// Copyright 2021 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 INCLUDE_V8_PROMISE_H_

#define INCLUDE_V8_PROMISE_H_

#include "v8-local-handle.h"  // NOLINT(build/include_directory)

#include "v8-object.h"        // NOLINT(build/include_directory)

#include "v8config.h"         // NOLINT(build/include_directory)

namespace v8 {

class Context;

#ifndef V8_PROMISE_INTERNAL_FIELD_COUNT

// Defined using gn arg `v8_promise_internal_field_count`.

#define V8_PROMISE_INTERNAL_FIELD_COUNT 0

#endif

/**

 * An instance of the built-in Promise constructor (ES6 draft).

 */

class V8_EXPORT Promise : public Object {

 public:

  /**

   * State of the promise. Each value corresponds to one of the possible values

   * of the [[PromiseState]] field.

   */

  enum PromiseState { kPending, kFulfilled, kRejected };

  class V8_EXPORT Resolver : public Object {

   public:

    /**

     * Create a new resolver, along with an associated promise in pending state.

     */

    static V8_WARN_UNUSED_RESULT MaybeLocal<Resolver> New(

        Local<Context> context);

    /**

     * Extract the associated promise.

     */

    Local<Promise> GetPromise();

    /**

     * Resolve/reject the associated promise with a given value.

     * Ignored if the promise is no longer pending.

     */

    V8_WARN_UNUSED_RESULT Maybe<bool> Resolve(Local<Context> context,

                                              Local<Value> value);

    V8_WARN_UNUSED_RESULT Maybe<bool> Reject(Local<Context> context,

                                             Local<Value> value);

    V8_INLINE static Resolver* Cast(Value* value) {

#ifdef V8_ENABLE_CHECKS

      CheckCast(value);

#endif

      return static_cast<Promise::Resolver*>(value);

    }

   private:

    Resolver();

    static void CheckCast(Value* obj);

  };

  /**

   * Register a resolution/rejection handler with a promise.

   * The handler is given the respective resolution/rejection value as

   * an argument. If the promise is already resolved/rejected, the handler is

   * invoked at the end of turn.

   */

  V8_WARN_UNUSED_RESULT MaybeLocal<Promise> Catch(Local<Context> context,

                                                  Local<Function> handler);

  V8_WARN_UNUSED_RESULT MaybeLocal<Promise> Then(Local<Context> context,

                                                 Local<Function> handler);

  V8_WARN_UNUSED_RESULT MaybeLocal<Promise> Then(Local<Context> context,

                                                 Local<Function> on_fulfilled,

                                                 Local<Function> on_rejected);

  /**

   * Returns true if the promise has at least one derived promise, and

   * therefore resolve/reject handlers (including default handler).

   */

  bool HasHandler() const;

  /**

   * Returns the content of the [[PromiseResult]] field. The Promise must not

   * be pending.

   */

  Local<Value> Result();

  /**

   * Returns the value of the [[PromiseState]] field.

   */

  PromiseState State();

  /**

   * Marks this promise as handled to avoid reporting unhandled rejections.

   */

  void MarkAsHandled();

  /**

   * Marks this promise as silent to prevent pausing the debugger when the

   * promise is rejected.

   */

  void MarkAsSilent();

  V8_INLINE static Promise* Cast(Value* value) {

#ifdef V8_ENABLE_CHECKS

    CheckCast(value);

#endif

    return static_cast<Promise*>(value);

  }

  static constexpr int kEmbedderFieldCount = V8_PROMISE_INTERNAL_FIELD_COUNT;

 private:

  Promise();

  static void CheckCast(Value* obj);

};

/**

 * PromiseHook with type kInit is called when a new promise is

 * created. When a new promise is created as part of the chain in the

 * case of Promise.then or in the intermediate promises created by

 * Promise.{race, all}/AsyncFunctionAwait, we pass the parent promise

 * otherwise we pass undefined.

 *

 * PromiseHook with type kResolve is called at the beginning of

 * resolve or reject function defined by CreateResolvingFunctions.

 *

 * PromiseHook with type kBefore is called at the beginning of the

 * PromiseReactionJob.

 *

 * PromiseHook with type kAfter is called right at the end of the

 * PromiseReactionJob.

 */

enum class PromiseHookType { kInit, kResolve, kBefore, kAfter };

using PromiseHook = void (*)(PromiseHookType type, Local<Promise> promise,

                             Local<Value> parent);

// --- Promise Reject Callback ---

enum PromiseRejectEvent {

  kPromiseRejectWithNoHandler = 0,

  kPromiseHandlerAddedAfterReject = 1,

  kPromiseRejectAfterResolved = 2,

  kPromiseResolveAfterResolved = 3,

};

class PromiseRejectMessage {

 public:

  PromiseRejectMessage(Local<Promise> promise, PromiseRejectEvent event,

                       Local<Value> value)

      : promise_(promise), event_(event), value_(value) {}

  V8_INLINE Local<Promise> GetPromise() const { return promise_; }

  V8_INLINE PromiseRejectEvent GetEvent() const { return event_; }

  V8_INLINE Local<Value> GetValue() const { return value_; }

 private:

  Local<Promise> promise_;

  PromiseRejectEvent event_;

  Local<Value> value_;

};

using PromiseRejectCallback = void (*)(PromiseRejectMessage message);

}  // namespace v8

#endif  // INCLUDE_V8_PROMISE_H_