fusabi-stdlib-ext 0.1.6

//! GPU module.
//!
//! Provides GPU monitoring and metrics using NVML (NVIDIA Management Library).
//! Useful for observability in GPU-intensive workloads like machine learning.
//!
//! ## Features
//!
//! - List available GPU devices
//! - Query GPU utilization
//! - Query memory usage
//! - Query temperature
//!
//! ## Requirements
//!
//! Requires NVML library (nvidia-smi) to be available on the system.
//!
//! ## Example
//!
//! ```rust,ignore
//! use fusabi_stdlib_ext::gpu;
//!
//! // List all GPUs
//! let devices = gpu::list_devices(&[], &ctx)?;
//!
//! // Get utilization for GPU 0
//! let utilization = gpu::utilization(&[Value::Int(0)], &ctx)?;
//!
//! // Get memory info
//! let memory = gpu::memory_info(&[Value::Int(0)], &ctx)?;
//! ```

use fusabi_host::{ExecutionContext, Result, Value, Error};
use std::collections::HashMap;

/// List all available GPU devices.
///
/// Returns a list of maps containing device information:
/// - `id`: Device index
/// - `name`: Device name
/// - `uuid`: Device UUID
///
/// # Returns
///
/// List of device info maps
pub fn list_devices(_args: &[Value], _ctx: &ExecutionContext) -> Result<Value> {
    // TODO: Implement using NVML bindings
    tracing::debug!("gpu.list_devices: returning mock data");

    // Mock data for development
    let mut device = HashMap::new();
    device.insert("id".to_string(), Value::Int(0));
    device.insert("name".to_string(), Value::String("Mock GPU".to_string()));
    device.insert("uuid".to_string(), Value::String("GPU-00000000-0000-0000-0000-000000000000".to_string()));

    Ok(Value::List(vec![Value::Map(device)]))
}

/// Get GPU utilization percentage.
///
/// # Arguments
///
/// * `args[0]` - Device ID (integer)
///
/// # Returns
///
/// Float representing utilization percentage (0.0 - 100.0)
pub fn utilization(args: &[Value], _ctx: &ExecutionContext) -> Result<Value> {
    let device_id = args
        .first()
        .and_then(|v| v.as_int())
        .ok_or_else(|| Error::host_function("gpu.utilization: missing device_id argument"))?;

    // TODO: Implement using NVML bindings
    tracing::debug!("gpu.utilization: device_id={}, returning mock data", device_id);

    // Mock data
    Ok(Value::Float(42.5))
}

/// Get GPU memory information.
///
/// Returns a map with:
/// - `total`: Total memory in bytes
/// - `used`: Used memory in bytes
/// - `free`: Free memory in bytes
///
/// # Arguments
///
/// * `args[0]` - Device ID (integer)
///
/// # Returns
///
/// Map with memory statistics
pub fn memory_info(args: &[Value], _ctx: &ExecutionContext) -> Result<Value> {
    let device_id = args
        .first()
        .and_then(|v| v.as_int())
        .ok_or_else(|| Error::host_function("gpu.memory_info: missing device_id argument"))?;

    // TODO: Implement using NVML bindings
    tracing::debug!("gpu.memory_info: device_id={}, returning mock data", device_id);

    // Mock data (16GB GPU)
    let total = 17179869184i64; // 16 GB
    let used = 8589934592i64;   // 8 GB
    let free = total - used;

    let mut info = HashMap::new();
    info.insert("total".to_string(), Value::Int(total));
    info.insert("used".to_string(), Value::Int(used));
    info.insert("free".to_string(), Value::Int(free));

    Ok(Value::Map(info))
}

/// Get GPU temperature in Celsius.
///
/// # Arguments
///
/// * `args[0]` - Device ID (integer)
///
/// # Returns
///
/// Float representing temperature in Celsius
pub fn temperature(args: &[Value], _ctx: &ExecutionContext) -> Result<Value> {
    let device_id = args
        .first()
        .and_then(|v| v.as_int())
        .ok_or_else(|| Error::host_function("gpu.temperature: missing device_id argument"))?;

    // TODO: Implement using NVML bindings
    tracing::debug!("gpu.temperature: device_id={}, returning mock data", device_id);

    // Mock data
    Ok(Value::Float(65.0))
}

/// Get GPU power usage in watts.
///
/// # Arguments
///
/// * `args[0]` - Device ID (integer)
///
/// # Returns
///
/// Float representing power usage in watts
pub fn power_usage(args: &[Value], _ctx: &ExecutionContext) -> Result<Value> {
    let device_id = args
        .first()
        .and_then(|v| v.as_int())
        .ok_or_else(|| Error::host_function("gpu.power_usage: missing device_id argument"))?;

    // TODO: Implement using NVML bindings
    tracing::debug!("gpu.power_usage: device_id={}, returning mock data", device_id);

    // Mock data (250W)
    Ok(Value::Float(250.0))
}

/// Get GPU clock speeds.
///
/// Returns a map with:
/// - `graphics`: Graphics clock in MHz
/// - `memory`: Memory clock in MHz
/// - `sm`: SM (streaming multiprocessor) clock in MHz
///
/// # Arguments
///
/// * `args[0]` - Device ID (integer)
///
/// # Returns
///
/// Map with clock speeds
pub fn clock_speeds(args: &[Value], _ctx: &ExecutionContext) -> Result<Value> {
    let device_id = args
        .first()
        .and_then(|v| v.as_int())
        .ok_or_else(|| Error::host_function("gpu.clock_speeds: missing device_id argument"))?;

    // TODO: Implement using NVML bindings
    tracing::debug!("gpu.clock_speeds: device_id={}, returning mock data", device_id);

    let mut clocks = HashMap::new();
    clocks.insert("graphics".to_string(), Value::Int(1500));
    clocks.insert("memory".to_string(), Value::Int(7000));
    clocks.insert("sm".to_string(), Value::Int(1500));

    Ok(Value::Map(clocks))
}