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

namespace aoc2017 {
static int64_t& get(char x, int64_t rs[26]) { return rs[x - 'a']; }
static void get_number(const char** pp, int64_t* d) {
  const char* p = *pp;
  int sign = 1;
  if (*p == '-') {
    sign = -1;
    p++;
  }
  while (*p >= '0' && *p <= '9') {
    *d = *d * 10 + *p - '0';
    p++;
  }
  *d *= sign;
  *pp = p;
}

static int64_t get_number(const char* p, int64_t rs[26]) {
  int64_t d{0};
  if (*p == '-' || (*p >= '0' && (*p <= '9'))) {
    get_number(&p, &d);
  } else {
    d = get(*p, rs);
  }
  return d;
}

struct message_queue {
  std::deque<int64_t>* qs;
  std::deque<int64_t>* qr;
  size_t c;
};

typedef void (*f18)(size_t*, const char*, const char*, int64_t rs[26], message_queue& q);

static void snd(size_t* i, const char* p1, const char* p2, int64_t rs[26], message_queue& q) {
  q.qs->push_back(get(*p1, rs));
  q.c += 1;
  *i += 1;
}

static void rcv0(size_t* i, const char* p1, const char* p2, int64_t rs[26], message_queue& q) {
  auto d = get_number(p1, rs);
  if (d != 0) {
    // printf("%ld\n", sounds.back());
    *i = INT64_MAX - 1;
  }
  *i += 1;
}

// static void rcv1(size_t* i, const char* p1, const char* p2, int64_t rs[26], message_queue& q) {
//   if (!q.qr->empty()) {
//     auto x = q.qr->front();
//     q.qr->pop_front();
//     get(*p1, rs) = x;
//     *i += 1;
//   }
// }

static void set(size_t* i, const char* p1, const char* p2, int64_t rs[26], message_queue& qs) {
  get(*p1, rs) = get_number(p2, rs);
  *i += 1;
}

static void add(size_t* i, const char* p1, const char* p2, int64_t rs[26], message_queue& q) {
  get(*p1, rs) += get_number(p2, rs);
  *i += 1;
}

static void mul(size_t* i, const char* p1, const char* p2, int64_t rs[26], message_queue& q) {
  get(*p1, rs) *= get_number(p2, rs);
  *i += 1;
}

static void mod(size_t* i, const char* p1, const char* p2, int64_t rs[26], message_queue& q) {
  get(*p1, rs) %= get_number(p2, rs);
  *i += 1;
}

static void jgz(size_t* i, const char* p1, const char* p2, int64_t rs[26], message_queue& q) {
  auto d0 = get_number(p1, rs);
  auto d1 = get_number(p2, rs);
  *i += d0 > 0 ? d1 : 1;
}

// static void print() {
//   char as[] = {'i', 'a', 'p', 'f', 'b'};
//   for (auto& a: as) {
//     printf("[%c: %ld] ", a, get(a));
//   }
//   printf("\n");
// }

static size_t exec(size_t index, const std::vector<line_view>& todos, int64_t rs[26], message_queue& q, f18 rcv) {
  if (index < todos.size()) {
    f18 fs[] = {snd, set, add, mul, mod, jgz, rcv};
    const char* cs[] = {"snd", "set", "add", "mul", "mod", "jgz", "rcv"};
    auto& todo = todos[index];
    const char* p = todo.line;
    auto match = [](const char* p, const char* p0) -> bool {
      for (int i = 0; i < 3; i++) {
        if (*(p + i) != *(p0 + i)) {
          return false;
        }
      }
      return true;
    };

    for (size_t i = 0; i < 7; i++) {
      if (match(p, cs[i])) {
        fs[i](&index, p + 4, p + 6, rs, q);
        break;
      }
    }
  }
  return index;
}

static int64_t part1(const std::vector<line_view>& todos) {
  size_t index{0};
  int64_t rs[26] = {0};
  std::deque<int64_t> q;
  message_queue mq = {&q, &q, 0};

  while (index < todos.size()) {
    index = exec(index, todos, rs, mq, rcv0);
  }
  return q.back();
}

// static void part2(const std::vector<line_view>& todos) {
//   size_t i0{0};
//   size_t i1{0};
// 
//   int64_t rs0[26] = {0};
//   get('p', rs0) = 0;
//   int64_t rs1[26] = {0};
//   get('p', rs1) = 1;
// 
//   std::deque<int64_t> q0;
//   std::deque<int64_t> q1;
//   message_queue mq0 = {&q1, &q0, 0};
//   message_queue mq1 = {&q0, &q1, 0};
// 
//   while (i0 < todos.size() && i1 < todos.size()) {
//     i0 = exec(i0, todos, rs0, mq0, rcv1);
//     i1 = exec(i1, todos, rs1, mq1, rcv1);
//     printf("%zu %zu\n", mq0.c, mq1.c);
//   }
// }

std::pair<int64_t, int64_t> day18(line_view file) {
  std::vector<line_view> todos;
  per_line(file, [&todos](line_view lv) {
    todos.push_back(lv);
    return true;
  });

  auto t0 = part1(todos);
  // part2(todos);
  return {t0, 0};
}
} // namespace aoc2017