torsh-profiler 0.1.2

//! Scope-based profiling utilities
//!
//! This module provides RAII-based profiling scope guards that automatically
//! capture timing information when entering and leaving scopes.

use crate::{core::profiler::global_profiler, ProfileEvent};
use backtrace::Backtrace;
use std::time::Instant;

/// RAII scope guard for automatic profiling
pub struct ScopeGuard {
    name: String,
    category: String,
    start: Instant,
}

impl ScopeGuard {
    /// Create a new scope guard with default category
    pub fn new(name: &str) -> Self {
        Self::with_category(name, "general")
    }

    /// Create a new scope guard with specified category
    pub fn with_category(name: &str, category: &str) -> Self {
        Self {
            name: name.to_string(),
            category: category.to_string(),
            start: Instant::now(),
        }
    }

    /// Get the current duration of this scope
    pub fn elapsed(&self) -> std::time::Duration {
        self.start.elapsed()
    }

    /// Get the scope name
    pub fn name(&self) -> &str {
        &self.name
    }

    /// Get the scope category
    pub fn category(&self) -> &str {
        &self.category
    }
}

impl Drop for ScopeGuard {
    fn drop(&mut self) {
        let duration = self.start.elapsed();
        let thread_id = get_thread_id();

        // Capture stack trace if enabled with overhead tracking
        let profiler_arc = global_profiler();
        let (stack_trace, stack_trace_overhead_ns) = {
            let profiler = profiler_arc.lock();
            if profiler.are_stack_traces_enabled() {
                if profiler.is_overhead_tracking_enabled() {
                    capture_stack_trace_with_overhead()
                } else {
                    (capture_stack_trace(), 0)
                }
            } else {
                (None, 0)
            }
        };

        let event = ProfileEvent {
            name: self.name.clone(),
            category: self.category.clone(),
            start_us: 0, // This will be adjusted by the profiler
            duration_us: duration.as_micros() as u64,
            thread_id,
            operation_count: None,
            flops: None,
            bytes_transferred: None,
            stack_trace,
        };

        // Update overhead stats if tracking is enabled
        {
            let mut profiler = profiler_arc.lock();
            if profiler.is_overhead_tracking_enabled() && stack_trace_overhead_ns > 0 {
                profiler.overhead_stats.stack_trace_time_ns += stack_trace_overhead_ns;
                profiler.overhead_stats.stack_trace_count += 1;
                profiler.overhead_stats.total_overhead_ns += stack_trace_overhead_ns;
            }
            profiler.add_event(event);
        }
    }
}

/// Get the current thread ID as a number
fn get_thread_id() -> usize {
    let thread_id = std::thread::current().id();
    format!("{thread_id:?}")
        .chars()
        .filter(|c| c.is_ascii_digit())
        .collect::<String>()
        .parse::<usize>()
        .unwrap_or(0)
}

/// Capture stack trace if enabled
fn capture_stack_trace() -> Option<String> {
    // Only capture if backtrace is available and not in release mode for performance
    #[cfg(debug_assertions)]
    {
        let bt = Backtrace::new();
        Some(format!("{:?}", bt))
    }
    #[cfg(not(debug_assertions))]
    None
}

/// Capture stack trace with overhead measurement
fn capture_stack_trace_with_overhead() -> (Option<String>, u64) {
    let start = Instant::now();
    let stack_trace = capture_stack_trace();
    let overhead_ns = start.elapsed().as_nanos() as u64;
    (stack_trace, overhead_ns)
}

/// Profile a function with automatic scope management
pub fn profile_function<F, R>(name: &str, func: F) -> R
where
    F: FnOnce() -> R,
{
    let _guard = ScopeGuard::new(name);
    func()
}

/// Profile a function with category and automatic scope management
pub fn profile_function_with_category<F, R>(name: &str, category: &str, func: F) -> R
where
    F: FnOnce() -> R,
{
    let _guard = ScopeGuard::with_category(name, category);
    func()
}

/// Enhanced scope guard with custom metrics
pub struct MetricsScope {
    guard: ScopeGuard,
    operation_count: Option<u64>,
    flops: Option<u64>,
    bytes_transferred: Option<u64>,
}

impl MetricsScope {
    /// Create a new metrics scope
    pub fn new(name: &str) -> Self {
        Self {
            guard: ScopeGuard::new(name),
            operation_count: None,
            flops: None,
            bytes_transferred: None,
        }
    }

    /// Create a new metrics scope with category
    pub fn with_category(name: &str, category: &str) -> Self {
        Self {
            guard: ScopeGuard::with_category(name, category),
            operation_count: None,
            flops: None,
            bytes_transferred: None,
        }
    }

    /// Set the number of operations performed
    pub fn set_operation_count(&mut self, count: u64) {
        self.operation_count = Some(count);
    }

    /// Set the number of floating point operations
    pub fn set_flops(&mut self, flops: u64) {
        self.flops = Some(flops);
    }

    /// Set the number of bytes transferred
    pub fn set_bytes_transferred(&mut self, bytes: u64) {
        self.bytes_transferred = Some(bytes);
    }

    /// Add to operation count
    pub fn add_operations(&mut self, count: u64) {
        self.operation_count = Some(self.operation_count.unwrap_or(0) + count);
    }

    /// Add to FLOPS count
    pub fn add_flops(&mut self, flops: u64) {
        self.flops = Some(self.flops.unwrap_or(0) + flops);
    }

    /// Add to bytes transferred
    pub fn add_bytes(&mut self, bytes: u64) {
        self.bytes_transferred = Some(self.bytes_transferred.unwrap_or(0) + bytes);
    }

    /// Get current metrics
    pub fn metrics(&self) -> (Option<u64>, Option<u64>, Option<u64>) {
        (self.operation_count, self.flops, self.bytes_transferred)
    }
}

impl Drop for MetricsScope {
    fn drop(&mut self) {
        let duration = self.guard.start.elapsed();
        let thread_id = get_thread_id();

        // Capture stack trace if enabled
        let profiler_arc = global_profiler();
        let (stack_trace, stack_trace_overhead_ns) = {
            let profiler = profiler_arc.lock();
            if profiler.are_stack_traces_enabled() {
                if profiler.is_overhead_tracking_enabled() {
                    capture_stack_trace_with_overhead()
                } else {
                    (capture_stack_trace(), 0)
                }
            } else {
                (None, 0)
            }
        };

        let event = ProfileEvent {
            name: self.guard.name.clone(),
            category: self.guard.category.clone(),
            start_us: 0, // Will be adjusted by profiler
            duration_us: duration.as_micros() as u64,
            thread_id,
            operation_count: self.operation_count,
            flops: self.flops,
            bytes_transferred: self.bytes_transferred,
            stack_trace,
        };

        // Update overhead stats and add event
        {
            let mut profiler = profiler_arc.lock();
            if profiler.is_overhead_tracking_enabled() && stack_trace_overhead_ns > 0 {
                profiler.overhead_stats.stack_trace_time_ns += stack_trace_overhead_ns;
                profiler.overhead_stats.stack_trace_count += 1;
                profiler.overhead_stats.total_overhead_ns += stack_trace_overhead_ns;
            }
            profiler.add_event(event);
        }
    }
}

/// Macros for convenient scope profiling
#[macro_export]
macro_rules! profile_scope {
    ($name:expr) => {
        let _guard = $crate::core::scope::ScopeGuard::new($name);
    };
    ($name:expr, $category:expr) => {
        let _guard = $crate::core::scope::ScopeGuard::with_category($name, $category);
    };
}

#[macro_export]
macro_rules! profile_function {
    ($name:expr, $func:expr) => {
        $crate::core::scope::profile_function($name, $func)
    };
    ($name:expr, $category:expr, $func:expr) => {
        $crate::core::scope::profile_function_with_category($name, $category, $func)
    };
}

#[macro_export]
macro_rules! profile_metrics {
    ($name:expr) => {
        $crate::core::scope::MetricsScope::new($name)
    };
    ($name:expr, $category:expr) => {
        $crate::core::scope::MetricsScope::with_category($name, $category)
    };
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::core::profiler::{
        clear_global_events, get_global_stats, start_profiling, stop_profiling,
    };
    use std::thread;
    use std::time::Duration;

    #[test]
    fn test_scope_guard_basic() {
        start_profiling();
        clear_global_events();

        {
            let _guard = ScopeGuard::new("test_scope");
            thread::sleep(Duration::from_millis(10));
        }

        let stats = get_global_stats().expect("get global stats should succeed");
        assert!(stats.0 > 0); // Should have at least one event

        stop_profiling();
    }

    #[test]
    fn test_scope_guard_with_category() {
        start_profiling();
        clear_global_events();

        {
            let _guard = ScopeGuard::with_category("test_scope", "testing");
            thread::sleep(Duration::from_millis(5));
        }

        let stats = get_global_stats().expect("get global stats should succeed");
        assert!(stats.0 > 0);

        stop_profiling();
    }

    #[test]
    fn test_profile_function() {
        start_profiling();
        clear_global_events();

        let result = profile_function("test_function", || {
            thread::sleep(Duration::from_millis(5));
            42
        });

        assert_eq!(result, 42);
        let stats = get_global_stats().expect("get global stats should succeed");
        assert!(stats.0 > 0);

        stop_profiling();
    }

    #[test]
    fn test_metrics_scope() {
        start_profiling();
        clear_global_events();

        {
            let mut scope = MetricsScope::new("test_metrics");
            scope.set_operation_count(100);
            scope.set_flops(500);
            scope.set_bytes_transferred(1024);

            thread::sleep(Duration::from_millis(5));

            let (ops, flops, bytes) = scope.metrics();
            assert_eq!(ops, Some(100));
            assert_eq!(flops, Some(500));
            assert_eq!(bytes, Some(1024));
        }

        let stats = get_global_stats().expect("get global stats should succeed");
        assert!(stats.0 > 0);

        stop_profiling();
    }

    #[test]
    fn test_metrics_scope_accumulation() {
        let mut scope = MetricsScope::new("test_accumulation");

        scope.add_operations(50);
        scope.add_operations(75);
        scope.add_flops(100);
        scope.add_flops(200);
        scope.add_bytes(512);
        scope.add_bytes(256);

        let (ops, flops, bytes) = scope.metrics();
        assert_eq!(ops, Some(125));
        assert_eq!(flops, Some(300));
        assert_eq!(bytes, Some(768));
    }

    #[test]
    fn test_profile_scope_macro() {
        start_profiling();
        clear_global_events();

        {
            profile_scope!("macro_test");
            thread::sleep(Duration::from_millis(5));
        }

        {
            profile_scope!("macro_test_with_category", "testing");
            thread::sleep(Duration::from_millis(5));
        }

        let stats = get_global_stats().expect("get global stats should succeed");
        assert!(stats.0 >= 2); // Should have at least 2 events

        stop_profiling();
    }

    #[test]
    fn test_thread_id_extraction() {
        let id1 = get_thread_id();
        let id2 = thread::spawn(|| get_thread_id())
            .join()
            .expect("join should succeed");

        // Thread IDs should be different
        assert_ne!(id1, id2);
        // Both should be valid numbers
        assert!(id1 > 0);
        assert!(id2 > 0);
    }
}