// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "flutter/testing/test_dart_native_resolver.h"

#include <mutex>
#include <vector>

#include "flutter/fml/synchronization/thread_annotations.h"
#include "tonic/converter/dart_converter.h"

namespace testing {

TestDartNativeResolver::TestDartNativeResolver() = default;

TestDartNativeResolver::~TestDartNativeResolver() = default;

void TestDartNativeResolver::AddNativeCallback(std::string name,
                                               Dart_NativeFunction callback) {
  native_callbacks_[name] = callback;
}

Dart_NativeFunction TestDartNativeResolver::ResolveCallback(
    std::string name) const {
  auto found = native_callbacks_.find(name);
  if (found == native_callbacks_.end()) {
    return nullptr;
  }

  return found->second;
}

static std::mutex gIsolateResolversMutex;
static std::map<Dart_Isolate, std::weak_ptr<TestDartNativeResolver>>
    gIsolateResolvers FML_GUARDED_BY(gIsolateResolversMutex);

Dart_NativeFunction TestDartNativeResolver::DartNativeEntryResolverCallback(
    Dart_Handle dart_name,
    int num_of_arguments,
    bool* auto_setup_scope) {
  auto name = tonic::StdStringFromDart(dart_name);

  std::lock_guard<std::mutex> lock(gIsolateResolversMutex);
  auto found = gIsolateResolvers.find(Dart_CurrentIsolate());
  if (found == gIsolateResolvers.end()) {
    return nullptr;
  }

  if (auto resolver = found->second.lock()) {
    return resolver->ResolveCallback(std::move(name));
  } else {
    gIsolateResolvers.erase(found);
  }

  return nullptr;
}

static const uint8_t* DartNativeEntrySymbolCallback(
    Dart_NativeFunction function) {
  return reinterpret_cast<const uint8_t*>("¯\\_(ツ)_/¯");
}

void TestDartNativeResolver::SetNativeResolverForIsolate() {
  auto result = Dart_SetNativeResolver(Dart_RootLibrary(),
                                       DartNativeEntryResolverCallback,
                                       DartNativeEntrySymbolCallback);

  if (Dart_IsError(result)) {
    return;
  }

  std::lock_guard<std::mutex> lock(gIsolateResolversMutex);
  gIsolateResolvers[Dart_CurrentIsolate()] = shared_from_this();

  std::vector<Dart_Isolate> isolates_with_dead_resolvers;
  for (const auto& entry : gIsolateResolvers) {
    if (!entry.second.lock()) {
      isolates_with_dead_resolvers.push_back(entry.first);
    }
  }

  for (const auto& dead_isolate : isolates_with_dead_resolvers) {
    gIsolateResolvers.erase(dead_isolate);
  }
}

}  // namespace testing