defmodule ExFlow.Commands.CreateEdgeCommand do
  @moduledoc """
  Command to create a new edge in the graph.
  """

  @behaviour ExFlow.Command

  alias ExFlow.Core.Graph

  defstruct [:edge_id, :source_id, :source_handle, :target_id, :target_handle, :label, :metadata]

  @type t :: %__MODULE__{
          edge_id: String.t(),
          source_id: String.t(),
          source_handle: String.t(),
          target_id: String.t(),
          target_handle: String.t(),
          label: String.t() | nil,
          metadata: map()
        }

  def new(edge_id, source_id, source_handle, target_id, target_handle, opts \\ %{}) do
    %__MODULE__{
      edge_id: edge_id,
      source_id: source_id,
      source_handle: source_handle,
      target_id: target_id,
      target_handle: target_handle,
      label: Map.get(opts, :label),
      metadata: Map.get(opts, :metadata, %{})
    }
  end

  @impl ExFlow.Command
  def execute(%__MODULE__{} = cmd, graph) do
    opts = %{label: cmd.label, metadata: cmd.metadata}

    Graph.add_edge(
      graph,
      cmd.edge_id,
      cmd.source_id,
      cmd.source_handle,
      cmd.target_id,
      cmd.target_handle,
      opts
    )
  end

  @impl ExFlow.Command
  def undo(%__MODULE__{} = cmd, graph) do
    Graph.delete_edge(graph, cmd.edge_id)
  end

  @impl ExFlow.Command
  def description(%__MODULE__{} = cmd) do
    "Create edge from '#{cmd.source_id}' to '#{cmd.target_id}'"
  end
end