//===-- ClangIncludeFixer.cpp - Standalone include fixer ------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "InMemorySymbolIndex.h"
#include "IncludeFixer.h"
#include "IncludeFixerContext.h"
#include "SymbolIndexManager.h"
#include "YamlSymbolIndex.h"
#include "clang/Format/Format.h"
#include "clang/Frontend/TextDiagnosticPrinter.h"
#include "clang/Rewrite/Core/Rewriter.h"
#include "clang/Tooling/CommonOptionsParser.h"
#include "clang/Tooling/Tooling.h"
#include "llvm/Support/CommandLine.h"

using namespace clang;
using namespace llvm;

namespace {
cl::OptionCategory IncludeFixerCategory("Tool options");

enum DatabaseFormatTy {
  fixed, ///< Hard-coded mapping.
  yaml,  ///< Yaml database created by find-all-symbols.
};

cl::opt<DatabaseFormatTy> DatabaseFormat(
    "db", cl::desc("Specify input format"),
    cl::values(clEnumVal(fixed, "Hard-coded mapping"),
               clEnumVal(yaml, "Yaml database created by find-all-symbols"),
               clEnumValEnd),
    cl::init(yaml), cl::cat(IncludeFixerCategory));

cl::opt<std::string> Input("input",
                           cl::desc("String to initialize the database"),
                           cl::cat(IncludeFixerCategory));

cl::opt<bool>
    MinimizeIncludePaths("minimize-paths",
                         cl::desc("Whether to minimize added include paths"),
                         cl::init(true), cl::cat(IncludeFixerCategory));

cl::opt<bool> Quiet("q", cl::desc("Reduce terminal output"), cl::init(false),
                    cl::cat(IncludeFixerCategory));

cl::opt<bool>
    STDINMode("stdin",
              cl::desc("Override source file's content (in the overlaying\n"
                       "virtual file system) with input from <stdin> and run\n"
                       "the tool on the new content with the compilation\n"
                       "options of the source file. This mode is currently\n"
                       "used for editor integration."),
              cl::init(false), cl::cat(IncludeFixerCategory));

cl::opt<bool> OutputHeaders(
    "output-headers",
    cl::desc("Output the symbol being quired and all its relevant headers.\n"
             "The first line is the symbol name; The other lines\n"
             "are the headers: \n"
             "   b::foo\n"
             "   path/to/foo_a.h\n"
             "   path/to/foo_b.h\n"),
    cl::init(false), cl::cat(IncludeFixerCategory));

cl::opt<std::string> InsertHeader(
    "insert-header",
    cl::desc("Insert a specific header. This should run with STDIN mode.\n"
             "The result is written to stdout. It is currently used for\n"
             "editor integration."),
    cl::init(""), cl::cat(IncludeFixerCategory));

cl::opt<std::string>
    Style("style",
          cl::desc("Fallback style for reformatting after inserting new "
                   "headers if there is no clang-format config file found."),
          cl::init("llvm"), cl::cat(IncludeFixerCategory));

std::unique_ptr<include_fixer::SymbolIndexManager>
createSymbolIndexManager(StringRef FilePath) {
  auto SymbolIndexMgr = llvm::make_unique<include_fixer::SymbolIndexManager>();
  switch (DatabaseFormat) {
  case fixed: {
    // Parse input and fill the database with it.
    // <symbol>=<header><, header...>
    // Multiple symbols can be given, separated by semicolons.
    std::map<std::string, std::vector<std::string>> SymbolsMap;
    SmallVector<StringRef, 4> SemicolonSplits;
    StringRef(Input).split(SemicolonSplits, ";");
    std::vector<find_all_symbols::SymbolInfo> Symbols;
    for (StringRef Pair : SemicolonSplits) {
      auto Split = Pair.split('=');
      std::vector<std::string> Headers;
      SmallVector<StringRef, 4> CommaSplits;
      Split.second.split(CommaSplits, ",");
      for (size_t I = 0, E = CommaSplits.size(); I != E; ++I)
        Symbols.push_back(find_all_symbols::SymbolInfo(
            Split.first.trim(),
            find_all_symbols::SymbolInfo::SymbolKind::Unknown,
            CommaSplits[I].trim(), 1, {}, /*NumOccurrences=*/E - I));
    }
    SymbolIndexMgr->addSymbolIndex(
        llvm::make_unique<include_fixer::InMemorySymbolIndex>(Symbols));
    break;
  }
  case yaml: {
    llvm::ErrorOr<std::unique_ptr<include_fixer::YamlSymbolIndex>> DB(nullptr);
    if (!Input.empty()) {
      DB = include_fixer::YamlSymbolIndex::createFromFile(Input);
    } else {
      // If we don't have any input file, look in the directory of the first
      // file and its parents.
      SmallString<128> AbsolutePath(tooling::getAbsolutePath(FilePath));
      StringRef Directory = llvm::sys::path::parent_path(AbsolutePath);
      DB = include_fixer::YamlSymbolIndex::createFromDirectory(
          Directory, "find_all_symbols_db.yaml");
    }

    if (!DB) {
      llvm::errs() << "Couldn't find YAML db: " << DB.getError().message()
                   << '\n';
      return nullptr;
    }

    SymbolIndexMgr->addSymbolIndex(std::move(*DB));
    break;
  }
  }
  return SymbolIndexMgr;
}

int includeFixerMain(int argc, const char **argv) {
  tooling::CommonOptionsParser options(argc, argv, IncludeFixerCategory);
  tooling::ClangTool tool(options.getCompilations(),
                          options.getSourcePathList());

  // In STDINMode, we override the file content with the <stdin> input.
  // Since `tool.mapVirtualFile` takes `StringRef`, we define `Code` outside of
  // the if-block so that `Code` is not released after the if-block.
  std::unique_ptr<llvm::MemoryBuffer> Code;
  if (STDINMode) {
    assert(options.getSourcePathList().size() == 1 &&
           "Expect exactly one file path in STDINMode.");
    llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>> CodeOrErr =
        MemoryBuffer::getSTDIN();
    if (std::error_code EC = CodeOrErr.getError()) {
      errs() << EC.message() << "\n";
      return 1;
    }
    Code = std::move(CodeOrErr.get());
    if (Code->getBufferSize() == 0)
      return 0;  // Skip empty files.

    tool.mapVirtualFile(options.getSourcePathList().front(), Code->getBuffer());
  }

  StringRef FilePath = options.getSourcePathList().front();
  format::FormatStyle InsertStyle = format::getStyle("file", FilePath, Style);

  if (!InsertHeader.empty()) {
    if (!STDINMode) {
      errs() << "Should be running in STDIN mode\n";
      return 1;
    }

    tooling::Replacements Replacements =
        clang::include_fixer::createInsertHeaderReplacements(
            Code->getBuffer(), FilePath, InsertHeader, InsertStyle);
    tooling::Replacements Replaces(Replacements.begin(), Replacements.end());
    std::string ChangedCode =
        tooling::applyAllReplacements(Code->getBuffer(), Replaces);
    llvm::outs() << ChangedCode;
    return 0;
  }

  // Set up data source.
  std::unique_ptr<include_fixer::SymbolIndexManager> SymbolIndexMgr =
      createSymbolIndexManager(options.getSourcePathList().front());
  if (!SymbolIndexMgr)
    return 1;

  // Now run our tool.
  include_fixer::IncludeFixerContext Context;
  include_fixer::IncludeFixerActionFactory Factory(*SymbolIndexMgr, Context,
                                                   Style, MinimizeIncludePaths);

  if (tool.run(&Factory) != 0) {
    llvm::errs()
        << "Clang died with a fatal error! (incorrect include paths?)\n";
    return 1;
  }

  if (OutputHeaders) {
    // FIXME: Output IncludeFixerContext as YAML.
    llvm::outs() << Context.SymbolIdentifer << "\n";
    for (const auto &Header : Context.Headers)
      llvm::outs() << Header << "\n";
    return 0;
  }

  if (Context.Headers.empty())
    return 0;

  auto Buffer = llvm::MemoryBuffer::getFile(FilePath);
  if (!Buffer) {
    errs() << "Couldn't open file: " << FilePath;
    return 1;
  }

  // FIXME: Rank the results and pick the best one instead of the first one.
  tooling::Replacements Replacements =
      clang::include_fixer::createInsertHeaderReplacements(
          /*Code=*/Buffer.get()->getBuffer(), FilePath, Context.Headers.front(),
          InsertStyle);

  if (!Quiet)
    llvm::errs() << "Added #include" << Context.Headers.front();

  // Set up a new source manager for applying the resulting replacements.
  IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts(new DiagnosticOptions);
  DiagnosticsEngine Diagnostics(new DiagnosticIDs, &*DiagOpts);
  TextDiagnosticPrinter DiagnosticPrinter(outs(), &*DiagOpts);
  SourceManager SM(Diagnostics, tool.getFiles());
  Diagnostics.setClient(&DiagnosticPrinter, false);

  if (STDINMode) {
    std::string ChangedCode =
        tooling::applyAllReplacements(Code->getBuffer(), Replacements);
    llvm::outs() << ChangedCode;
    return 0;
  }

  // Write replacements to disk.
  Rewriter Rewrites(SM, LangOptions());
  tooling::applyAllReplacements(Replacements, Rewrites);
  return Rewrites.overwriteChangedFiles();
}

} // namespace

int main(int argc, const char **argv) {
  return includeFixerMain(argc, argv);
}