1 files changed, 113 insertions, 0 deletions
diff --git a/lib/pleroma/instances/instance.ex b/lib/pleroma/instances/instance.ex
new file mode 100644
index 000000000..420803a8f
--- /dev/null
+++ b/lib/pleroma/instances/instance.ex
@@ -0,0 +1,113 @@
+defmodule Pleroma.Instances.Instance do
+  @moduledoc "Instance."
+
+  alias Pleroma.Instances
+  alias Pleroma.Instances.Instance
+  alias Pleroma.Repo
+
+  use Ecto.Schema
+
+  import Ecto.Query
+  import Ecto.Changeset
+
+  schema "instances" do
+    field(:host, :string)
+    field(:unreachable_since, :naive_datetime_usec)
+
+    timestamps()
+  end
+
+  defdelegate host(url_or_host), to: Instances
+
+  def changeset(struct, params \\ %{}) do
+    struct
+    |> cast(params, [:host, :unreachable_since])
+    |> validate_required([:host])
+    |> unique_constraint(:host)
+  end
+
+  def filter_reachable([]), do: %{}
+
+  def filter_reachable(urls_or_hosts) when is_list(urls_or_hosts) do
+    hosts =
+      urls_or_hosts
+      |> Enum.map(&(&1 && host(&1)))
+      |> Enum.filter(&(to_string(&1) != ""))
+
+    unreachable_since_by_host =
+      Repo.all(
+        from(i in Instance,
+          where: i.host in ^hosts,
+          select: {i.host, i.unreachable_since}
+        )
+      )
+      |> Map.new(& &1)
+
+    reachability_datetime_threshold = Instances.reachability_datetime_threshold()
+
+    for entry <- Enum.filter(urls_or_hosts, &is_binary/1) do
+      host = host(entry)
+      unreachable_since = unreachable_since_by_host[host]
+
+      if !unreachable_since ||
+           NaiveDateTime.compare(unreachable_since, reachability_datetime_threshold) == :gt do
+        {entry, unreachable_since}
+      end
+    end
+    |> Enum.filter(& &1)
+    |> Map.new(& &1)
+  end
+
+  def reachable?(url_or_host) when is_binary(url_or_host) do
+    !Repo.one(
+      from(i in Instance,
+        where:
+          i.host == ^host(url_or_host) and
+            i.unreachable_since <= ^Instances.reachability_datetime_threshold(),
+        select: true
+      )
+    )
+  end
+
+  def reachable?(_), do: true
+
+  def set_reachable(url_or_host) when is_binary(url_or_host) do
+    with host <- host(url_or_host),
+         %Instance{} = existing_record <- Repo.get_by(Instance, %{host: host}) do
+      {:ok, _instance} =
+        existing_record
+        |> changeset(%{unreachable_since: nil})
+        |> Repo.update()
+    end
+  end
+
+  def set_reachable(_), do: {:error, nil}
+
+  def set_unreachable(url_or_host, unreachable_since \\ nil)
+
+  def set_unreachable(url_or_host, unreachable_since) when is_binary(url_or_host) do
+    unreachable_since = unreachable_since || DateTime.utc_now()
+    host = host(url_or_host)
+    existing_record = Repo.get_by(Instance, %{host: host})
+
+    changes = %{unreachable_since: unreachable_since}
+
+    cond do
+      is_nil(existing_record) ->
+        %Instance{}
+        |> changeset(Map.put(changes, :host, host))
+        |> Repo.insert()
+
+      existing_record.unreachable_since &&
+          NaiveDateTime.compare(existing_record.unreachable_since, unreachable_since) != :gt ->
+        {:ok, existing_record}
+
+      true ->
+        existing_record
+        |> changeset(changes)
+        |> Repo.update()
+    end
+  end
+
+  def set_unreachable(_, _), do: {:error, nil}
+end