raxol

defmodule Raxol.Terminal.Buffer.UnifiedManager.Region do
  @moduledoc """
  Handles region operations for the unified buffer manager.

  This module provides functions for filling regions, validating regions,
  and managing region-based operations.
  """

  alias Raxol.Terminal.Buffer.Cell

  @doc """
  Validates if a region is within buffer bounds.
  """
  @spec region_valid?(
          map(),
          non_neg_integer(),
          non_neg_integer(),
          non_neg_integer(),
          non_neg_integer()
        ) :: boolean()
  def region_valid?(state, x, y, width, height) do
    coordinates_valid_for_set?(state, x, y) and
      x + width <= state.active_buffer.width and
      y + height <= state.active_buffer.height
  end

  @doc """
  Fills a region with a cell.
  """
  @spec fill_region_with_cell(
          map(),
          non_neg_integer(),
          non_neg_integer(),
          non_neg_integer(),
          non_neg_integer(),
          Cell.t()
        ) :: map()
  def fill_region_with_cell(buffer, x, y, width, height, cell) do
    new_cell = create_cell_from_input(cell)

    updated_cells =
      buffer.cells
      |> Enum.with_index()
      |> Enum.map(fn {row, row_y} ->
        if row_in_region?(row_y, y, height) do
          update_row_in_region(row, x, width, new_cell)
        else
          row
        end
      end)

    %{buffer | cells: updated_cells}
  end

  @doc """
  Checks if a row is within a region.
  """
  @spec row_in_region?(non_neg_integer(), non_neg_integer(), non_neg_integer()) ::
          boolean()
  def row_in_region?(row_y, y, height) do
    row_y >= y and row_y < y + height
  end

  @doc """
  Checks if a column is within a region.
  """
  @spec col_in_region?(non_neg_integer(), non_neg_integer(), non_neg_integer()) ::
          boolean()
  def col_in_region?(col_x, x, width) do
    col_x >= x and col_x < x + width
  end

  @doc """
  Updates a row within a region.
  """
  @spec update_row_in_region(
          list(),
          non_neg_integer(),
          non_neg_integer(),
          Cell.t()
        ) :: list()
  def update_row_in_region(row, x, width, new_cell) do
    row
    |> Enum.with_index()
    |> Enum.map(fn {col_cell, col_x} ->
      if col_in_region?(col_x, x, width) do
        new_cell
      else
        col_cell
      end
    end)
  end

  # Private functions

  defp coordinates_valid_for_set?(state, x, y) do
    x >= 0 and y >= 0 and x < state.active_buffer.width and
      y < state.active_buffer.height
  end

  alias Raxol.Terminal.Buffer.CellHelper

  defp create_cell_from_input(cell) do
    CellHelper.create_cell_from_input(cell)
  end
end