{ config, pkgs, modulesPath, lib, fetchGit, ... }:

let
  unstable = (import ../modules/unstable.nix config);
  customPkgs = import ../packages/overlay.nix;
in {
  imports = [
    ./generic.nix
    ../modules/hardware/generic.nix ../modules/hardware/video.nix ../modules/hardware/desktop.nix
    ../modules/fonts.nix
    ../modules/users/alexander.nix
    ../modules/programs/zsh ../modules/programs/git ../modules/programs/mpv ../modules/programs/tmux ../modules/programs/emacs ../modules/programs/firefox ../modules/programs/gnome-terminal ../modules/programs/gnome ../modules/programs/i18n.nix ../modules/programs/gamemode ../modules/programs/nonvm
    ../modules/programs/distributed-build/builder.nix
    ../modules/programs/music
  ];

  nixpkgs.overlays = [
    (import (builtins.fetchGit {
      url = "https://github.com/nix-community/emacs-overlay.git";
      ref = "master";
      rev = "ce0e9482d53d69bedc8416d8a984d00e17607826";
    }))

   #(import (builtins.fetchTarball {
   #  url = "https://github.com/nix-community/NUR/archive/master.tar.gz";
   #  sha256 = "0r2pcc6sjxmhg1xxk23648wrwccv2c5v44cfwglx35az5y0hmr1f";
   #}))

    (final: prev:
      let
        # NOTE: This is a really messy solution
        buildFHSUserEnvBubblewrap = prev.callPackage ../packages/build-support/build-fhs-userenv-bubblewrap {};
      in {
        steamPackages = prev.steamPackages.override {
          buildFHSUserEnv = buildFHSUserEnvBubblewrap;
          # Include gamemode in the FHS
          #extraPkgs = (pkgs: with pkgs; [ gamemode ]);
        };

        steam = final.steamPackages.steam-fhsenv.overrideAttrs (old: {
          specifyHomeDirs = true;
          chdirTo = "/home/$USER";
        });
        steam-run = final.steam.run;
        steam-run-native = (final.steam.override {
          nativeOnly = true;
        });
        steamcmd = final.steamPackages.steamcmd;
      })

    customPkgs
  ];

  nixpkgs.config.packageOverrides = pkgs: {
    unstable = unstable;
    nur = (import ../modules/nur.nix pkgs);
  };
  
  environment = {
    systemPackages = with pkgs; [
      emacsPgtkGcc
      unstable.firmwareLinuxNonfree
      gajim
      libvirt virt-manager qemu scream
      gamemode # Custom package
      key-mapper # Custom package
      replaysorcery # Custom package
      evdev-proxy # Custom package
      vfio-isolate # Custom Package
      steam
    ];

    sessionVariables = {
      # Prevent us from having to always type it out
      #NIXOS_CONFIG = "\${HOME}/Development/Personal/nixos-config/hosts/miku.nix";
    };

    etc = {
      "evdev-proxy/config.toml".source = pkgs.writeText "config.toml" ''
        log_level = "INFO"

        [[device]]
          [device.Simple]
            name = "EvdevProxyMouse"
            vendor = 0x1337
            model = 0x1337
            class = "Mouse"
            [[device.Simple.selector]]
              USBIDClass = {vendor=0x046d, model=0xc531, class="Mouse"}
            [[device.Simple.selector]]
              USBIDClass = {vendor=0x046d, model=0xc07c, class="Mouse"}
        [[device]]
          [device.Simple]
            name = "EvdevProxyTartarus"
            vendor = 0x1337
            model = 0x1338
            class = "Mouse"
            [[device.Simple.selector]]
              USBIDClass = {vendor=0x1532, model=0x022b, class="Keyboard"}
            [[device.Simple.selector]]
              EVDEVClass = {phys="\"key-mapper\""}
      '';
      "libvirt/hooks/qemu".source = let
        vfio-isolate-state = "/tmp/vfio-isolate-state";
      in pkgs.writeScript "qemu" ''
        #!${pkgs.stdenv.shell}
        guest=$1
        action=$2
        phase=$3
        extra=$4

        if [[ "$guest" = "win10" ]]; then
            case "$action" in
                prepare)
                # Only do this while in preparation
                [[ ! "$phase" = "prepare" ]] && exit 0

                sudo -u alexander systemctl --user start evdev-proxy.service
                sudo -u alexander systemctl --user start scream.service
                sleep 2

                ${pkgs.vfio-isolate}/bin/vfio-isolate \
                  -u ${vfio-isolate-state} \
                 	cpu-governor performance "$GUEST_CORES" \
                  cpuset-create --cpus "$GUEST_CORES" /guest.slice \
                  cpuset-create --cpus C0,4 /host.slice \
                  move-tasks / /host.slice \
                  irq-affinity mask "$GUEST_CORES"
                ;;
                stopped)
                # Only run when the VM is fully stopped
                [[ ! "$phase" = "end" ]] && exit 0
                sudo -u alexander systemctl --user stop evdev-proxy.service
                sudo -u alexander systemctl --user stop scream.service

                ${pkgs.vfio-isolate}/bin/vfio-isolate \
                  restore ${vfio-isolate-state}
            esac
        fi
      '';
    };
  };

  networking = {
    interfaces.enp6s0.useDHCP = false;
    hostName = "miku";
    # Nix otherwise has a conflict with this option
    wireless.enable = lib.mkForce false;

    # Allow scream to connect to this host
    firewall.allowedUDPPorts = [ 4010 ];
  };

  boot = {
    loader = {
      systemd-boot.enable = true;
      efi.canTouchEfiVariables = true;
    };
    extraModprobeConfig = ''
      options kvm_amd nested=1
      options vfio-pci ids=1002:67df,1002:aaf0
    '';
    initrd = {
      availableKernelModules = [ "xhci_pci" "ahci" "usbhid" "sd_mod" "amdgpu" "vendor-reset" ];
      kernelModules = [
        "amdgpu" # GPU (duh)
        "kvm-amd" "vfio_virqfd" "vfio_pci" "vfio_iommu_type1" "vfio" # Virt
        "uinput" # key-mapper
        "vendor-reset"
      ];
    };
    kernelParams = [
      "amd_iommu=on"
      "iommu=pt"
      "sysrq_always_enabled=1"
      "kvm.ignore_msrs=1"
      "kvm.report_ignored_msrs=N"
      "fbcon=rotate:1"
      "quiet"
    ];
    kernelModules = [];
    extraModulePackages = [ pkgs.linuxPackages.vendor-reset ];
    # NOTE: A regression appears to have happend between 5.10 and 5.12
    #       which leads to the RX590 to have the fence fallback timer on
    #       sdma0 time out (whatever this means). Maybe bisect?
    #kernelPackages = pkgs.linuxPackages_zen;
  };

  services = {
    # NOTE: key-mapper has a dbus policy file that we need to include
    dbus.packages = [ pkgs.key-mapper ];
    emacs.package = pkgs.emacsPgtkGcc;
    flatpak.enable = true;
    xserver.videoDrivers = [ "amdgpu" ];
    udev.extraRules = ''
      KERNEL=="uinput", GROUP="input"

      # This rule allows the input group to access /dev/uinput device to create virtual input devices
      KERNEL=="uinput", SUBSYSTEM=="misc", GROUP="input", MODE="660"

      # Create rules for your virtual devices to get persistent names
      KERNEL=="event*", SUBSYSTEM=="input", ATTRS{name}=="EvdevProxy*", SYMLINK+="input/by-id/virtual-event-$attr{name}"
    '';

    sshd.enable = true;
  };
  
  virtualisation.libvirtd = {
    enable = true;
    qemuOvmf = true;
    #qemuRunAsRoot = false;
    qemuPackage = unstable.qemu;
    qemuVerbatimConfig = ''
      seccomp_sandbox = 0
      cgroup_device_acl = [
      	"/dev/null", "/dev/full", "/dev/zero", 
      	"/dev/random", "/dev/urandom",
      	"/dev/ptmx", "/dev/kvm", "/dev/kqemu",
      	"/dev/rtc","/dev/hpet",
        "/dev/input/by-id/usb-Logitech_USB_Receiver-if02-event-mouse",
        "/dev/input/by-id/usb-Razer_Razer_Tartarus_V2-event-kbd",
        "/dev/input/by-id/virtual-event-EvdevProxyMouse",
        "/dev/input/by-id/usb-Razer_Razer_BlackWidow_Ultimate-event-kbd"
      ]
    '';
  };
  # NOTE: Workaround for libvirt's SYSCONFDIR being set to /var/lib
  # (See https://github.com/NixOS/nixpkgs/issues/51152#issuecomment-899374407)
  system.activationScripts.libvirt-hooks.text = ''
    ln -Tfs /etc/libvirt/hooks /var/lib/libvirt/hooks
  '';

  systemd = {
    services = {
      NetworkManager-wait-online.enable = false;
      libvirtd.path = with pkgs; [ vfio-isolate systemd ];
    };

    user.services = {
      scream = {
        description = "Audio receiver for the Scream virtual network sound card";
        #wantedBy = [ "default.target" ];
        serviceConfig = {
          Type = "simple";
          ExecStart = "${pkgs.scream}/bin/scream -i virbr0 -o pulse";
          Restart = "always";
        };
      };
      replaysorcery-kms = {
        description = "An open-source, instant-replay solution for Linux; KMS service";
        #wantedBy = [ "default.target" ];
        serviceConfig = {
          Type = "simple";
          ExecStart = "${pkgs.replaysorcery}/bin/replay-sorcery kms-service";
          Restart = "always";
        };
      };
      key-mapper = {
        description = "A tool to change the mapping of your input device buttons";
        wantedBy = [ "default.target" ];
        serviceConfig = {
          Type = "simple";
          ExecStart = "${pkgs.key-mapper}/bin/key-mapper-service";
          Restart = "always";
          # NOTE: The Tartarus may not be connected, so don't fail if we cannot set the preset
          ExecPostStart = "${pkgs.key-mapper}/bin/key-mapper --command start --preset NOOP --device \"Razer Razer Tartarus V2\"; exit 0";
        };
      };
      replaysorcery = {
        description = "An open-source, instant-replay solution for Linux";
        #wantedBy = [ "default.target" ];
        requires = [ "replaysorcery-kms.service" ];
        serviceConfig = {
          Type = "simple";
          ExecStart = "${pkgs.replaysorcery}/bin/replay-sorcery";
          Restart = "always";
        };
      };
      evdev-proxy = {
        description = "Creates virtual device to proxy evdev devices events";
        #wantedBy = [ "default.target" ];
        serviceConfig = {
          Type = "simple";
          ExecStart = "${pkgs.evdev-proxy}/bin/evdev-proxy";
          Restart = "always";
        };
      };
      gamemode = {
        description = "A daemon/lib combo for Linux that allows games to request a set of optimisations be temporarily applied to the host OS.";
        wantedBy = [ "default.target" ];
        serviceConfig = {
          Type = "simple";
          ExecStart = "${pkgs.gamemode}/bin/gamemoded";
          Restart = "always";
        };
      };
    };
  };
  
  fileSystems = {
    "/" = {
      device = "/dev/disk/by-label/root";
      fsType = "btrfs";
    };
    "/boot" = {
      device = "/dev/disk/by-label/boot";
      fsType = "vfat";
    };
    "/mnt/Storage" = {
      device = "/dev/disk/by-label/storage";
      fsType = "ext4";
    };
  };
  swapDevices = [ ];
}