#include "common.h"
#include <vector>
#include <stdint.h>

namespace aoc2022 {

struct hook {
  int64_t value = 0;
  hook* prev = nullptr;
  hook* next = nullptr;
};

struct message {
  static const int LEN = 5000;
  // static const int LEN = 7;
  hook msg[LEN];
  hook* head = nullptr;
  hook* zero = nullptr;

  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;
  }

  void print() const noexcept {
    hook* n = head->next;
    while (n != head) {
      printf("%ld ", n->value);
      n = n->next;
    }
    printf("\n");
  }

  hook* get(int index) {
    index %= LEN;
    return &msg[index];
  }

  void put(hook* n, hook* x) {
    x->prev->next = x->next;
    x->next->prev = x->prev;

    x->next = n->next;
    n->next->prev = x;
    x->prev = n;
    n->next = x;
  }

  hook* next(hook* x, int64_t i) {
    hook* n = x;
    bool foward = i > 0;
    i = std::abs(i) % (LEN - 1);
    if (foward) {
      while (i > 0) {
        n = n->next;
        if (n != head && n != x) {
          i--;
        }
      }
    } else { // i < 0
      while (i >= 0) {
        n = n->prev;
        if (n != head && n != x) {
          i--;
        }
      }
    }
    return n;
  }

  hook* nth(int n) {
    hook* x = zero;
    while(n > 0) {
      x = x->next;
      if (x != head) {
        n--;
      }
    }
    return x;
  }

  void relocate() {
    for (int i = 0; i < LEN; i++) {
      hook* h = &msg[i];
      if (h->value != 0) {
        hook* n = next(h, h->value);
        // printf("%ld put to %ld and %ld\n", h->value, n->value, n->next->value);
        put(n, h);
        // print();
      }
    }
  }

  void multiply(size_t n) {
    for (int i = 0; i < LEN; i++) {
      msg[i].value *= n;
    }
  }

  message(line_view lv) {
    const char* p = lv.line;
    head = new hook;
    head->value = INT32_MAX;

    hook* hs[LEN];
    for (int i = 0; i < LEN; i++) {
      hs[i] = &msg[i];
      if (i == 0) {
        head->next = hs[i];
        hs[i]->prev = head;
        hs[i]->next = &msg[i + 1];
      } else if (i == LEN - 1) {
        hs[i]->prev = &msg[i - 1];
        hs[i]->next = head;
        head->prev = hs[i];
      } else {
        hs[i]->prev = &msg[i - 1];
        hs[i]->next = &msg[i + 1];
      }
    }

    int n{0};
    while (p < lv.line + lv.length) {
      if (*p != ' ') {
        get_number(&p, &hs[n]->value);
        if (hs[n]->value == 0) {
          zero = hs[n];
        }
        n++;
      }
      p++;
    }
  }
};

std::pair<int, int64_t> day20(line_view);
} // namespace aoc2022