#include <stdio.h>
#include <vm/fzl_vm.h>
#include <vm/internals/opcode.h>

// Pop two numbers and push sum result
int op_add(fzl_vm_t *vm)
{
  if (vm->dtop < 2)
  {
    snprintf(last_err, sizeof(last_err),
             "runtime error - expected 2 values in stack");
    print_err_data(vm);
    return -1;
  }
  fzl_value_t add1 = vm->dstack[--vm->dtop];
  fzl_value_t add2 = vm->dstack[--vm->dtop];
  vm->dstack[vm->dtop++] =
      (fzl_value_t){.type = add1.type, .as.u = add1.as.u + add2.as.u};
  return 0;
}

// Pop two numbers and push sum result
int op_sub(fzl_vm_t *vm)
{
  if (vm->dtop < 2)
  {
    snprintf(last_err, sizeof(last_err),
             "runtime error - expected 2 values in stack");
    print_err_data(vm);
    return -1;
  }
  fzl_value_t sub2 = vm->dstack[--vm->dtop];
  fzl_value_t sub1 = vm->dstack[--vm->dtop];
  vm->dstack[vm->dtop++] =
      (fzl_value_t){.type = sub1.type, .as.u = sub1.as.u - sub2.as.u};
  return 0;
}

// Pop two numbers and push sum result
int op_mul(fzl_vm_t *vm)
{
  if (vm->dtop < 2)
  {
    snprintf(last_err, sizeof(last_err),
             "runtime error - expected 2 values in stack");
    print_err_data(vm);
    return -1;
  }
  fzl_value_t mul1 = vm->dstack[--vm->dtop];
  fzl_value_t mul2 = vm->dstack[--vm->dtop];
  vm->dstack[vm->dtop++] =
      (fzl_value_t){.type = mul1.type, .as.u = mul1.as.u * mul2.as.u};
  return 0;
}

// Pop two numbers and push sum result
int op_div(fzl_vm_t *vm)
{
  if (vm->dtop < 2)
  {
    snprintf(last_err, sizeof(last_err),
             "runtime error - expected 2 values in stack");
    print_err_data(vm);
    return -1;
  }
  fzl_value_t div1 = vm->dstack[--vm->dtop];
  fzl_value_t div2 = vm->dstack[--vm->dtop];
  vm->dstack[vm->dtop++] =
      (fzl_value_t){.type = div1.type, .as.u = div2.as.u / div1.as.u};
  return 0;
}

// Pop two numbers and push sum result
int op_pow(fzl_vm_t *vm)
{
  if (vm->dtop < 2)
  {
    snprintf(last_err, sizeof(last_err),
             "runtime error - expected 2 values in stack");
    print_err_data(vm);
    return -1;
  }
  fzl_value_t pow2 = vm->dstack[--vm->dtop];
  fzl_value_t pow1 = vm->dstack[--vm->dtop];

  uint64_t pow_n     = pow1.as.u;
  uint64_t pow_res   = pow_n;
  uint64_t pow_times = pow2.as.u;
  for (size_t i = 1; i < pow_times; i++)
    pow_res *= pow_n;

  vm->dstack[vm->dtop++] = (fzl_value_t){.type = pow1.type, .as.u = pow_res};
  return 0;
}

// Pop two numbers and push sum result
int op_mod(fzl_vm_t *vm)
{
  if (vm->dtop < 2)
  {
    snprintf(last_err, sizeof(last_err),
             "runtime error - expected 2 values in stack");
    print_err_data(vm);
    return -1;
  }
  fzl_value_t mod1 = vm->dstack[--vm->dtop];
  fzl_value_t mod2 = vm->dstack[--vm->dtop];
  vm->dstack[vm->dtop++] =
      (fzl_value_t){.type = mod1.type, .as.u = mod2.as.u % mod1.as.u};
  return 0;
}

// Pop two numbers and push sum result
int op_neg(fzl_vm_t *vm)
{
  if (vm->dtop < 1)
  {
    snprintf(last_err, sizeof(last_err),
             "runtime error - expected value in stack");
    print_err_data(vm);
    return -1;
  }
  fzl_value_t neg_n = vm->dstack[--vm->dtop];
  vm->dstack[vm->dtop++] =
      (fzl_value_t){.type = neg_n.type, .as.u = -neg_n.as.u};
  return 0;
}