nix/modules/virtualisation/podman-pod.nix

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

with lib;

let
  cfg = config.my.virtualisation.podmanPods;

  containerDefinition = config.virtualisation.oci-containers.containers.type.getSubOptions;

  # Add our enable option
  extendedContainerOptions = containerDefinition // {
    enable = mkEnableOption "Enable this container";
  };

  podOptions = {
    options = with types; {

      name = mkOption {
        type = str;
        description = "Name of the pod";
      };

      ports = mkOption {
        type = listOf str;
        default = [ ];
        description = "List of port mappings (e.g. ['8080:80'])";
      };

      containers = mkOption {
        type = attrsOf (submodule {
          options = extendedContainerOptions;
        });
        default = { };
        description = "Attribute set of OCI container configurations for this set";
      };
    };
  };

  createPodScript =
    name: podDef:
    let
      podDefinitionString = builtins.toJSON { inherit (podDef) ports; };
    in
    pkgs.writeScript "manage-pod-${name}.sh" ''
      #! /bin/sh
      set -e

      POD_NAME="${name}"
      POD_DEFINITION="${podDefinitionString}"

      create_pod() {
        podman pod create --name "$POD_NAME" \
          ${concatStringsSep " " (map (port: "--publish ${port}") podDef.ports)}
      }

      if podman pod exists "$POD_NAME"; then
        CURRENT_CONFIG=$(podman pod inspect "$POD_NAME" | jq -c '{ports: .[0].InfraConfig.PortBindings | to_entries | map("\(.value[0].HostPort):\(.key | split("/")[0])") | sort'})
        echo "POD_DEFINITION: $POD_DEFINITION"
        echo "CURRENT_CONFIG: $CURRENT_CONFIG"
        if [ "$CURRENT_CONFIG" != "$POD_DEFINITION" ]; then
          echo "Pod configuration has changed. Recreating pod..."
          podman pod rm -f "$POD_NAME"
          create_pod
        else
          echo "Pod configuration unchanged."
        fi
      else
        echo "Pod does not exist. Creating..."
        create_pod
      fi
    '';

  # flattenPodContainers =
  #   pods:
  #   mapAttrs' (
  #     podName: pod:
  #     mapAttrs' (
  #       containerName: container:
  #       nameValuePair "${podName}-${containerName}" (
  #         container
  #         # // {
  #         #   inherit (pod) name;
  #         #   extraOptions = (container.extraOptions or [ ]) ++ [ "--pod=${pod.name}" ];
  #         # }
  #       )
  #     ) (filterAttrs (n: v: v.enable or true) pod.containers)
  #   ) pods;

in
{
  options.my.virtualisation.podmanPods = mkOption {
    type = types.attrsOf (types.submodule podOptions);
    default = { };
    description = "Podman pods to create";
  };

  config = mkIf (cfg != { }) {

    my.virtualisation.podman.enable = true;

    environment.systemPackages = [ pkgs.jq ];

    # virtualisation.oci-containers.containers = listToAttrs (flatten (mapAttrsToList
    #   (podName: podDef:
    #     mapAttrs
    #       (containerName: containerDef:
    #         filterAttrs (attrName: attrValue: attrName != "enable") containerDef
    #         # nameValuePair "${podName}-${containerName}" ({
    #         #   inherit (containerDef) image;
    #         #   extraOptions = [ "--pod=${podName}" ] ++ containerDef.extraOptions;
    #         # })
    #       )
    #       podDef.containers
    #   )
    #   cfg));

    networking.firewall.allowedTCPPorts = flatten (
      mapAttrsToList
        (
          name: podDef: map (portMapping: lib.toInt (lib.head (lib.splitString ":" portMapping))) podDef.ports
        )
        cfg
    );

    systemd.services =
      let
        podServices = mapAttrs'
          (
            name: podDef:
              nameValuePair "podman-pod-${name}" {
                description = "Manage Podman pod: ${name}";
                serviceConfig = {
                  Type = "oneshot";
                  ExecStart = "${createPodScript name podDef}";
                };
                path = [
                  pkgs.jq
                  pkgs.podman
                ];
                after = [ "network.target" ];
                wantedBy = [ "multi-user.target" ];
              }
          )
          cfg;

        containerServices = mapAttrs'
          (
            name: container:
              nameValuePair "podman-${name}" {
                after = [ "podman-pod-${lib.head (lib.splitString "-" name)}.service" ];
                requires = [ "podman-pod-${lib.head (lib.splitString "-" name)}.service" ];
                partOf = [ "podman-pod-${lib.head (lib.splitString "-" name)}.service" ];
              }
          )
          config.containers;
      in
      podServices // containerServices;

  };
}