Refactor: Replace JSON with IDataNode abstraction in all interfaces

Major architectural improvement to decouple interfaces from JSON implementation:

**New Abstractions:**
- Created IDataValue interface for type-safe data access
- All interfaces now use IDataNode instead of nlohmann::json
- Enables future backend flexibility (JSON, MessagePack, etc.)

**Updated Interfaces:**
- ISerializable: serialize() returns IDataNode, deserialize() takes IDataNode
- IModule: process(), getState(), setState(), getHealthStatus() use IDataNode
- IIO: Message struct and publish() use IDataNode
- ITaskScheduler: scheduleTask() and getCompletedTask() use IDataNode
- IModuleSystem: queryModule() uses IDataNode
- IEngine: Removed JSON dependency
- IDataNode: getData(), setData(), queryByProperty() use IDataValue

**Benefits:**
- Clean separation between interface and implementation
- No JSON leakage into public APIs
- Easier testing and mocking
- Potential for multiple backend implementations
- Better encapsulation and abstraction

**Note:** Concrete implementations still use JSON internally -
this is an interface-only refactoring for better architecture.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

CMakeLists.txt

@@ -43,6 +43,11 @@ if(GROVE_BUILD_IMPLEMENTATIONS)
         GroveEngine::core
     )
 
+    # If imgui is available from parent project, link it
+    if(TARGET imgui_backends)
+        target_link_libraries(grove_impl PUBLIC imgui_backends)
+    endif()
+
     add_library(GroveEngine::impl ALIAS grove_impl)
 endif()
 

include/grove/ASerializable.h

@@ -1,9 +1,8 @@
 #pragma once
 
-#include <nlohmann/json.hpp>
+#include "IDataNode.h"
 #include <string>
-
+#include <memory>
-using json = nlohmann::json;
 
 namespace warfactory {
 
@@ -19,8 +18,8 @@ public:
 
     const std::string& getInstanceId() const { return instance_id; }
 
-    virtual json serialize() const = 0;
+    virtual std::unique_ptr<IDataNode> serialize() const = 0;
-    virtual void deserialize(const json& data) = 0;
+    virtual void deserialize(const IDataNode& data) = 0;
 
 protected:
     void registerForSerialization();

include/grove/IDataNode.h

@@ -4,18 +4,16 @@
 #include <vector>
 #include <memory>
 #include <functional>
-#include <nlohmann/json.hpp>
+#include "IDataValue.h"
 
 namespace warfactory {
 
-using json = nlohmann::json;
-
 /**
  * @brief Interface for a single node in the data tree
  *
  * Each node can have:
  * - Children nodes (tree navigation)
- * - Its own data blob (JSON)
+ * - Its own data blob (IDataValue)
  * - Properties accessible by name with type safety
  */
 class IDataNode {
@@ -112,12 +110,12 @@ public:
      *
      * Example:
      * // Find all tanks with armor > 150
-     * queryByProperty("armor", [](const json& val) {
+     * queryByProperty("armor", [](const IDataValue& val) {
-     *     return val.is_number() && val.get<int>() > 150;
+     *     return val.isNumber() && val.asInt() > 150;
      * });
      */
     virtual std::vector<IDataNode*> queryByProperty(const std::string& propName,
-                                                   const std::function<bool(const json&)>& predicate) = 0;
+                                                   const std::function<bool(const IDataValue&)>& predicate) = 0;
 
     // ========================================
     // NODE'S OWN DATA
@@ -125,9 +123,9 @@ public:
 
     /**
      * @brief Get this node's data blob
-     * @return JSON data or empty JSON if no data
+     * @return Data value or null if no data
      */
-    virtual json getData() const = 0;
+    virtual std::unique_ptr<IDataValue> getData() const = 0;
 
     /**
      * @brief Check if this node has data
@@ -137,9 +135,9 @@ public:
 
     /**
      * @brief Set this node's data
-     * @param data JSON data to set
+     * @param data Data to set
      */
-    virtual void setData(const json& data) = 0;
+    virtual void setData(std::unique_ptr<IDataValue> data) = 0;
 
     // ========================================
     // TYPED DATA ACCESS BY PROPERTY NAME

include/grove/IDataValue.h

@@ -0,0 +1,43 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <memory>
+
+namespace warfactory {
+
+/**
+ * @brief Interface for data values - abstracts underlying data format
+ *
+ * This allows IDataNode to work with values without exposing JSON directly.
+ * Concrete implementations can use JSON, MessagePack, or any other format.
+ */
+class IDataValue {
+public:
+    virtual ~IDataValue() = default;
+
+    // Type checking
+    virtual bool isNull() const = 0;
+    virtual bool isBool() const = 0;
+    virtual bool isNumber() const = 0;
+    virtual bool isString() const = 0;
+    virtual bool isArray() const = 0;
+    virtual bool isObject() const = 0;
+
+    // Value access with defaults
+    virtual bool asBool(bool defaultValue = false) const = 0;
+    virtual int asInt(int defaultValue = 0) const = 0;
+    virtual double asDouble(double defaultValue = 0.0) const = 0;
+    virtual std::string asString(const std::string& defaultValue = "") const = 0;
+
+    // Array/Object access
+    virtual size_t size() const = 0;
+    virtual std::unique_ptr<IDataValue> get(size_t index) const = 0;
+    virtual std::unique_ptr<IDataValue> get(const std::string& key) const = 0;
+    virtual bool has(const std::string& key) const = 0;
+
+    // Serialization
+    virtual std::string toString() const = 0;
+};
+
+} // namespace warfactory

include/grove/IEngine.h

@@ -2,15 +2,13 @@
 
 #include <string>
 #include <memory>
-#include <nlohmann/json.hpp>
 
 // Forward declarations to avoid circular dependencies
 namespace warfactory {
     class IModuleSystem;
+    class IIO;
 }
 
-using json = nlohmann::json;
-
 namespace warfactory {
 
 enum class EngineType {

include/grove/IIO.h

@@ -3,9 +3,8 @@
 #include <string>
 #include <vector>
 #include <functional>
-#include <nlohmann/json.hpp>
+#include <memory>
-
+#include "IDataNode.h"
-using json = nlohmann::json;
 
 namespace warfactory {
 
@@ -24,7 +23,7 @@ struct SubscriptionConfig {
 
 struct Message {
     std::string topic;
-    json data;
+    std::unique_ptr<IDataNode> data;
     uint64_t timestamp;
 };
 
@@ -55,9 +54,9 @@ public:
     /**
      * @brief Publish message to a topic
      * @param topic Topic name (e.g., "player:123", "economy:prices")
-     * @param message JSON message data
+     * @param message Message data
      */
-    virtual void publish(const std::string& topic, const json& message) = 0;
+    virtual void publish(const std::string& topic, std::unique_ptr<IDataNode> message) = 0;
 
     /**
      * @brief Subscribe to topic pattern (high-frequency)

include/grove/IModule.h

@@ -1,7 +1,7 @@
 #pragma once
 
 #include <string>
-#include <nlohmann/json.hpp>
+#include <memory>
 #include "IDataNode.h"
 #include "ITaskScheduler.h"
 
@@ -10,8 +10,6 @@ namespace warfactory {
     class IIO;
 }
 
-using json = nlohmann::json;
-
 namespace warfactory {
 
 
@@ -43,13 +41,13 @@ public:
 
     /**
      * @brief Process game logic
-     * @param input JSON input from other modules or the module system
+     * @param input Data input from other modules or the module system
      *
      * This is the core method where all module logic is implemented.
      * Modules communicate via IIO pub/sub and can delegate tasks via ITaskScheduler.
      * Must handle state properly through getState/setState for hot-reload.
      */
-    virtual void process(const json& input) = 0;
+    virtual void process(const IDataNode& input) = 0;
 
     /**
      * @brief Set module configuration (replaces initialize)
@@ -70,9 +68,9 @@ public:
 
     /**
      * @brief Get detailed health status of the module
-     * @return JSON health report with status, metrics, and diagnostics
+     * @return Health report with status, metrics, and diagnostics
      */
-    virtual json getHealthStatus() = 0;
+    virtual std::unique_ptr<IDataNode> getHealthStatus() = 0;
 
     /**
      * @brief Cleanup and shutdown the module
@@ -84,24 +82,24 @@ public:
 
     /**
      * @brief Get current module state for hot-reload support
-     * @return JSON representation of all module state
+     * @return Data representation of all module state
      *
      * Critical for hot-reload functionality. Must serialize all internal
      * state that needs to be preserved when the module is replaced.
-     * The returned JSON should be sufficient to restore the module to
+     * The returned data should be sufficient to restore the module to
      * its current state via setState().
      */
-    virtual json getState() = 0;
+    virtual std::unique_ptr<IDataNode> getState() = 0;
 
     /**
      * @brief Restore module state after hot-reload
-     * @param state JSON state previously returned by getState()
+     * @param state State previously returned by getState()
      *
      * Called after module replacement to restore the previous state.
-     * Must be able to reconstruct all internal state from the JSON
+     * Must be able to reconstruct all internal state from the data
      * to ensure seamless hot-reload without game disruption.
      */
-    virtual void setState(const json& state) = 0;
+    virtual void setState(const IDataNode& state) = 0;
 
     /**
      * @brief Get module type identifier

include/grove/IModuleSystem.h

@@ -2,7 +2,6 @@
 
 #include <string>
 #include <memory>
-#include <nlohmann/json.hpp>
 #include "ITaskScheduler.h"
 
 // Forward declarations to avoid circular dependencies
@@ -11,8 +10,6 @@ namespace warfactory {
     class IIO;
 }
 
-using json = nlohmann::json;
-
 namespace warfactory {
 
 enum class ModuleSystemType {
@@ -76,14 +73,14 @@ public:
     /**
      * @brief Query a specific module directly
      * @param name Name of the module to query
-     * @param input JSON input to send to the module
+     * @param input Input data to send to the module
-     * @return JSON response from the module
+     * @return Response data from the module
      *
      * This provides direct access to module functionality for debugging,
      * testing, or administrative purposes. The query bypasses normal
      * execution flow and calls the module's process() method directly.
      */
-    virtual json queryModule(const std::string& name, const json& input) = 0;
+    virtual std::unique_ptr<IDataNode> queryModule(const std::string& name, const IDataNode& input) = 0;
 
     /**
      * @brief Get module system type identifier

include/grove/ISerializable.h

@@ -1,8 +1,7 @@
 #pragma once
 
-#include <nlohmann/json.hpp>
+#include "IDataNode.h"
-
+#include <memory>
-using json = nlohmann::json;
 
 namespace warfactory {
 
@@ -10,8 +9,8 @@ class ISerializable {
 public:
     virtual ~ISerializable() = default;
 
-    virtual json serialize() const = 0;
+    virtual std::unique_ptr<IDataNode> serialize() const = 0;
-    virtual void deserialize(const json& data) = 0;
+    virtual void deserialize(const IDataNode& data) = 0;
 };
 
 } // namespace warfactory

include/grove/ITaskScheduler.h

@@ -1,9 +1,8 @@
 #pragma once
 
 #include <string>
-#include <nlohmann/json.hpp>
+#include <memory>
-
+#include "IDataNode.h"
-using json = nlohmann::json;
 
 namespace warfactory {
 
@@ -43,26 +42,28 @@ public:
     /**
      * @brief Schedule a task for execution
      * @param taskType Type of task (e.g., "pathfinding", "market_analysis", "belt_optimization")
-     * @param taskData JSON data for the task
+     * @param taskData Data for the task
      *
      * Example usage:
      * ```cpp
      * // TankModule delegates pathfinding
-     * scheduler->scheduleTask("pathfinding", {
+     * auto taskData = createDataNode({
      *     {"start", {x: 100, y: 200}},
      *     {"target", {x: 500, y: 600}},
      *     {"unit_id", "tank_001"}
      * });
+     * scheduler->scheduleTask("pathfinding", std::move(taskData));
      *
      * // ProductionModule delegates belt calculation
-     * scheduler->scheduleTask("belt_optimization", {
+     * auto beltData = createDataNode({
      *     {"factory_id", "main_base"},
      *     {"item_type", "iron_plate"},
      *     {"throughput_target", 240}
      * });
+     * scheduler->scheduleTask("belt_optimization", std::move(beltData));
      * ```
      */
-    virtual void scheduleTask(const std::string& taskType, const json& taskData) = 0;
+    virtual void scheduleTask(const std::string& taskType, std::unique_ptr<IDataNode> taskData) = 0;
 
     /**
      * @brief Check if completed tasks are available
@@ -75,7 +76,7 @@ public:
 
     /**
      * @brief Pull and consume one completed task
-     * @return Task result JSON. Task is removed from completed queue.
+     * @return Task result data. Task is removed from completed queue.
      *
      * Example results:
      * ```cpp
@@ -96,7 +97,7 @@ public:
      * }
      * ```
      */
-    virtual json getCompletedTask() = 0;
+    virtual std::unique_ptr<IDataNode> getCompletedTask() = 0;
 };
 
 } // namespace warfactory

src/DebugEngine.cpp

@@ -1,4 +1,4 @@
-#include <warfactory/DebugEngine.h>
+#include <grove/DebugEngine.h>
 #include <fstream>
 #include <filesystem>
 #include <spdlog/sinks/stdout_color_sinks.h>

src/EngineFactory.cpp

@@ -1,4 +1,4 @@
-#include <warfactory/EngineFactory.h>
+#include <grove/EngineFactory.h>
 #include <fstream>
 #include <algorithm>
 #include <nlohmann/json.hpp>

src/IOFactory.cpp

@@ -1,12 +1,12 @@
-#include <warfactory/IOFactory.h>
+#include <grove/IOFactory.h>
 #include <algorithm>
 #include <random>
 #include <functional>
 #include <spdlog/sinks/stdout_color_sinks.h>
 
 // Include implemented transports
-#include <warfactory/IntraIO.h>
+#include <grove/IntraIO.h>
-#include <warfactory/IntraIOManager.h>
+#include <grove/IntraIOManager.h>
 // Forward declarations for future implementations
 // #include "LocalIO.h"
 // #include "NetworkIO.h"

src/ImGuiUI.cpp

@@ -1,4 +1,4 @@
-#include "warfactory/ImGuiUI.h"
+#include <grove/ImGuiUI.h>
 #include <sstream>
 #include <iomanip>
 #include <iostream>

src/IntraIO.cpp

@@ -1,5 +1,5 @@
-#include <warfactory/IntraIO.h>
+#include <grove/IntraIO.h>
-#include <warfactory/IntraIOManager.h>
+#include <grove/IntraIOManager.h>
 #include <stdexcept>
 #include <algorithm>
 #include <thread>

src/IntraIOManager.cpp

@@ -1,5 +1,5 @@
-#include <warfactory/IntraIOManager.h>
+#include <grove/IntraIOManager.h>
-#include <warfactory/IntraIO.h>
+#include <grove/IntraIO.h>
 #include <stdexcept>
 #include <spdlog/sinks/stdout_color_sinks.h>
 #include <spdlog/sinks/basic_file_sink.h>

src/ModuleFactory.cpp

@@ -1,4 +1,4 @@
-#include <warfactory/ModuleFactory.h>
+#include <grove/ModuleFactory.h>
 #include <filesystem>
 #include <dlfcn.h>
 #include <algorithm>

src/ModuleSystemFactory.cpp

@@ -1,10 +1,10 @@
-#include <warfactory/ModuleSystemFactory.h>
+#include <grove/ModuleSystemFactory.h>
 #include <algorithm>
 #include <thread>
 #include <spdlog/sinks/stdout_color_sinks.h>
 
 // Include implemented systems
-#include <warfactory/SequentialModuleSystem.h>
+#include <grove/SequentialModuleSystem.h>
 // Forward declarations for future implementations
 // #include "ThreadedModuleSystem.h"
 // #include "ThreadPoolModuleSystem.h"

src/ResourceRegistry.cpp

@@ -1,4 +1,4 @@
-#include "warfactory/ResourceRegistry.h"
+#include <grove/ResourceRegistry.h>
 #include <algorithm>
 
 namespace warfactory {

src/SequentialModuleSystem.cpp

@@ -1,4 +1,4 @@
-#include <warfactory/SequentialModuleSystem.h>
+#include <grove/SequentialModuleSystem.h>
 #include <stdexcept>
 #include <spdlog/sinks/stdout_color_sinks.h>
 #include <spdlog/sinks/basic_file_sink.h>