autocore_std/

lib.rs

//! # AutoCore Standard Library
//!
//! The standard library for writing AutoCore control programs. This crate provides
//! everything you need to build real-time control applications that integrate with
//! the AutoCore server ecosystem.
//!
//! ## Overview
//!
//! AutoCore control programs run as separate processes that communicate with the
//! autocore-server via shared memory and IPC. This library handles all the low-level
//! details, allowing you to focus on your control logic.
//!
//! ```text
//! ┌─────────────────────────┐     ┌─────────────────────────┐
//! │   autocore-server       │     │   Your Control Program  │
//! │                         │     │                         │
//! │  ┌─────────────────┐    │     │  ┌─────────────────┐    │
//! │  │ Shared Memory   │◄───┼─────┼──│ ControlRunner   │    │
//! │  │ (GlobalMemory)  │    │     │  │                 │    │
//! │  └─────────────────┘    │     │  │ ┌─────────────┐ │    │
//! │                         │     │  │ │ Your Logic  │ │    │
//! │  ┌─────────────────┐    │     │  │ └─────────────┘ │    │
//! │  │ Tick Signal     │────┼─────┼──│                 │    │
//! │  └─────────────────┘    │     │  └─────────────────┘    │
//! └─────────────────────────┘     └─────────────────────────┘
//! ```
//!
//! ## Quick Start
//!
//! 1. Create a new control project using `acctl`:
//!    ```bash
//!    acctl clone <server-ip> <project-name>
//!    ```
//!
//! 2. Implement the [`ControlProgram`] trait:
//!    ```ignore
//!    use autocore_std::{ControlProgram, TickContext};
//!    use autocore_std::fb::RTrig;
//!
//!    // GlobalMemory is generated from your project.json
//!    mod gm;
//!    use gm::GlobalMemory;
//!
//!    pub struct MyProgram {
//!        start_button: RTrig,
//!    }
//!
//!    impl MyProgram {
//!        pub fn new() -> Self {
//!            Self {
//!                start_button: RTrig::new(),
//!            }
//!        }
//!    }
//!
//!    impl ControlProgram for MyProgram {
//!        type Memory = GlobalMemory;
//!
//!        fn process_tick(&mut self, ctx: &mut TickContext<Self::Memory>) {
//!            // Detect rising edge on start button
//!            if self.start_button.call(ctx.gm.inputs.start_button) {
//!                ctx.gm.outputs.motor_running = true;
//!                autocore_std::log::info!("Motor started!");
//!            }
//!        }
//!    }
//!    ```
//!
//! 3. Use the [`autocore_main!`] macro for the entry point:
//!    ```ignore
//!    autocore_std::autocore_main!(MyProgram, "my_project_shm", "tick");
//!    ```
//!
//! ## Function Blocks (IEC 61131-3 Inspired)
//!
//! This library includes standard function blocks commonly used in PLC programming:
//!
//! - [`fb::RTrig`] - Rising edge detector (false→true transition)
//! - [`fb::FTrig`] - Falling edge detector (true→false transition)
//! - [`fb::Ton`] - Timer On Delay (output after delay)
//! - [`fb::BitResetOnDelay`] - Resets a boolean after it has been true for a duration
//! - [`fb::SimpleTimer`] - Simple one-shot timer (NOT IEC 61131-3, for imperative use)
//! - [`fb::StateMachine`] - State machine helper with automatic timer management
//! - [`fb::RunningAverage`] - Accumulates values and computes their arithmetic mean
//! - [`fb::Beeper`] - Audible beeper controller with configurable beep sequences
//! - [`fb::Heartbeat`] - Monitors a remote heartbeat counter for connection loss
//!
//! ### Example: Edge Detection
//!
//! ```
//! use autocore_std::fb::RTrig;
//!
//! let mut trigger = RTrig::new();
//!
//! // First call with false - no edge
//! assert_eq!(trigger.call(false), false);
//!
//! // Rising edge detected!
//! assert_eq!(trigger.call(true), true);
//!
//! // Still true, but no edge (already high)
//! assert_eq!(trigger.call(true), false);
//!
//! // Back to false
//! assert_eq!(trigger.call(false), false);
//!
//! // Another rising edge
//! assert_eq!(trigger.call(true), true);
//! ```
//!
//! ### Example: Timer
//!
//! ```
//! use autocore_std::fb::Ton;
//! use std::time::Duration;
//!
//! let mut timer = Ton::new();
//! let delay = Duration::from_millis(100);
//!
//! // Timer not enabled - output is false
//! assert_eq!(timer.call(false, delay), false);
//!
//! // Enable timer - starts counting
//! assert_eq!(timer.call(true, delay), false);
//!
//! // Still counting...
//! std::thread::sleep(Duration::from_millis(50));
//! assert_eq!(timer.call(true, delay), false);
//! assert!(timer.et < delay); // Elapsed time < preset
//!
//! // After delay elapsed
//! std::thread::sleep(Duration::from_millis(60));
//! assert_eq!(timer.call(true, delay), true); // Output is now true!
//! ```
//!
//! ## Logging
//!
//! Control programs can send log messages to the autocore-server for display in the
//! web console. Logging is handled automatically when using [`ControlRunner`].
//!
//! ```ignore
//! use autocore_std::log;
//!
//! log::trace!("Detailed trace message");
//! log::debug!("Debug information");
//! log::info!("Normal operation message");
//! log::warn!("Warning condition detected");
//! log::error!("Error occurred!");
//! ```
//!
//! See the [`logger`] module for advanced configuration.
//!
//! ## Memory Synchronization
//!
//! The [`ControlRunner`] handles all shared memory synchronization automatically:
//!
//! 1. **Wait for tick** - Blocks until the server signals a new cycle
//! 2. **Read inputs** - Copies shared memory to local buffer (atomic snapshot)
//! 3. **Execute logic** - Your `process_tick` runs on the local buffer
//! 4. **Write outputs** - Copies local buffer back to shared memory
//!
//! This ensures your control logic always sees a consistent view of the data,
//! even when other processes are modifying shared memory.

#![warn(missing_docs)]
#![warn(rustdoc::missing_crate_level_docs)]
#![doc(html_root_url = "https://docs.rs/autocore-std/3.3.0")]

use anyhow::{anyhow, Result};
use futures_util::{SinkExt, StreamExt};
use log::LevelFilter;
use mechutil::ipc::{CommandMessage, MessageType};
use raw_sync::events::{Event, EventInit, EventState};
use raw_sync::Timeout;
use shared_memory::ShmemConf;
use std::collections::HashMap;
use std::sync::atomic::{fence, Ordering, AtomicBool};
use std::sync::Arc;
use std::time::Duration;
use tokio_tungstenite::{connect_async, tungstenite::Message};

/// UDP logger for sending log messages to autocore-server.
///
/// This module provides a non-blocking logger implementation that sends log messages
/// via UDP to the autocore-server. Messages are batched and sent asynchronously to
/// avoid impacting the control loop timing.
///
/// # Example
///
/// ```ignore
/// use autocore_std::logger;
/// use log::LevelFilter;
///
/// // Initialize the logger (done automatically by ControlRunner)
/// logger::init_udp_logger("127.0.0.1", 39101, LevelFilter::Info, "control")?;
///
/// // Now you can use the log macros
/// log::info!("System initialized");
/// ```
pub mod logger;

// Re-export log crate for convenience - control programs can use autocore_std::log::info!() etc.
pub use log;

/// Function blocks for control programs (IEC 61131-3 inspired).
pub mod fb;

/// Interface protocols for communication between control programs and external sources.
pub mod iface;

/// Client for sending IPC commands to external modules via WebSocket.
pub mod command_client;
pub use command_client::CommandClient;

/// Shared memory utilities for external modules.
pub mod shm;

// ============================================================================
// Core Framework
// ============================================================================

/// Marker trait for generated GlobalMemory structs.
///
/// This trait is implemented by the auto-generated `GlobalMemory` struct
/// that represents the shared memory layout. It serves as a marker for
/// type safety in the control framework.
///
/// You don't need to implement this trait yourself - it's automatically
/// implemented by the code generator.
pub trait AutoCoreMemory {}

/// Trait for detecting changes in memory structures.
pub trait ChangeTracker {
    /// Compare self with a previous state and return a list of changed fields.
    /// Returns a vector of (field_name, new_value).
    fn get_changes(&self, prev: &Self) -> Vec<(&'static str, serde_json::Value)>;
}

/// Per-tick context passed to the control program by the framework.
///
/// `TickContext` bundles all per-cycle data into a single struct so that the
/// [`ControlProgram::process_tick`] signature stays stable as new fields are
/// added in the future (e.g., delta time, diagnostics).
///
/// The framework constructs a fresh `TickContext` each cycle, calls
/// [`CommandClient::poll`] before handing it to the program, and writes
/// the memory back to shared memory after `process_tick` returns.
pub struct TickContext<'a, M> {
    /// Mutable reference to the local shared memory copy.
    pub gm: &'a mut M,
    /// IPC command client for communicating with external modules.
    pub client: &'a mut CommandClient,
    /// Current cycle number (starts at 1, increments each tick).
    pub cycle: u64,
}

/// The trait that defines a control program's logic.
///
/// Implement this trait to create your control program. The associated `Memory`
/// type should be the generated `GlobalMemory` struct from your project.
///
/// # Memory Type Requirements
///
/// The `Memory` type must implement `Copy` to allow efficient synchronization
/// between shared memory and local buffers. This is automatically satisfied
/// by the generated `GlobalMemory` struct.
///
/// # Lifecycle
///
/// 1. `initialize` is called once at startup
/// 2. `process_tick` is called repeatedly in the control loop with a
///    [`TickContext`] that provides shared memory, the IPC client, and the
///    current cycle number.
///
/// # Example
///
/// ```ignore
/// use autocore_std::{ControlProgram, TickContext};
///
/// mod gm;
/// use gm::GlobalMemory;
///
/// pub struct MyController {
///     cycle_counter: u64,
/// }
///
/// impl MyController {
///     pub fn new() -> Self {
///         Self { cycle_counter: 0 }
///     }
/// }
///
/// impl ControlProgram for MyController {
///     type Memory = GlobalMemory;
///
///     fn initialize(&mut self, mem: &mut GlobalMemory) {
///         // Set initial output states
///         mem.outputs.ready = true;
///         log::info!("Controller initialized");
///     }
///
///     fn process_tick(&mut self, ctx: &mut TickContext<Self::Memory>) {
///         self.cycle_counter = ctx.cycle;
///
///         // Your control logic here
///         if ctx.gm.inputs.start && !ctx.gm.inputs.estop {
///             ctx.gm.outputs.running = true;
///         }
///     }
/// }
/// ```
pub trait ControlProgram {
    /// The shared memory structure type (usually the generated `GlobalMemory`).
    ///
    /// Must implement `Copy` to allow efficient memory synchronization.
    type Memory: Copy + ChangeTracker;

    /// Called once when the control program starts.
    ///
    /// Use this to initialize output states, reset counters, or perform
    /// any one-time setup. The default implementation does nothing.
    ///
    /// # Arguments
    ///
    /// * `mem` - Mutable reference to the shared memory. Changes are written
    ///           back to shared memory after this method returns.
    fn initialize(&mut self, _mem: &mut Self::Memory) {}

    /// The main control loop - called once per scan cycle.
    ///
    /// This is where your control logic lives. Read inputs from `ctx.gm`,
    /// perform calculations, and write outputs back to `ctx.gm`. Use
    /// `ctx.client` for IPC commands and `ctx.cycle` for the current cycle
    /// number.
    ///
    /// The framework calls [`CommandClient::poll`] before each invocation,
    /// so incoming responses are already buffered when your code runs.
    ///
    /// # Arguments
    ///
    /// * `ctx` - A [`TickContext`] containing the local shared memory copy,
    ///           the IPC command client, and the current cycle number.
    ///
    /// # Timing
    ///
    /// This method should complete within the scan cycle time. Long-running
    /// operations will cause cycle overruns.
    fn process_tick(&mut self, ctx: &mut TickContext<Self::Memory>);
}

/// Configuration for the [`ControlRunner`].
///
/// Specifies connection parameters, shared memory names, and logging settings.
/// Use [`Default::default()`] for typical configurations.
///
/// # Example
///
/// ```
/// use autocore_std::RunnerConfig;
/// use log::LevelFilter;
///
/// let config = RunnerConfig {
///     server_host: "192.168.1.100".to_string(),
///     module_name: "my_controller".to_string(),
///     shm_name: "my_project_shm".to_string(),
///     tick_signal_name: "tick".to_string(),
///     busy_signal_name: Some("busy".to_string()),
///     log_level: LevelFilter::Debug,
///     ..Default::default()
/// };
/// ```
#[derive(Debug, Clone)]
pub struct RunnerConfig {
    /// Server host address (default: "127.0.0.1")
    pub server_host: String,
    /// WebSocket port for commands (default: 11969)
    pub ws_port: u16,
    /// Module name for identification (default: "control")
    pub module_name: String,
    /// Shared memory segment name (must match server configuration)
    pub shm_name: String,
    /// Name of the tick signal in shared memory (triggers each scan cycle)
    pub tick_signal_name: String,
    /// Optional name of the busy signal (set when cycle completes)
    pub busy_signal_name: Option<String>,
    /// Minimum log level to send to the server (default: Info)
    pub log_level: LevelFilter,
    /// UDP port for sending logs to the server (default: 39101)
    pub log_udp_port: u16,
}

/// Default WebSocket port for autocore-server
pub const DEFAULT_WS_PORT: u16 = 11969;

impl Default for RunnerConfig {
    fn default() -> Self {
        Self {
            server_host: "127.0.0.1".to_string(),
            ws_port: DEFAULT_WS_PORT,
            module_name: "control".to_string(),
            shm_name: "autocore_cyclic".to_string(),
            tick_signal_name: "tick".to_string(),
            busy_signal_name: None,
            log_level: LevelFilter::Info,
            log_udp_port: logger::DEFAULT_LOG_UDP_PORT,
        }
    }
}


/// The main execution engine for control programs.
///
/// `ControlRunner` handles all the infrastructure required to run a control program:
///
/// - Reading memory layout from the server's layout file
/// - Opening and mapping shared memory
/// - Setting up synchronization signals
/// - Running the real-time control loop
/// - Sending log messages to the server
///
/// # Usage
///
/// ```ignore
/// use autocore_std::{ControlRunner, RunnerConfig};
///
/// let config = RunnerConfig {
///     shm_name: "my_project_shm".to_string(),
///     tick_signal_name: "tick".to_string(),
///     ..Default::default()
/// };
///
/// ControlRunner::new(MyProgram::new())
///     .config(config)
///     .run()?;  // Blocks forever
/// ```
///
/// # Control Loop
///
/// The runner executes a synchronous control loop:
///
/// 1. **Wait** - Blocks until the tick signal is set by the server
/// 2. **Read** - Copies shared memory to a local buffer (acquire barrier)
/// 3. **Execute** - Calls your `process_tick` method
/// 4. **Write** - Copies local buffer back to shared memory (release barrier)
/// 5. **Signal** - Sets the busy signal (if configured) to indicate completion
///
/// This ensures your code always sees a consistent snapshot of the data
/// and that your writes are atomically visible to other processes.
pub struct ControlRunner<P: ControlProgram> {
    config: RunnerConfig,
    program: P,
}

impl<P: ControlProgram> ControlRunner<P> {
    /// Creates a new runner for the given control program.
    ///
    /// Uses default configuration. Call [`.config()`](Self::config) to customize.
    ///
    /// # Arguments
    ///
    /// * `program` - Your control program instance
    ///
    /// # Example
    ///
    /// ```ignore
    /// let runner = ControlRunner::new(MyProgram::new());
    /// ```
    pub fn new(program: P) -> Self {
        Self {
            config: RunnerConfig::default(),
            program,
        }
    }

    /// Sets the configuration for this runner.
    ///
    /// # Arguments
    ///
    /// * `config` - The configuration to use
    ///
    /// # Example
    ///
    /// ```ignore
    /// ControlRunner::new(MyProgram::new())
    ///     .config(RunnerConfig {
    ///         shm_name: "custom_shm".to_string(),
    ///         ..Default::default()
    ///     })
    ///     .run()?;
    /// ```
    pub fn config(mut self, config: RunnerConfig) -> Self {
        self.config = config;
        self
    }

    /// Starts the control loop.
    ///
    /// This method blocks indefinitely, running the control loop until
    /// an error occurs or the process is terminated.
    ///
    /// # Returns
    ///
    /// Returns `Ok(())` only if the loop exits cleanly (which typically
    /// doesn't happen). Returns an error if:
    ///
    /// - IPC connection fails
    /// - Shared memory cannot be opened
    /// - Signal offsets cannot be found
    /// - A critical error occurs during execution
    ///
    /// # Example
    ///
    /// ```ignore
    /// fn main() -> anyhow::Result<()> {
    ///     ControlRunner::new(MyProgram::new())
    ///         .config(config)
    ///         .run()
    /// }
    /// ```
    pub fn run(mut self) -> Result<()> {
        // Initialize UDP logger FIRST (before any log statements)
        if let Err(e) = logger::init_udp_logger(
            &self.config.server_host,
            self.config.log_udp_port,
            self.config.log_level,
            "control",
        ) {
            eprintln!("Warning: Failed to initialize UDP logger: {}", e);
            // Continue anyway - logging will just go nowhere
        }

        // Multi-threaded runtime so spawned WS read/write tasks can run
        // alongside the synchronous control loop.
        let rt = tokio::runtime::Builder::new_multi_thread()
            .worker_threads(2)
            .enable_all()
            .build()?;

        rt.block_on(async {
            log::info!("AutoCore Control Runner Starting...");

            // 1. Connect to server via WebSocket and get layout
            let ws_url = format!("ws://{}:{}/ws/", self.config.server_host, self.config.ws_port);
            log::info!("Connecting to server at {}", ws_url);

            let (ws_stream, _) = connect_async(&ws_url).await
                .map_err(|e| anyhow!("Failed to connect to server at {}: {}", ws_url, e))?;

            let (mut write, mut read) = ws_stream.split();

            // Send gm.get_layout request
            let request = CommandMessage::request("gm.get_layout", serde_json::Value::Null);
            let transaction_id = request.transaction_id;
            let request_json = serde_json::to_string(&request)?;

            write.send(Message::Text(request_json)).await
                .map_err(|e| anyhow!("Failed to send layout request: {}", e))?;

            // Wait for response with matching transaction_id
            let timeout = Duration::from_secs(10);
            let start = std::time::Instant::now();
            let mut layout: Option<HashMap<String, serde_json::Value>> = None;

            while start.elapsed() < timeout {
                match tokio::time::timeout(Duration::from_secs(1), read.next()).await {
                    Ok(Some(Ok(Message::Text(text)))) => {
                        if let Ok(response) = serde_json::from_str::<CommandMessage>(&text) {
                            if response.transaction_id == transaction_id {
                                if !response.success {
                                    return Err(anyhow!("Server error: {}", response.error_message));
                                }
                                layout = Some(serde_json::from_value(response.data)?);
                                break;
                            }
                            // Skip broadcasts and other messages
                            if response.message_type == MessageType::Broadcast {
                                continue;
                            }
                        }
                    }
                    Ok(Some(Ok(_))) => continue,
                    Ok(Some(Err(e))) => return Err(anyhow!("WebSocket error: {}", e)),
                    Ok(None) => return Err(anyhow!("Server closed connection")),
                    Err(_) => continue, // Timeout on single read, keep trying
                }
            }

            let layout = layout.ok_or_else(|| anyhow!("Timeout waiting for layout response"))?;
            log::info!("Layout received with {} entries.", layout.len());

            // Set up channels and background tasks for shared WebSocket access.
            // This allows both the control loop (gm.write) and CommandClient (IPC
            // commands) to share the write half, while routing incoming responses
            // to the CommandClient.
            let (ws_write_tx, mut ws_write_rx) = tokio::sync::mpsc::unbounded_channel::<String>();
            let (response_tx, response_rx) = tokio::sync::mpsc::unbounded_channel::<CommandMessage>();

            // Background task: WS write loop
            // Reads serialized messages from ws_write_rx and sends them over the WebSocket.
            tokio::spawn(async move {
                while let Some(msg_json) = ws_write_rx.recv().await {
                    if let Err(e) = write.send(Message::Text(msg_json)).await {
                        log::error!("WebSocket write error: {}", e);
                        break;
                    }
                }
            });

            // Background task: WS read loop
            // Reads all incoming WebSocket messages. Routes Response messages to
            // response_tx for the CommandClient; ignores broadcasts and others.
            tokio::spawn(async move {
                while let Some(result) = read.next().await {
                    match result {
                        Ok(Message::Text(text)) => {
                            if let Ok(msg) = serde_json::from_str::<CommandMessage>(&text) {
                                if msg.message_type == MessageType::Response {
                                    if response_tx.send(msg).is_err() {
                                        break; // receiver dropped
                                    }
                                }
                                // Broadcasts and other message types are ignored
                            }
                        }
                        Ok(Message::Close(_)) => {
                            log::info!("WebSocket closed by server");
                            break;
                        }
                        Err(e) => {
                            log::error!("WebSocket read error: {}", e);
                            break;
                        }
                        _ => {} // Ping/Pong/Binary - ignore
                    }
                }
            });

            // Construct CommandClient — owned by the runner, passed to the
            // program via TickContext each cycle.
            let mut command_client = CommandClient::new(ws_write_tx.clone(), response_rx);

            // 2. Find Signal Offsets
            let tick_offset = self.find_offset(&layout, &self.config.tick_signal_name)?;
            let busy_offset = if let Some(name) = &self.config.busy_signal_name {
                Some(self.find_offset(&layout, name)?)
            } else {
                None
            };

            // 4. Open Shared Memory
            let shmem = ShmemConf::new().os_id(&self.config.shm_name).open()?;
            let base_ptr = shmem.as_ptr();
            log::info!("Shared Memory '{}' mapped.", self.config.shm_name);

            // 5. Setup Pointers
            // SAFETY: We trust the server's layout matches the generated GlobalMemory struct.
            let gm = unsafe { &mut *(base_ptr as *mut P::Memory) };

            // Get tick event from shared memory
            log::info!("Setting up tick event at offset {} (base_ptr: {:p})", tick_offset, base_ptr);
            let (tick_event, _) = unsafe {
                Event::from_existing(base_ptr.add(tick_offset))
            }.map_err(|e| anyhow!("Failed to open tick event: {:?}", e))?;
            log::info!("Tick event ready");

            // Busy signal event (optional)
            let busy_event = busy_offset.map(|offset| {
                unsafe { Event::from_existing(base_ptr.add(offset)) }
                    .map(|(event, _)| event)
                    .ok()
            }).flatten();

            // 6. Initialize local memory buffer and user program
            // We use a local copy for the control loop to ensure:
            // - Consistent snapshot of inputs at start of cycle
            // - Atomic commit of outputs at end of cycle
            // - Proper memory barriers for cross-process visibility
            let mut local_mem: P::Memory = unsafe { std::ptr::read_volatile(gm) };
            let mut prev_mem: P::Memory = local_mem; // Snapshot for change detection

            fence(Ordering::Acquire); // Ensure we see all prior writes from other processes

            self.program.initialize(&mut local_mem);

            // Write back any changes from initialize
            fence(Ordering::Release);
            unsafe { std::ptr::write_volatile(gm, local_mem) };

            // Set up signal handler for graceful shutdown
            let running = Arc::new(AtomicBool::new(true));
            let r = running.clone();
            
            // Only set handler if not already set
            if let Err(e) = ctrlc::set_handler(move || {
                r.store(false, Ordering::SeqCst);
            }) {
                log::warn!("Failed to set signal handler: {}", e);
            }

            log::info!("Entering Control Loop - waiting for first tick...");
            let mut cycle_count: u64 = 0;

            while running.load(Ordering::SeqCst) {
                // Wait for Tick - Event-based synchronization
                // Use a timeout (1s) to allow checking the running flag periodically
                match tick_event.wait(Timeout::Val(Duration::from_secs(1))) {
                    Ok(_) => {},
                    Err(e) => {
                        // Check for timeout
                        let err_str = format!("{:?}", e);
                        if err_str.contains("Timeout") {
                            continue;
                        }
                        return Err(anyhow!("Tick wait failed: {:?}", e));
                    }
                }

                if !running.load(Ordering::SeqCst) {
                    log::info!("Shutdown signal received, exiting control loop.");
                    break;
                }

                cycle_count += 1;
                if cycle_count == 1 {
                    log::info!("First tick received!");
                }

                // === INPUT PHASE ===
                // Read all variables from shared memory into local buffer.
                // This gives us a consistent snapshot of inputs for this cycle.
                // Acquire fence ensures we see all writes from other processes (server, modules).
                local_mem = unsafe { std::ptr::read_volatile(gm) };
                
                // Update prev_mem before execution to track changes made IN THIS CYCLE
                // Actually, we want to know what changed in SHM relative to what we last knew,
                // OR what WE changed relative to what we read?
                // The user wants "writes on shared variables" to be broadcast.
                // Typically outputs.
                // If inputs changed (from other source), broadcasting them again is fine too.
                // Let's capture state BEFORE execution (which is what we just read from SHM).
                prev_mem = local_mem;

                fence(Ordering::Acquire);

                // === EXECUTE PHASE ===
                // Poll IPC responses so they are available during process_tick.
                command_client.poll();

                // Execute user logic on the local copy.
                // All reads/writes during process_tick operate on local_mem.
                let mut ctx = TickContext {
                    gm: &mut local_mem,
                    client: &mut command_client,
                    cycle: cycle_count,
                };
                self.program.process_tick(&mut ctx);

                // === OUTPUT PHASE ===
                // Write all variables from local buffer back to shared memory.
                // Release fence ensures our writes are visible to other processes.
                fence(Ordering::Release);
                unsafe { std::ptr::write_volatile(gm, local_mem) };

                // === CHANGE DETECTION & NOTIFICATION ===
                let changes = local_mem.get_changes(&prev_mem);
                if !changes.is_empty() {
                    // Construct bulk write message
                    let mut data_map = serde_json::Map::new();
                    for (key, val) in changes {
                        data_map.insert(key.to_string(), val);
                    }
                    
                    let msg = CommandMessage::request("gm.write", serde_json::Value::Object(data_map));
                    let msg_json = serde_json::to_string(&msg).unwrap_or_default();

                    // Send via the shared write channel (non-blocking)
                    if let Err(e) = ws_write_tx.send(msg_json) {
                        log::error!("Failed to send updates: {}", e);
                    }
                }

                // Signal Busy/Done event
                if let Some(ref busy_ev) = busy_event {
                    let _ = busy_ev.set(EventState::Signaled);
                }
            }

            Ok(())
        })
    }

    fn find_offset(&self, layout: &HashMap<String, serde_json::Value>, name: &str) -> Result<usize> {
        let info = layout.get(name).ok_or_else(|| anyhow!("Signal '{}' not found in layout", name))?;
        info.get("offset")
            .and_then(|v| v.as_u64())
            .map(|v| v as usize)
            .ok_or_else(|| anyhow!("Invalid offset for '{}'", name))
    }
}

/// Generates the standard `main` function for a control program.
///
/// This macro reduces boilerplate by creating a properly configured `main`
/// function that initializes and runs your control program.
///
/// # Arguments
///
/// * `$prog_type` - The type of your control program (must implement [`ControlProgram`])
/// * `$shm_name` - The shared memory segment name (string literal)
/// * `$tick_signal` - The tick signal name in shared memory (string literal)
///
/// # Example
///
/// ```ignore
/// mod gm;
/// use gm::GlobalMemory;
///
/// pub struct MyProgram;
///
/// impl MyProgram {
///     pub fn new() -> Self { Self }
/// }
///
/// impl autocore_std::ControlProgram for MyProgram {
///     type Memory = GlobalMemory;
///
///     fn process_tick(&mut self, ctx: &mut autocore_std::TickContext<Self::Memory>) {
///         // Your logic here
///     }
/// }
///
/// // This generates the main function
/// autocore_std::autocore_main!(MyProgram, "my_project_shm", "tick");
/// ```
///
/// # Generated Code
///
/// The macro expands to:
///
/// ```ignore
/// fn main() -> anyhow::Result<()> {
///     let config = autocore_std::RunnerConfig {
///         server_host: "127.0.0.1".to_string(),
///         ws_port: autocore_std::DEFAULT_WS_PORT,
///         module_name: "control".to_string(),
///         shm_name: "my_project_shm".to_string(),
///         tick_signal_name: "tick".to_string(),
///         busy_signal_name: None,
///         log_level: log::LevelFilter::Info,
///         log_udp_port: autocore_std::logger::DEFAULT_LOG_UDP_PORT,
///     };
///
///     autocore_std::ControlRunner::new(MyProgram::new())
///         .config(config)
///         .run()
/// }
/// ```
#[macro_export]
macro_rules! autocore_main {
    ($prog_type:ty, $shm_name:expr, $tick_signal:expr) => {
        fn main() -> anyhow::Result<()> {
            let config = autocore_std::RunnerConfig {
                server_host: "127.0.0.1".to_string(),
                ws_port: autocore_std::DEFAULT_WS_PORT,
                module_name: "control".to_string(),
                shm_name: $shm_name.to_string(),
                tick_signal_name: $tick_signal.to_string(),
                busy_signal_name: None,
                log_level: log::LevelFilter::Info,
                log_udp_port: autocore_std::logger::DEFAULT_LOG_UDP_PORT,
            };

            autocore_std::ControlRunner::new(<$prog_type>::new())
                .config(config)
                .run()
        }
    };
}