defmodule ProxmoxAgent.DiagnosticsTest do
  use ExUnit.Case, async: false

  alias ProxmoxAgent.Diagnostics

  setup do
    # Isolate tests: clear the env key before and after each test.
    Application.delete_env(:agent, :dump_dir)
    on_exit(fn -> Application.delete_env(:agent, :dump_dir) end)
    :ok
  end

  describe "configure/1 and enabled?/0" do
    test "nil disables and returns :ok" do
      assert :ok = Diagnostics.configure(nil)
      refute Diagnostics.enabled?()
    end

    test "empty string disables and returns :ok" do
      assert :ok = Diagnostics.configure("")
      refute Diagnostics.enabled?()
    end

    test "valid path creates the directory and enables" do
      dir = Path.join(System.tmp_dir!(), "diag-#{System.unique_integer([:positive])}")
      on_exit(fn -> File.rm_rf(dir) end)

      assert :ok = Diagnostics.configure(dir)
      assert Diagnostics.enabled?()
      assert File.dir?(dir)
      assert Application.get_env(:agent, :dump_dir) == dir
    end

    test "unreachable path disables (does not crash)" do
      # Point at a path under a non-directory file to force mkdir_p failure.
      parent = Path.join(System.tmp_dir!(), "diag-parent-#{System.unique_integer([:positive])}")
      File.write!(parent, "not a directory")
      dir = Path.join(parent, "child")
      on_exit(fn -> File.rm_rf(parent) end)

      assert :ok = Diagnostics.configure(dir)
      refute Diagnostics.enabled?()
    end
  end

  describe "log_command/4 and log_sample/2 (no writer running)" do
    test "log_command/4 no-ops and returns :ok when disabled" do
      assert :ok = Diagnostics.log_command("zpool", ["list"], {:ok, "body"}, 1_234)
    end

    test "log_sample/2 no-ops and returns :ok when disabled" do
      assert :ok = Diagnostics.log_sample("fast", %{foo: "bar"})
    end

    test "log_command/4 no-ops when enabled but writer is not running" do
      dir = Path.join(System.tmp_dir!(), "diag-#{System.unique_integer([:positive])}")
      on_exit(fn -> File.rm_rf(dir) end)

      :ok = Diagnostics.configure(dir)
      # Writer is not started in this test — log should still be safe.
      assert :ok = Diagnostics.log_command("zpool", ["list"], {:ok, "body"}, 1_234)
    end
  end

  describe "log_command/4 and log_sample/2 with writer running" do
    setup do
      dir = Path.join(System.tmp_dir!(), "diag-e2e-#{System.unique_integer([:positive])}")
      File.mkdir_p!(dir)
      :ok = Diagnostics.configure(dir)

      {:ok, pid} = ProxmoxAgent.Diagnostics.Writer.start_link(dir: dir)

      on_exit(fn ->
        if Process.alive?(pid), do: GenServer.stop(pid)
        File.rm_rf(dir)
      end)

      %{dir: dir}
    end

    test "log_command/4 writes to commands.log", %{dir: dir} do
      assert :ok = Diagnostics.log_command("zpool", ["list", "-j"], {:ok, "body"}, 2_500)
      :ok = GenServer.call(ProxmoxAgent.Diagnostics.Writer, :flush)

      body = File.read!(Path.join(dir, "commands.log"))
      assert body =~ "$ zpool list -j"
      assert body =~ "exit=0"
      assert body =~ "size=4"
    end

    test "log_sample/2 writes to samples.log", %{dir: dir} do
      assert :ok = Diagnostics.log_sample("fast", %{"zfs_pools" => %{"pools" => []}})
      :ok = GenServer.call(ProxmoxAgent.Diagnostics.Writer, :flush)

      body = File.read!(Path.join(dir, "samples.log"))
      assert body =~ "kind=fast"
      assert body =~ "\"zfs_pools\""
    end
  end
end