/*

 * Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>

 * Copyright (c) 2021-2022, Linus Groh <linusg@serenityos.org>

 *

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

 */

#include <LibJS/Runtime/Completion.h>

#include <LibJS/Runtime/DeclarativeEnvironment.h>

#include <LibJS/Runtime/EnvironmentCoordinate.h>

#include <LibJS/Runtime/GlobalEnvironment.h>

#include <LibJS/Runtime/GlobalObject.h>

#include <LibJS/Runtime/ObjectEnvironment.h>

namespace JS {

JS_DEFINE_ALLOCATOR(GlobalEnvironment);

// 9.1.2.5 NewGlobalEnvironment ( G, thisValue ), https://tc39.es/ecma262/#sec-newglobalenvironment

GlobalEnvironment::GlobalEnvironment(Object& global_object, Object& this_value)

    : Environment(nullptr)

    , m_global_this_value(&this_value)

{

    m_object_record = global_object.heap().allocate_without_realm<ObjectEnvironment>(global_object, ObjectEnvironment::IsWithEnvironment::No, nullptr);

    m_declarative_record = global_object.heap().allocate_without_realm<DeclarativeEnvironment>();

}

void GlobalEnvironment::visit_edges(Cell::Visitor& visitor)

{

    Base::visit_edges(visitor);

    visitor.visit(m_object_record);

    visitor.visit(m_global_this_value);

    visitor.visit(m_declarative_record);

}

// 9.1.1.4.11 GetThisBinding ( ), https://tc39.es/ecma262/#sec-global-environment-records-getthisbinding

ThrowCompletionOr<Value> GlobalEnvironment::get_this_binding(VM&) const

{

    // 1. Return envRec.[[GlobalThisValue]].

    return m_global_this_value;

}

// 9.1.1.4.1 HasBinding ( N ), https://tc39.es/ecma262/#sec-global-environment-records-hasbinding-n

ThrowCompletionOr<bool> GlobalEnvironment::has_binding(DeprecatedFlyString const& name, Optional<size_t>*) const

{

    // 1. Let DclRec be envRec.[[DeclarativeRecord]].

    // 2. If ! DclRec.HasBinding(N) is true, return true.

    if (MUST(m_declarative_record->has_binding(name)))

        return true;

    // 3. Let ObjRec be envRec.[[ObjectRecord]].

    // 4. Return ? ObjRec.HasBinding(N).

    return m_object_record->has_binding(name);

}

// 9.1.1.4.2 CreateMutableBinding ( N, D ), https://tc39.es/ecma262/#sec-global-environment-records-createmutablebinding-n-d

ThrowCompletionOr<void> GlobalEnvironment::create_mutable_binding(VM& vm, DeprecatedFlyString const& name, bool can_be_deleted)

{

    // 1. Let DclRec be envRec.[[DeclarativeRecord]].

    // 2. If ! DclRec.HasBinding(N) is true, throw a TypeError exception.

    if (MUST(m_declarative_record->has_binding(name)))

        return vm.throw_completion<TypeError>(ErrorType::GlobalEnvironmentAlreadyHasBinding, name);

    // 3. Return ! DclRec.CreateMutableBinding(N, D).

    return MUST(m_declarative_record->create_mutable_binding(vm, name, can_be_deleted));

}

// 9.1.1.4.3 CreateImmutableBinding ( N, S ), https://tc39.es/ecma262/#sec-global-environment-records-createimmutablebinding-n-s

ThrowCompletionOr<void> GlobalEnvironment::create_immutable_binding(VM& vm, DeprecatedFlyString const& name, bool strict)

{

    // 1. Let DclRec be envRec.[[DeclarativeRecord]].

    // 2. If ! DclRec.HasBinding(N) is true, throw a TypeError exception.

    if (MUST(m_declarative_record->has_binding(name)))

        return vm.throw_completion<TypeError>(ErrorType::GlobalEnvironmentAlreadyHasBinding, name);

    // 3. Return ! DclRec.CreateImmutableBinding(N, S).

    return MUST(m_declarative_record->create_immutable_binding(vm, name, strict));

}

// 9.1.1.4.4 InitializeBinding ( N, V, hint ), https://tc39.es/ecma262/#sec-global-environment-records-initializebinding-n-v

ThrowCompletionOr<void> GlobalEnvironment::initialize_binding(VM& vm, DeprecatedFlyString const& name, Value value, InitializeBindingHint hint)

{

    // 1. Let DclRec be envRec.[[DeclarativeRecord]].

    // 2. If ! DclRec.HasBinding(N) is true, then

    if (MUST(m_declarative_record->has_binding(name))) {

        // a. Return ! DclRec.InitializeBinding(N, V, hint).

        return MUST(m_declarative_record->initialize_binding(vm, name, value, hint));

    }

    // 3. Assert: If the binding exists, it must be in the object Environment Record.

    // 4. Assert: hint is normal.

    VERIFY(hint == Environment::InitializeBindingHint::Normal);

    // 5. Let ObjRec be envRec.[[ObjectRecord]].

    // 6. Return ? ObjRec.InitializeBinding(N, V, normal).

    return m_object_record->initialize_binding(vm, name, value, Environment::InitializeBindingHint::Normal);

}

// 9.1.1.4.5 SetMutableBinding ( N, V, S ), https://tc39.es/ecma262/#sec-global-environment-records-setmutablebinding-n-v-s

ThrowCompletionOr<void> GlobalEnvironment::set_mutable_binding(VM& vm, DeprecatedFlyString const& name, Value value, bool strict)

{

    // 1. Let DclRec be envRec.[[DeclarativeRecord]].

    // 2. If ! DclRec.HasBinding(N) is true, then

    if (MUST(m_declarative_record->has_binding(name))) {

        // a. Return ? DclRec.SetMutableBinding(N, V, S).

        return m_declarative_record->set_mutable_binding(vm, name, value, strict);

    }

    // 3. Let ObjRec be envRec.[[ObjectRecord]].

    // 4. Return ? ObjRec.SetMutableBinding(N, V, S).

    return m_object_record->set_mutable_binding(vm, name, value, strict);

}

// 9.1.1.4.6 GetBindingValue ( N, S ), https://tc39.es/ecma262/#sec-global-environment-records-getbindingvalue-n-s

ThrowCompletionOr<Value> GlobalEnvironment::get_binding_value(VM& vm, DeprecatedFlyString const& name, bool strict)

{

    // 1. Let DclRec be envRec.[[DeclarativeRecord]].

    // 2. If ! DclRec.HasBinding(N) is true, then

    Optional<size_t> index;

    if (MUST(m_declarative_record->has_binding(name, &index))) {

        // a. Return ? DclRec.GetBindingValue(N, S).

        if (index.has_value())

            return m_declarative_record->get_binding_value_direct(vm, index.value());

        return m_declarative_record->get_binding_value(vm, name, strict);

    }

    // 3. Let ObjRec be envRec.[[ObjectRecord]].

    // 4. Return ? ObjRec.GetBindingValue(N, S).

    return m_object_record->get_binding_value(vm, name, strict);

}

// 9.1.1.4.7 DeleteBinding ( N ), https://tc39.es/ecma262/#sec-global-environment-records-deletebinding-n

ThrowCompletionOr<bool> GlobalEnvironment::delete_binding(VM& vm, DeprecatedFlyString const& name)

{

    // 1. Let DclRec be envRec.[[DeclarativeRecord]].

    // 2. If ! DclRec.HasBinding(N) is true, then

    if (MUST(m_declarative_record->has_binding(name))) {

        // a. Return ! DclRec.DeleteBinding(N).

        return MUST(m_declarative_record->delete_binding(vm, name));

    }

    // 3. Let ObjRec be envRec.[[ObjectRecord]].

    // 4. Let globalObject be ObjRec.[[BindingObject]].

    // 5. Let existingProp be ? HasOwnProperty(globalObject, N).

    bool existing_prop = TRY(m_object_record->binding_object().has_own_property(name));

    // 6. If existingProp is true, then

    if (existing_prop) {

        // a. Let status be ? ObjRec.DeleteBinding(N).

        bool status = TRY(m_object_record->delete_binding(vm, name));

        // b. If status is true, then

        if (status) {

            // i. Let varNames be envRec.[[VarNames]].

            // ii. If N is an element of varNames, remove that element from the varNames.

            m_var_names.remove_all_matching([&](auto& entry) { return entry == name; });

        }

        // c. Return status.

        return status;

    }

    // 7. Return true.

    return true;

}

// 9.1.1.4.12 HasVarDeclaration ( N ), https://tc39.es/ecma262/#sec-hasvardeclaration

bool GlobalEnvironment::has_var_declaration(DeprecatedFlyString const& name) const

{

    // 1. Let varDeclaredNames be envRec.[[VarNames]].

    // 2. If varDeclaredNames contains N, return true.

    // 3. Return false.

    return m_var_names.contains_slow(name);

}

// 9.1.1.4.13 HasLexicalDeclaration ( N ), https://tc39.es/ecma262/#sec-haslexicaldeclaration

bool GlobalEnvironment::has_lexical_declaration(DeprecatedFlyString const& name) const

{

    // 1. Let DclRec be envRec.[[DeclarativeRecord]].

    // 2. Return ! DclRec.HasBinding(N).

    return MUST(m_declarative_record->has_binding(name));

}

// 9.1.1.4.14 HasRestrictedGlobalProperty ( N ), https://tc39.es/ecma262/#sec-hasrestrictedglobalproperty

ThrowCompletionOr<bool> GlobalEnvironment::has_restricted_global_property(DeprecatedFlyString const& name) const

{

    // 1. Let ObjRec be envRec.[[ObjectRecord]].

    // 2. Let globalObject be ObjRec.[[BindingObject]].

    auto& global_object = m_object_record->binding_object();

    // 3. Let existingProp be ? globalObject.[[GetOwnProperty]](N).

    auto existing_prop = TRY(global_object.internal_get_own_property(name));

    // 4. If existingProp is undefined, return false.

    if (!existing_prop.has_value())

        return false;

    // 5. If existingProp.[[Configurable]] is true, return false.

    if (*existing_prop->configurable)

        return false;

    // 6. Return true.

    return true;

}

// 9.1.1.4.15 CanDeclareGlobalVar ( N ), https://tc39.es/ecma262/#sec-candeclareglobalvar

ThrowCompletionOr<bool> GlobalEnvironment::can_declare_global_var(DeprecatedFlyString const& name) const

{

    // 1. Let ObjRec be envRec.[[ObjectRecord]].

    // 2. Let globalObject be ObjRec.[[BindingObject]].

    auto& global_object = m_object_record->binding_object();

    // 3. Let hasProperty be ? HasOwnProperty(globalObject, N).

    bool has_property = TRY(global_object.has_own_property(name));

    // 4. If hasProperty is true, return true.

    if (has_property)

        return true;

    // 5. Return ? IsExtensible(globalObject).

    return global_object.is_extensible();

}

// 9.1.1.4.16 CanDeclareGlobalFunction ( N ), https://tc39.es/ecma262/#sec-candeclareglobalfunction

ThrowCompletionOr<bool> GlobalEnvironment::can_declare_global_function(DeprecatedFlyString const& name) const

{

    // 1. Let ObjRec be envRec.[[ObjectRecord]].

    // 2. Let globalObject be ObjRec.[[BindingObject]].

    auto& global_object = m_object_record->binding_object();

    // 3. Let existingProp be ? globalObject.[[GetOwnProperty]](N).

    auto existing_prop = TRY(global_object.internal_get_own_property(name));

    // 4. If existingProp is undefined, return ? IsExtensible(globalObject).

    if (!existing_prop.has_value())

        return TRY(global_object.is_extensible());

    // 5. If existingProp.[[Configurable]] is true, return true.

    if (*existing_prop->configurable)

        return true;

    // 6. If IsDataDescriptor(existingProp) is true and existingProp has attribute values { [[Writable]]: true, [[Enumerable]]: true }, return true.

    if (existing_prop->is_data_descriptor() && *existing_prop->writable && *existing_prop->enumerable)

        return true;

    // 7. Return false.

    return false;

}

// 9.1.1.4.17 CreateGlobalVarBinding ( N, D ), https://tc39.es/ecma262/#sec-createglobalvarbinding

ThrowCompletionOr<void> GlobalEnvironment::create_global_var_binding(DeprecatedFlyString const& name, bool can_be_deleted)

{

    auto& vm = this->vm();

    // 1. Let ObjRec be envRec.[[ObjectRecord]].

    // 2. Let globalObject be ObjRec.[[BindingObject]].

    auto& global_object = m_object_record->binding_object();

    // 3. Let hasProperty be ? HasOwnProperty(globalObject, N).

    auto has_property = TRY(global_object.has_own_property(name));

    // 4. Let extensible be ? IsExtensible(globalObject).

    auto extensible = TRY(global_object.is_extensible());

    // 5. If hasProperty is false and extensible is true, then

    if (!has_property && extensible) {

        // a. Perform ? ObjRec.CreateMutableBinding(N, D).

        TRY(m_object_record->create_mutable_binding(vm, name, can_be_deleted));

        // b. Perform ? ObjRec.InitializeBinding(N, undefined, normal).

        TRY(m_object_record->initialize_binding(vm, name, js_undefined(), Environment::InitializeBindingHint::Normal));

    }

    // 6. Let varDeclaredNames be envRec.[[VarNames]].

    // 7. If varDeclaredNames does not contain N, then

    if (!m_var_names.contains_slow(name)) {

        // a. Append N to varDeclaredNames.

        m_var_names.append(name);

    }

    // 8. Return unused.

    return {};

}

// 9.1.1.4.18 CreateGlobalFunctionBinding ( N, V, D ), https://tc39.es/ecma262/#sec-createglobalfunctionbinding

ThrowCompletionOr<void> GlobalEnvironment::create_global_function_binding(DeprecatedFlyString const& name, Value value, bool can_be_deleted)

{

    // 1. Let ObjRec be envRec.[[ObjectRecord]].

    // 2. Let globalObject be ObjRec.[[BindingObject]].

    auto& global_object = m_object_record->binding_object();

    // 3. Let existingProp be ? globalObject.[[GetOwnProperty]](N).

    auto existing_prop = TRY(global_object.internal_get_own_property(name));

    PropertyDescriptor desc;

    // 4. If existingProp is undefined or existingProp.[[Configurable]] is true, then

    if (!existing_prop.has_value() || *existing_prop->configurable) {

        //     a. Let desc be the PropertyDescriptor { [[Value]]: V, [[Writable]]: true, [[Enumerable]]: true, [[Configurable]]: D }.

        desc = { .value = value, .writable = true, .enumerable = true, .configurable = can_be_deleted };

    }

    // 5. Else,

    else {

        // a. Let desc be the PropertyDescriptor { [[Value]]: V }.

        desc = { .value = value };

    }

    // 6. Perform ? DefinePropertyOrThrow(globalObject, N, desc).

    TRY(global_object.define_property_or_throw(name, desc));

    // 7. Perform ? Set(globalObject, N, V, false).

    TRY(global_object.set(name, value, Object::ShouldThrowExceptions::Yes));

    // 8. Let varDeclaredNames be envRec.[[VarNames]].

    // 9. If varDeclaredNames does not contain N, then

    if (!m_var_names.contains_slow(name)) {

        // a. Append N to varDeclaredNames.

        m_var_names.append(name);

    }

    // 10. Return unused.

    return {};

}

}