/*=========================================================================

  Program:   CMake - Cross-Platform Makefile Generator
  Module:    $RCSfile$
  Language:  C++
  Date:      $Date$
  Version:   $Revision$

  Copyright (c) 2002 Kitware, Inc., Insight Consortium.  All rights reserved.
  See Copyright.txt or http://www.cmake.org/HTML/Copyright.html for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#include "cmDependsFortran.h"

#include "cmSystemTools.h"

#include "cmDependsFortranParser.h" /* Interface to parser object.  */

#include <assert.h>
#include <stack>

// TODO: Test compiler for the case of the mod file.  Some always
// use lower case and some always use upper case.  I do not know if any
// use the case from the source code.

//----------------------------------------------------------------------------
// Parser methods not included in generated interface.

// Get the current buffer processed by the lexer.
YY_BUFFER_STATE cmDependsFortranLexer_GetCurrentBuffer(yyscan_t yyscanner);

// The parser entry point.
int cmDependsFortran_yyparse(yyscan_t);

//----------------------------------------------------------------------------
// Define parser object internal structure.
struct cmDependsFortranFile
{
  cmDependsFortranFile(FILE* file, YY_BUFFER_STATE buffer,
                       const std::string& dir):
    File(file), Buffer(buffer), Directory(dir) {}
  FILE* File;
  YY_BUFFER_STATE Buffer;
  std::string Directory;
};
struct cmDependsFortranParser_s
{
  cmDependsFortranParser_s(cmDependsFortran* self);
  ~cmDependsFortranParser_s();

  // Pointer back to the main class.
  cmDependsFortran* Self;

  // Lexical scanner instance.
  yyscan_t Scanner;

  // Stack of open files in the translation unit.
  std::stack<cmDependsFortranFile> FileStack;

  // Buffer for string literals.
  std::string TokenString;

  // Flag for whether lexer is reading from inside an interface.
  int InInterface;

  // Set of provided and required modules.
  std::set<cmStdString> Provides;
  std::set<cmStdString> Requires;

  // Set of files included in the translation unit.
  std::set<cmStdString> Includes;
};

//----------------------------------------------------------------------------
cmDependsFortran::cmDependsFortran():
  m_SourceFile(),
  m_IncludePath(0)
{
}

//----------------------------------------------------------------------------
cmDependsFortran::cmDependsFortran(const char* sourceFile,
                                   std::vector<std::string> const& includes):
  m_SourceFile(sourceFile),
  m_IncludePath(&includes)
{
}

//----------------------------------------------------------------------------
cmDependsFortran::~cmDependsFortran()
{
}

//----------------------------------------------------------------------------
bool cmDependsFortran::WriteDependencies(std::ostream& os)
{
  // Make sure this is a scanning instance.
  if(m_SourceFile == "")
    {
    cmSystemTools::Error("Cannot scan dependencies without an source file.");
    return false;
    }
  if(!m_IncludePath)
    {
    cmSystemTools::Error("Cannot scan dependencies without an include path.");
    return false;
    }

  // Create the parser object.
  cmDependsFortranParser parser(this);

  // Push on the starting file.
  cmDependsFortranParser_FilePush(&parser, m_SourceFile.c_str());

  // Parse the translation unit.
  if(cmDependsFortran_yyparse(parser.Scanner) != 0)
    {
    // Failed to parse the file.  Report failure to write dependencies.
    return false;
    }

  // Write the include dependencies to the output stream.
  for(std::set<cmStdString>::const_iterator i = parser.Includes.begin();
      i != parser.Includes.end(); ++i)
    {
    os << m_TargetFile.c_str() << ": "
       << cmSystemTools::ConvertToOutputPath(i->c_str()).c_str()
       << std::endl;
    }
  os << std::endl;

  // Write module requirements to the output stream.
  for(std::set<cmStdString>::const_iterator i = parser.Requires.begin();
      i != parser.Requires.end(); ++i)
    {
    // Require only modules not provided in the same source.
    if(parser.Provides.find(*i) == parser.Provides.end())
      {
      // since we require some things add them to our list of requirements
      os << m_TargetFile.c_str() << ".requires: " << i->c_str() << ".mod.proxy"
         << std::endl;
#if 0
      // Always use lower case for the mod stamp file name.
      std::string m = cmSystemTools::LowerCase(*i);
      os << m_TargetFile.c_str() << ": " << m.c_str() << ".mod.stamp"
         << std::endl;
      os << i->c_str() << ".mod.proxy:" << std::endl;
      std::string stampName = m_Directory;
      stampName += "/";
      stampName += m;
      stampName += ".mod.stamp";
      if(!cmSystemTools::FileExists(stampName.c_str()))
        {
        std::ofstream stamp(stampName.c_str());
        stamp << "# Dummy stamp file in case nothing provides it."
              << std::endl;
        }
#endif
      }
    }

  // Write provided modules to the output stream.
  for(std::set<cmStdString>::const_iterator i = parser.Provides.begin();
      i != parser.Provides.end(); ++i)
    {
    os << i->c_str() << ".mod.proxy: " << m_TargetFile.c_str()
       << ".provides" << std::endl;
    }
  
  // If any modules are provided then they must be converted to stamp files.
  if(!parser.Provides.empty())
    {
    os << m_TargetFile.c_str() << ".provides.build:\n";
    for(std::set<cmStdString>::const_iterator i = parser.Provides.begin();
        i != parser.Provides.end(); ++i)
      {
      // Always use lower case for the mod stamp file name.  The
      // cmake_copy_f90_mod will call back to this class, which will
      // try various cases for the real mod file name.
      std::string m = cmSystemTools::LowerCase(*i);
      os << "\t$(CMAKE_COMMAND) -E cmake_copy_f90_mod "
         << i->c_str() << " " << m.c_str() << ".mod.stamp\n";
      }
    os << "\t@touch " << m_TargetFile.c_str() << ".provides.build\n";
    }

#if 0
  // if it provides something then connect the requires rule to the build rule
  if(!parser.Provides.empty())
    {
    os << m_TargetFile.c_str() << ".requires: " << m_TargetFile.c_str()
       << ".requires.build" << std::endl;
    // provide empty build rule for old gen for now, TODO remove later
    os << m_TargetFile.c_str() << ".requires.build:" << std::endl;    
    }
#endif
  
  /*
  // TODO:
  What about .mod files provided in another directory and found with a
  -M search path?  The stamp file will not be updated, so things might
  not rebuild.  Possible solutions (not all thought through):

  Solution 1: Have all the .o.requires in a directory depend on a
  single .outside.requires that searches for .mod files in another
  directory of the build tree and uses copy-if-different to produce
  the local directory's stamp files. (won't work because the single
  rule cannot know about the modules)

  Solution 2: When the dependency is detected search the module
  include path for a mark file indicating the module is provided.  If
  not found just write the dummy stamp file.  If found, we need a rule
  to copy-if-different the module file.  When a module is provided,
  write this mark file.

  Solution 3: Use a set of make rules like this:

    # When required:
    foo.mod.proxy: foo.mod.default
    foo.mod.default:: foo.mod.hack
      @echo foo.mod.default2 # Search for and copy-if-different the mod file.
    foo.mod.hack:

    # When provided:
    foo.mod.proxy: foo.o.requires
      @rm -f foo.mod.hack foo.mod.default
    foo.o.requires: foo.mod.hack
      @echo foo.o.requires
    foo.mod.hack:
      @touch foo.mod.hack
      @touch foo.mod.default

  Solution 4:

  When scanning dependencies and providing a module:
    - Create a .mod.provided.
    - Add .mod.proxy rule depending on corresponding .o.requires.

  When scanning dependencies and requiring a module:
    - Search the module path for a .mod.provided or a .mod.
    - If a .mod.provided is found depend on the corresponding .mod.stamp
      (it is provided by CMake in another directory)
    - Else, if a .mod is found depend on it directly
      (it is provided in another directory by a non-CMake project)
    - Else:
      - Add the empty proxy rule (if it is provided locally this will hook it)
      - Depend on a local .mod.stamp (it might be provided locally)
      - Create the dummy local .mod.stamp (it might not be provided locally)

  */

  return true;
}

//----------------------------------------------------------------------------
bool cmDependsFortran::CheckDependencies(std::istream&)
{
  // TODO: Parse and check dependencies.
  return true;
}

//----------------------------------------------------------------------------
bool cmDependsFortran::CopyModule(const std::vector<std::string>& args)
{
  // Implements
  //
  //   $(CMAKE_COMMAND) -E cmake_copy_f90_mod input.mod output.mod.stamp
  //
  // Note that the case of the .mod file depends on the compiler.  In
  // the future this copy could also account for the fact that some
  // compilers include a timestamp in the .mod file so it changes even
  // when the interface described in the module does not.

  std::string mod = args[2];
  std::string stamp = args[3];
  std::string mod_upper = cmSystemTools::UpperCase(mod.c_str());
  std::string mod_lower = cmSystemTools::LowerCase(mod.c_str());
  mod += ".mod";
  mod_upper += ".mod";
  mod_lower += ".mod";

  if(cmSystemTools::FileExists(mod_upper.c_str()))
    {
    if(!cmSystemTools::CopyFileIfDifferent(mod_upper.c_str(), stamp.c_str()))
      {
      std::cerr << "Error copying Fortran module from \""
                << mod_upper.c_str() << "\" to \"" << stamp.c_str()
                << "\".\n";
      return false;
      }
    return true;
    }
  else if(cmSystemTools::FileExists(mod_lower.c_str()))
    {
    if(!cmSystemTools::CopyFileIfDifferent(mod_lower.c_str(), stamp.c_str()))
      {
      std::cerr << "Error copying Fortran module from \""
                << mod_lower.c_str() << "\" to \"" << stamp.c_str()
                << "\".\n";
      return false;
      }
    return true;
    }

  std::cerr << "Error copying Fortran module \"" << args[2].c_str()
            << "\".  Tried \"" << mod_upper.c_str()
            << "\" and \"" << mod_lower.c_str() << "\".\n";
  return false;
}

//----------------------------------------------------------------------------
bool cmDependsFortran::FindIncludeFile(const char* dir,
                                       const char* includeName,
                                       std::string& fileName)
{
  // If the file is a full path, include it directly.
  if(cmSystemTools::FileIsFullPath(includeName))
    {
    fileName = includeName;
    return cmSystemTools::FileExists(fileName.c_str());
    }
  else
    {
    // Check for the file in the directory containing the including
    // file.
    std::string fullName = dir;
    fullName += "/";
    fullName += includeName;
    if(cmSystemTools::FileExists(fullName.c_str()))
      {
      fileName = fullName;
      return true;
      }

    // Search the include path for the file.
    for(std::vector<std::string>::const_iterator i = m_IncludePath->begin();
        i != m_IncludePath->end(); ++i)
      {
      fullName = *i;
      fullName += "/";
      fullName += includeName;
      if(cmSystemTools::FileExists(fullName.c_str()))
        {
        fileName = fullName;
        return true;
        }
      }
    }
  return false;
}

//----------------------------------------------------------------------------
cmDependsFortranParser_s::cmDependsFortranParser_s(cmDependsFortran* self):
  Self(self)
{
  this->InInterface = 0;

  // Initialize the lexical scanner.
  cmDependsFortran_yylex_init(&this->Scanner);
  cmDependsFortran_yyset_extra(this, this->Scanner);

  // Create a dummy buffer that is never read but is the fallback
  // buffer when the last file is popped off the stack.
  YY_BUFFER_STATE buffer =
    cmDependsFortran_yy_create_buffer(0, 4, this->Scanner);
  cmDependsFortran_yy_switch_to_buffer(buffer, this->Scanner);
}

//----------------------------------------------------------------------------
cmDependsFortranParser_s::~cmDependsFortranParser_s()
{
  cmDependsFortran_yylex_destroy(this->Scanner);
}

//----------------------------------------------------------------------------
int cmDependsFortranParser_FilePush(cmDependsFortranParser* parser,
                                    const char* fname)
{
  // Open the new file and push it onto the stack.  Save the old
  // buffer with it on the stack.
  if(FILE* file = fopen(fname, "rb"))
    {
    YY_BUFFER_STATE current =
      cmDependsFortranLexer_GetCurrentBuffer(parser->Scanner);
    std::string dir = cmSystemTools::GetParentDirectory(fname);
    cmDependsFortranFile f(file, current, dir);
    YY_BUFFER_STATE buffer =
      cmDependsFortran_yy_create_buffer(0, 16384, parser->Scanner);
    cmDependsFortran_yy_switch_to_buffer(buffer, parser->Scanner);
    parser->FileStack.push(f);
    return 1;
    }
  else
    {
    return 0;
    }
}

//----------------------------------------------------------------------------
int cmDependsFortranParser_FilePop(cmDependsFortranParser* parser)
{
  // Pop one file off the stack and close it.  Switch the lexer back
  // to the next one on the stack.
  if(parser->FileStack.empty())
    {
    return 0;
    }
  else
    {
    cmDependsFortranFile f = parser->FileStack.top(); parser->FileStack.pop();
    fclose(f.File);
    YY_BUFFER_STATE current =
      cmDependsFortranLexer_GetCurrentBuffer(parser->Scanner);
    cmDependsFortran_yy_delete_buffer(current, parser->Scanner);
    cmDependsFortran_yy_switch_to_buffer(f.Buffer, parser->Scanner);
    return 1;
    }
}

//----------------------------------------------------------------------------
int cmDependsFortranParser_Input(cmDependsFortranParser* parser,
                                 char* buffer, size_t bufferSize)
{
  // Read from the file on top of the stack.  If the stack is empty,
  // the end of the translation unit has been reached.
  if(!parser->FileStack.empty())
    {
    FILE* file = parser->FileStack.top().File;
    return (int)fread(buffer, 1, bufferSize, file);
    }
  return 0;
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_StringStart(cmDependsFortranParser* parser)
{
  parser->TokenString = "";
}

//----------------------------------------------------------------------------
const char* cmDependsFortranParser_StringEnd(cmDependsFortranParser* parser)
{
  return parser->TokenString.c_str();
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_StringAppend(cmDependsFortranParser* parser,
                                         char c)
{
  parser->TokenString += c;
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_SetInInterface(cmDependsFortranParser* parser,
                                           int in)
{
  parser->InInterface = in;
}

//----------------------------------------------------------------------------
int cmDependsFortranParser_GetInInterface(cmDependsFortranParser* parser)
{
  return parser->InInterface;
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_Error(cmDependsFortranParser*, const char*)
{
  // If there is a parser error just ignore it.  The source will not
  // compile and the user will edit it.  Then dependencies will have
  // to be regenerated anyway.
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_RuleUse(cmDependsFortranParser* parser,
                                    const char* name)
{
  parser->Requires.insert(name);
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_RuleInclude(cmDependsFortranParser* parser,
                                        const char* name)
{
  // If processing an include statement there must be an open file.
  assert(!parser->FileStack.empty());

  // Get the directory containing the source in which the include
  // statement appears.  This is always the first search location for
  // Fortran include files.
  std::string dir = parser->FileStack.top().Directory;

  // Find the included file.  If it cannot be found just ignore the
  // problem because either the source will not compile or the user
  // does not care about depending on this included source.
  std::string fullName;
  if(parser->Self->FindIncludeFile(dir.c_str(), name, fullName))
    {
    // Found the included file.  Save it in the set of included files.
    parser->Includes.insert(fullName);

    // Parse it immediately to translate the source inline.
    cmDependsFortranParser_FilePush(parser, fullName.c_str());
    }
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_RuleModule(cmDependsFortranParser* parser,
                                       const char* name)
{
  parser->Provides.insert(name);
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_RuleDefine(cmDependsFortranParser*, const char*)
{
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_RuleUndef(cmDependsFortranParser*, const char*)
{
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_RuleIfdef(cmDependsFortranParser*, const char*)
{
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_RuleIfndef(cmDependsFortranParser*, const char*)
{
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_RuleIf(cmDependsFortranParser*)
{
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_RuleElif(cmDependsFortranParser*)
{
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_RuleElse(cmDependsFortranParser*)
{
}

//----------------------------------------------------------------------------
void cmDependsFortranParser_RuleEndif(cmDependsFortranParser*)
{
}
