logwise 0.5.1

// SPDX-License-Identifier: MIT OR Apache-2.0
/*!
Defines our Interval types.

These represent 2 paired log values, such as a start and end time.
*/

use crate::Level;
use crate::context::Context;
use crate::global_logger::global_loggers;
use crate::log_record::LogRecord;
use std::sync::atomic::{AtomicU64, Ordering};

/// Global counter for generating unique profile interval IDs.
///
/// This counter is used to correlate BEGIN and END log messages for profile
/// intervals, especially useful when profiling nested operations.
static PROFILE_ID_COUNTER: AtomicU64 = AtomicU64::new(1);

/// A performance warning interval that tracks execution time.
///
/// `PerfwarnInterval` measures the duration between its creation and destruction (drop),
/// logging the elapsed time as a performance warning. The duration is also accumulated
/// into the current task's statistics for aggregated reporting.
///
/// # Usage
///
/// This type is typically not created directly. Instead, use the `perfwarn!` or
/// `perfwarn_begin!` macros which properly set up the interval with source location
/// information.
///
/// # Example
///
/// ```rust
/// logwise::declare_logging_domain!();
/// # fn main() {
/// # fn perform_expensive_operation() {}
/// // Using the perfwarn! macro (recommended)
/// logwise::perfwarn!("database_query", {
///     perform_expensive_operation();
/// });
///
/// // Using perfwarn_begin! for more control
/// let interval = logwise::perfwarn_begin!("network_request");
/// perform_expensive_operation();
/// // Duration is logged when interval drops
/// drop(interval);
/// # }
/// ```
///
/// # Scaling
///
/// Use the [`scale`](PerfwarnInterval::scale) method to adjust the reported duration when
/// only a portion of the measured time is relevant:
///
/// ```rust
/// logwise::declare_logging_domain!();
/// # fn main() {
/// # fn perform_expensive_operation() {}
/// let mut interval = logwise::perfwarn_begin!("partial_operation");
/// perform_expensive_operation();
/// // Report only 20% of the actual duration
/// interval.scale(0.2);
/// # }
/// ```
#[derive(Debug)]
pub struct PerfwarnInterval {
    label: &'static str,
    start: crate::sys::Instant,
    scale: f32,
}

impl PerfwarnInterval {
    /**
        Creates a new interval.

        Do not use this manually, instead use the `perfwarn!` macro, or if you need to access the interval directly, use `perfwarn_begin!`.
    */
    #[inline]
    pub fn new(label: &'static str, time: crate::sys::Instant) -> Self {
        Self {
            label,
            start: time,
            scale: 1.0,
        }
    }

    #[inline]
    #[doc(hidden)]
    ///internal implementation detail
    pub fn log_timestamp(&self, record: &mut LogRecord) {
        let time = crate::sys::Instant::now();
        let duration = time.duration_since(self.start);
        record.log_owned(format!("[{:?}] ", duration));
    }

    /**
        Cause the reported time interval to be scaled by the amount.

        Consider a case where we're warning about "some subset of the interval".  For example,
        let's say by tweaking constants we can get a 20% speedup.  Warning about the entire interval
        would be misleading.  Instead, we can scale the interval by 0.2 to reflect the subset.
    */
    pub fn scale(&mut self, scale: f32) {
        self.scale = scale;
    }
}

impl Drop for PerfwarnInterval {
    fn drop(&mut self) {
        let end_time = crate::sys::Instant::now();
        let duration = end_time.duration_since(self.start);
        let ctx = Context::current();
        ctx._add_task_interval(self.label, duration);

        let mut record = LogRecord::new(Level::PerfWarn);
        let ctx = Context::current();
        ctx._log_prelude(&mut record);
        record.log("PERWARN: END ");
        record.log_time_since(end_time);

        record.log(self.label);
        record.log(" ");
        let scaled_duration = duration.mul_f32(self.scale);
        record.log_owned(format!("[interval took {:?}] ", scaled_duration));
        let global_loggers = global_loggers();
        for logger in global_loggers {
            logger.finish_log_record(record.clone());
        }
    }
}

/*
boilerplate notes.

1.  Copy, clone, no.  We don't want to copy the context?
2.  PartialEq, Ord, etc.  No, we don't want to compare these.
3.  Default, no, we don't want to create these without a start time.
4.  display, not really.
5.  From/Into, I think we want to avoid creating this without a line number.
6.  AsRef/AsMut, there's really nothing to desugar to
7.  Deref, similar
8.  Send/Sync, Probably?
 */

#[cfg(test)]
mod tests {
    #[cfg_attr(not(target_arch = "wasm32"), test)]
    #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test::wasm_bindgen_test)]
    fn assert_send_sync() {
        fn assert_send_sync<T: Send + Sync>() {}
        assert_send_sync::<super::PerfwarnInterval>();
        assert_send_sync::<super::PerfwarnIntervalIf>();
        assert_send_sync::<super::ProfileInterval>();
    }
}

/// A conditional performance warning interval that logs only if execution exceeds a threshold.
///
/// Unlike [`PerfwarnInterval`] which always logs, `PerfwarnIntervalIf` only emits a warning
/// if the measured duration exceeds the specified threshold. This is useful for operations
/// that are normally fast but occasionally slow down due to external factors.
///
/// # Usage
///
/// This type is typically not created directly. Instead, use the `perfwarn_begin_if!` macro
/// which properly sets up the interval with source location information.
///
/// # Example
///
/// ```rust
/// logwise::declare_logging_domain!();
/// # fn main() {
/// # use std::time::Duration;
/// # fn perform_database_query() {}
/// // Create a conditional interval that warns only if execution takes > 100ms
/// let _interval = logwise::perfwarn_begin_if!(Duration::from_millis(100), "database_query");
/// perform_database_query();
/// // If the query took longer than 100ms, a warning is logged when _interval drops
/// # }
/// ```
///
/// # Behavior
///
/// - The interval starts when created
/// - On drop, if the elapsed time exceeds the threshold:
///   - The duration is logged at the `PerfWarn` level
///   - The interval is added to the current task's statistics
/// - If the elapsed time is below the threshold, no log is emitted
#[derive(Debug)]
pub struct PerfwarnIntervalIf {
    label: &'static str,
    start: crate::sys::Instant,
    threshold: crate::sys::Duration,
    record: crate::log_record::LogRecord,
}

impl PerfwarnIntervalIf {
    /// Creates a new conditional performance warning interval.
    ///
    /// This method is used internally by the `perfwarn_begin_if!` macro. You should
    /// generally use the macro rather than calling this method directly, as the macro
    /// properly captures source location information.
    ///
    /// # Arguments
    ///
    /// * `label` - A static string identifying this interval in log messages
    /// * `time` - The start time of the interval
    /// * `threshold` - The duration threshold; warnings are only logged if exceeded
    /// * `record` - A pre-populated log record with source location information
    ///
    /// # Example
    ///
    /// Use the `perfwarn_begin_if!` macro instead:
    ///
    /// ```rust
    /// logwise::declare_logging_domain!();
    /// # fn main() {
    /// use std::time::Duration;
    ///
    /// let _interval = logwise::perfwarn_begin_if!(
    ///     Duration::from_millis(100),
    ///     "database_query"
    /// );
    /// // ... perform operation ...
    /// // Only logs if operation took > 100ms
    /// # }
    /// ```
    #[inline]
    pub fn new(
        label: &'static str,
        time: crate::sys::Instant,
        threshold: crate::sys::Duration,
        record: crate::log_record::LogRecord,
    ) -> Self {
        Self {
            label,
            start: time,
            threshold,
            record,
        }
    }
}

impl Drop for PerfwarnIntervalIf {
    fn drop(&mut self) {
        let end_time = crate::sys::Instant::now();
        let duration = end_time.duration_since(self.start);
        let ctx = Context::current();
        ctx._add_task_interval_if(self.label, duration, self.threshold);

        if duration > self.threshold {
            // We need to insert the timestamp before the label (which is already in the record).
            // The record parts structure is: [Prelude] "PERFWARN: " File ":line:col " [Label]
            // We want: ... ":line:col " [Timestamp] [Label] " is SLOW: " [Duration]

            let mut insert_idx = 0;
            let mut found = false;
            for (i, part) in self.record.parts.iter().enumerate() {
                if part == "PERFWARN: " {
                    // Found the marker. The next two parts are File and LineCol.
                    // So we want to insert at i + 3.
                    insert_idx = i + 3;
                    found = true;
                    break;
                }
            }

            if found && insert_idx <= self.record.parts.len() {
                // Generate timestamp string
                let mut temp_record = crate::log_record::LogRecord::new(Level::PerfWarn);
                temp_record.log_time_since(end_time);
                let timestamp = temp_record.parts.pop().unwrap();

                self.record.parts.insert(insert_idx, timestamp);
            }

            self.record.log(" is SLOW: ");
            self.record
                .log_owned(format!("[interval took {:?}] ", duration));

            let global_loggers = global_loggers();
            for logger in global_loggers {
                logger.finish_log_record(self.record.clone());
            }
        }
    }
}

/// Generates the next unique profile interval ID.
///
/// This function is used internally to assign unique IDs to profile intervals,
/// allowing BEGIN and END messages to be correlated in log output.
#[inline]
pub fn next_profile_id() -> u64 {
    PROFILE_ID_COUNTER.fetch_add(1, Ordering::Relaxed)
}

/// A profiling interval that logs when created and dropped.
///
/// `ProfileInterval` logs a BEGIN message when created and an END message with
/// elapsed duration when dropped. Each interval has a unique ID to correlate
/// BEGIN/END pairs, which is especially useful when profiling nested operations.
///
/// Unlike [`PerfwarnInterval`], this type:
/// - Always logs (no threshold)
/// - Logs both BEGIN and END messages
/// - Does not contribute to task statistics
/// - Is intended for temporary profiling that should be removed before committing
///
/// # Usage
///
/// This type is typically not created directly. Instead, use the `profile_begin!`
/// macro which properly sets up the interval with source location information.
///
/// # Example
///
/// ```rust
/// logwise::declare_logging_domain!();
/// # fn main() {
/// # fn perform_operation() {}
/// // Using profile_begin! for manual interval management
/// let interval = logwise::profile_begin!("database_query");
/// perform_operation();
/// // BEGIN logged when created, END logged when dropped
/// drop(interval);
/// # }
/// ```
///
/// # Log Output
///
/// The interval produces log messages like:
/// ```text
/// PROFILE: BEGIN [id=1] src/main.rs:10:5 [0ns] database_query
/// PROFILE: END [id=1] [elapsed: 150µs] database_query
/// ```
#[derive(Debug)]
pub struct ProfileInterval {
    id: u64,
    label: &'static str,
    start: crate::sys::Instant,
}

impl ProfileInterval {
    /// Creates a new profile interval.
    ///
    /// Do not use this manually. Instead use the `profile_begin!` macro which
    /// properly captures source location information.
    ///
    /// # Arguments
    ///
    /// * `id` - Unique identifier for correlating BEGIN/END messages
    /// * `label` - A static string identifying this interval in log messages
    /// * `time` - The start time of the interval
    #[inline]
    pub fn new(id: u64, label: &'static str, time: crate::sys::Instant) -> Self {
        Self {
            id,
            label,
            start: time,
        }
    }

    /// Returns the unique ID of this profile interval.
    #[inline]
    pub fn id(&self) -> u64 {
        self.id
    }
}

impl Drop for ProfileInterval {
    fn drop(&mut self) {
        let end_time = crate::sys::Instant::now();
        let duration = end_time.duration_since(self.start);

        let mut record = LogRecord::new(Level::Profile);
        let ctx = Context::current();
        ctx._log_prelude(&mut record);
        record.log_owned(format!("PROFILE: END [id={}] ", self.id));
        record.log_owned(format!("[elapsed: {:?}] ", duration));
        record.log(self.label);

        let global_loggers = global_loggers();
        for logger in global_loggers {
            logger.finish_log_record(record.clone());
        }
    }
}