defmodule ToweropsWeb.AgentChannelProcessingTest do
  @moduledoc """
  Additional coverage for ToweropsWeb.AgentChannel — focused on processing
  paths (poll/discovery/check/lldp/mikrotik) and lifecycle handle_info events
  not exercised in agent_channel_test.exs.
  """
  use Towerops.DataCase, async: false

  import Phoenix.ChannelTest

  alias Towerops.AccountsFixtures
  alias Towerops.Agent.AgentHeartbeat
  alias Towerops.Agent.AgentJobList
  alias Towerops.Agent.MikrotikResult
  alias Towerops.Agent.MikrotikSentence
  alias Towerops.Agent.SnmpResult
  alias Towerops.AgentsFixtures
  alias Towerops.DevicesFixtures
  alias Towerops.OrganizationsFixtures
  alias Towerops.Proto.Encode
  alias Towerops.Proto.Types.LldpNeighbor
  alias Towerops.Proto.Types.LldpTopologyResult
  alias Towerops.Snmp.AgentDiscovery
  alias ToweropsWeb.AgentSocket

  @endpoint ToweropsWeb.Endpoint

  setup do
    user = AccountsFixtures.user_fixture()
    organization = OrganizationsFixtures.organization_fixture(user.id)

    device =
      DevicesFixtures.device_fixture(%{
        organization_id: organization.id,
        snmp_version: "2c",
        snmp_community: "public"
      })

    {:ok, agent_token, token_string} =
      AgentsFixtures.agent_token_fixture(organization.id)

    {:ok, _assignment} =
      AgentsFixtures.agent_assignment_fixture(agent_token.id, device.id)

    {:ok, socket} = connect(AgentSocket, %{})

    {:ok, _, socket} =
      subscribe_and_join(socket, "agent:#{agent_token.id}", %{"token" => token_string})

    assert_push "jobs", _initial_jobs

    %{
      socket: socket,
      device: device,
      agent_token: agent_token,
      token_string: token_string,
      organization: organization
    }
  end

  defp encode_payload(struct) do
    binary = struct.__struct__.encode(struct)
    %{"binary" => Base.encode64(binary)}
  end

  defp poll_until(fun, opts \\ []) do
    max_attempts = Keyword.get(opts, :max_attempts, 100)
    delay_ms = Keyword.get(opts, :delay_ms, 20)

    Enum.reduce_while(1..max_attempts, nil, fn _, _ ->
      case fun.() do
        nil ->
          receive do
          after
            delay_ms -> :ok
          end

          {:cont, nil}

        false ->
          receive do
          after
            delay_ms -> :ok
          end

          {:cont, nil}

        result ->
          {:halt, result}
      end
    end) || fun.()
  end

  defp build_heartbeat do
    %AgentHeartbeat{
      version: "1.0.0",
      hostname: "test-agent",
      uptime_seconds: 3600,
      ip_address: "",
      arch: "x86_64"
    }
  end

  # ── Discovery error path ──────────────────────────────────────────

  describe "discovery error path" do
    test "discovery with empty oid_values does not update last_discovery_at", %{
      socket: socket,
      device: device
    } do
      assert is_nil(Towerops.Devices.get_device(device.id).last_discovery_at)

      result = %SnmpResult{
        device_id: device.id,
        job_type: :DISCOVER,
        job_id: "discover:#{device.id}",
        timestamp: DateTime.to_unix(DateTime.utc_now()),
        oid_values: %{}
      }

      push(socket, "result", encode_payload(result))

      ref = push(socket, "heartbeat", encode_payload(build_heartbeat()))
      refute_reply ref, :error

      assert is_nil(Towerops.Devices.get_device(device.id).last_discovery_at)
    end
  end

  # ── Polling status transitions (process_polling_result) ─────────

  describe "process_polling_result status transitions" do
    setup %{device: device} do
      oid_values = %{
        "1.3.6.1.2.1.1.1.0" => "Test Device",
        "1.3.6.1.2.1.1.2.0" => "1.3.6.1.4.1.9.1.1",
        "1.3.6.1.2.1.1.3.0" => "123456",
        "1.3.6.1.2.1.1.4.0" => "admin@test.com",
        "1.3.6.1.2.1.1.5.0" => "test-device",
        "1.3.6.1.2.1.1.6.0" => "Test Location"
      }

      {:ok, _discovered} = AgentDiscovery.process_agent_discovery(device, oid_values)
      device_with_details = Towerops.Devices.get_device_with_details(device.id)
      %{device: device_with_details}
    end

    test "successful poll transitions device from down to up and broadcasts", %{
      socket: socket,
      device: device
    } do
      {:ok, device} = Towerops.Devices.update_device_status(device, :down)
      Phoenix.PubSub.subscribe(Towerops.PubSub, "device:#{device.id}")

      result = %SnmpResult{
        device_id: device.id,
        job_type: :POLL,
        job_id: "poll:#{device.id}",
        timestamp: DateTime.to_unix(DateTime.utc_now()),
        oid_values: %{}
      }

      push(socket, "result", encode_payload(result))

      assert_receive {:device_status_changed, _, :up, _}, 1_000

      assert poll_until(fn ->
               d = Towerops.Devices.get_device(device.id)
               if d && d.status == :up, do: d
             end)
    end

    test "poll for already-up device does not re-broadcast status change", %{
      socket: socket,
      device: device
    } do
      {:ok, _device} = Towerops.Devices.update_device_status(device, :up)
      Phoenix.PubSub.subscribe(Towerops.PubSub, "device:#{device.id}")

      result = %SnmpResult{
        device_id: device.id,
        job_type: :POLL,
        job_id: "poll:#{device.id}",
        timestamp: DateTime.to_unix(DateTime.utc_now()),
        oid_values: %{}
      }

      push(socket, "result", encode_payload(result))

      refute_receive {:device_status_changed, _, _, _}, 100

      assert_receive {:state_sensors_updated, _}, 1_000
    end
  end

  # ── handle_in lldp_topology_result ───────────────────────────────

  describe "handle_in lldp_topology_result" do
    test "stores LLDP neighbors from topology result", %{socket: socket, device: device} do
      result = %LldpTopologyResult{
        device_id: device.id,
        job_id: Ecto.UUID.generate(),
        local_system_name: "test-device",
        neighbors: [
          %LldpNeighbor{
            neighbor_name: "switch-A",
            local_port: "Eth1/0/1",
            remote_port: "Gi0/1",
            remote_port_id: "Gi0/1",
            management_addresses: ["10.0.0.1"]
          },
          %LldpNeighbor{
            neighbor_name: "switch-B",
            local_port: "Eth1/0/2",
            remote_port: "Gi0/2",
            remote_port_id: "Gi0/2",
            management_addresses: ["10.0.0.2"]
          }
        ],
        timestamp: DateTime.to_unix(DateTime.utc_now())
      }

      binary = Encode.encode_lldp_topology_result(result)
      push(socket, "lldp_topology_result", %{"binary" => Base.encode64(binary)})

      neighbors =
        poll_until(
          fn ->
            n = Towerops.Topology.list_lldp_neighbors(device.id)
            if length(n) == 2, do: n
          end,
          max_attempts: 100,
          delay_ms: 20
        )

      assert length(neighbors) == 2
      assert Enum.any?(neighbors, &(&1.neighbor_name == "switch-A"))
      assert Enum.any?(neighbors, &(&1.neighbor_name == "switch-B"))
    end

    test "empty neighbor list does not crash", %{socket: socket, device: device} do
      result = %LldpTopologyResult{
        device_id: device.id,
        job_id: Ecto.UUID.generate(),
        local_system_name: "test-device",
        neighbors: [],
        timestamp: DateTime.to_unix(DateTime.utc_now())
      }

      binary = Encode.encode_lldp_topology_result(result)
      push(socket, "lldp_topology_result", %{"binary" => Base.encode64(binary)})

      ref = push(socket, "heartbeat", encode_payload(build_heartbeat()))
      refute_reply ref, :error
    end

    test "invalid base64 lldp_topology_result is handled gracefully", %{socket: socket} do
      push(socket, "lldp_topology_result", %{"binary" => "not-valid-base64!!!"})

      ref = push(socket, "heartbeat", encode_payload(build_heartbeat()))
      refute_reply ref, :error
    end

    test "invalid protobuf lldp_topology_result is handled gracefully", %{socket: socket} do
      push(socket, "lldp_topology_result", %{"binary" => Base.encode64("not-a-protobuf")})

      ref = push(socket, "heartbeat", encode_payload(build_heartbeat()))
      refute_reply ref, :error
    end
  end

  # ── mikrotik_result non-backup path ─────────────────────────────

  describe "mikrotik_result non-backup job_id" do
    test "non-backup job_id is processed without crash", %{socket: socket, device: device} do
      result = %MikrotikResult{
        device_id: device.id,
        job_id: Ecto.UUID.generate(),
        sentences: [%MikrotikSentence{attributes: %{"name" => "router1"}}],
        error: "",
        timestamp: DateTime.to_unix(DateTime.utc_now())
      }

      push(socket, "mikrotik_result", encode_payload(result))

      ref = push(socket, "heartbeat", encode_payload(build_heartbeat()))
      refute_reply ref, :error
    end
  end

  # ── backup_requested via PubSub ─────────────────────────────────

  describe "backup_requested via PubSub" do
    test "PubSub broadcast routes backup job to channel", %{
      agent_token: agent_token,
      device: device
    } do
      job_id = "backup:#{device.id}"

      Phoenix.PubSub.broadcast(
        Towerops.PubSub,
        "agent:#{agent_token.id}:backup",
        {:backup_requested, device.id, job_id}
      )

      assert_push "backup_job", %{binary: jobs_binary}, 200

      {:ok, decoded} = Base.decode64(jobs_binary)
      {:ok, job_list} = AgentJobList.decode(decoded)
      assert hd(job_list.jobs).job_id == job_id
    end
  end

  # ── latency_probe_jobs handle_info ──────────────────────────────

  describe "latency_probe_jobs handle_info" do
    test "sends 5 PING jobs per device for cloud poller", %{
      socket: socket,
      device: device
    } do
      send(socket.channel_pid, {:latency_probe_jobs, [device]})

      assert_push "jobs", %{binary: jobs_binary}, 500

      {:ok, decoded} = Base.decode64(jobs_binary)
      {:ok, job_list} = AgentJobList.decode(decoded)

      ping_jobs = Enum.filter(job_list.jobs, &(&1.job_type == :PING))
      assert length(ping_jobs) == 5
      assert Enum.all?(ping_jobs, &(&1.device_id == device.id))
    end

    test "empty device list does not push", %{socket: socket} do
      send(socket.channel_pid, {:latency_probe_jobs, []})
      refute_push "jobs", %{}, 100
    end
  end

  # ── checks_changed handle_info ──────────────────────────────────

  describe "checks_changed handle_info" do
    test "rebuilds and pushes check jobs", %{
      socket: socket,
      organization: organization,
      agent_token: agent_token
    } do
      {:ok, _check} =
        Towerops.Monitoring.create_check(%{
          organization_id: organization.id,
          agent_token_id: agent_token.id,
          check_type: "tcp",
          name: "TCP Check",
          interval_seconds: 60,
          timeout_ms: 5000,
          enabled: true,
          config: %{"host" => "example.com", "port" => 443}
        })

      send(socket.channel_pid, :checks_changed)

      assert_push "check_jobs", %{binary: _binary}, 500
    end
  end
end