////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 1996-2020 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave is free software: you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Octave is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
//
////////////////////////////////////////////////////////////////////////

#if defined (HAVE_CONFIG_H)
#  include "config.h"
#endif

#include "error.h"
#include "interpreter.h"
#include "ov.h"
#include "profiler.h"
#include "pt-binop.h"
#include "pt-eval.h"
#include "variables.h"

namespace octave
{
  // Binary expressions.

  void
  tree_binary_expression::matlab_style_short_circuit_warning (const char *op)
  {
    warning_with_id ("Octave:possible-matlab-short-circuit-operator",
                     "Matlab-style short-circuit operation performed for operator %s",
                     op);

    m_braindead_shortcircuit_warning_issued = true;
  }

  std::string
  tree_binary_expression::oper (void) const
  {
    return octave_value::binary_op_as_string (m_etype);
  }

  tree_expression *
  tree_binary_expression::dup (symbol_scope& scope) const
  {
    tree_binary_expression *new_be
      = new tree_binary_expression (m_lhs ? m_lhs->dup (scope) : nullptr,
                                    m_rhs ? m_rhs->dup (scope) : nullptr,
                                    line (), column (), m_etype);

    new_be->copy_base (*this);

    return new_be;
  }

  octave_value
  tree_binary_expression::evaluate (tree_evaluator& tw, int)
  {
    octave_value val;

    if (is_eligible_for_braindead_shortcircuit ())
      {
        if (m_lhs)
          {
            octave_value a = m_lhs->evaluate (tw);

            if (a.ndims () == 2 && a.rows () == 1 && a.columns () == 1)
              {
                bool result = false;

                bool a_true = a.is_true ();

                if (a_true)
                  {
                    if (m_etype == octave_value::op_el_or)
                      {
                        matlab_style_short_circuit_warning ("|");
                        return octave_value (true);
                      }
                  }
                else
                  {
                    if (m_etype == octave_value::op_el_and)
                      {
                        matlab_style_short_circuit_warning ("&");
                        return octave_value (false);
                      }
                  }

                if (m_rhs)
                  {
                    octave_value b = m_rhs->evaluate (tw);

                    result = b.is_true ();
                  }

                return octave_value (result);
              }
          }
      }

    if (m_lhs)
      {
        octave_value a = m_lhs->evaluate (tw);

        if (a.is_defined () && m_rhs)
          {
            octave_value b = m_rhs->evaluate (tw);

            if (b.is_defined ())
              {
                profiler::enter<tree_binary_expression>
                  block (tw.get_profiler (), *this);

                // Note: The profiler does not catch the braindead
                // short-circuit evaluation code above, but that should be
                // ok.  The evaluation of operands and the operator itself
                // is entangled and it's not clear where to start/stop
                // timing the operator to make it reasonable.

                interpreter& interp = tw.get_interpreter ();

                type_info& ti = interp.get_type_info ();

                val = binary_op (ti, m_etype, a, b);
              }
          }
      }

    return val;
  }

  // Boolean expressions.

  std::string
  tree_boolean_expression::oper (void) const
  {
    std::string retval = "<unknown>";

    switch (m_etype)
      {
      case bool_and:
        retval = "&&";
        break;

      case bool_or:
        retval = "||";
        break;

      default:
        break;
      }

    return retval;
  }

  tree_expression *
  tree_boolean_expression::dup (symbol_scope& scope) const
  {
    tree_boolean_expression *new_be
      = new tree_boolean_expression (m_lhs ? m_lhs->dup (scope) : nullptr,
                                     m_rhs ? m_rhs->dup (scope) : nullptr,
                                     line (), column (), m_etype);

    new_be->copy_base (*this);

    return new_be;
  }

  octave_value
  tree_boolean_expression::evaluate (tree_evaluator& tw, int)
  {
    octave_value val;

    bool result = false;

    // This evaluation is not caught by the profiler, since we can't find
    // a reasonable place where to time.  Note that we don't want to
    // include evaluation of LHS or RHS into the timing, but this is
    // entangled together with short-circuit evaluation here.

    if (m_lhs)
      {
        octave_value a = m_lhs->evaluate (tw);

        bool a_true = a.is_true ();

        if (a_true)
          {
            if (m_etype == tree_boolean_expression::bool_or)
              return octave_value (true);
          }
        else
          {
            if (m_etype == tree_boolean_expression::bool_and)
              return octave_value (false);
          }

        if (m_rhs)
          {
            octave_value b = m_rhs->evaluate (tw);

            result = b.is_true ();
          }

        val = octave_value (result);
      }

    return val;
  }
}