nixpkgs/modules/home-manager/ports.nix

# Home Manager Module for Port Management
#
# This module provides centralized port management for Home Manager configurations.
# Define ports once and use them consistently across user services, with support
# for host-specific overrides.
#
# Usage in your Home Manager configuration:
#
#   # In your home.nix or flake:
#   imports = [ inputs.m3ta-nixpkgs.homeManagerModules.default ];
#
#   m3ta.ports = {
#     enable = true;
#
#     # Define your default ports
#     definitions = {
#       vscodium = 8080;
#       jupyter = 8888;
#       dev-server = 3000;
#       local-api = 8000;
#       docs-preview = 4000;
#     };
#
#     # Define host-specific overrides
#     hostOverrides = {
#       laptop = {
#         dev-server = 3001;
#         vscodium = 8081;
#       };
#       desktop = {
#         jupyter = 9999;
#       };
#     };
#
#     # Set the current hostname
#     currentHost = "laptop";  # Or use config.networking.hostName if available
#   };
#
#   # Use ports in your configuration:
#   home.file.".config/myapp/config.json".text = builtins.toJSON {
#     port = config.m3ta.ports.get "dev-server";
#   };
#
#   # Generate environment variables:
#   home.sessionVariables = {
#     DEV_SERVER_PORT = toString (config.m3ta.ports.get "dev-server");
#     JUPYTER_PORT = toString (config.m3ta.ports.get "jupyter");
#   };
{
  config,
  lib,
  pkgs,
  ...
}:
with lib; let
  cfg = config.m3ta.ports;

  portsLib = import ../../lib/ports.nix {inherit lib;};

  portHelpers =
    if cfg.enable
    then
      portsLib.mkPortHelpers {
        ports = cfg.definitions;
        hostPorts = cfg.hostOverrides;
      }
    else null;
in {
  options.m3ta.ports = {
    enable = mkEnableOption "centralized port management for Home Manager";

    definitions = mkOption {
      type = types.attrsOf types.port;
      default = {};
      description = "Default port definitions for user services.";
    };

    hostOverrides = mkOption {
      type = types.attrsOf (types.attrsOf types.port);
      default = {};
      description = "Host-specific port overrides.";
    };

    currentHost = mkOption {
      type = types.nullOr types.str;
      default = null;
      description = "Hostname to use for port resolution.";
    };

    # Internal computed options
    get = mkOption {
      type = types.raw;
      readOnly = true;
      internal = true;
    };
    getForHost = mkOption {
      type = types.raw;
      readOnly = true;
      internal = true;
    };
    all = mkOption {
      type = types.attrsOf types.port;
      readOnly = true;
      internal = true;
    };
    allForHost = mkOption {
      type = types.raw;
      readOnly = true;
      internal = true;
    };
    services = mkOption {
      type = types.listOf types.str;
      readOnly = true;
      internal = true;
    };

    # Env var generation
    generateEnvVars = mkOption {
      type = types.bool;
      default = false;
      description = "Generate environment variables for all ports.";
    };

    envVarPrefix = mkOption {
      type = types.str;
      default = "PORT_";
      description = "Prefix for generated environment variables.";
    };
  };

  config = mkIf cfg.enable {
    m3ta.ports.get = service: portHelpers.getPort service cfg.currentHost;
    m3ta.ports.getForHost = host: service: portHelpers.getPort service host;
    m3ta.ports.all = portHelpers.getHostPorts cfg.currentHost;
    m3ta.ports.allForHost = portHelpers.getHostPorts;
    m3ta.ports.services = portHelpers.listServices;

    home.sessionVariables = mkIf cfg.generateEnvVars (
      let
        toEnvVarName = service:
          cfg.envVarPrefix + (lib.toUpper (builtins.replaceStrings ["-"] ["_"] service));
      in
        builtins.listToAttrs (
          map (service: {
            name = toEnvVarName service;
            value = toString (cfg.get service);
          })
          cfg.services
        )
    );

    home.file.".config/m3ta/ports.json".text = builtins.toJSON {
      hostname = cfg.currentHost;
      ports = cfg.all;
      allDefinitions = cfg.definitions;
      hostOverrides = cfg.hostOverrides;
    };
  };
}