// TODO: cleanup includes
#include "cache.h"
#include "code_completion.h"
#include "file_consumer.h"
#include "fuzzy.h"
#include "indexer.h"
#include "query.h"
#include "language_server_api.h"
#include "options.h"
#include "project.h"
#include "platform.h"
#include "test.h"
#include "timer.h"
#include "threaded_queue.h"
#include "typed_bidi_message_queue.h"
#include "working_files.h"

#include <doctest/doctest.h>
#include <rapidjson/istreamwrapper.h>
#include <rapidjson/ostreamwrapper.h>

#include <fstream>
#include <functional>
#include <iostream>
#include <string>
#include <unordered_map>
#include <thread>
#include <vector>

// TODO: provide a feature like 'https://github.com/goldsborough/clang-expand',
// ie, a fully linear view of a function with inline function calls expanded.
// We can probably use vscode decorators to achieve it.

namespace {

const bool kUseMultipleProcesses = false; // TODO: initialization options not passed properly when set to true.

std::vector<std::string> kEmptyArgs;










































struct IpcManager {
  // TODO: Rename TypedBidiMessageQueue to IpcTransport?
  using IpcMessageQueue = TypedBidiMessageQueue<IpcId, BaseIpcMessage>;

  static constexpr const char* kIpcLanguageClientName = "lanclient";
  static constexpr const int kQueueSizeBytes = 1024 * 8;

  static IpcManager* instance_;
  static IpcManager* instance() {
    return instance_;
  }
  static void CreateInstance() {
    instance_ = new IpcManager();
  }

  std::unique_ptr<ThreadedQueue<std::unique_ptr<BaseIpcMessage>>> threaded_queue_for_client_;
  std::unique_ptr<ThreadedQueue<std::unique_ptr<BaseIpcMessage>>> threaded_queue_for_server_;
  std::unique_ptr<IpcMessageQueue> ipc_queue_;

  enum class Destination {
    Client, Server
  };

  MessageQueue* GetMessageQueue(Destination destination) {
    assert(kUseMultipleProcesses);
    return destination == Destination::Client ? &ipc_queue_->for_client : &ipc_queue_->for_server;
  }
  ThreadedQueue<std::unique_ptr<BaseIpcMessage>>* GetThreadedQueue(Destination destination) {
    assert(!kUseMultipleProcesses);
    return destination == Destination::Client ? threaded_queue_for_client_.get() : threaded_queue_for_server_.get();
  }

  void SendOutMessageToClient(IpcId id, lsBaseOutMessage& response) {
    std::ostringstream sstream;
    response.Write(sstream);

    if (kUseMultipleProcesses) {
      Ipc_Cout out;
      out.content = sstream.str();
      out.original_ipc_id = id;
      ipc_queue_->SendMessage(&ipc_queue_->for_client, Ipc_Cout::kIpcId, out);
    }
    else {
      auto out = MakeUnique<Ipc_Cout>();
      out->content = sstream.str();
      out->original_ipc_id = id;
      GetThreadedQueue(Destination::Client)->Enqueue(std::move(out));
    }
  }

  void SendMessage(Destination destination, std::unique_ptr<BaseIpcMessage> message) {
    if (kUseMultipleProcesses)
      ipc_queue_->SendMessage(GetMessageQueue(destination), message->method_id, *message);
    else
      GetThreadedQueue(destination)->Enqueue(std::move(message));
  }

  std::vector<std::unique_ptr<BaseIpcMessage>> GetMessages(Destination destination) {
    if (kUseMultipleProcesses)
      return ipc_queue_->GetMessages(GetMessageQueue(destination));
    else
      return GetThreadedQueue(destination)->DequeueAll();
  }

 private:
  IpcManager() {
    if (kUseMultipleProcesses) {
      ipc_queue_ = BuildIpcMessageQueue(kIpcLanguageClientName, kQueueSizeBytes);
    }
    else {
      threaded_queue_for_client_ = MakeUnique<ThreadedQueue<std::unique_ptr<BaseIpcMessage>>>();
      threaded_queue_for_server_ = MakeUnique<ThreadedQueue<std::unique_ptr<BaseIpcMessage>>>();
    }
  }

  template<typename T>
  void RegisterId(IpcMessageQueue* t) {
    t->RegisterId(T::kIpcId,
      [](Writer& visitor, BaseIpcMessage& message) {
      T& m = static_cast<T&>(message);
      Reflect(visitor, m);
    }, [](Reader& visitor) {
      auto m = MakeUnique<T>();
      Reflect(visitor, *m);
      return m;
    });
  }

  std::unique_ptr<IpcMessageQueue> BuildIpcMessageQueue(const std::string& name, size_t buffer_size) {
    auto ipc = MakeUnique<IpcMessageQueue>(name, buffer_size);
    RegisterId<Ipc_CancelRequest>(ipc.get());
    RegisterId<Ipc_InitializeRequest>(ipc.get());
    RegisterId<Ipc_InitializedNotification>(ipc.get());
    RegisterId<Ipc_TextDocumentDidOpen>(ipc.get());
    RegisterId<Ipc_TextDocumentDidChange>(ipc.get());
    RegisterId<Ipc_TextDocumentDidClose>(ipc.get());
    RegisterId<Ipc_TextDocumentDidSave>(ipc.get());
    RegisterId<Ipc_TextDocumentRename>(ipc.get());
    RegisterId<Ipc_TextDocumentComplete>(ipc.get());
    RegisterId<Ipc_TextDocumentDefinition>(ipc.get());
    RegisterId<Ipc_TextDocumentDocumentHighlight>(ipc.get());
    RegisterId<Ipc_TextDocumentHover>(ipc.get());
    RegisterId<Ipc_TextDocumentReferences>(ipc.get());
    RegisterId<Ipc_TextDocumentDocumentSymbol>(ipc.get());
    RegisterId<Ipc_TextDocumentCodeLens>(ipc.get());
    RegisterId<Ipc_CodeLensResolve>(ipc.get());
    RegisterId<Ipc_WorkspaceSymbol>(ipc.get());
    RegisterId<Ipc_Quit>(ipc.get());
    RegisterId<Ipc_IsAlive>(ipc.get());
    RegisterId<Ipc_OpenProject>(ipc.get());
    RegisterId<Ipc_Cout>(ipc.get());
    RegisterId<Ipc_CqueryFreshenIndex>(ipc.get());
    return ipc;
  }
};

IpcManager* IpcManager::instance_ = nullptr;

bool IsQueryDbProcessRunningOutOfProcess() {
  if (!kUseMultipleProcesses)
    return false;

  IpcManager* ipc = IpcManager::instance();

  // Discard any left-over messages from previous runs.
  if (kUseMultipleProcesses)
    ipc->GetMessages(IpcManager::Destination::Client);

  // Emit an alive check. Sleep so the server has time to respond.
  std::cerr << "[setup] Sending IsAlive request to server" << std::endl;
  ipc->SendMessage(IpcManager::Destination::Server, MakeUnique<Ipc_IsAlive>());

  // TODO: Tune this value or make it configurable.
  std::this_thread::sleep_for(std::chrono::milliseconds(100));

  // Check if we got an IsAlive message back.
  std::vector<std::unique_ptr<BaseIpcMessage>> messages = ipc->GetMessages(IpcManager::Destination::Client);
  for (auto& message : messages) {
    if (IpcId::IsAlive == message->method_id) {
      return true;
    }
    else {
      std::cerr << "[setup] Unhandled IPC message " << IpcIdToString(message->method_id) << std::endl;
      exit(1);
    }
  }

  // No response back. Clear out server messages so server doesn't respond to stale request.
  ipc->GetMessages(IpcManager::Destination::Server);

  return false;
}























































void PushBack(NonElidedVector<lsLocation>* result, optional<lsLocation> location) {
  if (location)
    result->push_back(*location);
}

QueryFile* FindFile(QueryDatabase* db, const std::string& filename, QueryFileId* file_id) {
  auto it = db->usr_to_symbol.find(filename);
  if (it != db->usr_to_symbol.end()) {
    optional<QueryFile>& file = db->files[it->second.idx];
    if (file) {
      *file_id = QueryFileId(it->second.idx);
      return &file.value();
    }
  }

  std::cerr << "Unable to find file " << filename << std::endl;
  *file_id = QueryFileId(-1);
  return nullptr;
}

QueryFile* FindFile(QueryDatabase* db, const std::string& filename) {
  // TODO: consider calling NormalizePath here. It might add too much latency though.
  auto it = db->usr_to_symbol.find(filename);
  if (it != db->usr_to_symbol.end()) {
    optional<QueryFile>& file = db->files[it->second.idx];
    if (file)
      return &file.value();
  }

  std::cerr << "Unable to find file " << filename << std::endl;
  return nullptr;
}

optional<QueryFile>* GetQuery(QueryDatabase* db, const QueryFileId& id) {
  return &db->files[id.id];
}
optional<QueryType>* GetQuery(QueryDatabase* db, const QueryTypeId& id) {
  return &db->types[id.id];
}
optional<QueryFunc>* GetQuery(QueryDatabase* db, const QueryFuncId& id) {
  return &db->funcs[id.id];
}
optional<QueryVar>* GetQuery(QueryDatabase* db, const QueryVarId& id) {
  return &db->vars[id.id];
}



optional<QueryLocation> GetDefinitionSpellingOfSymbol(QueryDatabase* db, const QueryTypeId& id) {
  optional<QueryType>& type = db->types[id.id];
  if (type)
    return type->def.definition_spelling;
  return nullopt;
}

optional<QueryLocation> GetDefinitionSpellingOfSymbol(QueryDatabase* db, const QueryFuncId& id) {
  optional<QueryFunc>& func = db->funcs[id.id];
  if (func)
    return func->def.definition_spelling;
  return nullopt;
}

optional<QueryLocation> GetDefinitionSpellingOfSymbol(QueryDatabase* db, const QueryVarId& id) {
  optional<QueryVar>& var = db->vars[id.id];
  if (var)
    return var->def.definition_spelling;
  return nullopt;
}

optional<QueryLocation> GetDefinitionSpellingOfSymbol(QueryDatabase* db, const SymbolIdx& symbol) {
  switch (symbol.kind) {
    case SymbolKind::Type: {
      optional<QueryType>& type = db->types[symbol.idx];
      if (type)
        return type->def.definition_spelling;
      break;
    }
    case SymbolKind::Func: {
      optional<QueryFunc>& func = db->funcs[symbol.idx];
      if (func)
        return func->def.definition_spelling;
      break;
    }
    case SymbolKind::Var: {
      optional<QueryVar>& var = db->vars[symbol.idx];
      if (var)
        return var->def.definition_spelling;
      break;
    }
    case SymbolKind::File:
    case SymbolKind::Invalid: {
      assert(false && "unexpected");
      break;
    }
  }
  return nullopt;
}

optional<QueryLocation> GetDefinitionExtentOfSymbol(QueryDatabase* db, const SymbolIdx& symbol) {
  switch (symbol.kind) {
    case SymbolKind::Type: {
      optional<QueryType>& type = db->types[symbol.idx];
      if (type)
        return type->def.definition_extent;
      break;
    }
    case SymbolKind::Func: {
      optional<QueryFunc>& func = db->funcs[symbol.idx];
      if (func)
        return func->def.definition_extent;
      break;
    }
    case SymbolKind::Var: {
      optional<QueryVar>& var = db->vars[symbol.idx];
      if (var)
        return var->def.definition_extent;
      break;
    }
    case SymbolKind::File: {
      return QueryLocation(QueryFileId(symbol.idx), Range(Position(1, 1), Position(1, 1)));
    }
    case SymbolKind::Invalid: {
      assert(false && "unexpected");
      break;
    }
  }
  return nullopt;
}

std::string GetHoverForSymbol(QueryDatabase* db, const SymbolIdx& symbol) {
  switch (symbol.kind) {
    case SymbolKind::Type: {
      optional<QueryType>& type = db->types[symbol.idx];
      if (type)
        return type->def.detailed_name;
      break;
    }
    case SymbolKind::Func: {
      optional<QueryFunc>& func = db->funcs[symbol.idx];
      if (func)
        return func->def.detailed_name;
      break;
    }
    case SymbolKind::Var: {
      optional<QueryVar>& var = db->vars[symbol.idx];
      if (var)
        return var->def.detailed_name;
      break;
    }
    case SymbolKind::File:
    case SymbolKind::Invalid: {
      assert(false && "unexpected");
      break;
    }
  }
  return "";
}

std::vector<QueryLocation> ToQueryLocation(QueryDatabase* db, const std::vector<QueryFuncRef>& refs) {
  std::vector<QueryLocation> locs;
  locs.reserve(refs.size());
  for (const QueryFuncRef& ref : refs)
    locs.push_back(ref.loc);
  return locs;
}
std::vector<QueryLocation> ToQueryLocation(QueryDatabase* db, const std::vector<QueryTypeId>& ids) {
  std::vector<QueryLocation> locs;
  locs.reserve(ids.size());
  for (const QueryTypeId& id : ids) {
    optional<QueryLocation> loc = GetDefinitionSpellingOfSymbol(db, id);
    if (loc)
      locs.push_back(loc.value());
  }
  return locs;
}
std::vector<QueryLocation> ToQueryLocation(QueryDatabase* db, const std::vector<QueryFuncId>& ids) {
  std::vector<QueryLocation> locs;
  locs.reserve(ids.size());
  for (const QueryFuncId& id : ids) {
    optional<QueryLocation> loc = GetDefinitionSpellingOfSymbol(db, id);
    if (loc)
      locs.push_back(loc.value());
  }
  return locs;
}
std::vector<QueryLocation> ToQueryLocation(QueryDatabase* db, const std::vector<QueryVarId>& ids) {
  std::vector<QueryLocation> locs;
  locs.reserve(ids.size());
  for (const QueryVarId& id : ids) {
    optional<QueryLocation> loc = GetDefinitionSpellingOfSymbol(db, id);
    if (loc)
      locs.push_back(loc.value());
  }
  return locs;
}



std::vector<QueryLocation> GetUsesOfSymbol(QueryDatabase* db, const SymbolIdx& symbol) {
  switch (symbol.kind) {
    case SymbolKind::Type: {
      optional<QueryType>& type = db->types[symbol.idx];
      if (type)
        return type->uses;
      break;
    }
    case SymbolKind::Func: {
      // TODO: the vector allocation could be avoided.
      optional<QueryFunc>& func = db->funcs[symbol.idx];
      if (func) {
        std::vector<QueryLocation> result = ToQueryLocation(db, func->callers);
        AddRange(&result, func->declarations);
        if (func->def.definition_spelling)
          result.push_back(*func->def.definition_spelling);
        return result;
      }
      break;
    }
    case SymbolKind::Var: {
      optional<QueryVar>& var = db->vars[symbol.idx];
      if (var)
        return var->uses;
      break;
    }
    case SymbolKind::File:
    case SymbolKind::Invalid: {
      assert(false && "unexpected");
      break;
    }
  }
  return {};
}

std::vector<QueryLocation> GetDeclarationsOfSymbolForGotoDefinition(QueryDatabase* db, const SymbolIdx& symbol) {
  switch (symbol.kind) {
    case SymbolKind::Type: {
      // Returning the definition spelling of a type is a hack (and is why the
      // function has the postfix `ForGotoDefintion`, but it lets the user
      // jump to the start of a type if clicking goto-definition on the same
      // type from within the type definition.
      optional<QueryType>& type = db->types[symbol.idx];
      if (type) {
        optional<QueryLocation> declaration = type->def.definition_spelling;
        if (declaration)
          return { *declaration };
      }
      break;
    }
    case SymbolKind::Func: {
      optional<QueryFunc>& func = db->funcs[symbol.idx];
      if (func)
        return func->declarations;
      break;
    }
    case SymbolKind::Var: {
      optional<QueryVar>& var = db->vars[symbol.idx];
      if (var) {
        optional<QueryLocation> declaration = var->def.declaration;
        if (declaration)
          return { *declaration };
      }
      break;
    }
  }

  return {};
}

optional<QueryLocation> GetBaseDefinitionOrDeclarationSpelling(QueryDatabase* db, QueryFunc& func) {
  if (!func.def.base)
    return nullopt;
  optional<QueryFunc>& base = db->funcs[func.def.base->id];
  if (!base)
    return nullopt;

  auto def = base->def.definition_spelling;
  if (!def && !base->declarations.empty())
    def = base->declarations[0];
  return def;
}

std::vector<QueryFuncRef> GetCallersForAllBaseFunctions(QueryDatabase* db, QueryFunc& root) {
  std::vector<QueryFuncRef> callers;

  optional<QueryFuncId> func_id = root.def.base;
  while (func_id) {
    optional<QueryFunc>& func = db->funcs[func_id->id];
    if (!func)
      break;

    AddRange(&callers, func->callers);
    func_id = func->def.base;
  }

  return callers;
}

std::vector<QueryFuncRef> GetCallersForAllDerivedFunctions(QueryDatabase* db, QueryFunc& root) {
  std::vector<QueryFuncRef> callers;

  std::queue<QueryFuncId> queue;
  PushRange(&queue, root.derived);

  while (!queue.empty()) {
    optional<QueryFunc>& func = db->funcs[queue.front().id];
    queue.pop();
    if (!func)
      continue;

    PushRange(&queue, func->derived);
    AddRange(&callers, func->callers);
  }

  return callers;
}

optional<lsRange> GetLsRange(WorkingFile* working_file, const Range& location) {
  if (!working_file) {
    return lsRange(
      lsPosition(location.start.line - 1, location.start.column - 1),
      lsPosition(location.end.line - 1, location.end.column - 1));
  }

  optional<int> start = working_file->GetBufferLineFromIndexLine(location.start.line);
  optional<int> end = working_file->GetBufferLineFromIndexLine(location.end.line);
  if (!start || !end)
    return nullopt;

  return lsRange(
    lsPosition(*start - 1, location.start.column - 1),
    lsPosition(*end - 1, location.end.column - 1));
}

lsDocumentUri GetLsDocumentUri(QueryDatabase* db, QueryFileId file_id, std::string* path) {
  optional<QueryFile>& file = db->files[file_id.id];
  if (file) {
    *path = file->def.path;
    return lsDocumentUri::FromPath(*path);
  }
  else {
    *path = "";
    return lsDocumentUri::FromPath("");
  }
}

lsDocumentUri GetLsDocumentUri(QueryDatabase* db, QueryFileId file_id) {
  optional<QueryFile>& file = db->files[file_id.id];
  if (file) {
    return lsDocumentUri::FromPath(file->def.path);
  }
  else {
    return lsDocumentUri::FromPath("");
  }
}

optional<lsLocation> GetLsLocation(QueryDatabase* db, WorkingFiles* working_files, const QueryLocation& location) {
  std::string path;
  lsDocumentUri uri = GetLsDocumentUri(db, location.path, &path);
  optional<lsRange> range = GetLsRange(working_files->GetFileByFilename(path), location.range);
  if (!range)
    return nullopt;
  return lsLocation(uri, *range);
}

// Returns a symbol. The symbol will have *NOT* have a location assigned.
optional<lsSymbolInformation> GetSymbolInfo(QueryDatabase* db, WorkingFiles* working_files, SymbolIdx symbol) {
    switch (symbol.kind) {
    case SymbolKind::File: {
      optional<QueryFile>& file = db->files[symbol.idx];
      if (!file)
        return nullopt;

      lsSymbolInformation info;
      info.name = file->def.path;
      info.kind = lsSymbolKind::File;
      return info;
    }
    case SymbolKind::Type: {
      optional<QueryType>& type = db->types[symbol.idx];
      if (!type)
        return nullopt;

      lsSymbolInformation info;
      info.name = type->def.detailed_name;
      info.kind = lsSymbolKind::Class;
      return info;
    }
    case SymbolKind::Func: {
      optional<QueryFunc>& func = db->funcs[symbol.idx];
      if (!func)
        return nullopt;

      lsSymbolInformation info;
      info.name = func->def.detailed_name;
      info.kind = lsSymbolKind::Function;

      if (func->def.declaring_type.has_value()) {
        optional<QueryType>& container = db->types[func->def.declaring_type->id];
        if (container) {
          info.kind = lsSymbolKind::Method;
          info.containerName = container->def.detailed_name;
        }
      }

      return info;
    }
    case SymbolKind::Var: {
      optional<QueryVar>& var = db->vars[symbol.idx];
      if (!var)
        return nullopt;

      lsSymbolInformation info;
      info.name += var->def.detailed_name;
      info.kind = lsSymbolKind::Variable;
      return info;
    }
    case SymbolKind::Invalid: {
      return nullopt;
    }
  };

  return nullopt;
}

struct CommonCodeLensParams {
  std::vector<TCodeLens>* result;
  QueryDatabase* db;
  WorkingFiles* working_files;
  WorkingFile* working_file;
};

void AddCodeLens(
  CommonCodeLensParams* common,
  QueryLocation loc,
  const std::vector<QueryLocation>& uses,
  const char* singular,
  const char* plural,
  bool exclude_loc = false) {
  TCodeLens code_lens;
  optional<lsRange> range = GetLsRange(common->working_file, loc.range);
  if (!range)
    return;
  code_lens.range = *range;
  code_lens.command = lsCommand<lsCodeLensCommandArguments>();
  code_lens.command->command = "superindex.showReferences";
  code_lens.command->arguments.uri = GetLsDocumentUri(common->db, loc.path);
  code_lens.command->arguments.position = code_lens.range.start;

  // Add unique uses.
  std::unordered_set<lsLocation> unique_uses;
  for (const QueryLocation& use : uses) {
    if (exclude_loc && use == loc)
      continue;
    optional<lsLocation> location = GetLsLocation(common->db, common->working_files, use);
    if (!location)
      continue;
    unique_uses.insert(*location);
  }
  code_lens.command->arguments.locations.assign(unique_uses.begin(),
    unique_uses.end());

  // User visible label
  size_t num_usages = unique_uses.size();
  code_lens.command->title = std::to_string(num_usages) + " ";
  if (num_usages == 1)
    code_lens.command->title += singular;
  else
    code_lens.command->title += plural;

  if (exclude_loc || unique_uses.size() > 0)
    common->result->push_back(code_lens);
}

lsWorkspaceEdit BuildWorkspaceEdit(QueryDatabase* db, WorkingFiles* working_files, const std::vector<QueryLocation>& locations, const std::string& new_text) {
  std::unordered_map<QueryFileId, lsTextDocumentEdit> path_to_edit;

  for (auto& location : locations) {
    optional<lsLocation> ls_location = GetLsLocation(db, working_files, location);
    if (!ls_location)
      continue;

    if (path_to_edit.find(location.path) == path_to_edit.end()) {
      path_to_edit[location.path] = lsTextDocumentEdit();

      optional<QueryFile>& file = db->files[location.path.id];
      if (!file)
        continue;

      const std::string& path = file->def.path;
      path_to_edit[location.path].textDocument.uri = lsDocumentUri::FromPath(path);

      WorkingFile* working_file = working_files->GetFileByFilename(path);
      if (working_file)
        path_to_edit[location.path].textDocument.version = working_file->version;
    }

    lsTextEdit edit;
    edit.range = ls_location->range;
    edit.newText = new_text;

    // vscode complains if we submit overlapping text edits.
    auto& edits = path_to_edit[location.path].edits;
    if (std::find(edits.begin(), edits.end(), edit) == edits.end())
      edits.push_back(edit);
  }


  lsWorkspaceEdit edit;
  for (const auto& changes : path_to_edit)
    edit.documentChanges.push_back(changes.second);
  return edit;
}

std::vector<SymbolRef> FindSymbolsAtLocation(WorkingFile* working_file, QueryFile* file, lsPosition position) {
  std::vector<SymbolRef> symbols;
  symbols.reserve(1);

  int target_line = position.line + 1;
  int target_column = position.character + 1;
  if (working_file) {
    optional<int> index_line = working_file->GetIndexLineFromBufferLine(target_line);
    if (index_line)
      target_line = *index_line;
  }

  for (const SymbolRef& ref : file->def.all_symbols) {
    if (ref.loc.range.Contains(target_line, target_column))
      symbols.push_back(ref);
  }

  // Order function symbols first. This makes goto definition work better when
  // used on a constructor.
  std::sort(symbols.begin(), symbols.end(), [](const SymbolRef& a, const SymbolRef& b) {
    if (a.idx.kind != b.idx.kind && a.idx.kind == SymbolKind::Func)
      return 1;
    return 0;
  });

  return symbols;
}

}  // namespace































































struct Index_DoIndex {
  enum class Type {
    ImportAndUpdate,
    ImportOnly,
    Parse,
    Freshen,
  };

  Index_DoIndex(Type type, const std::string& path, const optional<std::vector<std::string>>& args)
    : type(type), path(path), args(args) {}

  Type type;
  std::string path;
  optional<std::vector<std::string>> args;
};

struct Index_DoIdMap {
  std::unique_ptr<IndexedFile> previous;
  std::unique_ptr<IndexedFile> current;

  explicit Index_DoIdMap(std::unique_ptr<IndexedFile> previous,
                         std::unique_ptr<IndexedFile> current)
    : previous(std::move(previous)),
      current(std::move(current)) {}
};

struct Index_OnIdMapped {
  std::unique_ptr<IndexedFile> previous_index;
  std::unique_ptr<IndexedFile> current_index;
  std::unique_ptr<IdMap> previous_id_map;
  std::unique_ptr<IdMap> current_id_map;
};

struct Index_OnIndexed {
  IndexUpdate update;
  explicit Index_OnIndexed(IndexUpdate& update) : update(update) {}
};

using Index_DoIndexQueue = ThreadedQueue<Index_DoIndex>;
using Index_DoIdMapQueue = ThreadedQueue<Index_DoIdMap>;
using Index_OnIdMappedQueue = ThreadedQueue<Index_OnIdMapped>;
using Index_OnIndexedQueue = ThreadedQueue<Index_OnIndexed>;

void RegisterMessageTypes() {
  MessageRegistry::instance()->Register<Ipc_CancelRequest>();
  MessageRegistry::instance()->Register<Ipc_InitializeRequest>();
  MessageRegistry::instance()->Register<Ipc_InitializedNotification>();
  MessageRegistry::instance()->Register<Ipc_TextDocumentDidOpen>();
  MessageRegistry::instance()->Register<Ipc_TextDocumentDidChange>();
  MessageRegistry::instance()->Register<Ipc_TextDocumentDidClose>();
  MessageRegistry::instance()->Register<Ipc_TextDocumentDidSave>();
  MessageRegistry::instance()->Register<Ipc_TextDocumentRename>();
  MessageRegistry::instance()->Register<Ipc_TextDocumentComplete>();
  MessageRegistry::instance()->Register<Ipc_TextDocumentDefinition>();
  MessageRegistry::instance()->Register<Ipc_TextDocumentDocumentHighlight>();
  MessageRegistry::instance()->Register<Ipc_TextDocumentHover>();
  MessageRegistry::instance()->Register<Ipc_TextDocumentReferences>();
  MessageRegistry::instance()->Register<Ipc_TextDocumentDocumentSymbol>();
  MessageRegistry::instance()->Register<Ipc_TextDocumentCodeLens>();
  MessageRegistry::instance()->Register<Ipc_CodeLensResolve>();
  MessageRegistry::instance()->Register<Ipc_WorkspaceSymbol>();
  MessageRegistry::instance()->Register<Ipc_CqueryFreshenIndex>();
}






























void DispatchDependencyImports(Index_DoIndexQueue* queue_do_index,
                               Index_DoIndex::Type request_type,
                               const std::vector<std::string>& dependencies) {
  // Import all dependencies.
  for (auto& dependency_path : dependencies) {
    std::cerr << "- Dispatching dependency import " << dependency_path << std::endl;
    queue_do_index->PriorityEnqueue(Index_DoIndex(request_type, dependency_path, nullopt));
  }

}

void ImportCachedIndex(IndexerConfig* config,
                       Index_DoIndexQueue* queue_do_index,
                       Index_DoIdMapQueue* queue_do_id_map,
                       const std::string path,
                       int64_t* last_modification_time) {
  *last_modification_time = 0;

  Timer time;

  std::unique_ptr<IndexedFile> cache = LoadCachedIndex(config, path);
  time.ResetAndPrint("Reading cached index from disk " + path);
  if (!cache)
    return;

  DispatchDependencyImports(queue_do_index, Index_DoIndex::Type::ImportOnly, cache->dependencies);

  *last_modification_time = cache->last_modification_time;
  Index_DoIdMap response(nullptr, std::move(cache));
  queue_do_id_map->Enqueue(std::move(response));
}

void ParseFile(IndexerConfig* config,
               FileConsumer::SharedState* file_consumer_shared,
               Index_DoIdMapQueue* queue_do_id_map,
               const std::string& path,
               const optional<std::vector<std::string>>& args,
               std::vector<std::string>* opt_out_dependencies) {
  Timer time;

  // Parse request and send a response.
  std::unique_ptr<IndexedFile> cached_path_index = LoadCachedIndex(config, path);

  if (cached_path_index) {
    // Give the user dependencies if requested.
    if (opt_out_dependencies)
      *opt_out_dependencies = cached_path_index->dependencies;

    // Skip index if file modification time didn't change.
    int64_t modification_time = GetLastModificationTime(path);
    if (modification_time == cached_path_index->last_modification_time) {
      time.ResetAndPrint("Skipping index update on " + path + " since file modification time has not changed");
      return;
    }
    else {
      time.ResetAndPrint("Modification time on " + path + " has changed from " + std::to_string(cached_path_index->last_modification_time) + " to " + std::to_string(modification_time));
    }
  }

  std::vector<std::unique_ptr<IndexedFile>> indexes = Parse(
    config, file_consumer_shared,
    path, cached_path_index ? cached_path_index->import_file : path,
    args ? *args : cached_path_index ? cached_path_index->args : kEmptyArgs);
  time.ResetAndPrint("Parsing/indexing " + path);

  for (std::unique_ptr<IndexedFile>& new_index : indexes) {
    std::cerr << "Got index for " << new_index->path << std::endl;

    // Load the cached index.
    std::unique_ptr<IndexedFile> cached_index;
    if (new_index->path == path)
      cached_index = std::move(cached_path_index);
    else
      cached_index = LoadCachedIndex(config, new_index->path);
    time.ResetAndPrint("Loading cached index");

    // Update dependencies on |new_index|, since they won't get reparsed if we
    // have parsed them once before.
    if (cached_index)
      AddRange(&new_index->dependencies, cached_index->dependencies);

    // Cache the newly indexed file. This replaces the existing cache.
    // TODO: Run this as another import pipeline stage.
    WriteToCache(config, new_index->path, *new_index);
    time.ResetAndPrint("Cache index update to disk");

    // Dispatch IdMap creation request, which will happen on querydb thread.
    Index_DoIdMap response(std::move(cached_index), std::move(new_index));
    queue_do_id_map->Enqueue(std::move(response));
  }

}

bool IndexMain_DoIndex(IndexerConfig* config,
                       FileConsumer::SharedState* file_consumer_shared,
                       Project* project,
                       Index_DoIndexQueue* queue_do_index,
                       Index_DoIdMapQueue* queue_do_id_map) {
  optional<Index_DoIndex> index_request = queue_do_index->TryDequeue();
  if (!index_request)
    return false;

  Timer time;

  switch (index_request->type) {
    case Index_DoIndex::Type::ImportOnly: {
      int64_t cache_modification_time;
      ImportCachedIndex(config, queue_do_index, queue_do_id_map, index_request->path, &cache_modification_time);
      break;
    }

    case Index_DoIndex::Type::ImportAndUpdate: {
      int64_t cache_modification_time;
      ImportCachedIndex(config, queue_do_index, queue_do_id_map, index_request->path, &cache_modification_time);

      // If the file has been updated, we need to reparse it.
      if (GetLastModificationTime(index_request->path) > cache_modification_time) {
        // Instead of parsing the file immediate, we push the request to the
        // back of the queue so we will finish all of the Import requests
        // before starting to run libclang. This gives the user a
        // partially-correct index potentially much sooner.
        index_request->type = Index_DoIndex::Type::Parse;
        queue_do_index->Enqueue(std::move(*index_request));
      }
      break;
    }

    case Index_DoIndex::Type::Parse: {
      ParseFile(config, file_consumer_shared, queue_do_id_map, index_request->path, index_request->args, nullptr);
      break;
    }

    case Index_DoIndex::Type::Freshen: {
      std::vector<std::string> dependencies;
      ParseFile(config, file_consumer_shared, queue_do_id_map, index_request->path, index_request->args, &dependencies);
      DispatchDependencyImports(queue_do_index, Index_DoIndex::Type::Freshen, dependencies);
      break;
    }
  }

  return true;
}

bool IndexMain_DoCreateIndexUpdate(
    Index_OnIdMappedQueue* queue_on_id_mapped,
    Index_OnIndexedQueue* queue_on_indexed) {
  optional<Index_OnIdMapped> response = queue_on_id_mapped->TryDequeue();
  if (!response)
    return false;

  Timer time;
  IndexUpdate update = IndexUpdate::CreateDelta(response->previous_id_map.get(), response->current_id_map.get(),
    response->previous_index.get(), response->current_index.get());
  time.ResetAndPrint("[indexer] Creating delta IndexUpdate");
  Index_OnIndexed reply(update);
  queue_on_indexed->Enqueue(std::move(reply));
  time.ResetAndPrint("[indexer] Sending update to server");

  return true;
}

void IndexJoinIndexUpdates(Index_OnIndexedQueue* queue_on_indexed) {
  optional<Index_OnIndexed> root = queue_on_indexed->TryDequeue();
  if (!root)
    return;

  while (true) {
    optional<Index_OnIndexed> to_join = queue_on_indexed->TryDequeue();
    if (!to_join) {
      queue_on_indexed->Enqueue(std::move(*root));
      return;
    }

    Timer time;
    root->update.Merge(to_join->update);
    time.ResetAndPrint("[indexer] Joining two querydb updates");
  }
}

void IndexMain(
  IndexerConfig* config,
  FileConsumer::SharedState* file_consumer_shared,
  Project* project,
  Index_DoIndexQueue* queue_do_index,
  Index_DoIdMapQueue* queue_do_id_map,
  Index_OnIdMappedQueue* queue_on_id_mapped,
  Index_OnIndexedQueue* queue_on_indexed) {

  SetCurrentThreadName("indexer");
  while (true) {
    // TODO: process all off IndexMain_DoIndex before calling IndexMain_DoCreateIndexUpdate for
    //       better icache behavior. We need to have some threads spinning on both though
    //       otherwise memory usage will get bad.

    int count = 0;

    // We need to make sure to run both IndexMain_DoIndex and
    // IndexMain_DoCreateIndexUpdate so we don't starve querydb from doing any
    // work. Running both also lets the user query the partially constructed
    // index.
    bool did_index = IndexMain_DoIndex(config, file_consumer_shared, project, queue_do_index, queue_do_id_map);
    bool did_create_update = IndexMain_DoCreateIndexUpdate(queue_on_id_mapped, queue_on_indexed);
    if (!did_index && !did_create_update) {

      //if (count++ > 2) {
      //  count = 0;
        IndexJoinIndexUpdates(queue_on_indexed);
      //}

      // TODO: use CV to wakeup?
      std::this_thread::sleep_for(std::chrono::milliseconds(25));
    }
  }
}



















































void QueryDbMainLoop(
  IndexerConfig* config,
  QueryDatabase* db,
  Index_DoIndexQueue* queue_do_index,
  Index_DoIdMapQueue* queue_do_id_map,
  Index_OnIdMappedQueue* queue_on_id_mapped,
  Index_OnIndexedQueue* queue_on_indexed,
  Project* project,
  WorkingFiles* working_files,
  CompletionManager* completion_manager) {
  IpcManager* ipc = IpcManager::instance();

  std::vector<std::unique_ptr<BaseIpcMessage>> messages = ipc->GetMessages(IpcManager::Destination::Server);
  for (auto& message : messages) {
    std::cerr << "[querydb] Processing message " << IpcIdToString(message->method_id) << std::endl;

    switch (message->method_id) {
    case IpcId::Quit: {
      std::cerr << "[querydb] Got quit message (exiting)" << std::endl;
      exit(0);
      break;
    }

    case IpcId::IsAlive: {
      std::cerr << "[querydb] Sending IsAlive response to client" << std::endl;
      ipc->SendMessage(IpcManager::Destination::Client, MakeUnique<Ipc_IsAlive>());
      break;
    }

    case IpcId::OpenProject: {
      Ipc_OpenProject* msg = static_cast<Ipc_OpenProject*>(message.get());
      std::string path = msg->project_path;

      project->Load(path);
      std::cerr << "Loaded compilation entries (" << project->entries.size() << " files)" << std::endl;

      project->ForAllFilteredFiles(config, [&](int i, const Project::Entry& entry) {
        std::cerr << "[" << i << "/" << (project->entries.size() - 1)
          << "] Dispatching index request for file " << entry.filename
          << std::endl;

        queue_do_index->Enqueue(Index_DoIndex(Index_DoIndex::Type::ImportAndUpdate, entry.filename, entry.args));
      });

      break;
    }

    case IpcId::CqueryFreshenIndex: {
      std::cerr << "Freshening " << project->entries.size() << " files" << std::endl;
      project->ForAllFilteredFiles(config, [&](int i, const Project::Entry& entry) {
        std::cerr << "[" << i << "/" << (project->entries.size() - 1)
          << "] Dispatching index request for file " << entry.filename
          << std::endl;
        queue_do_index->Enqueue(Index_DoIndex(Index_DoIndex::Type::Freshen, entry.filename, entry.args));
      });
      break;
    }

    case IpcId::TextDocumentDidOpen: {
      // NOTE: This function blocks code lens. If it starts taking a long time
      // we will need to find a way to unblock the code lens request.

      Timer time;
      auto msg = static_cast<Ipc_TextDocumentDidOpen*>(message.get());
      WorkingFile* working_file = working_files->OnOpen(msg->params);
      optional<std::string> cached_file_contents = LoadCachedFileContents(config, msg->params.textDocument.uri.GetPath());
      if (cached_file_contents)
        working_file->SetIndexContent(*cached_file_contents);
      else
        working_file->SetIndexContent(working_file->buffer_content);
      time.ResetAndPrint("[querydb] Loading cached index file for DidOpen");

      break;
    }
    case IpcId::TextDocumentDidChange: {
      auto msg = static_cast<Ipc_TextDocumentDidChange*>(message.get());
      working_files->OnChange(msg->params);
      break;
    }
    case IpcId::TextDocumentDidClose: {
      auto msg = static_cast<Ipc_TextDocumentDidClose*>(message.get());
      working_files->OnClose(msg->params);
      break;
    }

    case IpcId::TextDocumentDidSave: {
      auto msg = static_cast<Ipc_TextDocumentDidSave*>(message.get());

      std::string path = msg->params.textDocument.uri.GetPath();
      // Send an index update request.
      queue_do_index->Enqueue(Index_DoIndex(Index_DoIndex::Type::Parse, path, project->FindArgsForFile(path)));

      // Copy current buffer content so it can be applied when index request is done.
      WorkingFile* working_file = working_files->GetFileByFilename(path);
      if (working_file)
        working_file->pending_new_index_content = working_file->buffer_content;

      break;
    }

    case IpcId::TextDocumentRename: {
      auto msg = static_cast<Ipc_TextDocumentRename*>(message.get());

      QueryFileId file_id;
      QueryFile* file = FindFile(db, msg->params.textDocument.uri.GetPath(), &file_id);
      if (!file) {
        std::cerr << "Unable to find file " << msg->params.textDocument.uri.GetPath() << std::endl;
        break;
      }
      WorkingFile* working_file = working_files->GetFileByFilename(file->def.path);

      Out_TextDocumentRename response;
      response.id = msg->id;

      for (const SymbolRef& ref : FindSymbolsAtLocation(working_file, file, msg->params.position)) {
        // Found symbol. Return references to rename.
        std::vector<QueryLocation> uses = GetUsesOfSymbol(db, ref.idx);
        response.result = BuildWorkspaceEdit(db, working_files, uses, msg->params.newName);
        break;
      }

      response.Write(std::cerr);
      ipc->SendOutMessageToClient(IpcId::TextDocumentRename, response);
      break;
    }

    case IpcId::TextDocumentCompletion: {
      auto msg = static_cast<Ipc_TextDocumentComplete*>(message.get());
      lsTextDocumentPositionParams params = msg->params;

      CompletionManager::OnComplete callback = std::bind([](BaseIpcMessage* message, const NonElidedVector<lsCompletionItem>& results) {
        auto msg = static_cast<Ipc_TextDocumentComplete*>(message);
        auto ipc = IpcManager::instance();

        Out_TextDocumentComplete response;
        response.id = msg->id;
        response.result.isIncomplete = false;
        response.result.items = results;

        Timer timer;
        ipc->SendOutMessageToClient(IpcId::TextDocumentCompletion, response);
        timer.ResetAndPrint("Writing completion results");

        delete message;
      }, message.release(), std::placeholders::_1);

      completion_manager->CodeComplete(params, std::move(callback));

      break;
    }

    case IpcId::TextDocumentDefinition: {
      auto msg = static_cast<Ipc_TextDocumentDefinition*>(message.get());

      QueryFileId file_id;
      QueryFile* file = FindFile(db, msg->params.textDocument.uri.GetPath(), &file_id);
      if (!file) {
        std::cerr << "Unable to find file " << msg->params.textDocument.uri.GetPath() << std::endl;
        break;
      }
      WorkingFile* working_file = working_files->GetFileByFilename(file->def.path);

      Out_TextDocumentDefinition response;
      response.id = msg->id;

      int target_line = msg->params.position.line + 1;
      int target_column = msg->params.position.character + 1;

      for (const SymbolRef& ref : FindSymbolsAtLocation(working_file, file, msg->params.position)) {
        // Found symbol. Return definition.

        // Special cases which are handled:
        //  - symbol has declaration but no definition (ie, pure virtual)
        //  - start at spelling but end at extent for better mouse tooltip
        //  - goto declaration while in definition of recursive type

        optional<QueryLocation> def_loc = GetDefinitionSpellingOfSymbol(db, ref.idx);

        // We use spelling start and extent end because this causes vscode to
        // highlight the entire definition when previewing / hoving with the
        // mouse.
        optional<QueryLocation> def_extent = GetDefinitionExtentOfSymbol(db, ref.idx);
        if (def_loc && def_extent)
          def_loc->range.end = def_extent->range.end;

        // If the cursor is currently at or in the definition we should goto
        // the declaration if possible. We also want to use declarations if
        // we're pointing to, ie, a pure virtual function which has no
        // definition.
        if (!def_loc || (def_loc->path == file_id &&
                          def_loc->range.Contains(target_line, target_column))) {
          // Goto declaration.

          std::vector<QueryLocation> declarations = GetDeclarationsOfSymbolForGotoDefinition(db, ref.idx);
          for (auto declaration : declarations) {
            optional<lsLocation> ls_declaration = GetLsLocation(db, working_files, declaration);
            if (ls_declaration)
              response.result.push_back(*ls_declaration);
          }
          // We found some declarations. Break so we don't add the definition location.
          if (!response.result.empty())
            break;
        }

        if (def_loc)
          PushBack(&response.result, GetLsLocation(db, working_files, *def_loc));

        if (!response.result.empty())
          break;
      }

      ipc->SendOutMessageToClient(IpcId::TextDocumentDefinition, response);
      break;
    }

    case IpcId::TextDocumentDocumentHighlight: {
      auto msg = static_cast<Ipc_TextDocumentDocumentHighlight*>(message.get());

      QueryFileId file_id;
      QueryFile* file = FindFile(db, msg->params.textDocument.uri.GetPath(), &file_id);
      if (!file) {
        std::cerr << "Unable to find file " << msg->params.textDocument.uri.GetPath() << std::endl;
        break;
      }
      WorkingFile* working_file = working_files->GetFileByFilename(file->def.path);

      Out_TextDocumentDocumentHighlight response;
      response.id = msg->id;

      for (const SymbolRef& ref : FindSymbolsAtLocation(working_file, file, msg->params.position)) {
        // Found symbol. Return references to highlight.
        std::vector<QueryLocation> uses = GetUsesOfSymbol(db, ref.idx);
        response.result.reserve(uses.size());
        for (const QueryLocation& use : uses) {
          if (use.path != file_id)
            continue;

          optional<lsLocation> ls_location = GetLsLocation(db, working_files, use);
          if (!ls_location)
            continue;

          lsDocumentHighlight highlight;
          highlight.kind = lsDocumentHighlightKind::Text;
          highlight.range = ls_location->range;
          response.result.push_back(highlight);
        }
        break;
      }

      ipc->SendOutMessageToClient(IpcId::TextDocumentDocumentHighlight, response);
      break;
    }

    case IpcId::TextDocumentHover: {
      auto msg = static_cast<Ipc_TextDocumentHover*>(message.get());

      QueryFile* file = FindFile(db, msg->params.textDocument.uri.GetPath());
      if (!file) {
        std::cerr << "Unable to find file " << msg->params.textDocument.uri.GetPath() << std::endl;
        break;
      }
      WorkingFile* working_file = working_files->GetFileByFilename(file->def.path);

      Out_TextDocumentHover response;
      response.id = msg->id;

      for (const SymbolRef& ref : FindSymbolsAtLocation(working_file, file, msg->params.position)) {
        // Found symbol. Return hover.
        optional<lsRange> ls_range = GetLsRange(working_files->GetFileByFilename(file->def.path), ref.loc.range);
        if (!ls_range)
          continue;

        response.result.contents = GetHoverForSymbol(db, ref.idx);
        response.result.range = *ls_range;
        break;
      }

      ipc->SendOutMessageToClient(IpcId::TextDocumentHover, response);
      break;
    }

    case IpcId::TextDocumentReferences: {
      auto msg = static_cast<Ipc_TextDocumentReferences*>(message.get());

      QueryFile* file = FindFile(db, msg->params.textDocument.uri.GetPath());
      if (!file) {
        std::cerr << "Unable to find file " << msg->params.textDocument.uri.GetPath() << std::endl;
        break;
      }
      WorkingFile* working_file = working_files->GetFileByFilename(file->def.path);

      Out_TextDocumentReferences response;
      response.id = msg->id;

      for (const SymbolRef& ref : FindSymbolsAtLocation(working_file, file, msg->params.position)) {
        optional<QueryLocation> excluded_declaration;
        if (!msg->params.context.includeDeclaration) {
          std::cerr << "Excluding declaration in references" << std::endl;
          excluded_declaration = GetDefinitionSpellingOfSymbol(db, ref.idx);
        }

        // Found symbol. Return references.
        std::vector<QueryLocation> uses = GetUsesOfSymbol(db, ref.idx);
        response.result.reserve(uses.size());
        for (const QueryLocation& use : uses) {
          if (excluded_declaration.has_value() && use == *excluded_declaration)
            continue;

          optional<lsLocation> ls_location = GetLsLocation(db, working_files, use);
          if (ls_location)
            response.result.push_back(*ls_location);
        }
        break;
      }

      ipc->SendOutMessageToClient(IpcId::TextDocumentReferences, response);
      break;
    }

    case IpcId::TextDocumentDocumentSymbol: {
      auto msg = static_cast<Ipc_TextDocumentDocumentSymbol*>(message.get());

      Out_TextDocumentDocumentSymbol response;
      response.id = msg->id;

      QueryFile* file = FindFile(db, msg->params.textDocument.uri.GetPath());
      if (!file) {
        std::cerr << "Unable to find file " << msg->params.textDocument.uri.GetPath() << std::endl;
        break;
      }

      std::cerr << "File outline size is " << file->def.outline.size() << std::endl;
      for (SymbolRef ref : file->def.outline) {
        optional<lsSymbolInformation> info = GetSymbolInfo(db, working_files, ref.idx);
        if (!info)
          continue;

        optional<lsLocation> location = GetLsLocation(db, working_files, ref.loc);
        if (!location)
          continue;
        info->location = *location;
        response.result.push_back(*info);
      }

      ipc->SendOutMessageToClient(IpcId::TextDocumentDocumentSymbol, response);
      break;
    }

    case IpcId::TextDocumentCodeLens: {
      auto msg = static_cast<Ipc_TextDocumentCodeLens*>(message.get());

      Out_TextDocumentCodeLens response;
      response.id = msg->id;

      lsDocumentUri file_as_uri = msg->params.textDocument.uri;

      QueryFile* file = FindFile(db, file_as_uri.GetPath());
      if (!file) {
        std::cerr << "Unable to find file " << msg->params.textDocument.uri.GetPath() << std::endl;
        break;
      }
      CommonCodeLensParams common;
      common.result = &response.result;
      common.db = db;
      common.working_files = working_files;
      common.working_file = working_files->GetFileByFilename(file->def.path);

      Timer time;

      for (SymbolRef ref : file->def.outline) {
        // NOTE: We OffsetColumn so that the code lens always show up in a
        // predictable order. Otherwise, the client may randomize it.

        SymbolIdx symbol = ref.idx;
        switch (symbol.kind) {
        case SymbolKind::Type: {
          optional<QueryType>& type = db->types[symbol.idx];
          if (!type)
            continue;
          AddCodeLens(&common, ref.loc.OffsetStartColumn(0), type->uses, "ref", "refs");
          AddCodeLens(&common, ref.loc.OffsetStartColumn(1), ToQueryLocation(db, type->derived), "derived", "derived");
          AddCodeLens(&common, ref.loc.OffsetStartColumn(2), ToQueryLocation(db, type->instances), "var", "vars");
          break;
        }
        case SymbolKind::Func: {
          optional<QueryFunc>& func = db->funcs[symbol.idx];
          if (!func)
            continue;

          int offset = 0;

          std::vector<QueryFuncRef> base_callers = GetCallersForAllBaseFunctions(db, *func);
          std::vector<QueryFuncRef> derived_callers = GetCallersForAllDerivedFunctions(db, *func);
          if (base_callers.empty() && derived_callers.empty()) {
            // set exclude_loc to true to force the code lens to show up
            AddCodeLens(&common, ref.loc.OffsetStartColumn(offset++), ToQueryLocation(db, func->callers), "call", "calls", true /*exclude_loc*/);
          }
          else {
            AddCodeLens(&common, ref.loc.OffsetStartColumn(offset++), ToQueryLocation(db, func->callers), "direct call", "direct calls");
            if (!base_callers.empty())
              AddCodeLens(&common, ref.loc.OffsetStartColumn(offset++), ToQueryLocation(db, base_callers), "base call", "base calls");
            if (!derived_callers.empty())
              AddCodeLens(&common, ref.loc.OffsetStartColumn(offset++), ToQueryLocation(db, derived_callers), "derived call", "derived calls");
          }

          AddCodeLens(&common, ref.loc.OffsetStartColumn(offset++), ToQueryLocation(db, func->derived), "derived", "derived");

          // "Base"
          optional<QueryLocation> base_loc = GetBaseDefinitionOrDeclarationSpelling(db, *func);
          if (base_loc) {
            optional<lsLocation> ls_base = GetLsLocation(db, working_files, *base_loc);
            if (ls_base) {
              optional<lsRange> range = GetLsRange(common.working_file, ref.loc.range);
              if (range) {
                TCodeLens code_lens;
                code_lens.range = *range;
                code_lens.range.start.character += offset++;
                code_lens.command = lsCommand<lsCodeLensCommandArguments>();
                code_lens.command->title = "Base";
                code_lens.command->command = "superindex.goto";
                code_lens.command->arguments.uri = ls_base->uri;
                code_lens.command->arguments.position = ls_base->range.start;
                response.result.push_back(code_lens);
              }
            }
          }

          break;
        }
        case SymbolKind::Var: {
          optional<QueryVar>& var = db->vars[symbol.idx];
          if (!var)
            continue;

          AddCodeLens(&common, ref.loc.OffsetStartColumn(0), var->uses, "ref", "refs", true /*exclude_loc*/);
          break;
        }
        case SymbolKind::File:
        case SymbolKind::Invalid: {
          assert(false && "unexpected");
          break;
        }
        };
      }

      time.ResetAndPrint("[querydb] Building code lens for " + file->def.path);
      ipc->SendOutMessageToClient(IpcId::TextDocumentCodeLens, response);
      break;
    }

    case IpcId::WorkspaceSymbol: {
      auto msg = static_cast<Ipc_WorkspaceSymbol*>(message.get());

      Out_WorkspaceSymbol response;
      response.id = msg->id;


      std::cerr << "[querydb] Considering " << db->detailed_names.size()
        << " candidates for query " << msg->params.query << std::endl;

      std::string query = msg->params.query;
      for (int i = 0; i < db->detailed_names.size(); ++i) {
        if (response.result.size() >= config->maxWorkspaceSearchResults) {
          std::cerr << "[querydb] - Query exceeded maximum number of responses (" << config->maxWorkspaceSearchResults << "), output may not contain all results" << std::endl;
          break;
        }

        if (db->detailed_names[i].find(query) != std::string::npos) {
          optional<lsSymbolInformation> info = GetSymbolInfo(db, working_files, db->symbols[i]);
          if (!info)
            continue;

          optional<QueryLocation> location = GetDefinitionExtentOfSymbol(db, db->symbols[i]);
          if (!location) {
            auto decls = GetDeclarationsOfSymbolForGotoDefinition(db, db->symbols[i]);
            if (decls.empty())
              continue;
            location = decls[0];
          }

          optional<lsLocation> ls_location = GetLsLocation(db, working_files, *location);
          if (!ls_location)
            continue;
          info->location = *ls_location;
          response.result.push_back(*info);
        }
      }

      std::cerr << "[querydb] - Found " << response.result.size() << " results for query " << query << std::endl;
      ipc->SendOutMessageToClient(IpcId::WorkspaceSymbol, response);
      break;
    }

    default: {
      std::cerr << "[querydb] Unhandled IPC message " << IpcIdToString(message->method_id) << std::endl;
      exit(1);
    }
    }
  }

  // TODO: consider rate-limiting and checking for IPC messages so we don't block
  // requests / we can serve partial requests.


  while (true) {
    optional<Index_DoIdMap> request = queue_do_id_map->TryDequeue();
    if (!request)
      break;


    Index_OnIdMapped response;
    Timer time;

    if (request->previous) {
      response.previous_id_map = MakeUnique<IdMap>(db, request->previous->id_cache);
      response.previous_index = std::move(request->previous);
    }

    assert(request->current);
    response.current_id_map = MakeUnique<IdMap>(db, request->current->id_cache);
    time.ResetAndPrint("[querydb] Create IdMap " + request->current->path);
    response.current_index = std::move(request->current);

    queue_on_id_mapped->Enqueue(std::move(response));
  }

  while (true) {
    optional<Index_OnIndexed> response = queue_on_indexed->TryDequeue();
    if (!response)
      break;

    Timer time;

    for (auto& updated_file : response->update.files_def_update) {
      // TODO: We're reading a file on querydb thread. This is slow!! If it is a
      // problem in practice we need to create a file reader queue, dispatch the
      // read to it, get a response, and apply the new index then.
      WorkingFile* working_file = working_files->GetFileByFilename(updated_file.path);
      if (working_file) {
        if (working_file->pending_new_index_content) {
          working_file->SetIndexContent(*working_file->pending_new_index_content);
          working_file->pending_new_index_content = nullopt;
          time.ResetAndPrint("[querydb] Update WorkingFile index contents (via in-memory buffer) for " + updated_file.path);
        }
        else {
          optional<std::string> cached_file_contents = LoadCachedFileContents(config, updated_file.path);
          if (cached_file_contents)
            working_file->SetIndexContent(*cached_file_contents);
          else
            working_file->SetIndexContent(working_file->buffer_content);
          time.ResetAndPrint("[querydb] Update WorkingFile index contents (via disk load) for " + updated_file.path);
        }
      }
    }

    db->ApplyIndexUpdate(&response->update);
    time.ResetAndPrint("[querydb] Applying index update");
  }
}

void QueryDbMain(IndexerConfig* config) {
  //std::cerr << "Running QueryDb" << std::endl;

  // Create queues.
  Index_DoIndexQueue queue_do_index;
  Index_DoIdMapQueue queue_do_id_map;
  Index_OnIdMappedQueue queue_on_id_mapped;
  Index_OnIndexedQueue queue_on_indexed;

  Project project;
  WorkingFiles working_files;
  CompletionManager completion_manager(config, &project, &working_files);
  FileConsumer::SharedState file_consumer_shared;

  // Start indexer threads.
  int indexer_count = std::max<int>(std::thread::hardware_concurrency(), 2) - 1;
  if (config->indexerCount > 0)
    indexer_count = config->indexerCount;
  std::cerr << "[querydb] Starting " << indexer_count << " indexers" << std::endl;
  for (int i = 0; i < indexer_count; ++i) {
    new std::thread([&]() {
      IndexMain(config, &file_consumer_shared, &project, &queue_do_index, &queue_do_id_map, &queue_on_id_mapped, &queue_on_indexed);
    });
  }

  // Run query db main loop.
  SetCurrentThreadName("querydb");
  QueryDatabase db;
  while (true) {
    QueryDbMainLoop(config, &db, &queue_do_index, &queue_do_id_map, &queue_on_id_mapped, &queue_on_indexed, &project, &working_files, &completion_manager);
    std::this_thread::sleep_for(std::chrono::milliseconds(10));
  }
}































































// TODO: global lock on stderr output.

// Separate thread whose only job is to read from stdin and
// dispatch read commands to the actual indexer program. This
// cannot be done on the main thread because reading from std::cin
// blocks.
//
// |ipc| is connected to a server.
void LanguageServerStdinLoop(IndexerConfig* config, std::unordered_map<IpcId, Timer>* request_times) {
  IpcManager* ipc = IpcManager::instance();

  SetCurrentThreadName("stdin");
  while (true) {
    std::unique_ptr<BaseIpcMessage> message = MessageRegistry::instance()->ReadMessageFromStdin();

    // Message parsing can fail if we don't recognize the method.
    if (!message)
      continue;

    (*request_times)[message->method_id] = Timer();

    std::cerr << "[stdin] Got message \"" << IpcIdToString(message->method_id) << '"' << std::endl;
    switch (message->method_id) {
      // TODO: For simplicitly lets just proxy the initialize request like
      // all other requests so that stdin loop thread becomes super simple.
    case IpcId::Initialize: {
      auto request = static_cast<Ipc_InitializeRequest*>(message.get());
      if (request->params.rootUri) {
        std::string project_path = request->params.rootUri->GetPath();
        std::cerr << "[stdin] Initialize in directory " << project_path
          << " with uri " << request->params.rootUri->raw_uri
          << std::endl;
        auto open_project = MakeUnique<Ipc_OpenProject>();
        open_project->project_path = project_path;

        if (!request->params.initializationOptions) {
          std::cerr << "Initialization parameters (particularily cacheDirectory) are required" << std::endl;
          exit(1);
        }

        *config = *request->params.initializationOptions;

        // Make sure cache directory is valid.
        if (config->cacheDirectory.empty()) {
          std::cerr << "No cache directory" << std::endl;
          exit(1);
        }
        config->cacheDirectory = NormalizePath(config->cacheDirectory);
        if (config->cacheDirectory[config->cacheDirectory.size() - 1] != '/')
          config->cacheDirectory += '/';
        MakeDirectoryRecursive(config->cacheDirectory);

        // Startup querydb now that we have initialization state.
        // TODO: Pass init data to out of process querydb.
        bool has_querydb = IsQueryDbProcessRunningOutOfProcess();
        if (!has_querydb) {
          new std::thread([&config]() {
            QueryDbMain(config);
          });
        }

        ipc->SendMessage(IpcManager::Destination::Server, std::move(open_project));
      }

      // TODO: query request->params.capabilities.textDocument and support only things
      // the client supports.

      auto response = Out_InitializeResponse();
      response.id = request->id;

      //response.result.capabilities.textDocumentSync = lsTextDocumentSyncOptions();
      //response.result.capabilities.textDocumentSync->openClose = true;
      //response.result.capabilities.textDocumentSync->change = lsTextDocumentSyncKind::Full;
      //response.result.capabilities.textDocumentSync->willSave = true;
      //response.result.capabilities.textDocumentSync->willSaveWaitUntil = true;
      response.result.capabilities.textDocumentSync = lsTextDocumentSyncKind::Incremental;

      response.result.capabilities.renameProvider = true;

      response.result.capabilities.completionProvider = lsCompletionOptions();
      response.result.capabilities.completionProvider->resolveProvider = false;
      response.result.capabilities.completionProvider->triggerCharacters = { ".", "::", "->" };

      response.result.capabilities.codeLensProvider = lsCodeLensOptions();
      response.result.capabilities.codeLensProvider->resolveProvider = false;

      response.result.capabilities.definitionProvider = true;
      response.result.capabilities.documentHighlightProvider = true;
      response.result.capabilities.hoverProvider = true;
      response.result.capabilities.referencesProvider = true;

      response.result.capabilities.documentSymbolProvider = true;
      response.result.capabilities.workspaceSymbolProvider = true;

      //response.Write(std::cerr);
      response.Write(std::cout);
      break;
    }

    case IpcId::Initialized: {
      // TODO: don't send output until we get this notification
      break;
    }

    case IpcId::CancelRequest: {
      // TODO: support cancellation
      break;
    }

    case IpcId::TextDocumentDidOpen:
    case IpcId::TextDocumentDidChange:
    case IpcId::TextDocumentDidClose:
    case IpcId::TextDocumentDidSave:
    case IpcId::TextDocumentRename:
    case IpcId::TextDocumentCompletion:
    case IpcId::TextDocumentDefinition:
    case IpcId::TextDocumentDocumentHighlight:
    case IpcId::TextDocumentHover:
    case IpcId::TextDocumentReferences:
    case IpcId::TextDocumentDocumentSymbol:
    case IpcId::TextDocumentCodeLens:
    case IpcId::WorkspaceSymbol:
    case IpcId::CqueryFreshenIndex: {
      ipc->SendMessage(IpcManager::Destination::Server, std::move(message));
      break;
    }

    default: {
      std::cerr << "[stdin] Unhandled IPC message " << IpcIdToString(message->method_id) << std::endl;
      exit(1);
    }
    }
  }
}















































void LanguageServerMainLoop(std::unordered_map<IpcId, Timer>* request_times) {
  IpcManager* ipc = IpcManager::instance();

  std::vector<std::unique_ptr<BaseIpcMessage>> messages = ipc->GetMessages(IpcManager::Destination::Client);
  for (auto& message : messages) {
    std::cerr << "[server] Processing message " << IpcIdToString(message->method_id) << std::endl;

    switch (message->method_id) {
      case IpcId::Quit: {
        std::cerr << "[server] Got quit message (exiting)" << std::endl;
        exit(0);
        break;
      }

      case IpcId::Cout: {
        auto msg = static_cast<Ipc_Cout*>(message.get());

        Timer time = (*request_times)[msg->original_ipc_id];
        time.ResetAndPrint("[e2e] Running " + std::string(IpcIdToString(msg->original_ipc_id)));

        std::cout << msg->content;
        std::cout.flush();
        break;
      }

      default: {
        std::cerr << "[server] Unhandled IPC message " << IpcIdToString(message->method_id) << std::endl;
        exit(1);
      }
    }
  }
}

void LanguageServerMain(IndexerConfig* config) {
  std::unordered_map<IpcId, Timer> request_times;

  // Run language client.
  new std::thread([&]() {
    LanguageServerStdinLoop(config, &request_times);
  });

  SetCurrentThreadName("server");
  while (true) {
    LanguageServerMainLoop(&request_times);
    std::this_thread::sleep_for(std::chrono::milliseconds(2));
  }
}



















































int main(int argc, char** argv) {
  IpcManager::CreateInstance();

  //bool loop = true;
  //while (loop)
  //  std::this_thread::sleep_for(std::chrono::milliseconds(10));
  //std::this_thread::sleep_for(std::chrono::seconds(3));

  PlatformInit();
  IndexInit();

  RegisterMessageTypes();

  // if (argc == 1) {
  //  QueryDbMain();
  //  return 0;
  //}


  std::unordered_map<std::string, std::string> options =
    ParseOptions(argc, argv);

  if (argc == 1 || HasOption(options, "--test")) {
    doctest::Context context;
    context.applyCommandLine(argc, argv);
    int res = context.run();
    if (context.shouldExit())
      return res;

    RunTests();
    return 0;
  }
  else if (options.find("--help") != options.end()) {
    std::cout << R"help(clang-querydb help:

  clang-querydb is a low-latency C++ language server.

  General:
    --help        Print this help information.
    --language-server
                  Run as a language server. The language server will look for
                  an existing querydb process, otherwise it will run querydb
                  in-process. This implements the language server spec.
    --querydb     Run the querydb. The querydb stores the program index and
                  serves index request tasks.
    --test        Run tests. Does nothing if test support is not compiled in.

  Configuration:
    When opening up a directory, clang-querydb will look for a
    compile_commands.json file emitted by your preferred build system. If not
    present, clang-querydb will use a recursive directory listing instead.
    Command line flags can be provided by adding a "clang_args" file in the
    top-level directory. Each line in that file is a separate argument.
)help";
    exit(0);
  }
  else if (HasOption(options, "--language-server")) {
    //std::cerr << "Running language server" << std::endl;
    IndexerConfig config;
    LanguageServerMain(&config);
    return 0;
  }
  else if (HasOption(options, "--querydb")) {
    //std::cerr << "Running querydb" << std::endl;
    // TODO/FIXME: config is not shared between processes.
    IndexerConfig config;
    QueryDbMain(&config);
    return 0;
  }
  else {
    //std::cerr << "Running language server" << std::endl;
    IndexerConfig config;
    LanguageServerMain(&config);
    return 0;
  }

  return 1;
}