import "./option.zc"
import "./mem.zc"

struct Queue<T> {
  data: T*;
  len: usize;
  cap: usize;
}

impl Queue<T> {
  fn new() -> Queue<T> {
    return Queue<T>{data: NULL, len: 0, cap: 0};
  }

  fn free(self) {
    if (self.data) {
      free(self.data);
      self.data = NULL;
    }
    self.len = 0;
  }

  fn clone(self) -> Queue<T> {
    var new_queue = Queue<T>::new();
    new_queue.len = self.len;
    new_queue.cap = self.cap;
    new_queue.data = malloc(sizeof(T) * new_queue.cap);
    memcpy(new_queue.data, self.data, sizeof(T) * new_queue.cap);
    return new_queue;
  }

  fn push(self, value: T) {
    if (!self.data) {
      self.cap = 8;
      self.data = malloc(sizeof(T) * self.cap);
    }
    if (self.len == self.cap) {
      self.cap = self.cap * 2;
      self.data = realloc(self.data, sizeof(T) * self.cap);
    }

    // Assigns it at the back of 
    self.data[self.len] = value;
    self.len = self.len + 1;
  }

  fn pop(self) -> Option<T> {
    if (self.len > 0) {
      var value = self.data[0];
      self.len = self.len - 1;

      // Shifts the data in the queue "forward"
      memcpy(self.data, self.data + 1, sizeof(T) * self.len);

      return Option<T>::Some(value);
    }
    return Option<T>::None();
  }
}

impl Drop for Queue<T> {
  fn drop(self) {
    self.free();
  }
}