/* Copyright 2017-2018 ccls Authors

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

#include "message_handler.hh"
#include "pipeline.hh"
#include "working_files.hh"

#include <clang/Format/Format.h>
#include <clang/Tooling/Core/Replacement.h>

namespace ccls {
using namespace clang;

namespace {
llvm::Expected<tooling::Replacements>
FormatCode(std::string_view code, std::string_view file, tooling::Range Range) {
  StringRef Code(code.data(), code.size()), File(file.data(), file.size());
  auto Style = format::getStyle("file", File, "LLVM", Code, nullptr);
  if (!Style)
    return Style.takeError();
  tooling::Replacements IncludeReplaces =
      format::sortIncludes(*Style, Code, {Range}, File);
  auto Changed = tooling::applyAllReplacements(Code, IncludeReplaces);
  if (!Changed)
    return Changed.takeError();
  return IncludeReplaces.merge(format::reformat(
      *Style, *Changed,
      tooling::calculateRangesAfterReplacements(IncludeReplaces, {Range}),
      File));
}

std::vector<lsTextEdit>
ReplacementsToEdits(std::string_view code, const tooling::Replacements &Repls) {
  std::vector<lsTextEdit> ret;
  int i = 0, line = 0, col = 0;
  auto move = [&](int p) {
    for (; i < p; i++)
      if (code[i] == '\n')
        line++, col = 0;
      else {
        if ((uint8_t)code[i] >= 128) {
          while (128 <= (uint8_t)code[++i] && (uint8_t)code[i] < 192)
            ;
          i--;
        }
        col++;
      }
  };
  for (const auto &R : Repls) {
    move(R.getOffset());
    int l = line, c = col;
    move(R.getOffset() + R.getLength());
    ret.push_back({{{l, c}, {line, col}}, R.getReplacementText().str()});
  }
  return ret;
}

void Format(ReplyOnce &reply, WorkingFile *wfile, tooling::Range range) {
  std::string_view code = wfile->buffer_content;
  auto ReplsOrErr = FormatCode(code, wfile->filename, range);
  if (ReplsOrErr) {
    auto result = ReplacementsToEdits(code, *ReplsOrErr);
    reply(result);
  } else {
    lsResponseError err;
    err.code = lsErrorCodes::UnknownErrorCode;
    err.message = llvm::toString(ReplsOrErr.takeError());
    reply.Error(err);
  }
}
} // namespace

void MessageHandler::textDocument_formatting(DocumentFormattingParam &param,
                                             ReplyOnce &reply) {
  QueryFile *file = FindFile(reply, param.textDocument.uri.GetPath());
  if (!file)
    return;
  WorkingFile *wfile = wfiles->GetFileByFilename(file->def->path);
  if (!wfile)
    return;
  Format(reply, wfile, {0, (unsigned)wfile->buffer_content.size()});
}

void MessageHandler::textDocument_onTypeFormatting(
    DocumentOnTypeFormattingParam &param, ReplyOnce &reply) {
  QueryFile *file = FindFile(reply, param.textDocument.uri.GetPath());
  if (!file)
    return;
  WorkingFile *wfile = wfiles->GetFileByFilename(file->def->path);
  if (!wfile)
    return;
  std::string_view code = wfile->buffer_content;
  int pos = GetOffsetForPosition(param.position, code);
  auto lbrace = code.find_last_of('{', pos);
  if (lbrace == std::string::npos)
    lbrace = pos;
  Format(reply, wfile, {(unsigned)lbrace, unsigned(pos - lbrace)});
}

void MessageHandler::textDocument_rangeFormatting(
    DocumentRangeFormattingParam &param, ReplyOnce &reply) {
  QueryFile *file = FindFile(reply, param.textDocument.uri.GetPath());
  if (!file)
    return;
  WorkingFile *wfile = wfiles->GetFileByFilename(file->def->path);
  if (!wfile)
    return;
  std::string_view code = wfile->buffer_content;
  int begin = GetOffsetForPosition(param.range.start, code),
      end = GetOffsetForPosition(param.range.end, code);
  Format(reply, wfile, {(unsigned)begin, unsigned(end - begin)});
}
} // namespace ccls