feat(server): host schema, context, auth, status transitions

server/lib/server/hosts.ex

@@ -0,0 +1,66 @@
+defmodule Server.Hosts do
+  @moduledoc "Host registration, authentication, status tracking."
+
+  alias Server.Repo
+  alias Server.Schema.Host
+
+  @spec create_host(String.t()) :: {:ok, {Host.t(), String.t()}} | {:error, Ecto.Changeset.t()}
+  def create_host(name) do
+    token = generate_token()
+    hash = Bcrypt.hash_pwd_salt(token)
+
+    %Host{}
+    |> Host.create_changeset(%{name: name, token_hash: hash})
+    |> Repo.insert()
+    |> case do
+      {:ok, host} -> {:ok, {host, token}}
+      {:error, cs} -> {:error, cs}
+    end
+  end
+
+  @spec authenticate(String.t(), String.t()) ::
+          {:ok, Host.t()} | {:error, :unknown_host | :invalid_token}
+  def authenticate(name, token) when is_binary(name) and is_binary(token) do
+    case Repo.get_by(Host, name: name) do
+      nil ->
+        Bcrypt.no_user_verify()
+        {:error, :unknown_host}
+
+      host ->
+        if Bcrypt.verify_pass(token, host.token_hash) do
+          {:ok, host}
+        else
+          {:error, :invalid_token}
+        end
+    end
+  end
+
+  @spec mark_online(Host.t(), String.t() | nil) :: {:ok, Host.t()} | {:error, Ecto.Changeset.t()}
+  def mark_online(%Host{} = host, agent_version) do
+    host
+    |> Host.status_changeset(%{
+      status: "online",
+      last_seen_at: DateTime.utc_now(),
+      agent_version: agent_version
+    })
+    |> Repo.update()
+  end
+
+  @spec mark_offline(Host.t()) :: {:ok, Host.t()} | {:error, Ecto.Changeset.t()}
+  def mark_offline(%Host{} = host) do
+    host
+    |> Host.status_changeset(%{status: "offline"})
+    |> Repo.update()
+  end
+
+  @doc "Mark every host offline — called on server boot to clear stale online flags."
+  @spec mark_all_offline() :: {integer(), nil}
+  def mark_all_offline do
+    import Ecto.Query
+    Repo.update_all(from(h in Host), set: [status: "offline", updated_at: DateTime.utc_now()])
+  end
+
+  defp generate_token do
+    :crypto.strong_rand_bytes(32) |> Base.url_encode64(padding: false)
+  end
+end

server/lib/server/schema/host.ex

@@ -0,0 +1,32 @@
+defmodule Server.Schema.Host do
+  use Ecto.Schema
+  import Ecto.Changeset
+
+  @statuses ~w(never_connected online offline)
+
+  schema "hosts" do
+    field :name, :string
+    field :token_hash, :string
+    field :agent_version, :string
+    field :proxmox_version, :string
+    field :zfs_version, :string
+    field :status, :string, default: "never_connected"
+    field :last_seen_at, :utc_datetime_usec
+
+    timestamps(type: :utc_datetime_usec)
+  end
+
+  def create_changeset(host, attrs) do
+    host
+    |> cast(attrs, [:name, :token_hash])
+    |> validate_required([:name, :token_hash])
+    |> validate_length(:name, min: 1, max: 100)
+    |> unique_constraint(:name)
+  end
+
+  def status_changeset(host, attrs) do
+    host
+    |> cast(attrs, [:status, :last_seen_at, :agent_version])
+    |> validate_inclusion(:status, @statuses)
+  end
+end