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#include "findwarnings.h"
#include "checkidentifiers.h"

#include <QtQmlCompiler/private/qqmljsscope_p.h>
#include <QtQmlCompiler/private/qqmljstypedescriptionreader_p.h>
#include <QtQmlCompiler/private/qqmljstypereader_p.h>

#include <QtQml/private/qqmljsast_p.h>
#include <QtQml/private/qqmljslexer_p.h>
#include <QtQml/private/qqmljsparser_p.h>
#include <QtQml/private/qv4codegen_p.h>
#include <QtQml/private/qqmlimportresolver_p.h>

#include <QtCore/qfile.h>
#include <QtCore/qdiriterator.h>
#include <QtCore/qscopedvaluerollback.h>

void FindWarningVisitor::checkInheritanceCycle(QQmlJSScope::ConstPtr scope)
{
    QList<QQmlJSScope::ConstPtr> scopes;
    while (!scope.isNull()) {
        if (scopes.contains(scope)) {
            QString inheritenceCycle;
            for (const auto &seen: qAsConst(scopes)) {
                if (!inheritenceCycle.isEmpty())
                    inheritenceCycle.append(QLatin1String(" -> "));
                inheritenceCycle.append(seen->baseTypeName());
            }

            if (m_warnInheritanceCycle) {
                m_errors.append({
                                    QStringLiteral("%1 is part of an inheritance cycle: %2\n")
                                       .arg(scope->internalName())
                                       .arg(inheritenceCycle),
                                    QtWarningMsg,
                                    QQmlJS::SourceLocation()
                                });
            }

            m_unknownImports.insert(scope->internalName());
            m_visitFailed = true;
            break;
        }

        scopes.append(scope);

        if (scope->baseTypeName().isEmpty()) {
            break;
        } else if (auto newScope = scope->baseType()) {
            scope = newScope;
        } else {
            m_errors.append({
                                scope->baseTypeName() + QStringLiteral(
                                        " was not found. Did you add all import paths?\n"),
                                QtWarningMsg,
                                QQmlJS::SourceLocation()
                            });
            m_unknownImports.insert(scope->baseTypeName());
            m_visitFailed = true;
            break;
        }
    }
}

void FindWarningVisitor::checkGroupedScopes(QQmlJSScope::ConstPtr scope)
{
    auto children = scope->childScopes();
    while (!children.isEmpty()) {
        auto childScope = children.takeFirst();
        if (childScope->scopeType() != QQmlJSScope::GroupedPropertyScope)
            continue;

        if (!childScope->baseType()) {
            m_errors.append({
                                QStringLiteral("unknown grouped property scope %1.")
                                        .arg(childScope->internalName()),
                                QtWarningMsg,
                                childScope->sourceLocation()
                            });
            m_visitFailed = true;
        }

        children.append(childScope->childScopes());
    }
}

void FindWarningVisitor::flushPendingSignalParameters()
{
    const SignalHandler handler = m_signalHandlers[m_pendingSingalHandler];
    for (const QString &parameter : handler.signal.parameterNames()) {
        m_currentScope->insertJSIdentifier(
                    parameter, {
                        QQmlJSScope::JavaScriptIdentifier::Injected,
                        m_pendingSingalHandler
                    });
    }
    m_pendingSingalHandler = QQmlJS::SourceLocation();
}

void FindWarningVisitor::throwRecursionDepthError()
{
    QQmlJSImportVisitor::throwRecursionDepthError();
    m_visitFailed = true;
}

bool FindWarningVisitor::visit(QQmlJS::AST::ExpressionStatement *ast)
{
    if (m_pendingSingalHandler.isValid()) {
        enterEnvironment(QQmlJSScope::JSFunctionScope, "signalhandler", ast->firstSourceLocation());
        flushPendingSignalParameters();
    }
    return true;
}

void FindWarningVisitor::endVisit(QQmlJS::AST::ExpressionStatement *)
{
    if (m_currentScope->scopeType() == QQmlJSScope::JSFunctionScope
            && m_currentScope->baseTypeName() == "signalhandler") {
        leaveEnvironment();
    }
}

bool FindWarningVisitor::visit(QQmlJS::AST::Block *block)
{
    if (!QQmlJSImportVisitor::visit(block))
        return false;
    if (m_pendingSingalHandler.isValid())
        flushPendingSignalParameters();
    return true;
}

bool FindWarningVisitor::visit(QQmlJS::AST::WithStatement *withStatement)
{
    if (m_warnWithStatement) {
        m_errors.append({
                            QStringLiteral(
                                "with statements are strongly discouraged in QML "
                                "and might cause false positives when analysing unqualified "
                                "identifiers\n"),
                            QtWarningMsg,
                            withStatement->firstSourceLocation()
                        });
    }

    return QQmlJSImportVisitor::visit(withStatement);
}

static QString signalName(QStringView handlerName)
{
    if (handlerName.startsWith(u"on") && handlerName.size() > 2) {
        QString signal = handlerName.mid(2).toString();
        for (int i = 0; i < signal.length(); ++i) {
            QChar &ch = signal[i];
            if (ch.isLower())
                return QString();
            if (ch.isUpper()) {
                ch = ch.toLower();
                return signal;
            }
        }
    }
    return QString();
}

bool FindWarningVisitor::visit(QQmlJS::AST::UiScriptBinding *uisb)
{
    using namespace QQmlJS::AST;

    const auto qmlScope = m_currentScope;
    if (!QQmlJSImportVisitor::visit(uisb))
        return false;

    auto name = uisb->qualifiedId->name;
    if (name == QLatin1String("id")) {
        // Figure out whether the current scope is the root scope.
        if (auto parentScope = qmlScope->parentScope()) {
            if (!parentScope->parentScope()) {
                const auto expstat = cast<ExpressionStatement *>(uisb->statement);
                const auto identexp = cast<IdentifierExpression *>(expstat->expression);
                m_rootId = identexp->name.toString();
            }
        }
        return true;
    }

    const QString signal = signalName(name);
    if (signal.isEmpty())
        return true;


    if (!qmlScope->hasMethod(signal) && m_warnUnqualified) {
        m_errors.append({
                            QStringLiteral("no matching signal found for handler \"%1\"\n")
                               .arg(name.toString()),
                            QtWarningMsg,
                            uisb->firstSourceLocation()
                        });
        m_visitFailed = true;
        return true;
    }

    QQmlJSMetaMethod scopeSignal;
    for (QQmlJSScope::ConstPtr scope = qmlScope; scope; scope = scope->baseType()) {
        const auto methods = scope->ownMethods();
        const auto methodsRange = methods.equal_range(signal);
        for (auto method = methodsRange.first; method != methodsRange.second; ++method) {
            if (method->methodType() != QQmlJSMetaMethod::Signal)
                continue;
            scopeSignal = *method;
            break;
        }
    }

    const auto statement = uisb->statement;
    if (ExpressionStatement *expr = cast<ExpressionStatement *>(statement)) {
        if (FunctionExpression *func = expr->expression->asFunctionDefinition()) {
            // functions are already handled
            // they do not get names inserted according to the signal, but access their formal
            // parameters. Let's still check if the names match, though.
            const QStringList signalParameters = scopeSignal.parameterNames();
            qsizetype i = 0, end = signalParameters.length();
            for (FormalParameterList *formal = func->formals;
                 formal; ++i, formal = formal->next) {
                if (i == end) {
                    m_errors.append({
                                        QStringLiteral("Signal handler for \"%2\" has more formal"
                                                       " parameters than the signal it handles.")
                                                .arg(name),
                                        QtWarningMsg,
                                        uisb->firstSourceLocation()
                                    });
                    m_visitFailed = true;
                }

                const QStringView handlerParameter = formal->element->bindingIdentifier;
                const qsizetype j = signalParameters.indexOf(handlerParameter);
                if (j == i || j < 0)
                    continue;

                m_errors.append({
                                    QStringLiteral("Parameter %1 to signal handler for \"%2\""
                                                   " is called \"%3\". The signal has a parameter"
                                                   " of the same name in position %4.\n")
                                            .arg(i + 1).arg(name, handlerParameter).arg(j + 1),
                                    QtWarningMsg,
                                    uisb->firstSourceLocation()
                                });
                m_visitFailed = true;
            }

            return true;
        }
    }

    const auto firstSourceLocation = statement->firstSourceLocation();
    bool hasMultilineStatementBody
            = statement->lastSourceLocation().startLine > firstSourceLocation.startLine;
    m_pendingSingalHandler = firstSourceLocation;
    m_signalHandlers.insert(firstSourceLocation, {scopeSignal, hasMultilineStatementBody});
    return true;
}

bool FindWarningVisitor::visit(QQmlJS::AST::IdentifierExpression *idexp)
{
    m_memberAccessChains[m_currentScope].append(
                {{idexp->name.toString(), QString(), idexp->firstSourceLocation()}});
    m_fieldMemberBase = idexp;
    return true;
}

FindWarningVisitor::FindWarningVisitor(
        QQmlJSImporter *importer, QStringList qmltypesFiles, QString code, QString fileName,
        bool silent, bool warnUnqualified, bool warnWithStatement, bool warnInheritanceCycle)
    : QQmlJSImportVisitor(importer, QFileInfo {fileName}.canonicalPath(), qmltypesFiles),
      m_code(std::move(code)),
      m_rootId(QLatin1String("<id>")),
      m_filePath(std::move(fileName)),
      m_colorOut(silent),
      m_warnUnqualified(warnUnqualified),
      m_warnWithStatement(warnWithStatement),
      m_warnInheritanceCycle(warnInheritanceCycle)
{
    m_currentScope->setInternalName("global");

    // setup color output
    m_colorOut.insertMapping(Error, ColorOutput::RedForeground);
    m_colorOut.insertMapping(Warning, ColorOutput::PurpleForeground);
    m_colorOut.insertMapping(Info, ColorOutput::BlueForeground);
    m_colorOut.insertMapping(Normal, ColorOutput::DefaultColor);
    m_colorOut.insertMapping(Hint, ColorOutput::GreenForeground);
    QLatin1String jsGlobVars[] = {
        /* Not listed on the MDN page; browser and QML extensions: */
        // console/debug api
        QLatin1String("console"), QLatin1String("print"),
        // garbage collector
        QLatin1String("gc"),
        // i18n
        QLatin1String("qsTr"), QLatin1String("qsTrId"), QLatin1String("QT_TR_NOOP"),
        QLatin1String("QT_TRANSLATE_NOOP"), QLatin1String("QT_TRID_NOOP"),
        // XMLHttpRequest
        QLatin1String("XMLHttpRequest")
    };

    QQmlJSScope::JavaScriptIdentifier globalJavaScript = {
        QQmlJSScope::JavaScriptIdentifier::LexicalScoped,
        QQmlJS::SourceLocation()
    };
    for (const char **globalName = QV4::Compiler::Codegen::s_globalNames;
         *globalName != nullptr;
         ++globalName) {
        m_currentScope->insertJSIdentifier(QString::fromLatin1(*globalName), globalJavaScript);
    }
    for (const auto& jsGlobVar: jsGlobVars)
        m_currentScope->insertJSIdentifier(jsGlobVar, globalJavaScript);
}

static MessageColors messageColor(QtMsgType type)
{
    switch (type) {
    case QtDebugMsg:
        return Normal;
    case QtWarningMsg:
        return Warning;
    case QtCriticalMsg:
    case QtFatalMsg:
        return Error;
    case QtInfoMsg:
        return Info;
    }

    return Normal;
}

bool FindWarningVisitor::check()
{
    for (const auto &error : qAsConst(m_errors)) {
        if (error.loc.isValid()) {
            m_colorOut.writePrefixedMessage(
                        QStringLiteral("%1:%2: %3")
                            .arg(error.loc.startLine).arg(error.loc.startColumn).arg(error.message),
                        messageColor(error.type));
        } else {
            m_colorOut.writePrefixedMessage(error.message, messageColor(error.type));
        }
    }

    // now that all ids are known, revisit any Connections whose target were perviously unknown
    for (auto const &outstandingConnection: m_outstandingConnections) {
        auto targetScope = m_scopesById[outstandingConnection.targetName];
        if (outstandingConnection.scope) {
            for (const auto scope = targetScope; targetScope;
                 targetScope = targetScope->baseType()) {
                const auto connectionMethods = targetScope->ownMethods();
                for (const auto &method : connectionMethods)
                    outstandingConnection.scope->addOwnMethod(method);
            }
        }
        QScopedValueRollback<QQmlJSScope::Ptr> rollback(m_currentScope, outstandingConnection.scope);
        outstandingConnection.uiod->initializer->accept(this);
    }

    if (!m_warnUnqualified)
        return true;

    CheckIdentifiers check(&m_colorOut, m_code, m_rootScopeImports, m_filePath);
    return check(m_scopesById, m_signalHandlers, m_memberAccessChains, m_globalScope, m_rootId)
            && !m_visitFailed;
}

bool FindWarningVisitor::visit(QQmlJS::AST::UiObjectBinding *uiob)
{
    if (!QQmlJSImportVisitor::visit(uiob))
        return false;

    checkInheritanceCycle(m_currentScope);
    return true;
}

bool FindWarningVisitor::visit(QQmlJS::AST::UiObjectDefinition *uiod)
{
    using namespace QQmlJS::AST;

    if (!QQmlJSImportVisitor::visit(uiod))
        return false;

    const QString name = m_currentScope->baseTypeName();
    if (name.isEmpty() || name.front().isLower())
        return false; // Ignore grouped properties for now

    checkInheritanceCycle(m_currentScope);

    if (name.endsWith("Connections")) {
        QString target;
        auto member = uiod->initializer->members;
        while (member) {
            if (member->member->kind == QQmlJS::AST::Node::Kind_UiScriptBinding) {
                auto asBinding = static_cast<QQmlJS::AST::UiScriptBinding*>(member->member);
                if (asBinding->qualifiedId->name == QLatin1String("target")) {
                    if (asBinding->statement->kind == QQmlJS::AST::Node::Kind_ExpressionStatement) {
                        auto expr = static_cast<QQmlJS::AST::ExpressionStatement*>(asBinding->statement)->expression;
                        if (auto idexpr = QQmlJS::AST::cast<QQmlJS::AST::IdentifierExpression*>(expr)) {
                            target = idexpr->name.toString();
                        } else {
                            // more complex expressions are not supported
                        }
                    }
                    break;
                }
            }
            member = member->next;
        }
        QQmlJSScope::ConstPtr targetScope;
        if (target.isEmpty()) {
            // no target set, connection comes from parentF
            QQmlJSScope::Ptr scope = m_currentScope;
            do {
                scope = scope->parentScope(); // TODO: rename method
            } while (scope->scopeType() != QQmlJSScope::QMLScope);
            targetScope = m_rootScopeImports.value(scope->baseTypeName());
        } else {
            // there was a target, check if we already can find it
            auto scopeIt =  m_scopesById.find(target);
            if (scopeIt != m_scopesById.end()) {
                targetScope = *scopeIt;
            } else {
                m_outstandingConnections.push_back({target, m_currentScope, uiod});
                return false; // visit children later once target is known
            }
        }
        for (const auto scope = targetScope; targetScope; targetScope = targetScope->baseType()) {
            const auto connectionMethods = targetScope->ownMethods();
            for (const auto &method : connectionMethods)
                m_currentScope->addOwnMethod(method);
        }
    }
    return true;
}

bool FindWarningVisitor::visit(QQmlJS::AST::PatternElement *element)
{
    if (element->isVariableDeclaration()) {
        QQmlJS::AST::BoundNames names;
        element->boundNames(&names);
        for (const auto &name : names) {
            m_currentScope->insertJSIdentifier(
                        name.id, {
                            (element->scope == QQmlJS::AST::VariableScope::Var)
                                ? QQmlJSScope::JavaScriptIdentifier::FunctionScoped
                                : QQmlJSScope::JavaScriptIdentifier::LexicalScoped,
                            element->firstSourceLocation()
                        });
        }
    }

    return true;
}

void FindWarningVisitor::endVisit(QQmlJS::AST::UiObjectDefinition *uiod)
{
    auto childScope = m_currentScope;
    QQmlJSImportVisitor::endVisit(uiod);

    if (m_warnUnqualified)
        checkGroupedScopes(childScope);

    if (m_currentScope == m_globalScope
            || m_currentScope->baseTypeName() == QStringLiteral("Component")) {
        return;
    }

    auto property = childScope->property(QStringLiteral("parent"));
    if (!property.propertyName().isEmpty()) {
        property.setType(QQmlJSScope::ConstPtr(m_currentScope));
        childScope->addOwnProperty(property);
    }
}

bool FindWarningVisitor::visit(QQmlJS::AST::FieldMemberExpression *)
{
    return true;
}

void FindWarningVisitor::endVisit(QQmlJS::AST::FieldMemberExpression *fieldMember)
{
    using namespace QQmlJS::AST;
    ExpressionNode *base = fieldMember->base;
    while (auto *nested = cast<NestedExpression *>(base))
        base = nested->expression;

    if (m_fieldMemberBase == base) {
        QString type;
        if (auto *binary = cast<BinaryExpression *>(base)) {
            if (binary->op == QSOperator::As) {
                if (auto *right = cast<TypeExpression *>(binary->right))
                    type = right->m_type->toString();
            }
        }


        auto &chain = m_memberAccessChains[m_currentScope];
        Q_ASSERT(!chain.last().isEmpty());
        chain.last().append(FieldMember {
                                fieldMember->name.toString(), type, fieldMember->identifierToken
                            });
        m_fieldMemberBase = fieldMember;
    } else {
        m_fieldMemberBase = nullptr;
    }
}

bool FindWarningVisitor::visit(QQmlJS::AST::BinaryExpression *)
{
    return true;
}

void FindWarningVisitor::endVisit(QQmlJS::AST::BinaryExpression *binExp)
{
    if (binExp->op == QSOperator::As && m_fieldMemberBase == binExp->left)
        m_fieldMemberBase = binExp;
    else
        m_fieldMemberBase = nullptr;
}