// Clang plugin implementation
// Copyright (C) 2024  Nguyễn Gia Phong
//
// This file is part of GoatC.
//
// GoatC is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GoatC 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GoatC.  If not, see <https://www.gnu.org/licenses/>.

#include "goatc.hh"

#include <clang/AST/AST.h>
#include <clang/Frontend/CompilerInstance.h>
#include <clang/Sema/Sema.h>
#include <llvm/Support/raw_ostream.h>

bool
goatc::Visitor::VisitDecl (clang::Decl* decl)
{
  if (auto* named_decl = llvm::dyn_cast <clang::NamedDecl> (decl))
    {
      clang::FullSourceLoc loc = this->ctx->getFullLoc (decl->getBeginLoc ());
      if (loc.isValid ())
        llvm::outs ()
          << "Found " << named_decl->getQualifiedNameAsString ()
          << " at " << loc.getSpellingLineNumber ()
          << ':' << loc.getSpellingColumnNumber () << '\n';
    }
  return true;
}

void
goatc::Consumer::HandleTranslationUnit (clang::ASTContext& ctx)
{
  this->visitor.TraverseDecl (ctx.getTranslationUnitDecl ());
}

clang::PluginASTAction::ActionType
goatc::Action::getActionType ()
{
  return AddBeforeMainAction;
}

std::unique_ptr <clang::ASTConsumer>
goatc::Action::CreateASTConsumer (clang::CompilerInstance& ci,
                                  llvm::StringRef in_file)
{
  return std::make_unique <goatc::Consumer> (&ci.getASTContext (),
                                             in_file != this->source_file);
}

void
printHelp (llvm::raw_ostream& ros)
{
  ros << "Usage: goatcflags [OPTION]...\n\nOptions:\n";
  ros << "  -h, --help              show this help message and exit\n";
  ros << "  -s, --source-file PATH  path to the file to be chimera'd\n";
}

bool
goatc::Action::ParseArgs (const clang::CompilerInstance& ci,
                          const std::vector <std::string> &args)
{
  auto& d = ci.getDiagnostics ();
  for (unsigned i = 0, e = args.size(); i < e; ++i)
    if (args[i] == "-h" || args[i] == "--help")
      {
        printHelp (llvm::outs ());
        // FIXME: exit with status 0
        return false;
      }
    else if (args[i] == "-s" || args[i] == "--source-file")
      {
        if (++i == e)
          {
            d.Report (d.getCustomDiagID (clang::DiagnosticsEngine::Error,
                                         "missing --source-file argument"));
            return false;
          }
        // TODO: check if file exists
        this->source_file = args[i];
      }

  if (this->source_file.empty ())
    {
      d.Report (d.getCustomDiagID (clang::DiagnosticsEngine::Error,
                                   "unspecified --source-file"));
      return false;
    }

  return true;
}