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#include "checkidentifiers.h"

#include <QtQmlCompiler/private/qcoloroutput_p.h>

#include <QtCore/qqueue.h>
#include <QtCore/private/qduplicatetracker_p.h>
#include <QtCore/qsharedpointer.h>
#include <stack>

static const QStringList unknownBuiltins = {
    QStringLiteral("alias"),    // TODO: we cannot properly resolve aliases, yet
    QStringLiteral("QJSValue"), // We cannot say anything intelligent about untyped JS values.
    QStringLiteral("QVariant")  // Same for generic variants
};

template<typename Visitor>
static bool walkRelatedScopes(QQmlJSScope::ConstPtr rootType, const Visitor &visit)
{
    if (rootType.isNull())
        return false;
    std::stack<QQmlJSScope::ConstPtr> stack;
    QDuplicateTracker<QQmlJSScope::ConstPtr> seenTypes;
    stack.push(rootType);

    while (!stack.empty()) {
        const auto type = stack.top();
        stack.pop();

        // If we've seen this type before (can be caused by self attaching types), ignore it
        if (seenTypes.hasSeen(type))
            continue;

        if (visit(type))
            return true;

        if (auto attachedType = type->attachedType())
            stack.push(attachedType);

        if (auto baseType = type->baseType())
            stack.push(baseType);

        // Push extension type last. It overrides the base type.
        if (auto extensionType = type->extensionType())
            stack.push(extensionType);
    }

    return false;
}

void CheckIdentifiers::checkMemberAccess(const QVector<FieldMember> &members,
                                         const QQmlJSScope::ConstPtr &outerScope,
                                         const QQmlJSMetaProperty *prop) const
{

    QStringList expectedNext;
    QString detectedRestrictiveName;
    QString detectedRestrictiveKind;

    if (prop != nullptr && prop->isList()) {
        detectedRestrictiveKind = QLatin1String("list");
        expectedNext.append(QLatin1String("length"));
    }

    QQmlJSScope::ConstPtr scope = outerScope;
    for (qsizetype i = 0; i < members.size(); i++) {
        const FieldMember &access = members.at(i);

        if (scope.isNull()) {
            m_logger->logWarning(
                    QString::fromLatin1(
                            "Type \"%1\" of base \"%2\" not found when accessing member \"%3\"")
                            .arg(detectedRestrictiveKind)
                            .arg(detectedRestrictiveName)
                            .arg(access.m_name),
                    Log_Type, access.m_location);
            return;
        }

        if (!detectedRestrictiveKind.isEmpty()) {
            if (expectedNext.contains(access.m_name)) {
                expectedNext.clear();
                continue;
            }

            m_logger->logWarning(
                    QLatin1String("\"%1\" is a %2. You cannot access \"%3\" it from here")
                            .arg(detectedRestrictiveName)
                            .arg(detectedRestrictiveKind)
                            .arg(access.m_name),
                    Log_Type, access.m_location);
            return;
        }

        if (unknownBuiltins.contains(scope->internalName()))
            return;

        const auto property = scope->property(access.m_name);
        if (!property.propertyName().isEmpty()) {
            const auto binding = scope->propertyBinding(access.m_name);
            const QString typeName = access.m_parentType.isEmpty()
                    ? (binding.hasValue() ? binding.valueTypeName() : property.typeName())
                    : access.m_parentType;

            if (property.isList()) {
                detectedRestrictiveKind = QLatin1String("list");
                detectedRestrictiveName = access.m_name;
                expectedNext.append(QLatin1String("length"));
                continue;
            }

            if (access.m_parentType.isEmpty()) {
                if (binding.hasValue())
                    scope = binding.value();
                else
                    scope = property.type();

                if (scope.isNull()) {
                    // Properties should always have a type. Otherwise something
                    // was missing from the import already.
                    detectedRestrictiveKind = typeName;
                    detectedRestrictiveName = access.m_name;
                }
                continue;
            }

            if (unknownBuiltins.contains(typeName))
                return;

            const auto it = m_types.find(typeName);
            if (it == m_types.end()) {
                detectedRestrictiveKind = typeName;
                detectedRestrictiveName = access.m_name;
                scope = QQmlJSScope::ConstPtr();
            } else {
                scope = *it;
            }

            continue;
        }

        if (scope->hasMethod(access.m_name))
            return; // Access to property of JS function

        auto checkEnums = [&](const QQmlJSScope::ConstPtr &scope) {
            if (scope->hasEnumeration(access.m_name)) {
                detectedRestrictiveKind = QLatin1String("enum");
                detectedRestrictiveName = access.m_name;
                expectedNext.append(scope->enumeration(access.m_name).keys());
                return true;
            }

            if (scope->hasEnumerationKey(access.m_name)) {
                detectedRestrictiveKind = QLatin1String("enum");
                detectedRestrictiveName = access.m_name;
                return true;
            }

            return false;
        };

        checkEnums(scope);

        if (!detectedRestrictiveName.isEmpty())
            continue;

        QQmlJSScope::ConstPtr rootType;
        if (!access.m_parentType.isEmpty())
            rootType = m_types.value(access.m_parentType);
        else
            rootType = scope;

        bool typeFound =
                walkRelatedScopes(rootType, [&](QQmlJSScope::ConstPtr type) {
                    const auto typeProperties = type->ownProperties();
                    const auto typeIt = typeProperties.find(access.m_name);
                    if (typeIt != typeProperties.end()) {
                        scope = typeIt->type();
                        return true;
                    }

                    const auto typeMethods = type->ownMethods();
                    const auto typeMethodIt = typeMethods.find(access.m_name);
                    if (typeMethodIt != typeMethods.end()) {
                        detectedRestrictiveName = access.m_name;
                        detectedRestrictiveKind = QLatin1String("method");
                        return true;
                    }

                    return checkEnums(type);
                });
        if (typeFound)
            continue;

        if (access.m_name.front().isUpper() && scope->scopeType() == QQmlJSScope::QMLScope) {
            // may be an attached type

            auto it = m_types.find(access.m_name);

            // Something was found but it wasn't the attached type we were looking for, it could be a prefix
            if (it != m_types.end() && !(*it) && i+1 < members.length()) {
                // See whether this is due to us getting the prefixed property in two accesses (i.e. "T" and "Item")
                // by checking again with a fixed name.
                it = m_types.find(access.m_name + QLatin1Char('.') + members[++i].m_name);

                if (it == m_types.end() || !(*it) || (*it)->attachedTypeName().isEmpty())
                    --i;
            }

            if (it != m_types.end() && *it && !(*it)->attachedTypeName().isEmpty()) {
                if (const auto attached = (*it)->attachedType()) {
                    scope = attached;
                    continue;
                }
            }
        }

        m_logger->logWarning(QLatin1String("Property \"%1\" not found on type \"%2\"")
                                     .arg(access.m_name)
                                     .arg(scope->internalName().isEmpty() ? scope->baseTypeName()
                                                                          : scope->internalName()),
                             Log_Type, access.m_location);
        return;
    }
}

void CheckIdentifiers::operator()(
        const QHash<QString, QQmlJSScope::ConstPtr> &qmlIDs,
        const QHash<QQmlJS::SourceLocation, QQmlJSMetaSignalHandler> &signalHandlers,
        const MemberAccessChains &memberAccessChains, const QQmlJSScope::ConstPtr &root,
        const QString &rootId) const
{
    // revisit all scopes
    QQueue<QQmlJSScope::ConstPtr> workQueue;
    workQueue.enqueue(root);
    while (!workQueue.empty()) {
        const QQmlJSScope::ConstPtr currentScope = workQueue.dequeue();

        const auto scopeMemberAccessChains = memberAccessChains[currentScope];
        for (auto memberAccessChain : scopeMemberAccessChains) {
            if (memberAccessChain.isEmpty())
                continue;

            auto memberAccessBase = memberAccessChain.takeFirst();
            const auto jsId = currentScope->findJSIdentifier(memberAccessBase.m_name);
            if (jsId.has_value() && jsId->kind != QQmlJSScope::JavaScriptIdentifier::Injected) {
                if (memberAccessBase.m_location.end() < jsId->location.begin()) {
                    // TODO: Is there a more fitting category?
                    m_logger->logWarning(
                            QStringLiteral("Variable \"%1\" is used here before its declaration. "
                                           "The declaration is at %4:%5.")
                                    .arg(memberAccessBase.m_name)
                                    .arg(jsId->location.startLine)
                                    .arg(jsId->location.startColumn),
                            Log_Type, memberAccessBase.m_location);
                }
                continue;
            }

            auto it = qmlIDs.find(memberAccessBase.m_name);
            if (it != qmlIDs.end()) {
                if (!it->isNull()) {
                    checkMemberAccess(memberAccessChain, *it);
                    continue;
                } else if (!memberAccessChain.isEmpty()) {
                    // It could be a qualified type name
                    const QString scopedName = memberAccessChain.first().m_name;
                    if (scopedName.front().isUpper()) {
                        const QString qualified = memberAccessBase.m_name + QLatin1Char('.')
                                + scopedName;
                        const auto typeIt = m_types.find(qualified);
                        if (typeIt != m_types.end()) {
                            memberAccessChain.takeFirst();
                            checkMemberAccess(memberAccessChain, *typeIt);
                            continue;
                        }
                    }
                }
            }

            auto qmlScope = QQmlJSScope::findCurrentQMLScope(currentScope);
            if (qmlScope->hasMethod(memberAccessBase.m_name))
                continue;

            const auto property = qmlScope->property(memberAccessBase.m_name);
            if (!property.propertyName().isEmpty()) {
                if (memberAccessChain.isEmpty() || unknownBuiltins.contains(property.typeName()))
                    continue;

                const auto binding = qmlScope->propertyBinding(memberAccessBase.m_name);
                if (binding.hasValue()) {
                    checkMemberAccess(memberAccessChain, binding.value(), &property);
                } else if (!property.type()) {
                    m_logger->logWarning(QString::fromLatin1("Type of property \"%2\" not found")
                                                 .arg(memberAccessBase.m_name),
                                         Log_Type, memberAccessBase.m_location);
                } else {
                    checkMemberAccess(memberAccessChain, property.type(), &property);
                }

                continue;
            }

            const QString baseName = memberAccessBase.m_name;
            auto typeIt = m_types.find(memberAccessBase.m_name);
            bool baseIsPrefixed = false;
            while (typeIt != m_types.end() && typeIt->isNull()) {
                // This is a namespaced import. Check with the full name.
                if (!memberAccessChain.isEmpty()) {
                    auto location = memberAccessBase.m_location;
                    memberAccessBase = memberAccessChain.takeFirst();
                    memberAccessBase.m_name.prepend(baseName + u'.');
                    location.length = memberAccessBase.m_location.offset - location.offset
                            + memberAccessBase.m_location.length;
                    memberAccessBase.m_location = location;
                    typeIt = m_types.find(memberAccessBase.m_name);
                    baseIsPrefixed = true;
                }
            }

            if (typeIt != m_types.end() && !typeIt->isNull()) {
                checkMemberAccess(memberAccessChain, *typeIt);
                continue;
            }

            // If we're in a custom parser component (or one of their children) we cannot be sure
            // that this is really an unqualified access. We have to err on the side of producing
            // false negatives for the sake of usability.
            if (qmlScope->isInCustomParserParent()) {
                // We can handle Connections properly
                if (qmlScope->baseType()
                    && qmlScope->baseType()->internalName() != u"QQmlConnections"_qs)
                    continue;
            }

            const auto location = memberAccessBase.m_location;

            if (baseIsPrefixed) {
                m_logger->logWarning(QLatin1String("Type not found in namespace"), Log_Type,
                                     location);
            }

            Q_UNUSED(signalHandlers)
            Q_UNUSED(rootId)
        }
        const auto childScopes = currentScope->childScopes();
        for (auto const &childScope : childScopes)
            workQueue.enqueue(childScope);
    }
}