/*
 * Copyright (c) 2021-2022, Linus Groh <linusg@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <AK/DeprecatedFlyString.h>
#include <LibJS/Runtime/TypedArray.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/Encoding/TextEncoder.h>
#include <LibWeb/WebIDL/ExceptionOr.h>

namespace Web::Encoding {

WebIDL::ExceptionOr<JS::NonnullGCPtr<TextEncoder>> TextEncoder::construct_impl(JS::Realm& realm)
{
    return MUST_OR_THROW_OOM(realm.heap().allocate<TextEncoder>(realm, realm));
}

TextEncoder::TextEncoder(JS::Realm& realm)
    : PlatformObject(realm)
{
}

TextEncoder::~TextEncoder() = default;

JS::ThrowCompletionOr<void> TextEncoder::initialize(JS::Realm& realm)
{
    MUST_OR_THROW_OOM(Base::initialize(realm));
    set_prototype(&Bindings::ensure_web_prototype<Bindings::TextEncoderPrototype>(realm, "TextEncoder"));

    return {};
}

// https://encoding.spec.whatwg.org/#dom-textencoder-encode
JS::Uint8Array* TextEncoder::encode(DeprecatedString const& input) const
{
    // NOTE: The AK::DeprecatedString returned from PrimitiveString::string() is always UTF-8, regardless of the internal string type, so most of these steps are no-ops.

    // 1. Convert input to an I/O queue of scalar values.
    // 2. Let output be the I/O queue of bytes « end-of-queue ».
    // 3. While true:
    //     1. Let item be the result of reading from input.
    //     2. Let result be the result of processing an item with item, an instance of the UTF-8 encoder, input, output, and "fatal".
    //     3. Assert: result is not an error.
    //     4. If result is finished, then convert output into a byte sequence and return a Uint8Array object wrapping an ArrayBuffer containing output.

    auto byte_buffer = input.to_byte_buffer();
    auto array_length = byte_buffer.size();
    auto array_buffer = JS::ArrayBuffer::create(realm(), move(byte_buffer));
    return JS::Uint8Array::create(realm(), array_length, *array_buffer);
}

// https://encoding.spec.whatwg.org/#dom-textencoder-encoding
DeprecatedFlyString const& TextEncoder::encoding()
{
    static DeprecatedFlyString encoding = "utf-8"sv;
    return encoding;
}

}