/*
 * Code formatter project
 * CS 4481
 */
package submit.ast;

import submit.MIPSResult;
import submit.RegisterAllocator;
import submit.SymbolTable;

/**
 *
 * @author edwajohn
 */
public class BinaryOperator extends AbstractNode implements Expression {

  private final Expression lhs, rhs;
  private final BinaryOperatorType type;

  public BinaryOperator(Expression lhs, BinaryOperatorType type,
                        Expression rhs) {
    this.lhs = lhs;
    this.type = type;
    this.rhs = rhs;
  }

  public BinaryOperator(Expression lhs, String type, Expression rhs) {
    this.lhs = lhs;
    this.type = BinaryOperatorType.fromString(type);
    this.rhs = rhs;
  }

  @Override
  public void toCminus(StringBuilder builder, String prefix) {
    lhs.toCminus(builder, prefix);
    builder.append(" ").append(type).append(" ");
    rhs.toCminus(builder, prefix);
  }

  @Override
  public MIPSResult toMIPS(StringBuilder code, StringBuilder data,
                           SymbolTable symbolTable,
                           RegisterAllocator registerAllocator) {

    switch (type) {
    case PLUS:
    case MINUS:
    case TIMES:
    case DIVIDE:
      MIPSResult left = lhs.toMIPS(code, data, symbolTable, registerAllocator);
      String leftRegister =
          registerAllocator.getRegisterOrLoadIntoRegister(left, code);

      MIPSResult right = rhs.toMIPS(code, data, symbolTable, registerAllocator);
      String rightRegister =
          registerAllocator.getRegisterOrLoadIntoRegister(right, code);
      String resultRegister = registerAllocator.getAny();
      switch (type) {
      case PLUS:
        code.append(String.format("add %s %s %s\n", resultRegister,
                                  leftRegister, rightRegister));
        break;
      case MINUS:
        code.append(String.format("sub %s %s %s\n", resultRegister,
                                  leftRegister, rightRegister));
        break;
      case TIMES:
        code.append(String.format("mult %s %s\n", leftRegister, rightRegister));
        code.append(String.format("mflo %s\n", resultRegister));
        break;
      case DIVIDE:
        code.append(String.format("div %s %s\n", leftRegister, rightRegister));
        code.append(String.format("mflo %s\n", resultRegister));
        break;
      default:
        break;
      }

      registerAllocator.clear(leftRegister);
      registerAllocator.clear(rightRegister);

      return MIPSResult.createRegisterResult(resultRegister, VarType.INT);
    default:
      break;
    }

    return MIPSResult.createVoidResult();
  }
}