#include "aoc.h"
#include <deque>
#include <set>

namespace aoc2017 {

hexagon route(hexagon h, const std::vector<hd>& hds, int* max) {
  for (auto& hd : hds) {
    h = h.neighbour(hd);
    int d = h.a + h.r + h.c;
    if (d > *max) {
      *max = d;
    }
  }
  return h;
}

int bfs(hexagon start, hexagon target) {
  int step{0};
  std::deque<hexagon> q;
  std::set<hexagon> visited;
  q.push_back(start);

  while (!q.empty()) {
    auto s = q.size();
    while (s-- > 0) {
      auto h = q.front();
      q.pop_front();
      if (h == target) {
        return step;
      }

      hexagon ns[6] = {
          h.neighbour(hd::n),  h.neighbour(hd::nw), h.neighbour(hd::ne),
          h.neighbour(hd::sw), h.neighbour(hd::se), h.neighbour(hd::s),
      };
      for (auto& n : ns) {
        if (visited.find(n) == visited.end()) {
          visited.insert(n);
          q.push_back(n);
        }
      }
    }
    step++;
  }

  return INT32_MAX;
}

std::pair<int64_t, int64_t> day11(line_view file) {
  std::vector<hd> ds;
  const char* p0 = file.line;
  const char* p1 = p0;
  line_view d6[] = {"n", "ne", "nw", "se", "sw", "s"};
  while (p1 < file.line + file.length) {
    if (*p1 == ',' || *p1 == '\n') {
      line_view d{p0, p1};
      for (int i = 0; i < 6; i++) {
        if (d6[i] == d) {
          ds.push_back(static_cast<hd>(i));
          break;
        }
      }
      p0 = p1 + 1;
    }
    p1++;
  }

  int max{INT32_MIN};
  auto d = route({0, 0, 0}, ds, &max);
  return {d.a + d.r + d.c, max};
}

} // namespace aoc2017