#include "c_plugin_generator.h"
#include <QStringList>

// Convert a snake_case name to PascalCase
static QString toPascal(const QString& snake)
{
    QStringList parts = snake.split('_', Qt::SkipEmptyParts);
    QString result;
    for (const QString& p : parts) {
        if (p.isEmpty()) continue;
        result += p.at(0).toUpper() + p.mid(1);
    }
    return result;
}

// Map LIDL type to Qt/C++ type string for the plugin interface
static QString lidlToQt(const TypeExpr& t)
{
    if (t.kind == TypeExpr::Primitive) {
        if (t.name == "tstr") return "QString";
        if (t.name == "bstr") return "QByteArray";
        if (t.name == "int") return "int";
        if (t.name == "uint") return "int";
        if (t.name == "float64") return "double";
        if (t.name == "bool") return "bool";
        if (t.name == "void") return "void";
        if (t.name == "result") return "LogosResult";
        if (t.name == "any") return "QVariant";
    }
    if (t.kind == TypeExpr::Array) {
        if (!t.elements.empty() && t.elements[0].name == "tstr")
            return "QStringList";
        return "QVariantList";
    }
    if (t.kind == TypeExpr::Map)
        return "QVariantMap";
    return "QVariant";
}

// Map LIDL type to C type string for the function call
static QString lidlToC(const TypeExpr& t)
{
    if (t.kind == TypeExpr::Primitive) {
        if (t.name == "tstr") return "const char*";
        if (t.name == "int") return "int64_t";
        if (t.name == "uint") return "uint64_t";
        if (t.name == "float64") return "double";
        if (t.name == "bool") return "bool";
        if (t.name == "void") return "void";
    }
    return "void*"; // fallback
}

// Generate expression to convert a Qt-typed parameter to C type for the call
static QString qtToCallExpr(const TypeExpr& t, const QString& paramName)
{
    if (t.name == "tstr")
        return paramName + ".toUtf8().constData()";
    if (t.name == "int")
        return "static_cast<int64_t>(" + paramName + ")";
    if (t.name == "uint")
        return "static_cast<uint64_t>(" + paramName + ")";
    return paramName; // double, bool pass through
}

// Generate expression to convert a C return value to Qt type
static QString cRetToQt(const TypeExpr& t, const QString& expr)
{
    if (t.name == "tstr")
        return "QString::fromUtf8(" + expr + ")";
    if (t.name == "int")
        return "static_cast<int>(" + expr + ")";
    if (t.name == "uint")
        return "static_cast<int>(" + expr + ")";
    return expr; // double, bool, void pass through
}

QString cPluginMakeHeader(const ModuleDecl& module,
                          const QString& cHeaderInclude,
                          const QString& prefix)
{
    Q_UNUSED(prefix);
    QString pascal = toPascal(module.name);
    QString out;
    out += "// AUTO-GENERATED by logos-cpp-generator --from-c-header -- do not edit\n";
    out += "#pragma once\n\n";
    out += "#include <QObject>\n";
    out += "#include <QString>\n";
    out += "#include <QVariant>\n";
    out += "#include <QVariantList>\n";
    out += "#include \"interface.h\"\n";
    out += "#include \"logos_api.h\"\n\n";
    out += "extern \"C\" {\n";
    out += "#include \"" + cHeaderInclude + "\"\n";
    out += "}\n\n";

    // Interface class
    QString ifaceName = pascal + "Interface";
    QString ifaceIid = "\"org.logos." + ifaceName + "\"";
    out += "class " + ifaceName + " : public PluginInterface {\n";
    out += "public:\n";
    out += "    virtual ~" + ifaceName + "() = default;\n";
    for (const MethodDecl& m : module.methods) {
        out += "    Q_INVOKABLE virtual " + lidlToQt(m.returnType) + " " + m.name + "(";
        for (size_t i = 0; i < m.params.size(); ++i) {
            if (i > 0) out += ", ";
            out += lidlToQt(m.params[i].type) + " " + m.params[i].name;
        }
        out += ") = 0;\n";
    }
    out += "};\n\n";
    out += "#define " + ifaceName + "_iid " + ifaceIid + "\n";
    out += "Q_DECLARE_INTERFACE(" + ifaceName + ", " + ifaceName + "_iid)\n\n";

    // Plugin class
    QString pluginName = pascal + "Plugin";
    out += "class " + pluginName + " : public QObject, public " + ifaceName + " {\n";
    out += "    Q_OBJECT\n";
    out += "    Q_PLUGIN_METADATA(IID " + ifaceName + "_iid FILE \"metadata.json\")\n";
    out += "    Q_INTERFACES(" + ifaceName + " PluginInterface)\n\n";
    out += "public:\n";
    out += "    explicit " + pluginName + "(QObject* parent = nullptr);\n";
    out += "    ~" + pluginName + "() override;\n\n";
    out += "    QString name() const override { return QStringLiteral(\"" + module.name + "\"); }\n";
    out += "    QString version() const override { return QStringLiteral(\"" + module.version + "\"); }\n\n";
    out += "    Q_INVOKABLE void initLogos(LogosAPI* logosAPIInstance);\n\n";
    for (const MethodDecl& m : module.methods) {
        out += "    Q_INVOKABLE " + lidlToQt(m.returnType) + " " + m.name + "(";
        for (size_t i = 0; i < m.params.size(); ++i) {
            if (i > 0) out += ", ";
            out += lidlToQt(m.params[i].type) + " " + m.params[i].name;
        }
        out += ") override;\n";
    }
    out += "\nsignals:\n";
    out += "    void eventResponse(const QString& eventName, const QVariantList& args);\n";
    out += "};\n";

    return out;
}

QString cPluginMakeSource(const ModuleDecl& module,
                          const QString& prefix)
{
    QString pascal = toPascal(module.name);
    QString pluginName = pascal + "Plugin";
    QString out;
    out += "// AUTO-GENERATED by logos-cpp-generator --from-c-header -- do not edit\n";
    out += "#include \"" + module.name + "_plugin.h\"\n";
    out += "#include <QDebug>\n\n";

    // Constructor
    out += pluginName + "::" + pluginName + "(QObject* parent)\n";
    out += "    : QObject(parent)\n";
    out += "{\n";
    out += "    qDebug() << \"" + pluginName + ": created\";\n";
    out += "}\n\n";

    // Destructor
    out += pluginName + "::~" + pluginName + "()\n";
    out += "{\n";
    out += "    qDebug() << \"" + pluginName + ": destroyed\";\n";
    out += "}\n\n";

    // initLogos — store the API pointer (required by QtProviderObject::callMethod)
    out += "void " + pluginName + "::initLogos(LogosAPI* logosAPIInstance)\n";
    out += "{\n";
    out += "    logosAPI = logosAPIInstance;\n";
    out += "    qDebug() << \"" + pluginName + "::initLogos called, api=\" << (void*)logosAPIInstance << \"stored=\" << (void*)logosAPI;\n";
    out += "}\n\n";

    // Method implementations
    for (const MethodDecl& m : module.methods) {
        QString retQt = lidlToQt(m.returnType);
        out += retQt + " " + pluginName + "::" + m.name + "(";
        for (size_t i = 0; i < m.params.size(); ++i) {
            if (i > 0) out += ", ";
            out += lidlToQt(m.params[i].type) + " " + m.params[i].name;
        }
        out += ")\n{\n";

        // Build C function call
        QString cFunc = prefix + m.name;
        // Handle the reserved-name rename: if method is "libVersion", original C func is prefix + "version"
        if (m.name.startsWith("lib") && m.name.length() > 3 && m.name[3].isUpper()) {
            QString original = m.name.mid(3);
            original[0] = original[0].toLower();
            cFunc = prefix + original;
        }

        QString callArgs;
        for (size_t i = 0; i < m.params.size(); ++i) {
            if (i > 0) callArgs += ", ";
            callArgs += qtToCallExpr(m.params[i].type, m.params[i].name);
        }

        QString call = cFunc + "(" + callArgs + ")";

        if (m.returnType.name == "void") {
            out += "    " + call + ";\n";
        } else {
            out += "    return " + cRetToQt(m.returnType, call) + ";\n";
        }
        out += "}\n\n";
    }

    return out;
}