// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_TEST_INSPECTOR_PROTOCOL_TASK_RUNNER_H_
#define V8_TEST_INSPECTOR_PROTOCOL_TASK_RUNNER_H_

#include <map>

#include "include/v8-inspector.h"
#include "include/v8-platform.h"
#include "include/v8.h"
#include "src/base/atomic-utils.h"
#include "src/base/macros.h"
#include "src/base/platform/platform.h"
#include "src/locked-queue-inl.h"
#include "src/vector.h"

struct VectorCompare {
  bool operator()(const v8::internal::Vector<uint16_t>& lhs,
                  const v8::internal::Vector<uint16_t>& rhs) const {
    for (int i = 0; i < lhs.length() && i < rhs.length(); ++i) {
      if (lhs[i] != rhs[i]) return lhs[i] < rhs[i];
    }
    return false;
  }
};

class TaskRunner : public v8::base::Thread {
 public:
  class Task {
   public:
    virtual ~Task() {}
    virtual bool is_inspector_task() = 0;
    virtual void Run(v8::Isolate* isolate,
                     const v8::Global<v8::Context>& context) = 0;
  };

  class SetupGlobalTask {
   public:
    virtual ~SetupGlobalTask() = default;
    virtual void Run(v8::Isolate* isolate,
                     v8::Local<v8::ObjectTemplate> global) = 0;
  };
  using SetupGlobalTasks = std::vector<std::unique_ptr<SetupGlobalTask>>;

  TaskRunner(SetupGlobalTasks setup_global_tasks, bool catch_exceptions,
             v8::base::Semaphore* ready_semaphore);
  virtual ~TaskRunner();

  // Thread implementation.
  void Run() override;

  // Should be called from the same thread and only from task.
  void RunMessageLoop(bool only_protocol);
  void QuitMessageLoop();

  // TaskRunner takes ownership.
  void Append(Task* task);

  static TaskRunner* FromContext(v8::Local<v8::Context>);

  v8::Local<v8::Context> NewContextGroup(
      const SetupGlobalTasks& setup_global_tasks);
  v8::Local<v8::Context> GetContext(int context_group_id);
  static int GetContextGroupId(v8::Local<v8::Context> context);

  void Terminate();

  void RegisterModule(v8::internal::Vector<uint16_t> name,
                      v8::Local<v8::Module> module);
  static v8::MaybeLocal<v8::Module> ModuleResolveCallback(
      v8::Local<v8::Context> context, v8::Local<v8::String> specifier,
      v8::Local<v8::Module> referrer);

 private:
  void InitializeIsolate();
  Task* GetNext(bool only_protocol);

  SetupGlobalTasks setup_global_tasks_;
  bool catch_exceptions_;
  v8::base::Semaphore* ready_semaphore_;

  v8::Isolate* isolate_;
  intptr_t last_context_group_id_ = 0;
  std::map<intptr_t, v8::Global<v8::Context>> contexts_;

  // deferred_queue_ combined with queue_ (in this order) have all tasks in the
  // correct order. Sometimes we skip non-protocol tasks by moving them from
  // queue_ to deferred_queue_.
  v8::internal::LockedQueue<Task*> queue_;
  v8::internal::LockedQueue<Task*> deffered_queue_;
  v8::base::Semaphore process_queue_semaphore_;

  std::map<v8::internal::Vector<uint16_t>, v8::Global<v8::Module>,
           VectorCompare>
      modules_;

  int nested_loop_count_;

  v8::base::AtomicNumber<int> is_terminated_;

  DISALLOW_COPY_AND_ASSIGN(TaskRunner);
};

class AsyncTask : public TaskRunner::Task {
 public:
  AsyncTask(const char* task_name, v8_inspector::V8Inspector* inspector);
  virtual ~AsyncTask() = default;

  void Run(v8::Isolate* isolate,
           const v8::Global<v8::Context>& context) override;
  virtual void AsyncRun(v8::Isolate* isolate,
                        const v8::Global<v8::Context>& context) = 0;

 protected:
  v8_inspector::V8Inspector* inspector_;
};

class ExecuteStringTask : public AsyncTask {
 public:
  ExecuteStringTask(const v8::internal::Vector<uint16_t>& expression,
                    v8::Local<v8::String> name,
                    v8::Local<v8::Integer> line_offset,
                    v8::Local<v8::Integer> column_offset,
                    v8::Local<v8::Boolean> is_module, const char* task_name,
                    v8_inspector::V8Inspector* inspector);
  explicit ExecuteStringTask(
      const v8::internal::Vector<const char>& expression);
  bool is_inspector_task() override { return false; }

  void AsyncRun(v8::Isolate* isolate,
                const v8::Global<v8::Context>& context) override;

 private:
  v8::internal::Vector<uint16_t> expression_;
  v8::internal::Vector<const char> expression_utf8_;
  v8::internal::Vector<uint16_t> name_;
  int32_t line_offset_ = 0;
  int32_t column_offset_ = 0;
  bool is_module_ = false;

  DISALLOW_COPY_AND_ASSIGN(ExecuteStringTask);
};

#endif  //  V8_TEST_INSPECTOR_PROTOCOL_TASK_RUNNER_H_