import gleam/io
import gleam/list
import gleam/string

pub fn parse(input: String) -> Nil {
  let input =
    input
    |> string.to_graphemes()
    |> handle_comments([], False)
    |> handle_whitespace()

  input |> list.each(io.print)
}

// [TODO]: handle into slashdash comments for nodes
fn handle_comments(
  input: List(String),
  accumulator: List(String),
  in_comment: Bool,
) -> List(String) {
  case input {
    // [TODO]: Check if in a string.
    ["/", "/", ..input] ->
      input
      |> list.drop_while(fn(g) { g != "\n" })
      |> handle_comments(accumulator, in_comment)
    ["/", "*", ..input] -> input |> handle_comments(accumulator, True)
    ["*", "/", ..input] if in_comment ->
      input |> handle_comments(accumulator, False)
    [_, ..input] if in_comment ->
      input |> handle_comments(accumulator, in_comment)
    [g, ..input] -> input |> handle_comments([g, ..accumulator], in_comment)
    [] -> accumulator
  }
}

// [TODO]: Look into how KDL uses whitespace, and more potential things needed to be handled.
fn handle_whitespace(input: List(String)) -> List(String) {
  case input {
    [" ", ..input] -> handle_whitespace(input)
    ["\t", ..input] -> handle_whitespace(input)
    ["\n", ..input] -> handle_whitespace(input)
    ["\r\n", ..input] -> handle_whitespace(input)
    _ -> input
  }
}