//===-- ClangdLSPServerTests.cpp ------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "Annotations.h"
#include "ClangdLSPServer.h"
#include "LSPClient.h"
#include "Protocol.h"
#include "TestFS.h"
#include "support/Logger.h"
#include "support/TestTracer.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/JSON.h"
#include "llvm/Testing/Support/Error.h"
#include "llvm/Testing/Support/SupportHelpers.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"

namespace clang {
namespace clangd {
namespace {
using llvm::Succeeded;
using testing::ElementsAre;

MATCHER_P(DiagMessage, M, "") {
  if (const auto *O = arg.getAsObject()) {
    if (const auto Msg = O->getString("message"))
      return *Msg == M;
  }
  return false;
}

class LSPTest : public ::testing::Test {
protected:
  LSPTest() : LogSession(L) {
    ClangdServer::Options &Base = Opts;
    Base = ClangdServer::optsForTest();
    // This is needed to we can test index-based operations like call hierarchy.
    Base.BuildDynamicSymbolIndex = true;
    Base.FeatureModules = &FeatureModules;
  }

  LSPClient &start() {
    EXPECT_FALSE(Server.hasValue()) << "Already initialized";
    Server.emplace(Client.transport(), FS, Opts);
    ServerThread.emplace([&] { EXPECT_TRUE(Server->run()); });
    Client.call("initialize", llvm::json::Object{});
    return Client;
  }

  void stop() {
    assert(Server);
    Client.call("shutdown", nullptr);
    Client.notify("exit", nullptr);
    Client.stop();
    ServerThread->join();
    Server.reset();
    ServerThread.reset();
  }

  ~LSPTest() {
    if (Server)
      stop();
  }

  MockFS FS;
  ClangdLSPServer::Options Opts;
  FeatureModuleSet FeatureModules;

private:
  class Logger : public clang::clangd::Logger {
    // Color logs so we can distinguish them from test output.
    void log(Level L, const char *Fmt,
             const llvm::formatv_object_base &Message) override {
      raw_ostream::Colors Color;
      switch (L) {
      case Level::Verbose:
        Color = raw_ostream::BLUE;
        break;
      case Level::Error:
        Color = raw_ostream::RED;
        break;
      default:
        Color = raw_ostream::YELLOW;
        break;
      }
      std::lock_guard<std::mutex> Lock(LogMu);
      (llvm::outs().changeColor(Color) << Message << "\n").resetColor();
    }
    std::mutex LogMu;
  };

  Logger L;
  LoggingSession LogSession;
  llvm::Optional<ClangdLSPServer> Server;
  llvm::Optional<std::thread> ServerThread;
  LSPClient Client;
};

TEST_F(LSPTest, GoToDefinition) {
  Annotations Code(R"cpp(
    int [[fib]](int n) {
      return n >= 2 ? ^fib(n - 1) + fib(n - 2) : 1;
    }
  )cpp");
  auto &Client = start();
  Client.didOpen("foo.cpp", Code.code());
  auto &Def = Client.call("textDocument/definition",
                          llvm::json::Object{
                              {"textDocument", Client.documentID("foo.cpp")},
                              {"position", Code.point()},
                          });
  llvm::json::Value Want = llvm::json::Array{llvm::json::Object{
      {"uri", Client.uri("foo.cpp")}, {"range", Code.range()}}};
  EXPECT_EQ(Def.takeValue(), Want);
}

TEST_F(LSPTest, Diagnostics) {
  auto &Client = start();
  Client.didOpen("foo.cpp", "void main(int, char**);");
  EXPECT_THAT(Client.diagnostics("foo.cpp"),
              llvm::ValueIs(testing::ElementsAre(
                  DiagMessage("'main' must return 'int' (fix available)"))));

  Client.didChange("foo.cpp", "int x = \"42\";");
  EXPECT_THAT(Client.diagnostics("foo.cpp"),
              llvm::ValueIs(testing::ElementsAre(
                  DiagMessage("Cannot initialize a variable of type 'int' with "
                              "an lvalue of type 'const char [3]'"))));

  Client.didClose("foo.cpp");
  EXPECT_THAT(Client.diagnostics("foo.cpp"), llvm::ValueIs(testing::IsEmpty()));
}

TEST_F(LSPTest, DiagnosticsHeaderSaved) {
  auto &Client = start();
  Client.didOpen("foo.cpp", R"cpp(
    #include "foo.h"
    int x = VAR;
  )cpp");
  EXPECT_THAT(Client.diagnostics("foo.cpp"),
              llvm::ValueIs(testing::ElementsAre(
                  DiagMessage("'foo.h' file not found"),
                  DiagMessage("Use of undeclared identifier 'VAR'"))));
  // Now create the header.
  FS.Files["foo.h"] = "#define VAR original";
  Client.notify(
      "textDocument/didSave",
      llvm::json::Object{{"textDocument", Client.documentID("foo.h")}});
  EXPECT_THAT(Client.diagnostics("foo.cpp"),
              llvm::ValueIs(testing::ElementsAre(
                  DiagMessage("Use of undeclared identifier 'original'"))));
  // Now modify the header from within the "editor".
  FS.Files["foo.h"] = "#define VAR changed";
  Client.notify(
      "textDocument/didSave",
      llvm::json::Object{{"textDocument", Client.documentID("foo.h")}});
  // Foo.cpp should be rebuilt with new diagnostics.
  EXPECT_THAT(Client.diagnostics("foo.cpp"),
              llvm::ValueIs(testing::ElementsAre(
                  DiagMessage("Use of undeclared identifier 'changed'"))));
}

TEST_F(LSPTest, RecordsLatencies) {
  trace::TestTracer Tracer;
  auto &Client = start();
  llvm::StringLiteral MethodName = "method_name";
  EXPECT_THAT(Tracer.takeMetric("lsp_latency", MethodName), testing::SizeIs(0));
  llvm::consumeError(Client.call(MethodName, {}).take().takeError());
  stop();
  EXPECT_THAT(Tracer.takeMetric("lsp_latency", MethodName), testing::SizeIs(1));
}

TEST_F(LSPTest, IncomingCalls) {
  Annotations Code(R"cpp(
    void calle^e(int);
    void caller1() {
      [[callee]](42);
    }
  )cpp");
  auto &Client = start();
  Client.didOpen("foo.cpp", Code.code());
  auto Items = Client
                   .call("textDocument/prepareCallHierarchy",
                         llvm::json::Object{
                             {"textDocument", Client.documentID("foo.cpp")},
                             {"position", Code.point()}})
                   .takeValue();
  auto FirstItem = (*Items.getAsArray())[0];
  auto Calls = Client
                   .call("callHierarchy/incomingCalls",
                         llvm::json::Object{{"item", FirstItem}})
                   .takeValue();
  auto FirstCall = *(*Calls.getAsArray())[0].getAsObject();
  EXPECT_EQ(FirstCall["fromRanges"], llvm::json::Value{Code.range()});
  auto From = *FirstCall["from"].getAsObject();
  EXPECT_EQ(From["name"], "caller1");
}

TEST_F(LSPTest, CDBConfigIntegration) {
  auto CfgProvider =
      config::Provider::fromAncestorRelativeYAMLFiles(".clangd", FS);
  Opts.ConfigProvider = CfgProvider.get();

  // Map bar.cpp to a different compilation database which defines FOO->BAR.
  FS.Files[".clangd"] = R"yaml(
If:
  PathMatch: bar.cpp
CompileFlags:
  CompilationDatabase: bar
)yaml";
  FS.Files["bar/compile_flags.txt"] = "-DFOO=BAR";

  auto &Client = start();
  // foo.cpp gets parsed as normal.
  Client.didOpen("foo.cpp", "int x = FOO;");
  EXPECT_THAT(Client.diagnostics("foo.cpp"),
              llvm::ValueIs(testing::ElementsAre(
                  DiagMessage("Use of undeclared identifier 'FOO'"))));
  // bar.cpp shows the configured compile command.
  Client.didOpen("bar.cpp", "int x = FOO;");
  EXPECT_THAT(Client.diagnostics("bar.cpp"),
              llvm::ValueIs(testing::ElementsAre(
                  DiagMessage("Use of undeclared identifier 'BAR'"))));
}

TEST_F(LSPTest, ModulesTest) {
  class MathModule final : public FeatureModule {
    OutgoingNotification<int> Changed;
    void initializeLSP(LSPBinder &Bind, const llvm::json::Object &ClientCaps,
                       llvm::json::Object &ServerCaps) override {
      Bind.notification("add", this, &MathModule::add);
      Bind.method("get", this, &MathModule::get);
      Changed = Bind.outgoingNotification("changed");
    }

    int Value = 0;

    void add(const int &X) {
      Value += X;
      Changed(Value);
    }
    void get(const std::nullptr_t &, Callback<int> Reply) {
      scheduler().runQuick(
          "get", "",
          [Reply(std::move(Reply)), Value(Value)]() mutable { Reply(Value); });
    }
  };
  FeatureModules.add(std::make_unique<MathModule>());

  auto &Client = start();
  Client.notify("add", 2);
  Client.notify("add", 8);
  EXPECT_EQ(10, Client.call("get", nullptr).takeValue());
  EXPECT_THAT(Client.takeNotifications("changed"),
              ElementsAre(llvm::json::Value(2), llvm::json::Value(10)));
}

// Creates a Callback that writes its received value into an Optional<Expected>.
template <typename T>
llvm::unique_function<void(llvm::Expected<T>)>
capture(llvm::Optional<llvm::Expected<T>> &Out) {
  Out.reset();
  return [&Out](llvm::Expected<T> V) { Out.emplace(std::move(V)); };
}

TEST_F(LSPTest, FeatureModulesThreadingTest) {
  // A feature module that does its work on a background thread, and so
  // exercises the block/shutdown protocol.
  class AsyncCounter final : public FeatureModule {
    bool ShouldStop = false;
    int State = 0;
    std::deque<Callback<int>> Queue; // null = increment, non-null = read.
    std::condition_variable CV;
    std::mutex Mu;
    std::thread Thread;

    void run() {
      std::unique_lock<std::mutex> Lock(Mu);
      while (true) {
        CV.wait(Lock, [&] { return ShouldStop || !Queue.empty(); });
        if (ShouldStop) {
          Queue.clear();
          CV.notify_all();
          return;
        }
        Callback<int> &Task = Queue.front();
        if (Task)
          Task(State);
        else
          ++State;
        Queue.pop_front();
        CV.notify_all();
      }
    }

    bool blockUntilIdle(Deadline D) override {
      std::unique_lock<std::mutex> Lock(Mu);
      return clangd::wait(Lock, CV, D, [this] { return Queue.empty(); });
    }

    void stop() override {
      {
        std::lock_guard<std::mutex> Lock(Mu);
        ShouldStop = true;
      }
      CV.notify_all();
    }

  public:
    AsyncCounter() : Thread([this] { run(); }) {}
    ~AsyncCounter() {
      // Verify shutdown sequence was performed.
      // Real modules would not do this, to be robust to no ClangdServer.
      {
        // We still need the lock here, as Queue might be empty when
        // ClangdServer calls blockUntilIdle, but run() might not have returned
        // yet.
        std::lock_guard<std::mutex> Lock(Mu);
        EXPECT_TRUE(ShouldStop) << "ClangdServer should request shutdown";
        EXPECT_EQ(Queue.size(), 0u) << "ClangdServer should block until idle";
      }
      Thread.join();
    }

    void initializeLSP(LSPBinder &Bind, const llvm::json::Object &ClientCaps,
                       llvm::json::Object &ServerCaps) override {
      Bind.notification("increment", this, &AsyncCounter::increment);
    }

    // Get the current value, bypassing the queue.
    // Used to verify that sync->blockUntilIdle avoids races in tests.
    int getSync() {
      std::lock_guard<std::mutex> Lock(Mu);
      return State;
    }

    // Increment the current value asynchronously.
    void increment(const std::nullptr_t &) {
      {
        std::lock_guard<std::mutex> Lock(Mu);
        Queue.push_back(nullptr);
      }
      CV.notify_all();
    }
  };

  FeatureModules.add(std::make_unique<AsyncCounter>());
  auto &Client = start();

  Client.notify("increment", nullptr);
  Client.notify("increment", nullptr);
  Client.notify("increment", nullptr);
  EXPECT_THAT_EXPECTED(Client.call("sync", nullptr).take(), Succeeded());
  EXPECT_EQ(3, FeatureModules.get<AsyncCounter>()->getSync());
  // Throw some work on the queue to make sure shutdown blocks on it.
  Client.notify("increment", nullptr);
  Client.notify("increment", nullptr);
  Client.notify("increment", nullptr);
  // And immediately shut down. FeatureModule destructor verifies we blocked.
}

} // namespace
} // namespace clangd
} // namespace clang