "uptime",
      metric: metric,
      description: description,
      state: "ok"
    })
  end

  private

  def cpu_event(metric)
    description = "#{(metric * 100).round(2)}% user+nice+system\n\n#{`ps -eo pcpu,pid,comm | sort -nrb -k1 | head -10`.chomp}"
    event service: "cpu",
          description: description,
          metric: metric,
          state: service_state("cpu", metric * 100)
  end

  def iowait_event(metric)
    description = "#{metric * 100 }% iowait"
    event service: "iowait",
          description: description,
          metric: metric,
          state: service_state("iowait", metric * 100)
  end

end