#include "fh_error.h"
#include "fh_config.h"
#include "fh_runtime.h"
#include "fh_stack.h"
#include "fh_print.h"

// TODO stacks should grow down, not up!

enum fh_error ds_roll(struct fh_thread_s *fh, int n)
{
  if (fh->data_stack_top <= n) {
    LOG("DS roll UNDERFLOW");
    return FH_ERR_DS_UNDERFLOW;
  }

  uint32_t yn = fh->data_stack_top - 1 - n;
  uint32_t yoinked = fh->data_stack[yn];
  for (uint32_t i = yn; i < fh->data_stack_top; i++) {
    fh->data_stack[i] = fh->data_stack[i+1];
  }
  fh->data_stack[fh->data_stack_top - 1] = yoinked;
  return FH_OK;
}

/** Peek top of data stack */
enum fh_error ds_peek_n(struct fh_thread_s *fh, uint32_t *out, int n)
{
  if (fh->data_stack_top <= n) {
    LOG("DS peek_n UNDERFLOW");
    return FH_ERR_DS_UNDERFLOW;
  }
  *out = fh->data_stack[fh->data_stack_top - 1 - n];
  return FH_OK;
}

/** Peek top of return stack */
enum fh_error rs_peek_n(struct fh_thread_s *fh, uint32_t *out, int n)
{
  if (fh->return_stack_top <= n) {
    LOG("RS peek_n UNDERFLOW");
    return FH_ERR_RS_UNDERFLOW;
  }
  *out = fh->return_stack[fh->return_stack_top - 1 - n];
  return FH_OK;
}

/** Pop from data stack */
enum fh_error ds_pop(struct fh_thread_s *fh, uint32_t *out)
{
  if (fh->data_stack_top == 0) {
    LOG("DS pop UNDERFLOW");
    return FH_ERR_DS_UNDERFLOW;
  }
  *out = fh->data_stack[--fh->data_stack_top];
  LOG("DS pop %d", *out);
  return FH_OK;
}

/** Pop from return stack */
enum fh_error rs_pop(struct fh_thread_s *fh, uint32_t *out)
{
  if (fh->return_stack_top == 0) {
    LOG("RS pop UNDERFLOW");
    return FH_ERR_RS_UNDERFLOW;
  }
  *out = fh->return_stack[--fh->return_stack_top];
  LOG("RS pop %d", *out);
  return FH_OK;
}

#define UPDATE_HWM(hwm, top) \
  do {                       \
    if((hwm) < (top)) {      \
      (hwm) = (top);         \
    }                        \
  } while(0)

/** Push to data stack */
enum fh_error ds_push(struct fh_thread_s *fh, uint32_t in)
{
  LOG("DS push %d", in);
  if (fh->data_stack_top == DATA_STACK_DEPTH) {
    return FH_ERR_DS_OVERFLOW;
  }
  fh->data_stack[fh->data_stack_top++] = in;
  UPDATE_HWM(fh->data_stack_hwm, fh->data_stack_top);
  return FH_OK;
}

/** Push to return stack */
enum fh_error rs_push(struct fh_thread_s *fh, uint32_t in)
{
  LOG("RS push %d", in);
  if (fh->return_stack_top == RETURN_STACK_DEPTH) {
    return FH_ERR_RS_OVERFLOW;
  }
  fh->return_stack[fh->return_stack_top++] = in;
  UPDATE_HWM(fh->return_stack_hwm, fh->return_stack_top);
  return FH_OK;
}