/*

 * Copyright (c) 2021, Ali Mohammad Pur <mpfard@serenityos.org>

 * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>

 *

 * SPDX-License-Identifier: BSD-2-Clause

 */

#include <LibJS/Runtime/Realm.h>

#include <LibJS/Runtime/VM.h>

#include <LibWasm/Types.h>

#include <LibWeb/Bindings/Intrinsics.h>

#include <LibWeb/Bindings/TablePrototype.h>

#include <LibWeb/WebAssembly/Table.h>

#include <LibWeb/WebAssembly/WebAssembly.h>

namespace Web::WebAssembly {

JS_DEFINE_ALLOCATOR(Table);

static Wasm::ValueType table_kind_to_value_type(Bindings::TableKind kind)

{

    switch (kind) {

    case Bindings::TableKind::Externref:

        return Wasm::ValueType { Wasm::ValueType::ExternReference };

    case Bindings::TableKind::Anyfunc:

        return Wasm::ValueType { Wasm::ValueType::FunctionReference };

    }

    VERIFY_NOT_REACHED();

}

static JS::ThrowCompletionOr<Wasm::Value> value_to_reference(JS::VM& vm, JS::Value value, Wasm::ValueType const& reference_type)

{

    if (value.is_undefined())

        return Wasm::Value();

    return Detail::to_webassembly_value(vm, value, reference_type);

}

WebIDL::ExceptionOr<JS::NonnullGCPtr<Table>> Table::construct_impl(JS::Realm& realm, TableDescriptor& descriptor, JS::Value value)

{

    auto& vm = realm.vm();

    auto reference_type = table_kind_to_value_type(descriptor.element);

    auto reference_value = TRY(value_to_reference(vm, value, reference_type));

    Wasm::Limits limits { descriptor.initial, move(descriptor.maximum) };

    Wasm::TableType table_type { reference_type, move(limits) };

    auto& cache = Detail::get_cache(realm);

    auto address = cache.abstract_machine().store().allocate(table_type);

    if (!address.has_value())

        return vm.throw_completion<JS::TypeError>("Wasm Table allocation failed"sv);

    auto const& reference = reference_value.to<Wasm::Reference>();

    auto& table = *cache.abstract_machine().store().get(*address);

    for (auto& element : table.elements())

        element = reference;

    return vm.heap().allocate<Table>(realm, realm, *address);

}

Table::Table(JS::Realm& realm, Wasm::TableAddress address)

    : Bindings::PlatformObject(realm)

    , m_address(address)

{

}

void Table::initialize(JS::Realm& realm)

{

    Base::initialize(realm);

    WEB_SET_PROTOTYPE_FOR_INTERFACE_WITH_CUSTOM_NAME(Table, WebAssembly.Table);

}

// https://webassembly.github.io/spec/js-api/#dom-table-grow

WebIDL::ExceptionOr<u32> Table::grow(u32 delta, JS::Value value)

{

    auto& vm = this->vm();

    auto& cache = Detail::get_cache(realm());

    auto* table = cache.abstract_machine().store().get(address());

    if (!table)

        return vm.throw_completion<JS::RangeError>("Could not find the memory table to grow"sv);

    auto initial_size = table->elements().size();

    auto reference_value = TRY(value_to_reference(vm, value, table->type().element_type()));

    auto const& reference = reference_value.to<Wasm::Reference>();

    if (!table->grow(delta, reference))

        return vm.throw_completion<JS::RangeError>("Failed to grow table"sv);

    return initial_size;

}

// https://webassembly.github.io/spec/js-api/#dom-table-get

WebIDL::ExceptionOr<JS::Value> Table::get(u32 index) const

{

    auto& vm = this->vm();

    auto& cache = Detail::get_cache(realm());

    auto* table = cache.abstract_machine().store().get(address());

    if (!table)

        return vm.throw_completion<JS::RangeError>("Could not find the memory table"sv);

    if (table->elements().size() <= index)

        return vm.throw_completion<JS::RangeError>("Table element index out of range"sv);

    auto& ref = table->elements()[index];

    Wasm::Value wasm_value { ref };

    return Detail::to_js_value(vm, wasm_value, table->type().element_type());

}

// https://webassembly.github.io/spec/js-api/#dom-table-set

WebIDL::ExceptionOr<void> Table::set(u32 index, JS::Value value)

{

    auto& vm = this->vm();

    auto& cache = Detail::get_cache(realm());

    auto* table = cache.abstract_machine().store().get(address());

    if (!table)

        return vm.throw_completion<JS::RangeError>("Could not find the memory table"sv);

    if (table->elements().size() <= index)

        return vm.throw_completion<JS::RangeError>("Table element index out of range"sv);

    auto reference_value = TRY(value_to_reference(vm, value, table->type().element_type()));

    auto const& reference = reference_value.to<Wasm::Reference>();

    table->elements()[index] = reference;

    return {};

}

// https://webassembly.github.io/spec/js-api/#dom-table-length

WebIDL::ExceptionOr<u32> Table::length() const

{

    auto& vm = this->vm();

    auto& cache = Detail::get_cache(realm());

    auto* table = cache.abstract_machine().store().get(address());

    if (!table)

        return vm.throw_completion<JS::RangeError>("Could not find the memory table"sv);

    return table->elements().size();

}

}