/* SPDX-FileCopyrightText: 2026 Blender Authors
 *
 * SPDX-License-Identifier: Apache-2.0 */

#include "stdcycles.h"

int integer_math_divide_floor(int a, int b)
{
  int d = a / b;
  int r = a % b;
  return (r != 0) ? (d - int((a < 0) != (b < 0))) : d;
}

int integer_math_gcd(int a_in, int b_in)
{
  int a = abs(a_in);
  int b = abs(b_in);
  while (b != 0) {
    int t = b;
    b = a % b;
    a = t;
  }
  return a;
}

int integer_math_power(int base_in, int exponent_in)
{
  int base = base_in;
  int exponent = exponent_in;
  if (exponent < 0) {
    if (base == 1 || base == -1) {
      return (base < 0 && (exponent & 1) != 0) ? -1 : 1;
    }
    return 0;
  }
  int result = 1;
  while (exponent != 0) {
    if ((exponent & 1) != 0) {
      result *= base;
    }
    exponent = exponent >> 1;
    base = base * base;
  }
  return result;
}

shader node_integer_math(
    string math_type = "add", int Value1 = 0, int Value2 = 0, int Value3 = 0, output int Value = 0)
{
  if (math_type == "add")
    Value = Value1 + Value2;
  else if (math_type == "subtract")
    Value = Value1 - Value2;
  else if (math_type == "multiply")
    Value = Value1 * Value2;
  else if (math_type == "divide")
    Value = (Value2 != 0) ? (Value1 / Value2) : 0;
  else if (math_type == "multiply_add")
    Value = Value1 * Value2 + Value3;
  else if (math_type == "power")
    Value = integer_math_power(Value1, Value2);
  else if (math_type == "floored_modulo")
    Value = (Value2 != 0) ? (((Value1 % Value2) + Value2) % Value2) : 0;
  else if (math_type == "absolute")
    Value = abs(Value1);
  else if (math_type == "minimum")
    Value = min(Value1, Value2);
  else if (math_type == "maximum")
    Value = max(Value1, Value2);
  else if (math_type == "gcd")
    Value = integer_math_gcd(Value1, Value2);
  else if (math_type == "lcm") {
    int gcd = integer_math_gcd(Value1, Value2);
    Value = (gcd != 0) ? abs(Value1 / gcd * Value2) : 0;
  }
  else if (math_type == "negate")
    Value = -Value1;
  else if (math_type == "sign")
    Value = int(0 < Value1) - int(Value1 < 0);
  else if (math_type == "divide_floor")
    Value = (Value2 != 0) ? integer_math_divide_floor(Value1, Value2) : 0;
  else if (math_type == "divide_ceil")
    Value = (Value2 != 0) ? -integer_math_divide_floor(Value1, -Value2) : 0;
  else if (math_type == "divide_round") {
    int abs_b = abs(Value2);
    int sign_b = int(0 < Value2) - int(Value2 < 0);
    if (Value1 >= 0)
      Value = ((abs_b != 0) ? ((2 * Value1 + abs_b) / (2 * abs_b)) : 0) * sign_b;
    else
      Value = -((abs_b != 0) ? ((2 * -Value1 + abs_b) / (2 * abs_b)) : 0) * sign_b;
  }
  else if (math_type == "modulo")
    Value = (Value2 != 0) ? (Value1 % Value2) : 0;
  else
    Value = 0;
}