# ============================================================================
# FS & Storage Configuration
# ============================================================================
# This module defines:
# - Disko partition layout (EFI, swap, root)
# - Filesystem options (device, swap size)

{ config, lib, ... }:

{
  options.athenix = {
    host.filesystem = {
      device = lib.mkOption {
        type = lib.types.nullOr lib.types.str;
        default = null;
        description = ''
          The main disk device to use for automated partitioning and installation.

          When set, enables disko for declarative disk management with:
          - 1GB EFI boot partition
          - Optional swap partition (see swapSize)
          - Root partition using remaining space

          Leave null for systems that don't need disk partitioning (containers, WSL).
        '';
        example = "/dev/nvme0n1";
      };
      useSwap = lib.mkOption {
        type = lib.types.bool;
        default = true;
        description = ''
          Whether to create and use a swap partition.
          Disable for systems with ample RAM or SSDs where swap is undesirable.
        '';
      };
      swapSize = lib.mkOption {
        type = lib.types.nullOr lib.types.str;
        default = null;
        description = ''
          Size of the swap partition (e.g., "16G", "32G").

          Recommended sizes:
          - 8-16GB for desktops with 16GB+ RAM
          - 32GB for laptops (enables hibernation)
          - Match RAM size for systems <8GB RAM
        '';
        example = "32G";
      };
    };
  };

  config = {
    # ========== Disk Partitioning (Disko) ==========
    disko.enableConfig = lib.mkDefault (config.athenix.host.filesystem.device != null);

    disko.devices = {
      disk.main = {
        type = "disk";
        device = config.athenix.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 = lib.mkIf config.athenix.host.filesystem.useSwap {
              name = "swap";
              label = "swap";
              size = config.athenix.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"
                ];
              };
            };
          };
        };
      };
    };
  };
}