// Copyright 2024 RustFS Team
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//! Deadlock detection metrics recording functions.

use std::time::Duration;

/// Record potential deadlock detected.
#[inline(always)]
pub fn record_deadlock_detected(cycle_length: usize) {
    use metrics::{counter, histogram};
    counter!("rustfs.deadlock.detected").increment(1);
    histogram!("rustfs.deadlock.cycle_length").record(cycle_length as f64);
}

/// Record long-held lock.
#[inline(always)]
pub fn record_long_held_lock(_lock_id: u64, hold_time: Duration) {
    use metrics::{counter, histogram};
    counter!("rustfs.deadlock.long_held").increment(1);
    histogram!("rustfs.deadlock.hold_time.secs").record(hold_time.as_secs_f64());
}

/// Record lock acquisition.
#[inline(always)]
pub fn record_lock_acquisition(lock_type: &str) {
    use metrics::counter;
    counter!("rustfs.lock.acquisitions", "type" => lock_type.to_string()).increment(1);
}

/// Record lock release.
#[inline(always)]
pub fn record_lock_release(lock_type: &str, hold_time: Duration) {
    use metrics::{counter, histogram};
    counter!("rustfs.lock.releases", "type" => lock_type.to_string()).increment(1);
    histogram!("rustfs.lock.hold_time.secs", "type" => lock_type.to_string()).record(hold_time.as_secs_f64());
}

/// Record lock contention.
#[inline(always)]
pub fn record_lock_contention(lock_type: &str) {
    use metrics::counter;
    counter!("rustfs.lock.contentions", "type" => lock_type.to_string()).increment(1);
}

/// Record wait graph edge added.
#[inline(always)]
pub fn record_wait_edge_added() {
    use metrics::counter;
    counter!("rustfs.deadlock.wait_edges.added").increment(1);
}

/// Record wait graph edge removed.
#[inline(always)]
pub fn record_wait_edge_removed() {
    use metrics::counter;
    counter!("rustfs.deadlock.wait_edges.removed").increment(1);
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_record_deadlock_detected() {
        record_deadlock_detected(3);
        record_deadlock_detected(5);
    }

    #[test]
    fn test_record_long_held_lock() {
        record_long_held_lock(1, Duration::from_secs(30));
        record_long_held_lock(2, Duration::from_secs(60));
    }

    #[test]
    fn test_record_lock_acquisition() {
        record_lock_acquisition("mutex");
        record_lock_acquisition("rwlock");
    }

    #[test]
    fn test_record_lock_release() {
        record_lock_release("mutex", Duration::from_millis(10));
        record_lock_release("rwlock", Duration::from_millis(5));
    }

    #[test]
    fn test_record_lock_contention() {
        record_lock_contention("mutex");
        record_lock_contention("rwlock");
    }

    #[test]
    fn test_record_wait_edge() {
        record_wait_edge_added();
        record_wait_edge_removed();
    }
}
