homey/modules/services/home-assistant.nix

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

# Home Assistant — home automation hub.
#
# Auth model: command_line auth provider → OpenLDAP (primary).
#   The auth script (ha-ldap-auth.py) does a search-bind as the readonly
#   service account, then re-binds as the user to verify the password.
#   A local homeassistant provider is kept as break-glass fallback.
#   No Authelia forward_auth — HA handles its own sessions and tokens.
#
# Network: --network=host so mDNS/device-discovery works on the LAN.
#   Caddy proxies https://home.<domain> → http://localhost:8123.
#   LAN devices can also reach HA directly at 192.168.1.100:8123.
#
# Volume layout:
#   <dataDir>/home-assistant/config/  →  /config  (configuration.yaml, automations…)
#
# Secrets consumed from sops:
#   openldap/ro_password  (shared with openldap/mealie modules)

let
  cfg     = config.homey.homeAssistant;
  dataDir = config.homey.storage.mountPoint;
  domain  = homeyConfig.domain;

  # ldap3 and pyasn1 are pure Python. Extract their .py source files from
  # the PyPI tarballs so the HA container's Python (any version) can import
  # them. The Nix-compiled site-packages approach fails because everything in
  # there is a symlink into /nix/store, which doesn't exist inside the container.
  ldap3Libs = pkgs.runCommand "ldap3-py-libs" {} ''
    mkdir -p $out
    cd $TMPDIR

    mkdir ldap3-extract && cd ldap3-extract
    tar -xf ${pkgs.python3Packages.ldap3.src} --strip-components=1
    cp -r ldap3 $out/
    cd $TMPDIR

    mkdir pyasn1-extract && cd pyasn1-extract
    tar -xf ${pkgs.python3Packages.pyasn1.src} --strip-components=1
    cp -r pyasn1 $out/
  '';

  # Auth script: shebang uses the container's own Python (/usr/bin/env python3)
  # and prepends the mounted ldap3 source tree to sys.path at runtime.
  haLdapAuth = pkgs.writeTextFile {
    name       = "ha-ldap-auth";
    executable = true;
    text = ''
      #!/usr/bin/env python3
      import sys
      sys.path.insert(0, "/auth/site-packages")
    '' + builtins.readFile ./ha-ldap-auth.py;
  };

  # Placed in the Nix store; copied to /config only on first boot.
  initialConfig = pkgs.writeText "ha-initial-configuration.yaml" ''
    homeassistant:
      auth_providers:
        - type: command_line
          command: /auth/ha-ldap-auth
          args: []
          meta: true
        - type: homeassistant

    http:
      use_x_forwarded_for: true
      trusted_proxies:
        - 127.0.0.1
        - "::1"

    mobile_app:
  '';
in
{
  options.homey.homeAssistant = {
    enable = lib.mkEnableOption "Home Assistant";

    image = lib.mkOption {
      type    = lib.types.str;
      default = "ghcr.io/home-assistant/home-assistant:stable";
    };

    port = lib.mkOption {
      type        = lib.types.port;
      default     = 8123;
      description = "Port HA listens on (host network, so this is a real host port).";
    };
  };

  config = lib.mkIf cfg.enable {

    # openldap/ro_password is also declared by mealie.nix — NixOS merges them.
    sops.secrets."openldap/ro_password" = { owner = "root"; };

    # -------------------------------------------------------------------------
    # Container
    # -------------------------------------------------------------------------
    virtualisation.oci-containers.containers.home-assistant = {
      image       = cfg.image;
      environment = { TZ = homeyConfig.timezone; };
      volumes = [
        "${dataDir}/home-assistant/config:/config"
        "${haLdapAuth}:/auth/ha-ldap-auth:ro"
        "${ldap3Libs}:/auth/site-packages:ro"
        "${config.sops.secrets."openldap/ro_password".path}:/run/secrets/ldap-ro-password:ro"
      ];
      # host network: mDNS / Matter / direct LAN access all require this.
      # No ports[] mapping needed — HA binds to 0.0.0.0:8123 on the host.
      extraOptions = [
        "--network=host"
        "--cap-add=NET_ADMIN"
        "--cap-add=NET_RAW"
      ];
    };

    # -------------------------------------------------------------------------
    # Systemd service: ordering + first-boot config init
    # -------------------------------------------------------------------------
    systemd.services."podman-home-assistant" = {
      after    = lib.mkAfter [ "mnt-data.mount" ];
      requires = lib.mkAfter [ "mnt-data.mount" ];
      serviceConfig.ExecStartPre = [
        (pkgs.writeShellScript "ha-init-config" ''
          CFG="${dataDir}/home-assistant/config/configuration.yaml"
          if [ ! -f "$CFG" ]; then
            mkdir -p "$(dirname "$CFG")"
            install -m 644 ${initialConfig} "$CFG"
          fi
        '')
      ];
    };

    # Open 8123 in the NixOS firewall for direct LAN access.
    # The HA mobile app connects here directly; Caddy also proxies via this port.
    networking.firewall.allowedTCPPorts = [ cfg.port ];

    # -------------------------------------------------------------------------
    # Caddy virtual host — no forward_auth; HA handles its own sessions
    # -------------------------------------------------------------------------
    homey.caddy.virtualHosts = [{
      subdomain = "home";
      port      = cfg.port;
      auth      = false;
    }];

    # -------------------------------------------------------------------------
    # Authelia: bypass entirely for home.domain
    # Priority 18 — blanket bypass range (10–19)
    # -------------------------------------------------------------------------
    homey.authelia.accessControlRules = [{
      priority = 18;
      domain   = [ "home.${domain}" ];
      policy   = "bypass";
    }];

    # -------------------------------------------------------------------------
    # Storage directories
    # -------------------------------------------------------------------------
    homey.storage.upholds = [ "podman-home-assistant.service" ];

    homey.storage.extraDirs = [
      { path = "home-assistant"; }
      { path = "home-assistant/config"; mode = "0755"; }
    ];

    # -------------------------------------------------------------------------
    # Backup
    # -------------------------------------------------------------------------
    homey.backup.extraPaths = [ "${dataDir}/home-assistant/config" ];
    # Uncomment to exclude the recorder SQLite DB if it grows too large:
    # homey.backup.extraExcludePaths = [
    #   "${dataDir}/home-assistant/config/home-assistant_v2.db"
    # ];

    # -------------------------------------------------------------------------
    # Uptime Kuma monitor
    # -------------------------------------------------------------------------
    homey.monitoring.monitors = [{
      name     = "Home Assistant";
      url      = "https://home.${domain}";
      interval = 60;
    }];
  };
}