//! Information about the network's clock, ticks, slots, etc.

use {
    crate::{clone_zeroed, copy_field},
    std::mem::MaybeUninit,
};

// The default tick rate that the cluster attempts to achieve.  Note that the actual tick
// rate at any given time should be expected to drift
pub const DEFAULT_TICKS_PER_SECOND: u64 = 160;

#[cfg(test)]
static_assertions::const_assert_eq!(MS_PER_TICK, 6);
pub const MS_PER_TICK: u64 = 1000 / DEFAULT_TICKS_PER_SECOND;

#[cfg(test)]
static_assertions::const_assert_eq!(SLOT_MS, 400);
pub const SLOT_MS: u64 = (DEFAULT_TICKS_PER_SLOT * 1000) / DEFAULT_TICKS_PER_SECOND;

// At 160 ticks/s, 64 ticks per slot implies that leader rotation and voting will happen
// every 400 ms. A fast voting cadence ensures faster finality and convergence
pub const DEFAULT_TICKS_PER_SLOT: u64 = 64;

// GCP n1-standard hardware and also a xeon e5-2520 v4 are about this rate of hashes/s
pub const DEFAULT_HASHES_PER_SECOND: u64 = 2_000_000;

#[cfg(test)]
static_assertions::const_assert_eq!(DEFAULT_HASHES_PER_TICK, 12_500);
pub const DEFAULT_HASHES_PER_TICK: u64 = DEFAULT_HASHES_PER_SECOND / DEFAULT_TICKS_PER_SECOND;

// 1 Dev Epoch = 400 ms * 8192 ~= 55 minutes
pub const DEFAULT_DEV_SLOTS_PER_EPOCH: u64 = 8192;

#[cfg(test)]
static_assertions::const_assert_eq!(SECONDS_PER_DAY, 86_400);
pub const SECONDS_PER_DAY: u64 = 24 * 60 * 60;

#[cfg(test)]
static_assertions::const_assert_eq!(TICKS_PER_DAY, 13_824_000);
pub const TICKS_PER_DAY: u64 = DEFAULT_TICKS_PER_SECOND * SECONDS_PER_DAY;

#[cfg(test)]
static_assertions::const_assert_eq!(DEFAULT_SLOTS_PER_EPOCH, 432_000);
// 1 Epoch ~= 2 days
pub const DEFAULT_SLOTS_PER_EPOCH: u64 = 2 * TICKS_PER_DAY / DEFAULT_TICKS_PER_SLOT;

// leader schedule is governed by this
pub const NUM_CONSECUTIVE_LEADER_SLOTS: u64 = 4;

#[cfg(test)]
static_assertions::const_assert_eq!(DEFAULT_MS_PER_SLOT, 400);
pub const DEFAULT_MS_PER_SLOT: u64 = 1_000 * DEFAULT_TICKS_PER_SLOT / DEFAULT_TICKS_PER_SECOND;
pub const DEFAULT_S_PER_SLOT: f64 = DEFAULT_TICKS_PER_SLOT as f64 / DEFAULT_TICKS_PER_SECOND as f64;

/// The time window of recent block hash values that the bank will track the signatures
/// of over. Once the bank discards a block hash, it will reject any transactions that use
/// that `recent_blockhash` in a transaction. Lowering this value reduces memory consumption,
/// but requires clients to update its `recent_blockhash` more frequently. Raising the value
/// lengthens the time a client must wait to be certain a missing transaction will
/// not be processed by the network.
pub const MAX_HASH_AGE_IN_SECONDS: usize = 120;

#[cfg(test)]
static_assertions::const_assert_eq!(MAX_RECENT_BLOCKHASHES, 300);
// Number of maximum recent blockhashes (one blockhash per non-skipped slot)
pub const MAX_RECENT_BLOCKHASHES: usize =
    MAX_HASH_AGE_IN_SECONDS * DEFAULT_TICKS_PER_SECOND as usize / DEFAULT_TICKS_PER_SLOT as usize;

#[cfg(test)]
static_assertions::const_assert_eq!(MAX_PROCESSING_AGE, 150);
// The maximum age of a blockhash that will be accepted by the leader
pub const MAX_PROCESSING_AGE: usize = MAX_RECENT_BLOCKHASHES / 2;

/// This is maximum time consumed in forwarding a transaction from one node to next, before
/// it can be processed in the target node
pub const MAX_TRANSACTION_FORWARDING_DELAY_GPU: usize = 2;

/// More delay is expected if CUDA is not enabled (as signature verification takes longer)
pub const MAX_TRANSACTION_FORWARDING_DELAY: usize = 6;

/// Slot is a unit of time given to a leader for encoding,
///  is some some number of Ticks long.
pub type Slot = u64;

/// Uniquely distinguishes every version of a slot, even if the
/// slot number is the same, i.e. duplicate slots
pub type BankId = u64;

/// Epoch is a unit of time a given leader schedule is honored,
///  some number of Slots.
pub type Epoch = u64;

pub const GENESIS_EPOCH: Epoch = 0;
// must be sync with Account::rent_epoch::default()
pub const INITIAL_RENT_EPOCH: Epoch = 0;

/// SlotIndex is an index to the slots of a epoch
pub type SlotIndex = u64;

/// SlotCount is the number of slots in a epoch
pub type SlotCount = u64;

/// UnixTimestamp is an approximate measure of real-world time,
/// expressed as Unix time (ie. seconds since the Unix epoch)
pub type UnixTimestamp = i64;

/// Clock represents network time.  Members of Clock start from 0 upon
///  network boot.  The best way to map Clock to wallclock time is to use
///  current Slot, as Epochs vary in duration (they start short and grow
///  as the network progresses).
///
#[repr(C)]
#[derive(Serialize, Deserialize, Debug, Default, PartialEq, Eq)]
pub struct Clock {
    /// the current network/bank Slot
    pub slot: Slot,
    /// the timestamp of the first Slot in this Epoch
    pub epoch_start_timestamp: UnixTimestamp,
    /// the bank Epoch
    pub epoch: Epoch,
    /// the future Epoch for which the leader schedule has
    ///  most recently been calculated
    pub leader_schedule_epoch: Epoch,
    /// originally computed from genesis creation time and network time
    /// in slots (drifty); corrected using validator timestamp oracle as of
    /// timestamp_correction and timestamp_bounding features
    pub unix_timestamp: UnixTimestamp,
}

impl Clone for Clock {
    fn clone(&self) -> Self {
        clone_zeroed(|cloned: &mut MaybeUninit<Self>| {
            let ptr = cloned.as_mut_ptr();
            unsafe {
                copy_field!(ptr, self, slot);
                copy_field!(ptr, self, epoch_start_timestamp);
                copy_field!(ptr, self, epoch);
                copy_field!(ptr, self, leader_schedule_epoch);
                copy_field!(ptr, self, unix_timestamp);
            }
        })
    }
}

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

    #[test]
    fn test_clone() {
        let clock = Clock {
            slot: 1,
            epoch_start_timestamp: 2,
            epoch: 3,
            leader_schedule_epoch: 4,
            unix_timestamp: 5,
        };
        let cloned_clock = clock.clone();
        assert_eq!(cloned_clock, clock);
    }
}