// Copyright 2018 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.

namespace array {
transitioning javascript builtin
ArrayFilterLoopEagerDeoptContinuation(
    js-implicit context: NativeContext, receiver: JSAny)(
    callback: JSAny, thisArg: JSAny, array: JSAny, initialK: JSAny,
    length: JSAny, initialTo: JSAny): JSAny {
  // All continuation points in the optimized filter implementation are
  // after the ToObject(O) call that ensures we are dealing with a
  // JSReceiver.
  //
  // Also, this great mass of casts is necessary because the signature
  // of Torque javascript builtins requires JSAny type for all parameters
  // other than {context}.
  const jsreceiver = Cast<JSReceiver>(receiver) otherwise unreachable;
  const callbackfn = Cast<Callable>(callback) otherwise unreachable;
  const outputArray = Cast<JSReceiver>(array) otherwise unreachable;
  const numberK = Cast<Number>(initialK) otherwise unreachable;
  const numberTo = Cast<Number>(initialTo) otherwise unreachable;
  const numberLength = Cast<Number>(length) otherwise unreachable;

  return ArrayFilterLoopContinuation(
      jsreceiver, callbackfn, thisArg, outputArray, jsreceiver, numberK,
      numberLength, numberTo);
}

transitioning javascript builtin
ArrayFilterLoopLazyDeoptContinuation(
    js-implicit context: NativeContext, receiver: JSAny)(
    callback: JSAny, thisArg: JSAny, array: JSAny, initialK: JSAny,
    length: JSAny, valueK: JSAny, initialTo: JSAny, result: JSAny): JSAny {
  // All continuation points in the optimized filter implementation are
  // after the ToObject(O) call that ensures we are dealing with a
  // JSReceiver.
  const jsreceiver = Cast<JSReceiver>(receiver) otherwise unreachable;
  const callbackfn = Cast<Callable>(callback) otherwise unreachable;
  const outputArray = Cast<JSReceiver>(array) otherwise unreachable;
  let numberK = Cast<Number>(initialK) otherwise unreachable;
  let numberTo = Cast<Number>(initialTo) otherwise unreachable;
  const numberLength = Cast<Number>(length) otherwise unreachable;

  // This custom lazy deopt point is right after the callback. filter() needs
  // to pick up at the next step, which is setting the callback
  // result in the output array. After incrementing k and to, we can glide
  // into the loop continuation builtin.
  if (ToBoolean(result)) {
    FastCreateDataProperty(outputArray, numberTo, valueK);
    numberTo = numberTo + 1;
  }

  numberK = numberK + 1;

  return ArrayFilterLoopContinuation(
      jsreceiver, callbackfn, thisArg, outputArray, jsreceiver, numberK,
      numberLength, numberTo);
}

transitioning builtin ArrayFilterLoopContinuation(implicit context: Context)(
    _receiver: JSReceiver, callbackfn: Callable, thisArg: JSAny,
    array: JSReceiver, o: JSReceiver, initialK: Number, length: Number,
    initialTo: Number): JSAny {
  let to: Number = initialTo;
  // 5. Let k be 0.
  // 6. Repeat, while k < len
  for (let k: Number = initialK; k < length; k++) {
    // 6a. Let Pk be ! ToString(k).
    // k is guaranteed to be a positive integer, hence ToString is
    // side-effect free and HasProperty/GetProperty do the conversion inline.

    // 6b. Let kPresent be ? HasProperty(O, Pk).
    const kPresent: Boolean = HasProperty_Inline(o, k);

    // 6c. If kPresent is true, then
    if (kPresent == True) {
      // 6c. i. Let kValue be ? Get(O, Pk).
      const kValue: JSAny = GetProperty(o, k);

      // 6c. ii. Perform ? Call(callbackfn, T, <kValue, k, O>).
      const result: JSAny = Call(context, callbackfn, thisArg, kValue, k, o);

      // iii. If selected is true, then...
      if (ToBoolean(result)) {
        // 1. Perform ? CreateDataPropertyOrThrow(A, ToString(to), kValue).
        FastCreateDataProperty(array, to, kValue);
        // 2. Increase to by 1.
        to = to + 1;
      }
    }

    // 6d. Increase k by 1. (done by the loop).
  }
  return array;
}

transitioning macro FastArrayFilter(implicit context: Context)(
    fastO: FastJSArray, len: Smi, callbackfn: Callable, thisArg: JSAny,
    output: FastJSArray) labels
Bailout(Number, Number) {
  let k: Smi = 0;
  let to: Smi = 0;
  let fastOW = NewFastJSArrayWitness(fastO);
  let fastOutputW = NewFastJSArrayWitness(output);

  fastOutputW.EnsureArrayPushable() otherwise goto Bailout(k, to);

  // Build a fast loop over the array.
  for (; k < len; k++) {
    fastOW.Recheck() otherwise goto Bailout(k, to);

    // Ensure that we haven't walked beyond a possibly updated length.
    if (k >= fastOW.Get().length) goto Bailout(k, to);
    const value: JSAny = fastOW.LoadElementNoHole(k) otherwise continue;
    const result: JSAny =
        Call(context, callbackfn, thisArg, value, k, fastOW.Get());
    if (ToBoolean(result)) {
      try {
        // Since the call to {callbackfn} is observable, we can't
        // use the Bailout label until we've successfully stored.
        // Hence the {SlowStore} label.
        fastOutputW.Recheck() otherwise SlowStore;
        if (fastOutputW.Get().length != to) goto SlowStore;
        fastOutputW.Push(value) otherwise SlowStore;
      } label SlowStore {
        FastCreateDataProperty(fastOutputW.stable, to, value);
      }
      to = to + 1;
    }
  }
}

// This method creates a 0-length array with the ElementsKind of the
// receiver if possible, otherwise, bails out. It makes sense for the
// caller to know that the slow case needs to be invoked.
macro FastFilterSpeciesCreate(implicit context: Context)(receiver: JSReceiver):
    JSReceiver labels Slow {
  const len: Smi = 0;
  if (IsArraySpeciesProtectorCellInvalid()) goto Slow;
  const o = Cast<FastJSArray>(receiver) otherwise Slow;
  const newMap: Map =
      LoadJSArrayElementsMap(o.map.elements_kind, LoadNativeContext(context));
  return AllocateJSArray(ElementsKind::PACKED_SMI_ELEMENTS, newMap, len, len);
}

// https://tc39.github.io/ecma262/#sec-array.prototype.filter
transitioning javascript builtin
ArrayFilter(
    js-implicit context: NativeContext, receiver: JSAny)(...arguments): JSAny {
  try {
    RequireObjectCoercible(receiver, 'Array.prototype.filter');

    // 1. Let O be ? ToObject(this value).
    const o: JSReceiver = ToObject_Inline(context, receiver);

    // 2. Let len be ? ToLength(? Get(O, "length")).
    const len: Number = GetLengthProperty(o);

    // 3. If IsCallable(callbackfn) is false, throw a TypeError exception.
    if (arguments.length == 0) {
      goto TypeError;
    }
    const callbackfn = Cast<Callable>(arguments[0]) otherwise TypeError;

    // 4. If thisArg is present, let T be thisArg; else let T be undefined.
    const thisArg: JSAny = arguments[1];
    let output: JSReceiver;

    // Special cases.
    let k: Number = 0;
    let to: Number = 0;
    try {
      output = FastFilterSpeciesCreate(o) otherwise SlowSpeciesCreate;

      try {
        const smiLen: Smi = Cast<Smi>(len) otherwise goto Bailout(k, to);
        const fastOutput =
            Cast<FastJSArray>(output) otherwise goto Bailout(k, to);
        const fastO = Cast<FastJSArray>(o) otherwise goto Bailout(k, to);

        FastArrayFilter(fastO, smiLen, callbackfn, thisArg, fastOutput)
            otherwise Bailout;
        return output;
      } label Bailout(kValue: Number, toValue: Number) deferred {
        k = kValue;
        to = toValue;
      }
    } label SlowSpeciesCreate {
      output = ArraySpeciesCreate(context, receiver, 0);
    }

    return ArrayFilterLoopContinuation(
        o, callbackfn, thisArg, output, o, k, len, to);
  } label TypeError deferred {
    ThrowTypeError(MessageTemplate::kCalledNonCallable, arguments[0]);
  }
}
}