defmodule ProxmoxAgent.Collectors.Vms do
  @moduledoc """
  Collects VM/LXC runtime (fast path) and per-VM detail incl. IPs (medium path).
  """

  @spec collect_runtime(keyword()) :: %{vms: [map()], errors: [map()]}
  def collect_runtime(opts) do
    runner = runner(opts)
    node = Keyword.fetch!(opts, :node)

    {qemu, e1} = list(runner, node, "qemu")
    {lxc, e2} = list(runner, node, "lxc")

    vms =
      Enum.map(qemu, &normalize_runtime(&1, "qemu")) ++
        Enum.map(lxc, &normalize_runtime(&1, "lxc"))

    %{vms: vms, errors: Enum.filter([e1, e2], & &1)}
  end

  @spec collect_detail(keyword()) :: %{vms: [map()], errors: [map()]}
  def collect_detail(opts) do
    runner = runner(opts)
    node = Keyword.fetch!(opts, :node)

    {qemu, e1} = list(runner, node, "qemu")
    {lxc, e2} = list(runner, node, "lxc")

    qemu_details = Enum.map(qemu, &qemu_detail(runner, node, &1))
    lxc_details = Enum.map(lxc, &lxc_detail(runner, node, &1))

    %{vms: qemu_details ++ lxc_details, errors: Enum.filter([e1, e2], & &1)}
  end

  defp runner(opts), do: Keyword.get(opts, :runner, &ProxmoxAgent.Shell.run/2)

  defp list(runner, node, type) do
    case runner.("pvesh", ["get", "/nodes/#{node}/#{type}", "--output-format", "json"]) do
      {:ok, body} ->
        case Jason.decode(body) do
          {:ok, list} when is_list(list) -> {list, nil}
          {:error, e} -> {[], %{tag: "decode_#{type}", message: Exception.message(e)}}
        end

      {:error, reason} ->
        {[], %{tag: "list_#{type}", message: inspect(reason)}}
    end
  end

  defp normalize_runtime(entry, type) do
    %{
      vmid: entry["vmid"],
      type: type,
      name: entry["name"] || entry["hostname"],
      status: entry["status"],
      uptime_seconds: entry["uptime"] || 0,
      cpu_usage: entry["cpu"] || 0.0,
      mem_bytes: entry["mem"] || 0,
      max_mem_bytes: entry["maxmem"] || 0,
      tags: parse_tags(entry["tags"])
    }
  end

  defp parse_tags(nil), do: []
  defp parse_tags(""), do: []

  defp parse_tags(str) when is_binary(str) do
    str |> String.split([";", ","], trim: true) |> Enum.map(&String.trim/1)
  end

  defp qemu_detail(runner, node, entry) do
    vmid = entry["vmid"]
    {config, cfg_err} = fetch_json(runner, "/nodes/#{node}/qemu/#{vmid}/config")
    {ips, ip_err} = fetch_qemu_agent_ips(runner, node, vmid)

    %{
      vmid: vmid,
      type: "qemu",
      name: entry["name"],
      config: config || %{},
      ips: ips,
      errors: Enum.filter([cfg_err, ip_err], & &1)
    }
  end

  defp lxc_detail(runner, node, entry) do
    vmid = entry["vmid"]
    {config, cfg_err} = fetch_json(runner, "/nodes/#{node}/lxc/#{vmid}/config")
    ips = extract_lxc_ips(config || %{})

    %{
      vmid: vmid,
      type: "lxc",
      name: entry["name"],
      config: config || %{},
      ips: ips,
      errors: Enum.filter([cfg_err], & &1)
    }
  end

  defp fetch_json(runner, path) do
    case runner.("pvesh", ["get", path, "--output-format", "json"]) do
      {:ok, body} ->
        case Jason.decode(body) do
          {:ok, map} -> {map, nil}
          {:error, e} -> {nil, %{tag: "decode", message: Exception.message(e)}}
        end

      {:error, reason} ->
        {nil, %{tag: "pvesh", message: inspect(reason)}}
    end
  end

  defp fetch_qemu_agent_ips(runner, node, vmid) do
    case runner.("pvesh", [
           "get",
           "/nodes/#{node}/qemu/#{vmid}/agent/network-get-interfaces",
           "--output-format",
           "json"
         ]) do
      {:ok, body} ->
        case Jason.decode(body) do
          {:ok, %{"result" => interfaces}} ->
            ips =
              interfaces
              |> Enum.reject(&(&1["name"] == "lo"))
              |> Enum.flat_map(&Map.get(&1, "ip-addresses", []))
              |> Enum.filter(&(&1["ip-address-type"] == "ipv4"))
              |> Enum.map(& &1["ip-address"])

            {ips, nil}

          _ ->
            {[], %{tag: "agent_ips", message: "unexpected shape"}}
        end

      {:error, _reason} ->
        {[], nil}
    end
  end

  defp extract_lxc_ips(config) do
    config
    |> Enum.filter(fn {k, _} -> String.starts_with?(to_string(k), "net") end)
    |> Enum.flat_map(fn {_, val} -> parse_lxc_net(val) end)
  end

  defp parse_lxc_net(val) when is_binary(val) do
    val
    |> String.split(",")
    |> Enum.find_value([], fn pair ->
      case String.split(pair, "=", parts: 2) do
        ["ip", ip] ->
          ip = ip |> String.split("/") |> hd()
          if ip == "dhcp", do: [], else: [ip]

        _ ->
          nil
      end
    end)
  end

  defp parse_lxc_net(_), do: []
end