defmodule ProxmoxAgent.Collectors.ZfsTest do
  use ExUnit.Case, async: true

  alias ProxmoxAgent.Collectors.Zfs

  @fixtures Path.expand("../../fixtures/zfs", __DIR__)

  defp fake_runner do
    fn
      "zpool", ["list", "-j", "--json-int"] ->
        {:ok, File.read!(Path.join(@fixtures, "zpool_list.json"))}

      "zpool", ["status", "-j", "--json-flat-vdevs", "--json-int"] ->
        {:ok, File.read!(Path.join(@fixtures, "zpool_status.json"))}

      "zfs", ["list", "-j", "--json-int", "-t", "all"] ->
        {:ok, File.read!(Path.join(@fixtures, "zfs_list.json"))}
    end
  end

  describe "collect_pools/1" do
    test "returns a summary per pool" do
      sample = Zfs.collect_pools(runner: fake_runner())
      assert is_list(sample.pools)
      assert length(sample.pools) == 2
      rpool = Enum.find(sample.pools, &(&1.name == "rpool"))
      tank = Enum.find(sample.pools, &(&1.name == "tank"))

      assert rpool.health == "ONLINE"
      assert rpool.capacity_percent == 40
      assert rpool.fragmentation_percent == 17
      assert rpool.size_bytes == 500_000_000_000
      assert rpool.error_count == 0
      assert rpool.degraded_vdev_count == 0
      assert rpool.pool_type == "mirror"
      assert rpool.scan_function == "scrub"
      assert rpool.scan_state == "FINISHED"
      assert [%{name: "mirror-0", type: "mirror", state: "ONLINE",
                read_errors: 0, write_errors: 0, checksum_errors: 0}] = rpool.vdevs

      assert tank.health == "DEGRADED"
      assert tank.error_count == 2
      assert tank.degraded_vdev_count == 1
      assert tank.pool_type == "raidz2"
      assert tank.scan_state == "SCANNING"
      assert [%{name: "raidz2-0", type: "raidz2", state: "DEGRADED",
                checksum_errors: 2}] = tank.vdevs
    end

    test "populates errors list when zpool fails" do
      failing = fn _, _ -> {:error, {:enoent, "zpool"}} end
      sample = Zfs.collect_pools(runner: failing)
      assert sample.pools == []
      assert length(sample.errors) >= 1
    end

    test "classifies pool_type for stripe, mixed, and special vdevs" do
      list_json =
        Jason.encode!(%{
          "pools" => %{
            "stripe" => %{"name" => "stripe", "size" => 1, "alloc" => 0, "free" => 1,
                         "frag" => 0, "cap" => 0, "health" => "ONLINE"},
            "mixed" => %{"name" => "mixed", "size" => 1, "alloc" => 0, "free" => 1,
                        "frag" => 0, "cap" => 0, "health" => "ONLINE"},
            "mirror_with_log" => %{"name" => "mirror_with_log", "size" => 1, "alloc" => 0, "free" => 1,
                                    "frag" => 0, "cap" => 0, "health" => "ONLINE"}
          }
        })

      vdev = fn name, type ->
        {name, %{"name" => name, "vdev_type" => type, "state" => "ONLINE",
                 "read_errors" => "0", "write_errors" => "0", "checksum_errors" => "0"}}
      end

      status_json =
        Jason.encode!(%{
          "pools" => %{
            "stripe" => %{
              "name" => "stripe", "state" => "ONLINE", "error_count" => "0",
              "vdevs" => Map.new([vdev.("sda", "disk"), vdev.("sdb", "disk")])
            },
            "mixed" => %{
              "name" => "mixed", "state" => "ONLINE", "error_count" => "0",
              "vdevs" => Map.new([vdev.("mirror-0", "mirror"), vdev.("raidz1-1", "raidz1")])
            },
            "mirror_with_log" => %{
              "name" => "mirror_with_log", "state" => "ONLINE", "error_count" => "0",
              "vdevs" => Map.new([vdev.("mirror-0", "mirror"), vdev.("log-0", "log")])
            }
          }
        })

      runner = fn
        "zpool", ["list" | _] -> {:ok, list_json}
        "zpool", ["status" | _] -> {:ok, status_json}
      end

      sample = Zfs.collect_pools(runner: runner)
      by_name = Map.new(sample.pools, &{&1.name, &1})

      assert by_name["stripe"].pool_type == "stripe"
      assert by_name["mixed"].pool_type == "mixed"
      assert by_name["mirror_with_log"].pool_type == "mirror"
      # log vdev is retained in the per-pool vdevs list even though it's ignored for layout classification
      assert Enum.any?(by_name["mirror_with_log"].vdevs, &(&1.type == "log"))
    end

    test "tolerates nil and non-integer error counters" do
      list_json =
        Jason.encode!(%{
          "pools" => %{
            "weird" => %{"name" => "weird", "size" => 1, "alloc" => 0, "free" => 1,
                        "frag" => 0, "cap" => 0, "health" => "ONLINE"}
          }
        })

      status_json =
        Jason.encode!(%{
          "pools" => %{
            "weird" => %{
              "name" => "weird", "state" => "ONLINE", "error_count" => nil,
              "vdevs" => %{
                "disk-0" => %{"name" => "disk-0", "vdev_type" => "disk", "state" => "ONLINE",
                              "read_errors" => nil, "write_errors" => "abc",
                              "checksum_errors" => "0"}
              }
            }
          }
        })

      runner = fn
        "zpool", ["list" | _] -> {:ok, list_json}
        "zpool", ["status" | _] -> {:ok, status_json}
      end

      sample = Zfs.collect_pools(runner: runner)
      [pool] = sample.pools
      assert pool.error_count == 0
      [vdev] = pool.vdevs
      assert vdev.read_errors == 0
      assert vdev.write_errors == 0
      assert vdev.checksum_errors == 0
    end
  end

  describe "collect_datasets/1" do
    test "returns datasets and per-dataset snapshot summary" do
      sample = Zfs.collect_datasets(runner: fake_runner())
      assert length(sample.datasets) == 2

      rpool_data = Enum.find(sample.datasets, &(&1.name == "rpool/data"))
      assert rpool_data.used_bytes == 100_000_000_000
      assert rpool_data.usedbysnapshots_bytes == 2_000_000_000
      assert rpool_data.snapshot_count == 2
      assert rpool_data.newest_snapshot_unix == 1_745_193_600
      assert rpool_data.oldest_snapshot_unix == 1_745_107_200
    end
  end
end