use serde::{Deserialize, Serialize};

use utoipa::ToSchema;

pub const MODERATE_MEMORY_PRESSURE_THRESHOLD: f64 = 0.85;

pub const HIGH_MEMORY_PRESSURE_THRESHOLD: f64 = 0.90;

pub const CRITICAL_MEMORY_PRESSURE_THRESHOLD: f64 = 0.95;

/// Memory pressure level.

///

/// The current memory pressure level is computed as a function of the current process

/// resident set size (RSS) and the user-configured memory limit (`max_rss`).

///

/// As the memory pressure level increases, the system will apply increasing backpressure to

/// push state cached in memory to storage.

///

/// - `Low`: less than 85% of the user-configured memory limit has been allocated.

/// - `Moderate`: between 85% and 90% of the user-configured memory limit has been allocated.

/// - `High`: between 90% and 95% of the user-configured memory limit has been allocated.

/// - `Critical`: more than 95% of the user-configured memory limit has been allocated.

#[derive(

Debug, Default, Clone, Copy, Eq, PartialEq, PartialOrd, Ord, Serialize, Deserialize, ToSchema,

)]

#[repr(u8)]

#[serde(rename_all = "snake_case")]

pub enum MemoryPressure {

/// Less than 85% of the user-configured memory limit has been allocated.

#[default]

Low = 0,

/// Between 85% and 90% of the user-configured memory limit has been allocated.

Moderate = 1,

/// Between 90% and 95% of the user-configured memory limit has been allocated.

High = 2,

/// More than 95% of the user-configured memory limit has been allocated.

Critical = 3,

}

impl TryFrom<u8> for MemoryPressure {

type Error = ();

fn try_from(value: u8) -> Result<Self, Self::Error> {

match value {

0 => Ok(MemoryPressure::Low),

1 => Ok(MemoryPressure::Moderate),

2 => Ok(MemoryPressure::High),

3 => Ok(MemoryPressure::Critical),

_ => Err(()),

}

}

}