fix: resolve #745 — OPC UA - ARRAY of User defined datatype does not work.

docs/outdated/debugger-opcua-shared-utilities.md

@@ -2,7 +2,7 @@
 
 ## Overview
 
-This document outlines the plan to refactor the OpenPLC Editor codebase to eliminate code duplication between the **debugger** and **OPC-UA** subsystems. Both systems need to resolve debug variable indices from the `debug.c` file generated during compilation, but currently they use separate implementations with duplicated logic.
+This document outlines the plan to refactor the OpenPLC Editor codebase to eliminate code duplication between the **debugger** and **OPC-UA** subsystems. Both systems need to resolve debug variable indices from the `debug.c` file generated during compilation, but currently they use separate implementations with duplicated logic. Additionally, the shared utilities require updates to properly handle array serialization for UDT arrays.
 
 ## Problem Statement
 

docs/outdated/opcua-server-configuration/01-design-overview.md

@@ -1,5 +1,25 @@
 # OPC-UA Server Configuration - Design Overview
 
+## Review Required: UDT Array Handling
+
+The current design needs review for proper handling of User-Defined Datatype (UDT) arrays. This section should document how PLC arrays of UDTs are mapped to OPC UA nodes and address any gaps in the array handling logic.
+
+### Current Gaps Identified
+
+- Missing specification for UDT array node structure in OPC UA address space
+- No defined approach for indexing UDT array elements
+- Unclear mapping between PLC array declarations and OPC UA array nodes
+
+### Required Updates
+
+This design document must be updated to specify:
+- How UDT arrays are represented in the OPC UA address space
+- The node structure for UDT array elements
+- Indexing mechanism for UDT array members
+- Mapping rules from PLC array syntax to OPC UA array nodes
+
+
+
 ## 1. Architecture Overview
 
 ### 1.1 System Context

docs/outdated/opcua-server-configuration/03-json-configuration-mapping.md

@@ -105,6 +105,9 @@ interface OpcUaNodeConfig {
   // For arrays: element count (derived from type)
   arrayLength?: number
   elementType?: string
+
+  // For UDT arrays: track if this is a user-defined datatype array
+  isUdtArray?: boolean
 }
 
 interface OpcUaFieldConfig {

docs/ports/debugger-port.ts

@@ -43,13 +43,23 @@ export interface DebuggerPort {
    */
   connect(): Promise<{ success: boolean; error?: string }>
 
+  /** Disconnect from the current debug target. */
+  disconnect(): Promise<{ success: boolean }>
+  /**
+   * Connect to a debug target.
+   * The adapter resolves the actual transport (TCP, RTU, WebSocket, WebRTC, simulator)
+   * based on the current device configuration and platform capabilities.
+   */
+  connect(): Promise<{ success: boolean; error?: string }>
+
   /** Disconnect from the current debug target. */
   disconnect(): Promise<{ success: boolean }>
 
   /**
    * Read variable values by their debug indexes (batched).
    * Returns tick count, last index processed, and raw data array.
    * `needsReconnect` signals the UI to re-establish the connection.
+   * Supports UDT array data structures with proper type information.
    */
   getVariablesList(indexes: number[]): Promise<DebugVariableResult>
 
@@ -58,6 +68,7 @@ export interface DebuggerPort {
    * @param index — Variable debug index
    * @param force — If true, the value is forced (overrides PLC logic)
    * @param valueBuffer — Raw value bytes (Uint8Array)
+   * Supports UDT array data structures with proper type information.
    */
   setVariable(index: number, force: boolean, valueBuffer?: Uint8Array): Promise<DebugSetResult>
 

docs/ports/runtime-port.ts

@@ -133,4 +133,22 @@ export interface RuntimePort {
    * Returns unsubscribe function.
    */
   onTokenRefreshed?(callback: (newToken: string) => void): Unsubscribe
+
+  /**
+   * Enumerate variables available for external access.
+   * Used by OPC UA server to discover and publish variables.
+   */
+  enumerateVariables?(): Promise<{ success: boolean; variables?: Array<{name: string, type: string, isArray: boolean, dimensions?: number[]}>; error?: string }>
+
+  /**
+   * Read the value of a variable by name.
+   * Supports scalar and array variables, including UDT arrays.
+   */
+  readVariable?(variableName: string): Promise<{ success: boolean; value?: any; error?: string }>
+
+  /**
+   * Write a value to a variable by name.
+   * Supports scalar and array variables, including UDT arrays.
+   */
+  writeVariable?(variableName: string, value: any): Promise<{ success: boolean; error?: string }>
 }