/*

 * Copyright (c) 2021, Luke Wilde <lukew@serenityos.org>

 * Copyright (c) 2024, Tim Ledbetter <tim.ledbetter@ladybird.org>

 *

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

 */

#include <LibWeb/Bindings/AbortSignalPrototype.h>

#include <LibWeb/Bindings/Intrinsics.h>

#include <LibWeb/DOM/AbortSignal.h>

#include <LibWeb/DOM/Document.h>

#include <LibWeb/DOM/EventDispatcher.h>

#include <LibWeb/HTML/EventHandler.h>

#include <LibWeb/HTML/Window.h>

#include <LibWeb/HTML/WindowOrWorkerGlobalScope.h>

namespace Web::DOM {

JS_DEFINE_ALLOCATOR(AbortSignal);

WebIDL::ExceptionOr<JS::NonnullGCPtr<AbortSignal>> AbortSignal::construct_impl(JS::Realm& realm)

{

    return realm.heap().allocate<AbortSignal>(realm, realm);

}

AbortSignal::AbortSignal(JS::Realm& realm)

    : EventTarget(realm)

{

}

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

{

    Base::initialize(realm);

    WEB_SET_PROTOTYPE_FOR_INTERFACE(AbortSignal);

}

// https://dom.spec.whatwg.org/#abortsignal-add

void AbortSignal::add_abort_algorithm(Function<void()> abort_algorithm)

{

    // 1. If signal is aborted, then return.

    if (aborted())

        return;

    // 2. Append algorithm to signal’s abort algorithms.

    m_abort_algorithms.append(JS::create_heap_function(vm().heap(), move(abort_algorithm)));

}

// https://dom.spec.whatwg.org/#abortsignal-signal-abort

void AbortSignal::signal_abort(JS::Value reason)

{

    // 1. If signal is aborted, then return.

    if (aborted())

        return;

    // 2. Set signal’s abort reason to reason if it is given; otherwise to a new "AbortError" DOMException.

    if (!reason.is_undefined())

        m_abort_reason = reason;

    else

        m_abort_reason = WebIDL::AbortError::create(realm(), "Aborted without reason"_string).ptr();

    // 3. Let dependentSignalsToAbort be a new list.

    Vector<JS::Handle<AbortSignal>> dependent_signals_to_abort;

    // 4. For each dependentSignal of signal’s dependent signals:

    for (auto const& dependent_signal : m_dependent_signals) {

        // 1. If dependentSignal is not aborted, then:

        if (!dependent_signal->aborted()) {

            // 1. Set dependentSignal’s abort reason to signal’s abort reason.

            dependent_signal->set_reason(m_abort_reason);

            // 2. Append dependentSignal to dependentSignalsToAbort.

            dependent_signals_to_abort.append(*dependent_signal);

        }

    }

    // https://dom.spec.whatwg.org/#run-the-abort-steps

    auto run_the_abort_steps = [](auto& signal) {

        // 1. For each algorithm in signal’s abort algorithms: run algorithm.

        for (auto& algorithm : signal.m_abort_algorithms)

            algorithm->function()();

        // 2. Empty signal’s abort algorithms.

        signal.m_abort_algorithms.clear();

        // 3. Fire an event named abort at signal.

        auto abort_event = Event::create(signal.realm(), HTML::EventNames::abort);

        abort_event->set_is_trusted(true);

        signal.dispatch_event(abort_event);

    };

    // 5. Run the abort steps for signal.

    run_the_abort_steps(*this);

    // 6. For each dependentSignal of dependentSignalsToAbort, run the abort steps for dependentSignal.

    for (auto const& dependent_signal : dependent_signals_to_abort)

        run_the_abort_steps(*dependent_signal);

}

void AbortSignal::set_onabort(WebIDL::CallbackType* event_handler)

{

    set_event_handler_attribute(HTML::EventNames::abort, event_handler);

}

WebIDL::CallbackType* AbortSignal::onabort()

{

    return event_handler_attribute(HTML::EventNames::abort);

}

// https://dom.spec.whatwg.org/#dom-abortsignal-throwifaborted

JS::ThrowCompletionOr<void> AbortSignal::throw_if_aborted() const

{

    // The throwIfAborted() method steps are to throw this’s abort reason, if this is aborted.

    if (!aborted())

        return {};

    return JS::throw_completion(m_abort_reason);

}

void AbortSignal::visit_edges(JS::Cell::Visitor& visitor)

{

    Base::visit_edges(visitor);

    visitor.visit(m_abort_reason);

    visitor.visit(m_abort_algorithms);

    visitor.visit(m_source_signals);

    visitor.visit(m_dependent_signals);

}

// https://dom.spec.whatwg.org/#dom-abortsignal-abort

WebIDL::ExceptionOr<JS::NonnullGCPtr<AbortSignal>> AbortSignal::abort(JS::VM& vm, JS::Value reason)

{

    // 1. Let signal be a new AbortSignal object.

    auto signal = TRY(construct_impl(*vm.current_realm()));

    // 2. Set signal’s abort reason to reason if it is given; otherwise to a new "AbortError" DOMException.

    if (reason.is_undefined())

        reason = WebIDL::AbortError::create(*vm.current_realm(), "Aborted without reason"_string).ptr();

    signal->set_reason(reason);

    // 3. Return signal.

    return signal;

}

// https://dom.spec.whatwg.org/#dom-abortsignal-timeout

WebIDL::ExceptionOr<JS::NonnullGCPtr<AbortSignal>> AbortSignal::timeout(JS::VM& vm, WebIDL::UnsignedLongLong milliseconds)

{

    auto& realm = *vm.current_realm();

    // 1. Let signal be a new AbortSignal object.

    auto signal = TRY(construct_impl(realm));

    // 2. Let global be signal’s relevant global object.

    auto& global = HTML::relevant_global_object(signal);

    auto* window_or_worker = dynamic_cast<HTML::WindowOrWorkerGlobalScopeMixin*>(&global);

    VERIFY(window_or_worker);

    // 3. Run steps after a timeout given global, "AbortSignal-timeout", milliseconds, and the following step:

    window_or_worker->run_steps_after_a_timeout(milliseconds, [&realm, &global, signal]() {

        // 1. Queue a global task on the timer task source given global to signal abort given signal and a new "TimeoutError" DOMException.

        HTML::queue_global_task(HTML::Task::Source::TimerTask, global, JS::create_heap_function(realm.heap(), [&realm, signal]() mutable {

            auto reason = WebIDL::TimeoutError::create(realm, "Signal timed out"_string);

            signal->signal_abort(reason);

        }));

    });

    // 4. Return signal.

    return signal;

}

// https://dom.spec.whatwg.org/#dom-abortsignal-any

WebIDL::ExceptionOr<JS::NonnullGCPtr<AbortSignal>> AbortSignal::any(JS::VM& vm, Vector<JS::Handle<AbortSignal>> const& signals)

{

    // The static any(signals) method steps are to return the result of creating a dependent abort signal from signals using AbortSignal and the current realm.

    return create_dependent_abort_signal(*vm.current_realm(), signals);

}

// https://dom.spec.whatwg.org/#create-a-dependent-abort-signal

WebIDL::ExceptionOr<JS::NonnullGCPtr<AbortSignal>> AbortSignal::create_dependent_abort_signal(JS::Realm& realm, Vector<JS::Handle<AbortSignal>> const& signals)

{

    // 1. Let resultSignal be a new object implementing signalInterface using realm.

    auto result_signal = TRY(construct_impl(realm));

    // 2. For each signal of signals: if signal is aborted, then set resultSignal’s abort reason to signal’s abort reason and return resultSignal.

    for (auto const& signal : signals) {

        if (signal->aborted()) {

            result_signal->set_reason(signal->reason());

            return result_signal;

        }

    }

    // 3. Set resultSignal’s dependent to true.

    result_signal->set_dependent(true);

    // 4. For each signal of signals:

    for (auto const& signal : signals) {

        // 1. If signal’s dependent is false, then:

        if (!signal->dependent()) {

            // 1. Append signal to resultSignal’s source signals.

            result_signal->append_source_signal({ signal });

            // 2. Append resultSignal to signal’s dependent signals.

            signal->append_dependent_signal(result_signal);

        }

        // 2. Otherwise, for each sourceSignal of signal’s source signals:

        else {

            for (auto const& source_signal : signal->source_signals()) {

                // 1. Assert: sourceSignal is not aborted and not dependent.

                VERIFY(source_signal);

                VERIFY(!source_signal->aborted());

                VERIFY(!source_signal->dependent());

                // 2. Append sourceSignal to resultSignal’s source signals.

                result_signal->append_source_signal(source_signal);

                // 3. Append resultSignal to sourceSignal’s dependent signals.

                source_signal->append_dependent_signal(result_signal);

            }

        }

    }

    // 5. Return resultSignal

    return result_signal;

}

}