#include "node.hpp"
#include "to_string.hpp"

namespace Sass {


  /*
		This is the equivalent of ruby's Sass::Util.paths.

    # Return an array of all possible paths through the given arrays.
    #
    # @param arrs [NodeCollection<NodeCollection<Node>>]
    # @return [NodeCollection<NodeCollection<Node>>]
    #
    # @example
    #   paths([[1, 2], [3, 4], [5]]) #=>
    #     # [[1, 3, 5],
    #     #  [2, 3, 5],
    #     #  [1, 4, 5],
    #     #  [2, 4, 5]]

   The following is the modified version of the ruby code that was more portable to C++. You
   should be able to drop it into ruby 3.2.19 and get the same results from ruby sass.

    def paths(arrs)
     	// I changed the inject and maps to an iterative approach to make it easier to implement in C++
      loopStart = [[]]

      for arr in arrs do
        permutations = []
        for e in arr do
          for path in loopStart do
            permutations.push(path + [e])
          end
        end
        loopStart = permutations
      end
    end
	*/
  Node paths(const Node& arrs, Context& ctx) {
    To_String to_string(&ctx);

    Node loopStart = Node::createCollection();
    loopStart.collection()->push_back(Node::createCollection());

    for (NodeDeque::iterator arrsIter = arrs.collection()->begin(), arrsEndIter = arrs.collection()->end();
    	arrsIter != arrsEndIter; ++arrsIter) {

      Node& arr = *arrsIter;

      Node permutations = Node::createCollection();

      for (NodeDeque::iterator arrIter = arr.collection()->begin(), arrIterEnd = arr.collection()->end();
      	arrIter != arrIterEnd; ++arrIter) {

        Node& e = *arrIter;

        for (NodeDeque::iterator loopStartIter = loopStart.collection()->begin(), loopStartIterEnd = loopStart.collection()->end();
          loopStartIter != loopStartIterEnd; ++loopStartIter) {

          Node& path = *loopStartIter;

          Node newPermutation = Node::createCollection();
          newPermutation.plus(path);
          newPermutation.collection()->push_back(e);

          permutations.collection()->push_back(newPermutation);
        }
      }

      loopStart = permutations;
    }

    return loopStart;
  }


	/*
  This is the equivalent of ruby sass' Sass::Util.flatten and [].flatten.
  Sass::Util.flatten requires the number of levels to flatten, while
  [].flatten doesn't and will flatten the entire array. This function
  supports both.

  # Flattens the first `n` nested arrays. If n == -1, all arrays will be flattened
  #
  # @param arr [NodeCollection] The array to flatten
  # @param n [int] The number of levels to flatten
  # @return [NodeCollection] The flattened array

  The following is the modified version of the ruby code that was more portable to C++. You
  should be able to drop it into ruby 3.2.19 and get the same results from ruby sass.

  def flatten(arr, n = -1)
    if n != -1 and n == 0 then
      return arr
    end

    flattened = []

    for e in arr do
      if e.is_a?(Array) then
        flattened.concat(flatten(e, n - 1))
      else
        flattened << e
      end
    end

    return flattened
  end
  */
  Node flatten(const Node& arr, Context& ctx, int n = -1) {
    if (n != -1 && n == 0) {
      return arr;
    }

    Node flattened = Node::createCollection();

    for (NodeDeque::iterator iter = arr.collection()->begin(), iterEnd = arr.collection()->end();
    	iter != iterEnd; iter++) {
    	Node& e = *iter;

      if (e.isCollection()) {
      	Node recurseFlattened = flatten(e, ctx, n - 1);
        flattened.collection()->insert(flattened.collection()->end(), recurseFlattened.collection()->begin(), recurseFlattened.collection()->end());
      } else {
      	flattened.collection()->push_back(e);
      }
    }

    return flattened;
  }
}