#pragma once

#include "minicc.h"

#include <deque>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using BNF = std::unordered_map<std::string, std::vector<std::vector<std::string>>>;

std::unordered_map<std::string, std::unordered_set<std::string>> Reverse(const BNF& bnf); // unused now, remove?
std::unordered_map<std::string, std::unordered_set<std::string>> reverseFirst(const BNF& bnf);

BNF SubBNF(const BNF& bnf, const std::string& top);
BNF removeHeadRecursion(const BNF& bnf);

bool isTerminal(const BNF& bnf, const std::string& symbol);
std::unordered_set<std::string> getTerminals(const BNF& bnf);

struct PairHash {
 size_t operator()(const std::pair<std::string,size_t>& p) const noexcept
 {
  size_t h0 {std::hash<std::string>{}(p.first)};
  size_t h1 {std::hash<size_t     >{}(p.second)};
  return h0 ^ (h1 << 1);
 }
};
std::unordered_set<std::pair<std::string, size_t>, PairHash> getEmptyPositions(const BNF& bnf);

std::unordered_map<std::string, std::unordered_set<std::pair<std::string, index_t>, PairHash>> reversePosFirst(const BNF& bnf); // like reverseFirstPos, but including variant