// Copyright 2019 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.

#include 'src/builtins/builtins-promise-gen.h'

namespace promise {

transitioning
macro RejectPromiseReactionJob(
    context: Context,
    promiseOrCapability: JSPromise|PromiseCapability|Undefined, reason: JSAny,
    reactionType: constexpr PromiseReactionType): JSAny {
  if constexpr (reactionType == kPromiseReactionReject) {
    typeswitch (promiseOrCapability) {
      case (promise: JSPromise): {
        // For fast native promises we can skip the indirection via the
        // promiseCapability.[[Reject]] function and run the resolve logic
        // directly from here.
        return RejectPromise(promise, reason, False);
      }
      case (Undefined): {
        return Undefined;
      }
      case (capability: PromiseCapability): {
        // In the general case we need to call the (user provided)
        // promiseCapability.[[Reject]] function.
        const reject = UnsafeCast<Callable>(capability.reject);
        return Call(context, reject, Undefined, reason);
      }
    }
  } else {
    static_assert(reactionType == kPromiseReactionFulfill);
    // We have to call out to the dedicated PromiseRejectReactionJob
    // builtin here, instead of just doing the work inline, as otherwise
    // the catch predictions in the debugger will be wrong, which just
    // walks the stack and checks for certain builtins.
    return PromiseRejectReactionJob(reason, Undefined, promiseOrCapability);
  }
}

transitioning
macro FuflfillPromiseReactionJob(
    context: Context,
    promiseOrCapability: JSPromise|PromiseCapability|Undefined, result: JSAny,
    reactionType: constexpr PromiseReactionType): JSAny {
  typeswitch (promiseOrCapability) {
    case (promise: JSPromise): {
      // For fast native promises we can skip the indirection via the
      // promiseCapability.[[Resolve]] function and run the resolve logic
      // directly from here.
      return ResolvePromise(context, promise, result);
    }
    case (Undefined): {
      return Undefined;
    }
    case (capability: PromiseCapability): {
      // In the general case we need to call the (user provided)
      // promiseCapability.[[Resolve]] function.
      const resolve = UnsafeCast<Callable>(capability.resolve);
      try {
        return Call(context, resolve, Undefined, result);
      } catch (e) {
        return RejectPromiseReactionJob(
            context, promiseOrCapability, e, reactionType);
      }
    }
  }
}

// https://tc39.es/ecma262/#sec-promisereactionjob
transitioning
macro PromiseReactionJob(
    context: Context, argument: JSAny, handler: Callable|Undefined,
    promiseOrCapability: JSPromise|PromiseCapability|Undefined,
    reactionType: constexpr PromiseReactionType): JSAny {
  if (handler == Undefined) {
    if constexpr (reactionType == kPromiseReactionFulfill) {
      return FuflfillPromiseReactionJob(
          context, promiseOrCapability, argument, reactionType);
    } else {
      static_assert(reactionType == kPromiseReactionReject);
      return RejectPromiseReactionJob(
          context, promiseOrCapability, argument, reactionType);
    }
  } else {
    try {
      const result =
          Call(context, UnsafeCast<Callable>(handler), Undefined, argument);
      if (promiseOrCapability == Undefined) {
        // There's no [[Capability]] for this promise reaction job, which
        // means that this is a specification-internal operation (aka
        // await) where the result does not matter (see the specification
        // change in https://github.com/tc39/ecma262/pull/1146 for
        // details).
        return Undefined;
      } else {
        return FuflfillPromiseReactionJob(
            context, promiseOrCapability, result, reactionType);
      }
    } catch (e) {
      return RejectPromiseReactionJob(
          context, promiseOrCapability, e, reactionType);
    }
  }
}

transitioning builtin
PromiseFulfillReactionJob(implicit context: Context)(
    value: JSAny, handler: Callable|Undefined,
    promiseOrCapability: JSPromise|PromiseCapability|Undefined): JSAny {
  return PromiseReactionJob(
      context, value, handler, promiseOrCapability, kPromiseReactionFulfill);
}

transitioning builtin
PromiseRejectReactionJob(implicit context: Context)(
    reason: JSAny, handler: Callable|Undefined,
    promiseOrCapability: JSPromise|PromiseCapability|Undefined): JSAny {
  return PromiseReactionJob(
      context, reason, handler, promiseOrCapability, kPromiseReactionReject);
}
}