homey/modules/common.nix

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

# Common configuration shared by every host in the homey ecosystem.
# Hardware-specific settings (disk layout, device trees, etc.) go in
# hosts/<name>/hardware.nix instead.

{
  # -------------------------------------------------------------------------
  # Nix / flakes
  # -------------------------------------------------------------------------
  nix = {
    settings = {
      experimental-features = [ "nix-command" "flakes" ];
      auto-optimise-store = true;
      # Extra binary caches — speeds up aarch64-linux builds significantly
      substituters = [
        "https://cache.nixos.org"
        "https://nix-community.cachix.org"
      ];
      trusted-public-keys = [
        "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
        "nix-community.cachix.org-1:mB9FkXj6Q3Q4ohOcbM4FJ9Z1X2kCrVK4vZOqsDqqNqk="
      ];
      # Trigger GC automatically when free space drops below 2 GB;
      # stop once 5 GB is free. Prevents CI builds from filling the disk
      # between weekly GC runs.
      min-free = 2147483648;   # 2 GiB
      max-free = 5368709120;   # 5 GiB
    };
    gc = {
      automatic = true;
      dates     = "weekly";
      options   = "--delete-older-than 14d";
    };
  };

  # Allow unfree packages (e.g. cloudflared binary)
  nixpkgs.config.allowUnfree = true;

  # -------------------------------------------------------------------------
  # Boot — set in hardware.nix; this is just a safe default
  # -------------------------------------------------------------------------
  # boot.loader is intentionally left to hardware.nix

  # -------------------------------------------------------------------------
  # Locale / timezone
  # -------------------------------------------------------------------------
  time.timeZone = homeyConfig.timezone;
  i18n.defaultLocale = "en_US.UTF-8";

  # -------------------------------------------------------------------------
  # Networking
  # -------------------------------------------------------------------------
  networking = {
    # hostname is set per-host in default.nix
    firewall = {
      enable = true;
      allowedTCPPorts = [
        22    # SSH
        80    # Caddy HTTP (redirect to HTTPS or ACME challenge)
        443   # Caddy HTTPS
      ];
    };
    # Use systemd-resolved for DNS — supports mDNS and local overrides
    nameservers = [ "1.1.1.1" "8.8.8.8" ];
  };

  # -------------------------------------------------------------------------
  # SSH
  # -------------------------------------------------------------------------
  services.openssh = {
    enable = true;
    settings = {
      PasswordAuthentication = false;
      PermitRootLogin        = "no";
    };
  };

  # -------------------------------------------------------------------------
  # Container runtime — podman (rootless-capable, no daemon needed)
  # -------------------------------------------------------------------------
  virtualisation.podman = {
    enable            = true;
    dockerCompat      = true;   # allow `docker` CLI commands against podman
    defaultNetwork.settings.dns_enabled = true;
  };

  # Create the shared "homey" podman network that all service containers join.
  # DNS is enabled by default on netavark-backed networks, so containers can
  # reach each other by container name (e.g. "openldap", "nextcloud-postgres").
  systemd.services.podman-homey-network = {
    description = "Create homey podman network";
    wantedBy    = [ "multi-user.target" ];
    before      = [ "podman-openldap.service" "podman-authelia.service"
                    "podman-gitea.service" "podman-nextcloud-postgres.service"
                    "podman-nextcloud.service" "podman-phpldapadmin.service"
                    "podman-jellyfin.service" "podman-transmission.service" ];
    serviceConfig = {
      Type            = "oneshot";
      RemainAfterExit = true;
      ExecStart = pkgs.writeShellScript "create-homey-network" ''
        ${pkgs.podman}/bin/podman network exists homey \
          || ${pkgs.podman}/bin/podman network create homey
      '';
    };
  };

  # -------------------------------------------------------------------------
  # Core packages available on every host
  # -------------------------------------------------------------------------
  environment.systemPackages = with pkgs; [
    git
    vim
    htop
    curl
    wget
    rsync
    lsof
    sops      # secret editing
    age       # key generation for sops
    restic    # backup (CLI, also used by services.restic)
    podman-compose
  ];

  # -------------------------------------------------------------------------
  # sops-nix global config — point at the secrets file and the host's age key
  # -------------------------------------------------------------------------
  sops = {
    defaultSopsFile = ../secrets/secrets.yaml;
    # The age private key must be present on the host at this path.
    # Generate on the Pi with: age-keygen -o /var/lib/sops-nix/key.txt
    # Then add the PUBLIC key to secrets/.sops.yaml before encrypting.
    age.keyFile = "/var/lib/sops-nix/key.txt";
  };

  # -------------------------------------------------------------------------
  # Admin user — adjust username / SSH key in hosts/<name>/default.nix
  # -------------------------------------------------------------------------
  users.mutableUsers = false;   # all user config must be declared here

  # The actual admin user is declared in hosts/<name>/default.nix so the
  # SSH authorized key can be host-specific.

  # -------------------------------------------------------------------------
  # System state version — do not change after first install
  # (tracks NixOS backwards-compat markers)
  # -------------------------------------------------------------------------
  system.stateVersion = "25.05";
}