{ pkgs, lib, ... }:
let
  batt-gpu = pkgs.writeShellScript "batt-igpu" ''
        ${pkgs.intel-gpu-tools}/bin/intel_gpu_frequency -e
    		echo "800" > /sys/class/drm/card1/gt_boost_freq_mhz
  '';
  ac-gpu = pkgs.writeShellScript "ac-igpu" ''
        ${pkgs.intel-gpu-tools}/bin/intel_gpu_frequency -d
    		echo "2350" > /sys/class/drm/card1/gt_boost_freq_mhz
  '';
in
{
  services.tlp = {
    enable = true;
    settings = {
      # Wireless power saving
      WIFI_PWR_ON_BAT = "1";

      # USB autosuspend
      USB_AUTOSUSPEND = "1";

      # SATA drive power management
      SATA_LINKPWR_ON_BAT = "min_power";

      # PCI Express Active-State Power Management (ASPM)
      PCIE_ASPM_ON_BAT = "powersupersave";

      RUNTIME_PM_ON_AC = "on";
      RUNTIME_PM_ON_BAT = "auto";

      # Disable Bluetooth on battery
      # DEVICES_TO_DISABLE_ON_BAT = "bluetooth";

      # Restore brightness on battery
      RESTORE_BRIGHTNESS_ON_BAT = "1";
      PCIE_ASPM_ON_AC = "balanced";
      DEVICES_TO_DISABLE_ON_BAT_NOT_IN_USE = "bluetooth";
      INTEL_GPU_MAX_FREQ_ON_AC = 0;
      INTEL_GPU_MAX_FREQ_ON_BAT = 800;
      INTEL_GPU_BOOST_FREQ_ON_AC = 0;
      INTEL_GPU_BOOST_FREQ_ON_BAT = 800;

      CPU_MAX_PERF_ON_BAT = 50;

      PLATFORM_PROFILE_ON_AC = "balanced";
      PLATFORM_PROFILE_ON_BAT = "quiet";
      START_CHARGE_THRESH_BAT0 = 40; # 40 and below it starts to charge
      STOP_CHARGE_THRESH_BAT0 = 80; # 80 and above it stops charging
    };
  };
  services.thermald.enable = true;
  services.upower = {
    enable = true;
  };
  services.auto-cpufreq.enable = true;

  systemd.targets = {
    "ac" = {
      description = "On AC power";
      unitConfig = {
        StopWhenUnneeded = "yes";
      };
    };
    "battery" = {
      description = "On battery power";
      unitConfig = {
        StopWhenUnneeded = "yes";
      };
    };
  };

  services.udev.extraRules = ''
    SUBSYSTEM=="power_supply",ENV{POWER_SUPPLY_ONLINE}=="0", RUN+="/run/current-system/systemd/bin/systemctl start battery.target"
    SUBSYSTEM=="power_supply", ENV{POWER_SUPPLY_ONLINE}=="1", RUN+="/run/current-system/systemd/bin/systemctl start ac.target"
  '';

  services.auto-cpufreq.settings = {
    battery = {
      governor = "powersave";
      turbo = "never";
    };
    charger = {
      governor = "performance";
      turbo = "auto";
    };
  };
  boot.kernelParams = [
    # "mem_sleep_default=deep"
    # "i915.fastboot=1"
    "pcie_aspm=force"
    "ahci.mobile_lpm_policy=1"
  ];
  services.logind.settings.Login = {
    HandleLidSwitch = "suspend";
    HandleLidSwitchExternalPower = "suspend";
    HandleLidSwitchDocked = "ignore";
  };
  systemd.sleep.extraConfig = ''
        HibernateDelaySec=30min
    		SuspendEstimationSec=120
  '';

  systemd.services.gpu-limit-on-batt = {
    enable = true;
    description = "Using rfkill; disable all rf devices before sleeping.";
    before = [ "battery.target" ];

    serviceConfig = {
      Type = "oneshot";
      ExecStart = "${batt-gpu}";
      RemainAfterExit = true;
    };
    wantedBy = [ "battery.target" ];
    partOf = [ "battery.target" ];
  };
  systemd.services.gpu-limit-on-ac = {
    enable = true;
    description = "Using rfkill; disable all rf devices before sleeping.";
    before = [ "ac.target" ];

    serviceConfig = {
      Type = "oneshot";
      ExecStart = "${ac-gpu}";
      RemainAfterExit = true;
    };
    wantedBy = [ "ac.target" ];
    partOf = [ "ac.target" ];
  };
  systemd.services.rfkill-sleep-wake = {
    enable = true;
    description = "Using rfkill; disable all rf devices before sleeping.";
    before = [ "sleep.target" ];

    serviceConfig = {
      Type = "oneshot";
      ExecStop = "${pkgs.utillinux}/bin/rfkill unblock all";
      ExecStart = "${pkgs.utillinux}/bin/rfkill block all";
      RemainAfterExit = true;
    };
    wantedBy = [ "sleep.target" ];
    partOf = [ "sleep.target" ];

  };
  # one of "ignore", "poweroff", "reboot", "halt", "kexec", "suspend", "hibernate", "hybrid-sleep", "suspend-then-hibernate", "lock"
  powerManagement = {
    enable = true;
    # powertop.enable = true;
  };
}