logos-view-module-runtime/include/LogosQmlBridge.h

#pragma once

#include <QObject>
#include <QString>
#include <QVariant>
#include <QVariantList>
#include <QJSValue>
#include <QMap>

class LogosAPI;
class QRemoteObjectNode;
class QAbstractItemModelReplica;
class LogosViewReplicaFactory;
class QPluginLoader;

// ── LogosQmlBridge ───────────────────────────────────────────────────────────
//
// Single entry point for QML to talk to modules.
//
// Non-view (backend) modules — go through LogosAPI IPC:
//   logos.callModule(name, method, [args])              // sync, returns JSON
//   logos.callModuleAsync(name, method, [args], cb, ms) // async, JSON payload
//
// View modules — each view module ships a typed replica factory plugin
// (generated by logos_module() from a .rep file). The host loads it and
// exposes the typed replica directly to QML, so this API is dead simple:
//
//   property var backend: logos.module("my_view_module")
//   Text { text: backend.someProperty }
//   Button { onClicked: backend.someSlot() }
//   Connections { target: backend; function onSomeSignal() { ... } }
//
//   // Enums declared in the .rep are available under the QML URI the
//   // factory registered (typically "Logos.<ModuleName>"):
//   import Logos.MyViewModule 1.0
//   Text { text: backend.status === MyViewModule.Active ? "on" : "off" }
//
//   // QAbstractItemModel* Q_PROPERTYs are still remoted separately:
//   ListView { model: logos.model("my_view_module", "items") }
//
class LogosQmlBridge : public QObject {
    Q_OBJECT
public:
    explicit LogosQmlBridge(LogosAPI* api, QObject* parent = nullptr);

    // ── Backend (non-view) module calls via LogosAPI IPC ────────────────
    Q_INVOKABLE QString callModule(const QString& module,
                                   const QString& method,
                                   const QVariantList& args = QVariantList());

    // timeoutMs: if > 0, the callback is invoked with an error payload when
    // no reply arrives within that many milliseconds. Default 30000 (30s);
    // pass 0 to disable.
    Q_INVOKABLE void callModuleAsync(const QString& module,
                                     const QString& method,
                                     const QVariantList& args,
                                     QJSValue callback,
                                     int timeoutMs = 30000);

    // ── View module API ─────────────────────────────────────────────────

    // Returns the typed replica for a view module. Safe to call before the
    // replica is Valid — QML will see default-constructed values until then
    // and property NOTIFYs fire once the source meta arrives.
    Q_INVOKABLE QObject* module(const QString& moduleName);

    // Returns a QAbstractItemModelReplica* for a QAbstractItemModel*
    // Q_PROPERTY on the view module. ui-host auto-remotes every such
    // property as "<module>/<propertyName>".
    //
    // prefetch=true acquires with QtRemoteObjects::PrefetchData, so the
    // replica caches all roles for the initial rowCount before it reports
    // populated — kills the "row exists but roles are still null" flash
    // that FetchRootSize (the default) shows. Only safe for bounded /
    // paged models; a raw source of 100k rows would fetch 100k *
    // roles up front.
    Q_INVOKABLE QObject* model(const QString& moduleName,
                               const QString& modelName,
                               bool prefetch = false);

    // True once the view module's replica is Valid (source meta received).
    Q_INVOKABLE bool isViewModuleReady(const QString& moduleName) const;

    // Watch a QRemoteObjectPendingCall returned by a replica slot call and
    // invoke callbacks with the result. Replaces QtRemoteObjects.watch() so
    // QML plugins don't need to import QtRemoteObjects (keeping the sandbox
    // locked down).
    //
    // Usage:
    //   logos.watch(backend.add(1, 2),
    //     function(value) { display.text = value },
    //     function(error) { console.log(error) })
    Q_INVOKABLE void watch(const QVariant& pendingCall,
                           QJSValue onSuccess,
                           QJSValue onError = QJSValue());

    // Called by the host application during setup.
    void setViewModuleSocket(const QString& moduleName, const QString& socketName);
    void setViewReplicaPlugin(const QString& moduleName, const QString& pluginPath);

    // Called when the view module's child process exits unexpectedly.
    void notifyViewModuleCrashed(const QString& moduleName);

    // ── Test-friendly helpers ───────────────────────────────────────────
    //
    // Stateless serializer for a QVariant result into the JSON string
    // shape QML consumers expect. Exposed as a public static method so
    // unit tests (and callers who want the same format without going
    // through callModule()) can exercise it directly.
    static QString serializeResultForTesting(const QVariant& result);

    // Introspection helpers used by unit tests to assert routing state
    // without needing a real QRemoteObjectNode.
    bool hasViewModuleSocket(const QString& moduleName) const;
    QString viewModuleSocket(const QString& moduleName) const;
    QString viewReplicaPluginPath(const QString& moduleName) const;

    // Subscribe to events emitted by core (non-view) modules. When the
    // module emits an event, the moduleEventReceived signal fires.
    //
    // Usage:
    //   Component.onCompleted: logos.onModuleEvent("calc_module", "resultReady")
    //   Connections {
    //       target: logos
    //       function onModuleEventReceived(moduleName, eventName, data) {
    //           if (eventName === "resultReady")
    //               console.log("Got result:", JSON.stringify(data))
    //       }
    //   }
    //
    // Returns true if the subscription succeeded.
    Q_INVOKABLE bool onModuleEvent(const QString& moduleName, const QString& eventName);

signals:
    void viewModuleReadyChanged(const QString& moduleName, bool ready);
    void viewModuleCrashed(const QString& moduleName);
    void moduleEventReceived(const QString& moduleName,
                             const QString& eventName,
                             const QVariantList& data);

private:
    void dropViewModuleCaches(const QString& moduleName);
    QRemoteObjectNode* getOrCreateNode(const QString& moduleName);
    LogosViewReplicaFactory* loadFactory(const QString& moduleName);

    LogosAPI* m_logosAPI;

    // Per-view-module state
    QMap<QString, QString> m_viewModuleSockets;
    QMap<QString, QString> m_replicaPluginPaths;
    QMap<QString, QRemoteObjectNode*> m_replicaNodes;
    QMap<QString, QPluginLoader*> m_factoryLoaders;
    QMap<QString, LogosViewReplicaFactory*> m_factories;
    QMap<QString, QObject*> m_replicas;
    QMap<QString, QAbstractItemModelReplica*> m_modelReplicas;
};