// Copyright 2017-2018 ccls Authors
// SPDX-License-Identifier: Apache-2.0

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

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

using namespace ccls;
using namespace clang;

namespace {
const MethodType formatting = "textDocument/formatting",
                 onTypeFormatting = "textDocument/onTypeFormatting",
                 rangeFormatting = "textDocument/rangeFormatting";

struct lsFormattingOptions {
  // Size of a tab in spaces.
  int tabSize;
  // Prefer spaces over tabs.
  bool insertSpaces;
};
MAKE_REFLECT_STRUCT(lsFormattingOptions, tabSize, insertSpaces);

struct Out_TextDocumentFormatting
    : public lsOutMessage<Out_TextDocumentFormatting> {
  lsRequestId id;
  std::vector<lsTextEdit> result;
};
MAKE_REFLECT_STRUCT(Out_TextDocumentFormatting, jsonrpc, id, result);

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(WorkingFile *wfile, tooling::Range range, lsRequestId id) {
  std::string_view code = wfile->buffer_content;
  auto ReplsOrErr =
      FormatCode(code, wfile->filename, range);
  if (ReplsOrErr) {
    Out_TextDocumentFormatting out;
    out.id = id;
    out.result = ReplacementsToEdits(code, *ReplsOrErr);
    pipeline::WriteStdout(formatting, out);
  } else {
    Out_Error err;
    err.id = id;
    err.error.code = lsErrorCodes::UnknownErrorCode;
    err.error.message = llvm::toString(ReplsOrErr.takeError());
    pipeline::WriteStdout(kMethodType_Unknown, err);
  }
}

struct In_TextDocumentFormatting : public RequestInMessage {
  MethodType GetMethodType() const override { return formatting; }
  struct Params {
    lsTextDocumentIdentifier textDocument;
    lsFormattingOptions options;
  } params;
};
MAKE_REFLECT_STRUCT(In_TextDocumentFormatting::Params, textDocument, options);
MAKE_REFLECT_STRUCT(In_TextDocumentFormatting, id, params);
REGISTER_IN_MESSAGE(In_TextDocumentFormatting);

struct Handler_TextDocumentFormatting
    : BaseMessageHandler<In_TextDocumentFormatting> {
  MethodType GetMethodType() const override { return formatting; }
  void Run(In_TextDocumentFormatting *request) override {
    auto &params = request->params;
    QueryFile *file;
    if (!FindFileOrFail(db, project, request->id,
                        params.textDocument.uri.GetPath(), &file))
      return;
    WorkingFile *wfile = working_files->GetFileByFilename(file->def->path);
    if (!wfile)
      return;
    Format(wfile, {0, (unsigned)wfile->buffer_content.size()}, request->id);
  }
};
REGISTER_MESSAGE_HANDLER(Handler_TextDocumentFormatting);

struct In_TextDocumentOnTypeFormatting : public RequestInMessage {
  MethodType GetMethodType() const override { return onTypeFormatting; }
  struct Params {
    lsTextDocumentIdentifier textDocument;
    lsPosition position;
    std::string ch;
    lsFormattingOptions options;
  } params;
};
MAKE_REFLECT_STRUCT(In_TextDocumentOnTypeFormatting::Params, textDocument,
                    position, ch, options);
MAKE_REFLECT_STRUCT(In_TextDocumentOnTypeFormatting, id, params);
REGISTER_IN_MESSAGE(In_TextDocumentOnTypeFormatting);

struct Handler_TextDocumentOnTypeFormatting
    : BaseMessageHandler<In_TextDocumentOnTypeFormatting> {
  MethodType GetMethodType() const override { return onTypeFormatting; }
  void Run(In_TextDocumentOnTypeFormatting *request) override {
    auto &params = request->params;
    QueryFile *file;
    if (!FindFileOrFail(db, project, request->id,
                        params.textDocument.uri.GetPath(), &file))
      return;
    WorkingFile *wfile = working_files->GetFileByFilename(file->def->path);
    if (!wfile)
      return;
    std::string_view code = wfile->buffer_content;
    int pos = GetOffsetForPosition(params.position, code);
    auto lbrace = code.find_last_of('{', pos);
    if (lbrace == std::string::npos)
      lbrace = pos;
    Format(wfile, {(unsigned)lbrace, unsigned(pos - lbrace)}, request->id);
  }
};
REGISTER_MESSAGE_HANDLER(Handler_TextDocumentOnTypeFormatting);

struct In_TextDocumentRangeFormatting : public RequestInMessage {
  MethodType GetMethodType() const override { return rangeFormatting; }
  struct Params {
    lsTextDocumentIdentifier textDocument;
    lsRange range;
    lsFormattingOptions options;
  } params;
};
MAKE_REFLECT_STRUCT(In_TextDocumentRangeFormatting::Params, textDocument, range,
                    options);
MAKE_REFLECT_STRUCT(In_TextDocumentRangeFormatting, id, params);
REGISTER_IN_MESSAGE(In_TextDocumentRangeFormatting);

struct Handler_TextDocumentRangeFormatting
    : BaseMessageHandler<In_TextDocumentRangeFormatting> {
  MethodType GetMethodType() const override { return rangeFormatting; }

  void Run(In_TextDocumentRangeFormatting *request) override {
    auto &params = request->params;
    QueryFile *file;
    if (!FindFileOrFail(db, project, request->id,
                        params.textDocument.uri.GetPath(), &file))
      return;
    WorkingFile *wfile = working_files->GetFileByFilename(file->def->path);
    if (!wfile)
      return;
    std::string_view code = wfile->buffer_content;
    int begin = GetOffsetForPosition(params.range.start, code),
        end = GetOffsetForPosition(params.range.end, code);
    Format(wfile, {(unsigned)begin, unsigned(end - begin)}, request->id);
  }
};
REGISTER_MESSAGE_HANDLER(Handler_TextDocumentRangeFormatting);
} // namespace