/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file cppTemplateParameterList.cxx
 * @author drose
 * @date 1999-10-28
 */

#include "cppTemplateParameterList.h"
#include "cppClassTemplateParameter.h"
#include "cppInstance.h"
#include "cppExpression.h"

/**
 *
 */
CPPTemplateParameterList::
CPPTemplateParameterList() {
}

/**
 *
 */
std::string CPPTemplateParameterList::
get_string() const {
  std::ostringstream strname;
  strname << "< " << *this << " >";
  return strname.str();
}

/**
 * Matches up the actual parameters one-to-one with the formal parameters they
 * are replacing, so the template may be instantiated by swapping out each
 * occurrence of a template standin type with its appropriate replacement.
 */
void CPPTemplateParameterList::
build_subst_decl(const CPPTemplateParameterList &formal_params,
                 CPPDeclaration::SubstDecl &subst,
                 CPPScope *current_scope, CPPScope *global_scope) const {

  Parameters::const_iterator pfi, pai;
  for (pfi = formal_params._parameters.begin(), pai = _parameters.begin();
       pfi != formal_params._parameters.end() && pai != _parameters.end();
       ++pfi, ++pai) {
    CPPDeclaration *formal = *pfi;
    CPPDeclaration *actual = *pai;

    if (actual->as_type()) {
      actual = actual->as_type()->resolve_type(current_scope, global_scope);
    }

    if (!(formal == actual)) {
      subst.insert(CPPDeclaration::SubstDecl::value_type(formal, actual));
    }
  }

  // Fill in the default template parameters.
  while (pfi != formal_params._parameters.end()) {
    CPPDeclaration *decl = (*pfi);
    if (decl->as_instance()) {
      // A value template parameter.  Its default is an expression.
      CPPInstance *inst = decl->as_instance();
      if (inst->_initializer != nullptr) {
        CPPDeclaration *decl =
          inst->_initializer->substitute_decl(subst, current_scope,
                                              global_scope);
        if (!(*decl == *inst)) {
          subst.insert(CPPDeclaration::SubstDecl::value_type
                       (inst, decl));
        }
      }
    } else if (decl->as_class_template_parameter()) {
      // A class template parameter.
      CPPClassTemplateParameter *cparam = decl->as_class_template_parameter();
      if (cparam->_default_type != nullptr) {
        CPPDeclaration *decl =
          cparam->_default_type->substitute_decl(subst, current_scope,
                                                 global_scope);
        if (!(*cparam == *decl)) {
          subst.insert(CPPDeclaration::SubstDecl::value_type
                       (cparam, decl));
        }
      }
    }
    ++pfi;
  }
}

/**
 * This function returns true if all the parameters in the list are real
 * expressions or classes, and not types yet to-be-determined or template
 * parameter types.  That is, this returns true for a normal template
 * instantiation, and false for a template instantiation based on template
 * parameters that have not yet been specified.
 */
bool CPPTemplateParameterList::
is_fully_specified() const {
  for (int i = 0; i < (int)_parameters.size(); ++i) {
    if (!_parameters[i]->is_fully_specified()) {
      return false;
    }
  }
  return true;
}

/**
 * Returns true if any type within the parameter list is a CPPTBDType and thus
 * isn't fully determined right now.
 */
bool CPPTemplateParameterList::
is_tbd() const {
  for (int i = 0; i < (int)_parameters.size(); ++i) {
    CPPType *type = _parameters[i]->as_type();
    if (type != nullptr &&
        (type->is_tbd() || type->as_class_template_parameter() != nullptr)) {
      return true;
    }
    CPPExpression *expr = _parameters[i]->as_expression();
    if (expr != nullptr && expr->is_tbd()) {
      return true;
    }
  }
  return false;
}

/**
 *
 */
bool CPPTemplateParameterList::
operator == (const CPPTemplateParameterList &other) const {
  if (_parameters.size() != other._parameters.size()) {
    return false;
  }
  for (int i = 0; i < (int)_parameters.size(); ++i) {
    if (*_parameters[i] != *other._parameters[i]) {
      return false;
    }
  }
  return true;
}

/**
 *
 */
bool CPPTemplateParameterList::
operator != (const CPPTemplateParameterList &other) const {
  return !(*this == other);
}

/**
 *
 */
bool CPPTemplateParameterList::
operator < (const CPPTemplateParameterList &other) const {
  if (_parameters.size() != other._parameters.size()) {
    return _parameters.size() < other._parameters.size();
  }
  for (int i = 0; i < (int)_parameters.size(); ++i) {
    if (*_parameters[i] != *other._parameters[i]) {
      return *_parameters[i] < *other._parameters[i];
    }
  }
  return false;
}

/**
 *
 */
CPPTemplateParameterList *CPPTemplateParameterList::
substitute_decl(CPPDeclaration::SubstDecl &subst,
                CPPScope *current_scope, CPPScope *global_scope) {
  CPPTemplateParameterList *rep = new CPPTemplateParameterList(*this);

  bool anything_changed = false;
  for (int i = 0; i < (int)rep->_parameters.size(); ++i) {
    rep->_parameters[i] =
      _parameters[i]->substitute_decl(subst, current_scope, global_scope);
    if (rep->_parameters[i] != _parameters[i]) {
      anything_changed = true;
    }
  }

  if (!anything_changed) {
    delete rep;
    rep = this;
  }

  return rep;
}

/**
 *
 */
void CPPTemplateParameterList::
output(std::ostream &out, CPPScope *scope) const {
  if (!_parameters.empty()) {
    Parameters::const_iterator pi = _parameters.begin();
    (*pi)->output(out, 0, scope, false);

    ++pi;
    while (pi != _parameters.end()) {
      out << ", ";
      (*pi)->output(out, 0, scope, false);
      ++pi;
    }
  }
}

/**
 * Writes the list as a set of formal parameters for a template scope.
 * Includes the keyword "template" and the angle brackets, as well as the
 * trailing newline.
 */
void CPPTemplateParameterList::
write_formal(std::ostream &out, CPPScope *scope) const {
  out << "template<";
  if (!_parameters.empty()) {
    Parameters::const_iterator pi = _parameters.begin();
    (*pi)->output(out, 0, scope, true);

    ++pi;
    while (pi != _parameters.end()) {
      out << ", ";
      (*pi)->output(out, 0, scope, true);
      ++pi;
    }
  }
  out << ">\n";
}