{ config, options, lib, diskoLib, parent, device, ... }:
let
  sortedPartitions = lib.sort (x: y: x.priority < y.priority) (lib.attrValues config.partitions);
  sortedHybridPartitions = lib.filter (p: p.hybrid != null) sortedPartitions;
in
{
  options = {
    type = lib.mkOption {
      type = lib.types.enum [ "gpt" ];
      internal = true;
      description = "Partition table";
    };
    device = lib.mkOption {
      type = lib.types.str;
      default = device;
      description = "Device to use for the partition table";
    };
    partitions = lib.mkOption {
      type = lib.types.attrsOf (lib.types.submodule ({ name, ... }@partition: {
        options = {
          type = lib.mkOption {
            type =
              let
                hexPattern = len: "[A-Fa-f0-9]{${toString len}}";
              in
              lib.types.either
                (lib.types.strMatching (hexPattern 4))
                (lib.types.strMatching (lib.concatMapStringsSep "-" hexPattern [ 8 4 4 4 12 ]));
            default = "8300";
            description = ''
              Filesystem type to use.
              This can either be an sgdisk-specific short code (run sgdisk -L to see what is available),
              or a fully specified GUID (see https://en.wikipedia.org/wiki/GUID_Partition_Table#Partition_type_GUIDs).
            '';
          };
          device = lib.mkOption {
            type = lib.types.str;
            default =
              if config._parent.type == "mdadm" then
              # workaround because mdadm partlabel do not appear in /dev/disk/by-partlabel
                "/dev/disk/by-id/md-name-any:${config._parent.name}-part${toString partition.config._index}"
              else
                "/dev/disk/by-partlabel/${partition.config.label}";
            description = "Device to use for the partition";
          };
          priority = lib.mkOption {
            type = lib.types.int;
            default = if (partition.config.size or "" == "100%") then 9001 else 1000;
            description = "Priority of the partition, smaller values are created first";
          };
          name = lib.mkOption {
            type = lib.types.str;
            description = "Name of the partition";
            default = name;
          };
          label = lib.mkOption {
            type = lib.types.str;
            default =
              let
                # 72 bytes is the maximum length of a GPT partition name
                # the labels seem to be in UTF-16, so 2 bytes per character
                limit = 36;
                label = "${config._parent.type}-${config._parent.name}-${partition.config.name}";
              in
              if (lib.stringLength label) > limit then
                builtins.substring 0 limit (builtins.hashString "sha256" label)
              else
                label;
          };
          size = lib.mkOption {
            type = lib.types.either (lib.types.enum [ "100%" ]) (lib.types.strMatching "[0-9]+[KMGTP]?");
            default = "0";
            description = ''
              Size of the partition, in sgdisk format.
              sets end automatically with the + prefix
              can be 100% for the whole remaining disk, will be done last in that case.
            '';
          };
          alignment = lib.mkOption {
            type = lib.types.int;
            default = if (builtins.substring (builtins.stringLength partition.config.start - 1) 1 partition.config.start == "s" || (builtins.substring (builtins.stringLength partition.config.end - 1) 1 partition.config.end == "s")) then 1 else 0;
            description = "Alignment of the partition, if sectors are used as start or end it can be aligned to 1";
          };
          start = lib.mkOption {
            type = lib.types.str;
            default = "0";
            description = "Start of the partition, in sgdisk format, use 0 for next available range";
          };
          end = lib.mkOption {
            type = lib.types.str;
            default = if partition.config.size == "100%" then "-0" else "+${partition.config.size}";
            description = ''
              End of the partition, in sgdisk format.
              Use + for relative sizes from the partitions start
              or - for relative sizes from the disks end
            '';
          };
          content = diskoLib.partitionType { parent = config; device = partition.config.device; };
          hybrid = lib.mkOption {
            type = lib.types.nullOr (lib.types.submodule ({ ... } @ hp: {
              options = {
                mbrPartitionType = lib.mkOption {
                  type = lib.types.nullOr lib.types.str;
                  default = null;
                  description = "MBR type code";
                };
                mbrBootableFlag = lib.mkOption {
                  type = lib.types.bool;
                  default = false;
                  description = "Set the bootable flag (aka the active flag) on any or all of your hybridized partitions";
                };
                _create = diskoLib.mkCreateOption {
                  inherit config options;
                  default = ''
                    ${lib.optionalString (hp.config.mbrPartitionType != null) ''
                      sfdisk --label-nested dos --part-type ${parent.device} ${(toString partition.config._index)} ${hp.config.mbrPartitionType}
                      udevadm trigger --subsystem-match=block
                      udevadm settle
                    ''}
                    ${lib.optionalString hp.config.mbrBootableFlag ''
                      sfdisk --label-nested dos --activate ${parent.device} ${(toString partition.config._index)}
                    ''}
                  '';
                };
              };
            }));
            default = null;
            description = "Entry to add to the Hybrid MBR table";
          };
          _index = lib.mkOption {
            internal = true;
            default = diskoLib.indexOf (x: x.name == partition.config.name) sortedPartitions 0;
          };
        };
      }));
      default = { };
      description = "Attrs of partitions to add to the partition table";
    };
    efiGptPartitionFirst = lib.mkOption {
      type = lib.types.bool;
      default = true;
      description = "Place EFI GPT (0xEE) partition first in MBR (good for GRUB)";
    };
    _parent = lib.mkOption {
      internal = true;
      default = parent;
    };
    _meta = lib.mkOption {
      internal = true;
      readOnly = true;
      type = lib.types.functionTo diskoLib.jsonType;
      default = dev:
        lib.foldr lib.recursiveUpdate { } (map
          (partition:
            lib.optionalAttrs (partition.content != null) (partition.content._meta dev)
          )
          (lib.attrValues config.partitions));
      description = "Metadata";
    };
    _create = diskoLib.mkCreateOption {
      inherit config options;
      default = ''
        if ! blkid "${config.device}" >&2; then
          sgdisk --clear ${config.device}
        fi
        ${lib.concatStrings (map (partition: ''
          # try to create the partition, if it fails, try to change the type and name
          if ! sgdisk \
            --align-end ${lib.optionalString (partition.alignment != 0) ''--set-alignment=${builtins.toString partition.alignment}''} \
            --new=${toString partition._index}:${partition.start}:${partition.end} \
            --change-name=${toString partition._index}:${partition.label} \
            --typecode=${toString partition._index}:${partition.type} \
            ${config.device}
          then sgdisk \
            --change-name=${toString partition._index}:${partition.label} \
            --typecode=${toString partition._index}:${partition.type} \
            ${config.device}
          fi
          # ensure /dev/disk/by-path/..-partN exists before continuing
          partprobe ${config.device} || : # sometimes partprobe fails, but the partitions are still up2date
          udevadm trigger --subsystem-match=block
          udevadm settle
        '') sortedPartitions)}

        ${
          lib.optionalString (sortedHybridPartitions != [])
          ("sgdisk -h "
            + (lib.concatStringsSep ":" (map (p: (toString p._index)) sortedHybridPartitions))
            + (
              lib.optionalString (!config.efiGptPartitionFirst) ":EE "
            )
            + parent.device)
        }
        ${lib.concatMapStrings (p:
            p.hybrid._create
          )
          sortedHybridPartitions
        }

        ${lib.concatStrings (map (partition: ''
          ${lib.optionalString (partition.content != null) partition.content._create}
        '') sortedPartitions)}
      '';
    };
    _mount = diskoLib.mkMountOption {
      inherit config options;
      default =
        let
          partMounts = lib.foldr lib.recursiveUpdate { } (map
            (partition:
              lib.optionalAttrs (partition.content != null) partition.content._mount
            )
            (lib.attrValues config.partitions));
        in
        {
          dev = partMounts.dev or "";
          fs = partMounts.fs or { };
        };
    };
    _config = lib.mkOption {
      internal = true;
      readOnly = true;
      default = (map
        (partition:
          lib.optional (partition.content != null) partition.content._config
        )
        (lib.attrValues config.partitions))
      ++ (lib.optional (lib.any (part: part.type == "EF02") (lib.attrValues config.partitions)) {
        boot.loader.grub.devices = [ config.device ];
      });
      description = "NixOS configuration";
    };
    _pkgs = lib.mkOption {
      internal = true;
      readOnly = true;
      type = lib.types.functionTo (lib.types.listOf lib.types.package);
      default = pkgs:
        [
          pkgs.gptfdisk
          pkgs.systemdMinimal
          pkgs.parted # for partprobe
        ] ++ lib.flatten (map
          (partition:
            lib.optional (partition.content != null) (partition.content._pkgs pkgs)
          )
          (lib.attrValues config.partitions));
      description = "Packages";
    };
  };
}