loom_ex

defmodule LoomEx.Tools.Grep do
  use LoomEx.Tool

  @max_results 100

  @impl true
  def name, do: "grep"

  @impl true
  def description,
    do:
      "Search file contents for a pattern. Returns matching lines with file paths and line numbers."

  @impl true
  def parameters do
    %{
      type: "object",
      properties: %{
        pattern: %{type: "string", description: "Search pattern (regex supported)"},
        path: %{
          type: "string",
          description: "Directory or file to search in (default: current directory)"
        },
        glob: %{
          type: "string",
          description: "File glob pattern to filter, e.g. '*.ex' (optional)"
        },
        case_insensitive: %{
          type: "boolean",
          description: "Case insensitive search (default: false)"
        }
      },
      required: ["pattern"]
    }
  end

  @impl true
  def execute(%{"pattern" => pattern} = args, ctx) do
    search_path = args["path"] || "."
    full_path = resolve_path(search_path, ctx)
    case_insensitive = args["case_insensitive"] || false

    # Build grep arguments
    grep_args = ["-rn"]
    grep_args = if case_insensitive, do: grep_args ++ ["-i"], else: grep_args
    grep_args = if glob = args["glob"], do: grep_args ++ ["--include", glob], else: grep_args
    grep_args = grep_args ++ [pattern, full_path]

    try do
      {output, exit_code} = System.cmd("grep", grep_args, stderr_to_stdout: true)

      case exit_code do
        0 ->
          lines = String.split(output, "\n", trim: true)
          total = length(lines)
          truncated = Enum.take(lines, @max_results)
          result = Enum.join(truncated, "\n")

          result =
            if total > @max_results do
              result <> "\n... [#{total - @max_results} more matches truncated]"
            else
              result
            end

          {:ok, %{"matches" => result, "count" => min(total, @max_results), "total" => total}}

        1 ->
          {:ok, %{"matches" => "", "count" => 0, "total" => 0}}

        _ ->
          {:error, "grep failed (exit #{exit_code}): #{String.trim(output)}"}
      end
    rescue
      e -> {:error, "grep error: #{Exception.message(e)}"}
    end
  end

  defp resolve_path(path, ctx) do
    if Path.type(path) == :absolute do
      path
    else
      Path.join(ctx[:cwd] || ".", path)
    end
  end
end