#include "fuzzy_match.h"
#include "message_handler.h"
#include "pipeline.hh"
#include "query_utils.h"
using namespace ccls;

#include <ctype.h>
#include <limits.h>
#include <algorithm>
#include <functional>

namespace {
MethodType kMethodType = "workspace/symbol";

// Lookup |symbol| in |db| and insert the value into |result|.
bool AddSymbol(
    DB* db,
    WorkingFiles* working_files,
    SymbolIdx sym,
    bool use_detailed,
    std::vector<std::tuple<lsSymbolInformation, int, SymbolIdx>>* result) {
  std::optional<lsSymbolInformation> info =
      GetSymbolInfo(db, working_files, sym, true);
  if (!info)
    return false;

  Use loc;
  if (Maybe<Use> location = GetDefinitionExtent(db, sym))
    loc = *location;
  else {
    auto decls = GetNonDefDeclarations(db, sym);
    if (decls.empty())
      return false;
    loc = decls[0];
  }

  std::optional<lsLocation> ls_location = GetLsLocation(db, working_files, loc);
  if (!ls_location)
    return false;
  info->location = *ls_location;
  result->emplace_back(*info, int(use_detailed), sym);
  return true;
}

struct In_WorkspaceSymbol : public RequestInMessage {
  MethodType GetMethodType() const override { return kMethodType; }
  struct Params {
    std::string query;
  };
  Params params;
};
MAKE_REFLECT_STRUCT(In_WorkspaceSymbol::Params, query);
MAKE_REFLECT_STRUCT(In_WorkspaceSymbol, id, params);
REGISTER_IN_MESSAGE(In_WorkspaceSymbol);

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

///// Fuzzy matching

struct Handler_WorkspaceSymbol : BaseMessageHandler<In_WorkspaceSymbol> {
  MethodType GetMethodType() const override { return kMethodType; }
  void Run(In_WorkspaceSymbol* request) override {
    Out_WorkspaceSymbol out;
    out.id = request->id;

    std::string query = request->params.query;

    // {symbol info, matching detailed_name or short_name, index}
    std::vector<std::tuple<lsSymbolInformation, int, SymbolIdx>> cands;
    bool sensitive = g_config->workspaceSymbol.caseSensitivity;

    // Find subsequence matches.
    std::string query_without_space;
    query_without_space.reserve(query.size());
    for (char c : query)
      if (!isspace(c))
        query_without_space += c;

    auto Add = [&](SymbolIdx sym) {
      std::string_view detailed_name = db->GetSymbolName(sym, true);
      int pos =
        ReverseSubseqMatch(query_without_space, detailed_name, sensitive);
      return pos >= 0 &&
             AddSymbol(db, working_files, sym,
                       detailed_name.find(':', pos) != std::string::npos,
                       &cands) &&
             cands.size() >= g_config->workspaceSymbol.maxNum;
    };
    for (auto& func : db->funcs)
      if (Add({func.usr, SymbolKind::Func}))
        goto done_add;
    for (auto& type : db->types)
      if (Add({type.usr, SymbolKind::Type}))
        goto done_add;
    for (auto& var : db->vars)
      if (var.def.size() && !var.def[0].is_local() &&
          Add({var.usr, SymbolKind::Var}))
        goto done_add;
 done_add:

    if (g_config->workspaceSymbol.sort && query.size() <= FuzzyMatcher::kMaxPat) {
      // Sort results with a fuzzy matching algorithm.
      int longest = 0;
      for (auto& cand : cands)
        longest = std::max(
            longest, int(db->GetSymbolName(std::get<2>(cand), true).size()));
      FuzzyMatcher fuzzy(query, g_config->workspaceSymbol.caseSensitivity);
      for (auto& cand : cands)
        std::get<1>(cand) = fuzzy.Match(
            db->GetSymbolName(std::get<2>(cand), std::get<1>(cand)));
      std::sort(cands.begin(), cands.end(), [](const auto& l, const auto& r) {
        return std::get<1>(l) > std::get<1>(r);
      });
      out.result.reserve(cands.size());
      for (auto& cand: cands) {
        // Discard awful candidates.
        if (std::get<1>(cand) <= FuzzyMatcher::kMinScore)
          break;
        out.result.push_back(std::get<0>(cand));
      }
    } else {
      out.result.reserve(cands.size());
      for (auto& cand : cands)
        out.result.push_back(std::get<0>(cand));
    }

    pipeline::WriteStdout(kMethodType, out);
  }
};
REGISTER_MESSAGE_HANDLER(Handler_WorkspaceSymbol);
}  // namespace