defmodule Tui do
  use GenServer

  @render_intvl 100
  @bullshit_rotation_interval 2500

  @bullshit_sf_phrases [
    "Reversing the polarity of the context window",
    "Recalibrating the embedding matrix flux",
    "Initializing quantum token shuffler",
    "Stabilizing token interference",
    "Aligning latent vector manifold",
    "Charging semantic field resonator",
    "Inverting prompt entropy",
    "Redirecting gradient descent pathways",
    "Synchronizing the decoder attention",
    "Calibrating neural activation dampener",
    "Polarizing self-attention mechanism",
    "Recharging photonic energy in the deep learning nodes",
    "Fluctuating the vector space harmonics",
    "Boosting the backpropagation neutrino field",
    "Cross-referencing the hallucination core"
  ]

  # -----------------------------------------------------------------------------
  # Client API
  # -----------------------------------------------------------------------------
  def start_link(opts) do
    Owl.LiveScreen.start_link(refresh_every: @render_intvl)
    GenServer.start_link(__MODULE__, opts, name: __MODULE__)
  end

  def stop(_pid, status \\ :normal) do
    case GenServer.whereis(__MODULE__) do
      nil -> :ok
      pid when is_pid(pid) -> GenServer.stop(pid, status)
    end
  end

  def add_step() do
    case GenServer.whereis(__MODULE__) do
      nil -> {:ok, nil}
      pid when is_pid(pid) -> GenServer.call(__MODULE__, {:add_step})
    end
  end

  def add_step(msg, detail \\ nil) do
    case GenServer.whereis(__MODULE__) do
      nil -> {:ok, nil}
      pid when is_pid(pid) -> GenServer.call(__MODULE__, {:add_step, msg, detail})
    end
  end

  def update_step(id, msg, detail \\ nil) do
    case GenServer.whereis(__MODULE__) do
      nil -> :ok
      pid when is_pid(pid) -> GenServer.cast(__MODULE__, {:update_step, id, msg, detail})
    end
  end

  def finish_step(id, outcome) do
    case GenServer.whereis(__MODULE__) do
      nil -> :ok
      pid when is_pid(pid) -> GenServer.cast(__MODULE__, {:finish_step, id, outcome})
    end
  end

  def finish_step(id, outcome, msg, detail \\ nil) do
    case GenServer.whereis(__MODULE__) do
      nil -> :ok
      pid when is_pid(pid) -> GenServer.cast(__MODULE__, {:finish_step, id, outcome, msg, detail})
    end
  end

  # -----------------------------------------------------------------------------
  # Server callbacks
  # -----------------------------------------------------------------------------
  def init(opts) do
    if opts[:quiet] do
      {:ok, nil}
    else
      {:ok, render_proc} = Task.start_link(&render_interval/0)

      state = %{
        opts: opts,
        id_counter: 0,
        statuses: %{},
        progress_char: "⠋",
        progress_color: :magenta,
        render_proc: render_proc
      }

      Owl.LiveScreen.add_block(:ask, state: status_box(state))

      {:ok, state}
    end
  end

  def terminate(_reason, nil), do: :ok

  def terminate(_reason, state) do
    completed =
      state.statuses
      |> Enum.map(fn
        {id, {msg, detail, :processing}} -> {id, {msg, detail, :ok}}
        {id, {msg, detail, outcome}} -> {id, {msg, detail, outcome}}
      end)

    %{state | statuses: Map.new(completed)}
    |> render()

    Owl.LiveScreen.await_render()
    Owl.LiveScreen.flush()

    :ok
  end

  def handle_call({:add_step, _msg, _detail}, _from, nil) do
    {:reply, nil, nil}
  end

  def handle_call({:add_step, msg, detail}, _from, state) do
    {id, state} = next_id(state)
    state = %{state | statuses: Map.put(state.statuses, id, {msg, detail, :processing})}
    {:reply, id, state}
  end

  def handle_call({:add_step}, _from, nil) do
    {:reply, nil, nil}
  end

  def handle_call({:add_step}, _from, state) do
    {id, state} = next_id(state)
    state = %{state | statuses: Map.put(state.statuses, id, {nil, nil, :processing})}
    start_bs_label_changer(id)
    {:reply, id, state}
  end

  def handle_cast({:update_step, _id, _msg, _detail}, nil) do
    {:noreply, nil}
  end

  def handle_cast({:update_step, id, msg, detail}, state) do
    state = %{state | statuses: Map.put(state.statuses, id, {msg, detail, :processing})}
    {:noreply, state}
  end

  def handle_cast({:finish_step, _id, _outcome}, nil) do
    {:noreply, nil}
  end

  def handle_cast({:finish_step, id, outcome}, state) do
    {msg, detail, _old_outcome} = Map.get(state.statuses, id)
    state = %{state | statuses: Map.put(state.statuses, id, {msg, detail, outcome})}
    {:noreply, state}
  end

  def handle_cast({:finish_step, _id, _outcome, _msg, _detail}, nil) do
    {:noreply, nil}
  end

  def handle_cast({:finish_step, id, outcome, msg, detail}, state) do
    state = %{state | statuses: Map.put(state.statuses, id, {msg, detail, outcome})}
    {:noreply, state}
  end

  def handle_cast(:render, nil) do
    {:noreply, nil}
  end

  def handle_cast(:render, state) do
    {:noreply, render(state)}
  end

  # -----------------------------------------------------------------------------
  # Internal functions
  # -----------------------------------------------------------------------------
  defp next_id(state) do
    id = state.id_counter
    {id, %{state | id_counter: state.id_counter + 1}}
  end

  defp render_interval() do
    GenServer.cast(__MODULE__, :render)
    Process.send_after(self(), :tick, @render_intvl)

    receive do
      :tick -> render_interval()
    end
  end

  defp render(state) do
    state = %{
      state
      | progress_char: next_progress_char(state.progress_char),
        progress_color: next_progress_color(state.progress_color)
    }

    Owl.LiveScreen.update(:ask, status_box(state))
    state
  end

  defp status_box(state) do
    cols = Owl.IO.columns()
    rows = Owl.IO.rows() - 2

    state
    |> status()
    |> Owl.Box.new(
      min_height: 1,
      min_width: cols,
      max_height: rows,
      max_width: cols,
      horizontal_align: :left,
      vertical_align: :top,
      truncate_lines: true,
      border_style: :none
    )
  end

  defp status(state) do
    state.statuses
    |> Map.keys()
    |> Enum.sort()
    |> Enum.map(fn id ->
      {msg, detail, outcome} = Map.get(state.statuses, id)
      format_msg(state, msg, detail, outcome)
    end)
    |> Enum.join("\n")
  end

  defp format_msg(state, msg, detail, outcome) do
    glyph = outcome_glyph(state, outcome)

    if is_nil(detail) do
      [glyph, " ", Owl.Data.tag(msg, :cyan)]
    else
      detail =
        if String.contains?(detail, "\n") do
          detail |> String.split("\n") |> hd()
        else
          detail
        end

      [glyph, " ", Owl.Data.tag([msg, ":"], :cyan), " ", Owl.Data.tag(detail, :yellow)]
    end
    |> Owl.Data.to_chardata()
  end

  defp outcome_glyph(state, outcome) do
    case outcome do
      :processing -> Owl.Data.tag(state.progress_char, state.progress_color)
      :ok -> Owl.Data.tag("✔", :green)
      :error -> Owl.Data.tag("✖", :red)
    end
  end

  defp start_bs_label_changer(status_id) do
    Task.start(fn ->
      phrases = Enum.shuffle(@bullshit_sf_phrases)

      Enum.each(phrases, fn phrase ->
        update_step(status_id, phrase)
        Process.sleep(@bullshit_rotation_interval)
      end)

      # Restart the cycle after completing the list
      start_bs_label_changer(status_id)
    end)
  end

  # ⠋ ⠙ ⠹ ⠸ ⠼ ⠴ ⠦ ⠧ ⠏
  defp next_progress_char("⠋"), do: "⠙"
  defp next_progress_char("⠙"), do: "⠹"
  defp next_progress_char("⠹"), do: "⠸"
  defp next_progress_char("⠸"), do: "⠼"
  defp next_progress_char("⠼"), do: "⠴"
  defp next_progress_char("⠴"), do: "⠦"
  defp next_progress_char("⠦"), do: "⠧"
  defp next_progress_char("⠧"), do: "⠏"
  defp next_progress_char("⠏"), do: "⠋"

  # :magenta :red :yellow :green :blue :cyan
  defp next_progress_color(:magenta), do: :red
  defp next_progress_color(:red), do: :yellow
  defp next_progress_color(:yellow), do: :green
  defp next_progress_color(:green), do: :blue
  defp next_progress_color(:blue), do: :cyan
  defp next_progress_color(:cyan), do: :magenta
end