// Copyright 2021 TiKV Project Authors. Licensed under Apache-2.0.
use std::sync::atomic::{AtomicI32, AtomicU64, Ordering};

use fail::fail_point;
pub use kvproto::disk_usage::DiskUsage;

// DISK_RESERVED_SPACE means if left space is less than this, tikv will
// turn to maintenance mode. There are another 2 value derived from this,
// 50% for a migration only mode and 20% for disk space holder size.
// Percent is not configurable, But if you want to change, please make sure
// the percent in both the init fs and store monitor are keep the same.
static DISK_RESERVED_SPACE: AtomicU64 = AtomicU64::new(0);
static RAFT_DISK_RESERVED_SPACE: AtomicU64 = AtomicU64::new(0);
static DISK_STATUS: AtomicI32 = AtomicI32::new(0);

pub fn set_disk_reserved_space(v: u64) {
    DISK_RESERVED_SPACE.store(v, Ordering::Release)
}

pub fn get_disk_reserved_space() -> u64 {
    DISK_RESERVED_SPACE.load(Ordering::Acquire)
}

pub fn set_raft_disk_reserved_space(v: u64) {
    RAFT_DISK_RESERVED_SPACE.store(v, Ordering::Release)
}

pub fn get_raft_disk_reserved_space() -> u64 {
    RAFT_DISK_RESERVED_SPACE.load(Ordering::Acquire)
}

pub fn set_disk_status(status: DiskUsage) {
    let v = match status {
        DiskUsage::Normal => 0,
        DiskUsage::AlmostFull => 1,
        DiskUsage::AlreadyFull => 2,
    };
    DISK_STATUS.store(v, Ordering::Release);
}

pub fn get_disk_status(_store_id: u64) -> DiskUsage {
    fail_point!("disk_almost_full_peer_1", _store_id == 1, |_| {
        DiskUsage::AlmostFull
    });
    fail_point!("disk_almost_full_peer_2", _store_id == 2, |_| {
        DiskUsage::AlmostFull
    });
    fail_point!("disk_almost_full_peer_3", _store_id == 3, |_| {
        DiskUsage::AlmostFull
    });
    fail_point!("disk_almost_full_peer_4", _store_id == 4, |_| {
        DiskUsage::AlmostFull
    });
    fail_point!("disk_almost_full_peer_5", _store_id == 5, |_| {
        DiskUsage::AlmostFull
    });
    fail_point!("disk_already_full_peer_1", _store_id == 1, |_| {
        DiskUsage::AlreadyFull
    });
    fail_point!("disk_already_full_peer_2", _store_id == 2, |_| {
        DiskUsage::AlreadyFull
    });
    fail_point!("disk_already_full_peer_3", _store_id == 3, |_| {
        DiskUsage::AlreadyFull
    });
    fail_point!("disk_already_full_peer_4", _store_id == 4, |_| {
        DiskUsage::AlreadyFull
    });
    fail_point!("disk_already_full_peer_5", _store_id == 5, |_| {
        DiskUsage::AlreadyFull
    });

    let s = DISK_STATUS.load(Ordering::Acquire);
    match s {
        0 => DiskUsage::Normal,
        1 => DiskUsage::AlmostFull,
        2 => DiskUsage::AlreadyFull,
        _ => panic!("Disk Status Value not meet expectations"),
    }
}