/*

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

 *

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

 */

#pragma once

#include <LibJS/Bytecode/Interpreter.h>

#include <LibJS/Runtime/ECMAScriptFunctionObject.h>

#include <LibJS/Runtime/Object.h>

namespace JS {

class GeneratorObject : public Object {

    JS_OBJECT(GeneratorObject, Object);

    JS_DECLARE_ALLOCATOR(GeneratorObject);

public:

    static ThrowCompletionOr<NonnullGCPtr<GeneratorObject>> create(Realm&, Value, ECMAScriptFunctionObject*, NonnullOwnPtr<ExecutionContext>);

    virtual ~GeneratorObject() override = default;

    void visit_edges(Cell::Visitor&) override;

    ThrowCompletionOr<Value> resume(VM&, Value value, Optional<StringView> const& generator_brand);

    ThrowCompletionOr<Value> resume_abrupt(VM&, JS::Completion abrupt_completion, Optional<StringView> const& generator_brand);

    enum class GeneratorState {

        SuspendedStart,

        SuspendedYield,

        Executing,

        Completed,

    };

    GeneratorState generator_state() const { return m_generator_state; }

    void set_generator_state(GeneratorState generator_state) { m_generator_state = generator_state; }

protected:

    GeneratorObject(Realm&, Object& prototype, NonnullOwnPtr<ExecutionContext>, Optional<StringView> generator_brand = {});

    ThrowCompletionOr<GeneratorState> validate(VM&, Optional<StringView> const& generator_brand);

    virtual ThrowCompletionOr<Value> execute(VM&, JS::Completion const& completion);

private:

    NonnullOwnPtr<ExecutionContext> m_execution_context;

    GCPtr<ECMAScriptFunctionObject> m_generating_function;

    Value m_previous_value;

    GeneratorState m_generator_state { GeneratorState::SuspendedStart };

    Optional<StringView> m_generator_brand;

};

}