/*
 * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
 * Copyright (c) 2022, stelar7 <dudedbz@gmail.com>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <AK/Random.h>
#include <LibJS/Runtime/TypedArray.h>
#include <LibWeb/Bindings/Crypto.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/Crypto/Crypto.h>
#include <LibWeb/Crypto/SubtleCrypto.h>
#include <LibWeb/WebIDL/Buffers.h>
#include <LibWeb/WebIDL/QuotaExceededError.h>

namespace Web::Crypto {

GC_DEFINE_ALLOCATOR(Crypto);

GC::Ref<Crypto> Crypto::create(JS::Realm& realm)
{
    return realm.create<Crypto>(realm);
}

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

Crypto::~Crypto() = default;

void Crypto::initialize(JS::Realm& realm)
{
    WEB_SET_PROTOTYPE_FOR_INTERFACE(Crypto);
    Base::initialize(realm);
    m_subtle = SubtleCrypto::create(realm);
}

void Crypto::visit_edges(Cell::Visitor& visitor)
{
    Base::visit_edges(visitor);
    visitor.visit(m_subtle);
}

GC::Ref<SubtleCrypto> Crypto::subtle() const
{
    return *m_subtle;
}

// https://w3c.github.io/webcrypto/#dfn-Crypto-method-getRandomValues
WebIDL::ExceptionOr<WebIDL::ArrayBufferViewVariant> Crypto::get_random_values(WebIDL::ArrayBufferViewVariant array) const
{
    WebIDL::ArrayBufferView array_view { array };

    // 1. If array is not an Int8Array, Uint8Array, Uint8ClampedArray, Int16Array, Uint16Array, Int32Array, Uint32Array, BigInt64Array, or BigUint64Array, then throw a TypeMismatchError and terminate the algorithm.
    auto typed_array = array_view.typed_array_base();
    if (!typed_array)
        return WebIDL::TypeMismatchError::create(realm(), "array must be one of Int8Array, Uint8Array, Uint8ClampedArray, Int16Array, Uint16Array, Int32Array, Uint32Array, BigInt64Array, or BigUint64Array"_utf16);

    if (!typed_array->element_name().is_one_of("Int8Array"sv, "Uint8Array"sv, "Uint8ClampedArray"sv, "Int16Array"sv, "Uint16Array"sv, "Int32Array"sv, "Uint32Array"sv, "BigInt64Array"sv, "BigUint64Array"sv))
        return WebIDL::TypeMismatchError::create(realm(), "array must be one of Int8Array, Uint8Array, Uint8ClampedArray, Int16Array, Uint16Array, Int32Array, Uint32Array, BigInt64Array, or BigUint64Array"_utf16);

    auto typed_array_record = JS::make_typed_array_with_buffer_witness_record(*typed_array, JS::ArrayBuffer::Order::SeqCst);

    // IMPLEMENTATION DEFINED: If the viewed array buffer is out-of-bounds, throw a InvalidStateError and terminate the algorithm.
    if (JS::is_typed_array_out_of_bounds(typed_array_record))
        return WebIDL::InvalidStateError::create(realm(), Utf16String::formatted(JS::ErrorType::BufferOutOfBounds.format(), "TypedArray"sv));

    // 2. If the byteLength of array is greater than 65536, throw a QuotaExceededError and terminate the algorithm.
    if (JS::typed_array_byte_length(typed_array_record) > 65536)
        return WebIDL::QuotaExceededError::create(realm(), "array's byteLength may not be greater than 65536"_utf16);

    // 3. Overwrite all elements of array with cryptographically strong random values of the appropriate type.
    fill_with_random(array_view.viewed_array_buffer()->bytes().slice(array_view.byte_offset(), array_view.byte_length()));

    // 4. Return array.
    return array;
}

// https://w3c.github.io/webcrypto/#dfn-Crypto-method-randomUUID
String Crypto::random_uuid() const
{
    return generate_random_uuid();
}

// https://w3c.github.io/webcrypto/#dfn-generate-a-random-uuid
String generate_random_uuid()
{
    return AK::generate_random_uuid();
}

}
