/* 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.h"
#include "pipeline.hh"
#include "query_utils.h"
using namespace ccls;
using namespace clang;

MAKE_HASHABLE(SymbolIdx, t.usr, t.kind);

namespace {
MethodType kMethodType = "textDocument/documentSymbol";

struct In_TextDocumentDocumentSymbol : public RequestMessage {
  MethodType GetMethodType() const override { return kMethodType; }
  struct Params {
    lsTextDocumentIdentifier textDocument;
    // false: outline; true: all symbols
    bool all = false;
    // If >= 0, return Range[] instead of SymbolInformation[] to reduce output.
    int startLine = -1;
    int endLine = -1;
  } params;
};
MAKE_REFLECT_STRUCT(In_TextDocumentDocumentSymbol::Params, textDocument, all,
                    startLine, endLine);
MAKE_REFLECT_STRUCT(In_TextDocumentDocumentSymbol, id, params);
REGISTER_IN_MESSAGE(In_TextDocumentDocumentSymbol);

struct lsDocumentSymbol {
  std::string name;
  std::string detail;
  lsSymbolKind kind;
  lsRange range;
  lsRange selectionRange;
  std::vector<std::unique_ptr<lsDocumentSymbol>> children;
};
void Reflect(Writer &vis, std::unique_ptr<lsDocumentSymbol> &v);
MAKE_REFLECT_STRUCT(lsDocumentSymbol, name, detail, kind, range, selectionRange,
                    children);
void Reflect(Writer &vis, std::unique_ptr<lsDocumentSymbol> &v) {
  Reflect(vis, *v);
}

template <typename Def>
bool Ignore(const Def *def) {
  return false;
}
template <>
bool Ignore(const QueryType::Def *def) {
  return !def || def->kind == lsSymbolKind::TypeParameter;
}
template<>
bool Ignore(const QueryVar::Def *def) {
  return !def || def->is_local();
}

struct Handler_TextDocumentDocumentSymbol
    : BaseMessageHandler<In_TextDocumentDocumentSymbol> {
  MethodType GetMethodType() const override { return kMethodType; }
  void Run(In_TextDocumentDocumentSymbol *request) override {
    auto &params = request->params;

    QueryFile *file;
    int file_id;
    if (!FindFileOrFail(db, project, request->id,
                        params.textDocument.uri.GetPath(), &file, &file_id))
      return;
    WorkingFile *wfile = working_files->GetFileByFilename(file->def->path);
    if (!wfile)
      return;

    if (params.startLine >= 0) {
      std::vector<lsRange> result;
      for (auto [sym, refcnt] : file->symbol2refcnt)
        if (refcnt > 0 && (params.all || sym.extent.Valid()) &&
            params.startLine <= sym.range.start.line &&
            sym.range.start.line <= params.endLine)
          if (auto loc = GetLsLocation(db, working_files, sym, file_id))
            result.push_back(loc->range);
      std::sort(result.begin(), result.end());
      pipeline::Reply(request->id, result);
    } else if (g_config->client.hierarchicalDocumentSymbolSupport) {
      std::unordered_map<SymbolIdx, std::unique_ptr<lsDocumentSymbol>> sym2ds;
      std::vector<std::pair<std::vector<const void *>, lsDocumentSymbol *>>
          funcs, types;
      for (auto [sym, refcnt] : file->symbol2refcnt) {
        if (refcnt <= 0 || !sym.extent.Valid())
          continue;
        auto r = sym2ds.try_emplace(SymbolIdx{sym.usr, sym.kind});
        if (!r.second)
          continue;
        auto &ds = r.first->second;
        ds = std::make_unique<lsDocumentSymbol>();
        std::vector<const void *> def_ptrs;
        WithEntity(db, sym, [&, sym = sym](const auto &entity) {
          auto *def = entity.AnyDef();
          if (!def)
            return;
          ds->name = def->Name(false);
          ds->detail = def->Name(true);
          if (auto ls_range = GetLsRange(wfile, sym.range)) {
            ds->selectionRange = *ls_range;
            ds->range = ds->selectionRange;
            if (sym.extent.Valid())
              if (auto ls_range1 = GetLsRange(wfile, sym.extent))
                ds->range = *ls_range1;
          }

          for (auto &def : entity.def)
            if (def.file_id == file_id && !Ignore(&def)) {
              ds->kind = def.kind;
              if (def.spell || def.kind == lsSymbolKind::Namespace)
                def_ptrs.push_back(&def);
            }
        });
        if (def_ptrs.empty() || !(params.all || sym.role & Role::Definition ||
                                  ds->kind == lsSymbolKind::Namespace)) {
          ds.reset();
          continue;
        }
        if (sym.kind == SymbolKind::Func)
          funcs.emplace_back(std::move(def_ptrs), ds.get());
        else if (sym.kind == SymbolKind::Type)
          types.emplace_back(std::move(def_ptrs), ds.get());
      }

      for (auto &[def_ptrs, ds] : funcs)
        for (const void *def_ptr : def_ptrs)
          for (Usr usr1 : ((const QueryFunc::Def *)def_ptr)->vars) {
            auto it = sym2ds.find(SymbolIdx{usr1, SymbolKind::Var});
            if (it != sym2ds.end() && it->second)
              ds->children.push_back(std::move(it->second));
          }
      for (auto &[def_ptrs, ds] : types)
        for (const void *def_ptr : def_ptrs) {
          auto *def = (const QueryType::Def *)def_ptr;
          for (Usr usr1 : def->funcs) {
            auto it = sym2ds.find(SymbolIdx{usr1, SymbolKind::Func});
            if (it != sym2ds.end() && it->second)
              ds->children.push_back(std::move(it->second));
          }
          for (Usr usr1 : def->types) {
            auto it = sym2ds.find(SymbolIdx{usr1, SymbolKind::Type});
            if (it != sym2ds.end() && it->second)
              ds->children.push_back(std::move(it->second));
          }
          for (auto [usr1, _] : def->vars) {
            auto it = sym2ds.find(SymbolIdx{usr1, SymbolKind::Var});
            if (it != sym2ds.end() && it->second)
              ds->children.push_back(std::move(it->second));
          }
        }
      std::vector<std::unique_ptr<lsDocumentSymbol>> result;
      for (auto &[_, ds] : sym2ds)
        if (ds)
          result.push_back(std::move(ds));
      pipeline::Reply(request->id, result);
    } else {
      std::vector<lsSymbolInformation> result;
      for (auto [sym, refcnt] : file->symbol2refcnt) {
        if (refcnt <= 0 || !sym.extent.Valid() ||
            !(params.all || sym.role & Role::Definition))
          continue;
        if (std::optional<lsSymbolInformation> info =
                GetSymbolInfo(db, sym, false)) {
          if ((sym.kind == SymbolKind::Type &&
               Ignore(db->GetType(sym).AnyDef())) ||
              (sym.kind == SymbolKind::Var &&
               Ignore(db->GetVar(sym).AnyDef())))
            continue;
          if (auto loc = GetLsLocation(db, working_files, sym, file_id)) {
            info->location = *loc;
            result.push_back(*info);
          }
        }
      }
      pipeline::Reply(request->id, result);
    }
  }
};
REGISTER_MESSAGE_HANDLER(Handler_TextDocumentDocumentSymbol);
} // namespace