# Save this as podman-pod.nix
{ config, lib, pkgs, ... }:

with lib;

let
  cfg = config.services.podmanPods;

  podOptions = { name, config, ... }: {
    options = {
      name = mkOption {
        type = types.str;
        description = "Name of the pod";
      };
      ports = mkOption {
        type = types.listOf types.str;
        default = [ ];
        description = "List of port mappings (e.g. ['8080:80'])";
      };
      containers = mkOption {
        type = types.attrsOf (
          types.submodule
            {
              options = {
                image = mkOption {
                  type = types.str;
                  description = "Docker image for the container";
                };
                extraOptions = mkOption {
                  type = types.listOf types.str;
                  default = [ ];
                  description = "Additional options for the container";
                };
              };
            }
        );
        default = { };
        description = "Containers to run in the pod";
      };
    };
  };

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

  config = mkIf (cfg != { }) {
    virtualisation.podman.enable = true;
    virtualisation.oci-containers.backend = "podman";

    environment.systemPackages = [ pkgs.jq ];

    virtualisation.oci-containers.containers = listToAttrs (flatten (mapAttrsToList
      (podName: podDef:
        mapAttrsToList
          (containerName: 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.virtualisation.oci-containers.containers;
      in
      podServices // containerServices;
  };
}