# vm.nix
let
  pkgs = import <nixpkgs> {};
in

let
  # 1. SOURCE YOUR DEBIAN IMAGE
  debianImage = pkgs.fetchurl {
    name = "debian-13-genericcloud-amd64.qcow2";
    url = "https://cloud.debian.org/images/cloud/trixie/latest/debian-13-genericcloud-amd64.qcow2";
    hash = "sha256-V9a6DUghJB5j4Vz9Y5aikZ8syhx5Zn2593m8/8xNwIU=";
  };

  # 2. VM DATA DIRECTORY
  vmDataDir = "/home/${builtins.getEnv "USER"}/.local/share/debian-vm";

  # 3. CREATE ALL FILES IN A SCRIPT
  setupScript = pkgs.writeShellScriptBin "setup-vm-files" ''
    set -e

    # Create VM directory
    mkdir -p "${vmDataDir}"

    # Create persistent disk if it doesn't exist (with 20GB initial size)
    if [ ! -f "${vmDataDir}/debian-persistent.qcow2" ]; then
      echo "Creating persistent disk from base image..."
      ${pkgs.qemu}/bin/qemu-img create -f qcow2 \
        -b "${debianImage}" \
        -F qcow2 \
        "${vmDataDir}/debian-persistent.qcow2" \
        20G
    fi

    # Create cloud-init configuration
    cat > "${vmDataDir}/user-data" << 'EOF'
#cloud-config
# User configuration
users:
  - name: debian
    sudo: ALL=(ALL) NOPASSWD:ALL
    groups: sudo, users, adm, video, render
    shell: /bin/bash
    lock_passwd: false
    passwd: nixos
    system: false
    create_groups: true

# Enable password authentication
ssh_pwauth: true
chpasswd:
  expire: false
  list: |
    debian:nixos
    root:nixos

# Update system
package_update: true
package_upgrade: true

# Install packages - ADDED GPU DRIVERS
packages:
  - git
  - firefox-esr
  - sway
  - sudo
  - curl
  - wget
  # GPU/Display drivers
  - mesa-vulkan-drivers
  - libgl1-mesa-dri
  - xwayland
  - seatd
  # Utilities
  - dbus-x11
  - xdg-utils
  - policykit-1

# Write setup script
write_files:
  - path: /home/debian/first-boot-setup.sh
    owner: debian:debian
    permissions: '0755'
    content: |
      #!/bin/bash
      set -e
      echo "Starting first-boot setup as debian user..."

      # Enable seatd service for non-systemd login
      sudo systemctl enable seatd || true
      sudo systemctl start seatd || true

      # Add user to necessary groups for Wayland
      sudo usermod -a -G video,render,seat,input debian

      # Clone repository
      cd /home/debian
      echo "Cloning GRCon23Tutorial repository..."
      git clone https://github.com/ARDC-TOBB-ETU/GRCon23Tutorial --depth=1

      # Run installation
      cd GRCon23Tutorial
      echo "Running installation script..."
      chmod +x install.sh
      ./install.sh

      cat > ~/start-sway.sh << 'LAUNCHEREOF'
      #!/bin/bash
      # Start a bare X server with a virtual display
      Xorg :10 -ac -screen 1024x768 &
      XPID=$!
      # Set the DISPLAY environment variable for the new X server
      export DISPLAY=:10
      # Wait for X to be ready, then start Sway using XWayland
      sleep 2
      dbus-run-session sway --unsupported-gpu
      # Cleanup: when Sway exits, kill the X server
      kill $XPID
      LAUNCHEREOF

      chmod +x ~/start-sway.sh
      echo "Created launcher script: ~/start-sway.sh"

      echo "First-boot setup completed!"
      echo "Installed packages:"
      dpkg -l git firefox-esr sway mesa-vulkan-drivers | grep ^ii

      # Create marker file
      sudo touch /etc/vm-initialized
      echo "User setup completed at $(date)" | sudo tee -a /var/log/vm-init.log

# Run commands
runcmd:
  # Configure sudo
  - [sed, -i, '/^%sudo/s/ALL$/NOPASSWD:ALL/', /etc/sudoers]

  # Create log directory
  - [mkdir, -p, /var/log]

  # Update and install packages
  - [apt-get, update]
  - [apt-get, install, -y, git, firefox-esr, sway, sudo, mesa-vulkan-drivers, libgl1-mesa-dri, xwayland, seatd, dbus-x11]

  # Set up user environment
  - [chown, -R, debian:debian, /home/debian]
  - [chmod, 700, /home/debian]

  # Enable services
  - [systemctl, enable, seatd]
  - [systemctl, start, seatd]

  # Run user setup
  - [sudo, -u, debian, /bin/bash, /home/debian/first-boot-setup.sh]

  # Final setup
  - [echo, "VM setup completed at $(date)", ">>", /var/log/vm-init.log]
  - [echo, "User groups:", ">>", /var/log/vm-init.log]
  - [groups, debian, ">>", /var/log/vm-init.log]

# Final message
final_message: |
  VM initialization complete!

  For Sway/Wayland to work:
  1. The VM needs GPU acceleration
  2. User 'debian' added to video, render, seat groups
  3. seatd service enabled for Wayland sessions

  Login with:
    Username: debian
    Password: nixos

  To start Sway manually:
    sway --unsupported-gpu

  Or SSH and run: dbus-run-session sway

  Important: Sway is installed but requires a workaround for the virtual environment.

  To start Sway:
  1. SSH into the VM: ssh debian@localhost -p 2222
  2. Run the launcher script: ~/start-sway.sh

  This script starts an X server and runs Sway within it using XWayland.
  The display will be accessible via the QEMU GTK window.
EOF

    # Create cloud-init ISO
    ${pkgs.cloud-utils}/bin/cloud-localds \
      "${vmDataDir}/cloud-init.iso" \
      "${vmDataDir}/user-data"

    echo "VM files created in ${vmDataDir}"
    echo "First boot will set up GPU acceleration for Sway"
  '';

  # 4. LAUNCH SCRIPT WITH GPU SUPPORT
  runScript = pkgs.writeShellScriptBin "run-debian-vm" ''
    set -e

    # Run setup first
    ${setupScript}/bin/setup-vm-files

    # Check if VM is already running
    if pgrep -f "debian-persistent.qcow2" > /dev/null; then
      echo "VM appears to be already running. Stopping it first..."
      pkill -f "debian-persistent.qcow2"
      sleep 2
    fi

    echo "Starting Debian VM with GPU acceleration..."
    echo ""
    echo "GPU/Display configuration:"
    echo "- Using virtio-gpu-pci with OpenGL"
    echo "- User added to video, render groups"
    echo "- Mesa Vulkan drivers installed"
    echo "- seatd service enabled for Wayland"
    echo ""
    echo "After boot, to start Sway:"
    echo "  SSH: ssh debian@localhost -p 2222"
    echo "  Password: nixos"
    echo "  Then run: dbus-run-session sway"
    echo "  Or: sway --unsupported-gpu"
    echo ""
    echo "Press Ctrl+Alt+G to release mouse"

    # Launch QEMU with GPU acceleration
    ${pkgs.qemu_kvm}/bin/qemu-kvm \
      -name "Debian-GRCon-VM" \
      -machine q35,accel=kvm \
      -cpu host,-hypervisor \
      -smp 4 \
      -m 4096 \
      -drive file="${vmDataDir}/debian-persistent.qcow2",format=qcow2,if=virtio \
      -drive file="${vmDataDir}/cloud-init.iso",format=raw,if=virtio \
      -netdev user,id=n1,hostfwd=tcp::2222-:22 \
      -device virtio-net-pci,netdev=n1 \
      # GPU CONFIGURATION:
      -device virtio-vga-gl \
      -display gtk,gl=on \
      -device virtio-keyboard-pci \
      -device virtio-mouse-pci \
      -device usb-tablet \
      -audiodev pa,id=audio0,server=/run/user/1000/pulse/native \
      -device AC97,audiodev=audio0 \
      -vga none \
      "$@"
  '';

in
{
  system.build.customVM = runScript;
}