# ============================================================================
# Boot & Storage Configuration
# ============================================================================
# This module defines:
# - Disko partition layout (EFI, swap, root)
# - Bootloader configuration (systemd-boot with Plymouth)
# - Filesystem options (device, swap size)
# - Build method options (ISO, iPXE, LXC, Proxmox)
# - Garbage collection settings
# - Convenience options (forUser, useHostPrefix)

{ config, lib, ... }:

{
  options.ugaif = {
    forUser = lib.mkOption {
      type = lib.types.nullOr lib.types.str;
      default = null;
      description = ''
        Convenience option to configure a host for a specific user.
        Automatically enables the user (sets ugaif.users.username.enable = true).
        Value should be a username from ugaif.users.accounts.
      '';
    };

    host = {
      useHostPrefix = lib.mkOption {
        type = lib.types.bool;
        default = true;
        description = "Whether to prepend the host prefix to the hostname (used in inventory).";
      };
      filesystem = {
        device = lib.mkOption {
          type = lib.types.str;
          description = "The main disk device to use for installation.";
        };
        swapSize = lib.mkOption {
          type = lib.types.str;
          description = "The size of the swap partition.";
        };
      };
      buildMethods = lib.mkOption {
        type = lib.types.listOf lib.types.str;
        default = [ "installer-iso" ];
        description = ''
          List of allowed build methods for this host.
          Supported methods:
          - "installer-iso": Generates an auto-install ISO that installs this configuration to disk.
          - "iso": Generates a live ISO (using nixos-generators).
          - "ipxe": Generates iPXE netboot artifacts (kernel, initrd, script).
          - "lxc": Generates an LXC container tarball.
          - "proxmox": Generates a Proxmox VMA archive.
        '';
      };
    };

    system.gc = {
      enable = lib.mkOption {
        type = lib.types.bool;
        default = true;
        description = "Whether to enable automatic garbage collection.";
      };
      frequency = lib.mkOption {
        type = lib.types.str;
        default = "weekly";
        description = "How often to run garbage collection (systemd timer format).";
      };
      retentionDays = lib.mkOption {
        type = lib.types.int;
        default = 30;
        description = "Number of days to keep old generations before deletion.";
      };
      optimise = lib.mkOption {
        type = lib.types.bool;
        default = true;
        description = "Whether to automatically optimize the Nix store.";
      };
    };
  };

  config = lib.mkMerge [
    # Enable forUser if specified
    (lib.mkIf (config.ugaif.forUser != null) {
      ugaif.users.${config.ugaif.forUser}.enable = true;
    })

    # Main configuration
    {
      # ========== Disk Partitioning (Disko) ==========
      disko.enableConfig = lib.mkDefault true;

      disko.devices = {
        disk.main = {
          type = "disk";
          device = config.ugaif.host.filesystem.device;
          content = {
            type = "gpt";
            partitions = {
              # EFI System Partition
              ESP = {
                name = "ESP";
                label = "BOOT";
                size = "1G";
                type = "EF00";
                content = {
                  type = "filesystem";
                  format = "vfat";
                  mountpoint = "/boot";
                  mountOptions = [ "umask=0077" ];
                  extraArgs = [
                    "-n"
                    "BOOT"
                  ];
                };
              };

              # Swap Partition (size configurable per host)
              swap = {
                name = "swap";
                label = "swap";
                size = config.ugaif.host.filesystem.swapSize;
                content = {
                  type = "swap";
                };
              };

              # Root Partition (takes remaining space)
              root = {
                name = "root";
                label = "root";
                size = "100%";
                content = {
                  type = "filesystem";
                  format = "ext4";
                  mountpoint = "/";
                  extraArgs = [
                    "-L"
                    "ROOT"
                  ];
                };
              };
            };
          };
        };
      };

      # Bootloader Configuration
      boot = {
        loader.systemd-boot.enable = true;
        loader.efi.canTouchEfiVariables = true;
        plymouth.enable = true;

        # Enable "Silent boot"
        consoleLogLevel = 3;
        initrd.verbose = false;

        # Hide the OS choice for bootloaders.
        # It's still possible to open the bootloader list by pressing any key
        # It will just not appear on screen unless a key is pressed
        loader.timeout = lib.mkDefault 0;
      };

      # Set your time zone.
      time.timeZone = "America/New_York";

      # Select internationalisation properties.
      i18n.defaultLocale = "en_US.UTF-8";

      i18n.extraLocaleSettings = {
        LC_ADDRESS = "en_US.UTF-8";
        LC_IDENTIFICATION = "en_US.UTF-8";
        LC_MEASUREMENT = "en_US.UTF-8";
        LC_MONETARY = "en_US.UTF-8";
        LC_NAME = "en_US.UTF-8";
        LC_NUMERIC = "en_US.UTF-8";
        LC_PAPER = "en_US.UTF-8";
        LC_TELEPHONE = "en_US.UTF-8";
        LC_TIME = "en_US.UTF-8";
      };

      systemd.sleep.extraConfig = ''
        SuspendState=freeze
        HibernateDelaySec=2h
      '';

      system.stateVersion = "25.11"; # Did you read the comment?
    }
  ];
}