orderwal 0.5.1

use core::{
  convert::Infallible,
  ops::{Bound, RangeBounds},
};

use crossbeam_skiplist_mvcc::nested::SkipMap;
pub use crossbeam_skiplist_mvcc::nested::{Entry, Iter, IterAll, Range, RangeAll, VersionedEntry};

use dbutils::{
  equivalent::Comparable,
  types::{KeyRef, Type},
};

use crate::{
  memtable::{self, BaseEntry, VersionedMemtableEntry},
  sealed::WithVersion,
  types::Kind,
  wal::{KeyPointer, ValuePointer},
};

/// An memory table implementation based on [`crossbeam_skiplist::SkipSet`].
pub struct MultipleVersionTable<K: ?Sized, V: ?Sized>(SkipMap<KeyPointer<K>, ValuePointer<V>>);

impl<K, V> Default for MultipleVersionTable<K, V>
where
  K: ?Sized,
  V: ?Sized,
{
  #[inline]
  fn default() -> Self {
    Self(SkipMap::new())
  }
}

impl<'a, K, V> BaseEntry<'a> for Entry<'a, KeyPointer<K>, ValuePointer<V>>
where
  K: ?Sized + Type + Ord,
  K::Ref<'a>: KeyRef<'a, K>,
  V: ?Sized,
{
  type Key = K;
  type Value = V;

  #[inline]
  fn next(&mut self) -> Option<Self> {
    Entry::next(self)
  }

  #[inline]
  fn prev(&mut self) -> Option<Self> {
    Entry::prev(self)
  }

  #[inline]
  fn key(&self) -> KeyPointer<K> {
    *self.key()
  }
}

impl<'a, K, V> memtable::VersionedMemtableEntry<'a> for Entry<'a, KeyPointer<K>, ValuePointer<V>>
where
  K: ?Sized + Type + Ord,
  K::Ref<'a>: KeyRef<'a, K>,
  V: ?Sized,
{
  #[inline]
  fn value(&self) -> Option<ValuePointer<V>> {
    Some(*self.value())
  }

  #[inline]
  fn version(&self) -> u64 {
    Entry::version(self)
  }
}

impl<K, V> WithVersion for Entry<'_, KeyPointer<K>, ValuePointer<V>>
where
  K: ?Sized,
  V: ?Sized,
{
}

impl<'a, K, V> BaseEntry<'a> for VersionedEntry<'a, KeyPointer<K>, ValuePointer<V>>
where
  K: ?Sized + Type + Ord,
  K::Ref<'a>: KeyRef<'a, K>,
  V: ?Sized,
{
  type Key = K;
  type Value = V;

  #[inline]
  fn next(&mut self) -> Option<Self> {
    VersionedEntry::next(self)
  }

  #[inline]
  fn prev(&mut self) -> Option<Self> {
    VersionedEntry::prev(self)
  }

  #[inline]
  fn key(&self) -> KeyPointer<K> {
    *self.key()
  }
}

impl<'a, K, V> VersionedMemtableEntry<'a> for VersionedEntry<'a, KeyPointer<K>, ValuePointer<V>>
where
  K: ?Sized + Type + Ord,
  K::Ref<'a>: KeyRef<'a, K>,
  V: ?Sized,
{
  #[inline]
  fn version(&self) -> u64 {
    VersionedEntry::version(self)
  }

  #[inline]
  fn value(&self) -> Option<ValuePointer<V>> {
    self.value().copied()
  }
}

impl<K, V> WithVersion for VersionedEntry<'_, KeyPointer<K>, ValuePointer<V>>
where
  K: ?Sized,
  V: ?Sized,
{
}

impl<K, V> memtable::BaseTable for MultipleVersionTable<K, V>
where
  K: ?Sized + Type + Ord + 'static,
  for<'a> K::Ref<'a>: KeyRef<'a, K>,
  V: ?Sized + 'static,
{
  type Key = K;
  type Value = V;
  type Item<'a>
    = Entry<'a, KeyPointer<Self::Key>, ValuePointer<Self::Value>>
  where
    Self: 'a;

  type Iterator<'a>
    = Iter<'a, KeyPointer<Self::Key>, ValuePointer<Self::Value>>
  where
    Self: 'a;

  type Range<'a, Q, R>
    = Range<'a, Q, R, KeyPointer<Self::Key>, ValuePointer<Self::Value>>
  where
    Self: 'a,
    R: RangeBounds<Q> + 'a,
    Q: ?Sized + Comparable<KeyPointer<Self::Key>>;

  type Options = ();
  type Error = Infallible;

  fn new(_: Self::Options) -> Result<Self, Self::Error>
  where
    Self: Sized,
  {
    Ok(Self(SkipMap::new()))
  }

  #[inline]
  fn insert(
    &self,
    version: Option<u64>,
    kp: KeyPointer<Self::Key>,
    vp: ValuePointer<Self::Value>,
  ) -> Result<(), Self::Error>
  where
    KeyPointer<Self::Key>: Ord + 'static,
  {
    self.0.insert_unchecked(version.unwrap_or(0), kp, vp);
    Ok(())
  }

  #[inline]
  fn remove(&self, version: Option<u64>, key: KeyPointer<Self::Key>) -> Result<(), Self::Error>
  where
    KeyPointer<Self::Key>: Ord + 'static,
  {
    self.0.remove_unchecked(version.unwrap_or(0), key);
    Ok(())
  }

  #[inline]
  fn kind() -> Kind {
    Kind::MultipleVersion
  }
}

impl<K, V> memtable::MultipleVersionMemtable for MultipleVersionTable<K, V>
where
  K: ?Sized + Type + Ord + 'static,
  for<'a> K::Ref<'a>: KeyRef<'a, K>,
  V: ?Sized + 'static,
{
  type VersionedItem<'a>
    = VersionedEntry<'a, KeyPointer<Self::Key>, ValuePointer<Self::Value>>
  where
    Self: 'a;

  type IterAll<'a>
    = IterAll<'a, KeyPointer<Self::Key>, ValuePointer<Self::Value>>
  where
    Self: 'a;

  type RangeAll<'a, Q, R>
    = RangeAll<'a, Q, R, KeyPointer<Self::Key>, ValuePointer<Self::Value>>
  where
    Self: 'a,
    R: RangeBounds<Q> + 'a,
    Q: ?Sized + Comparable<KeyPointer<Self::Key>>;

  #[inline]
  fn maximum_version(&self) -> u64 {
    self.0.maximum_version()
  }

  #[inline]
  fn minimum_version(&self) -> u64 {
    self.0.minimum_version()
  }

  #[inline]
  fn may_contain_version(&self, version: u64) -> bool {
    self.0.may_contain_version(version)
  }

  fn upper_bound<Q>(&self, version: u64, bound: Bound<&Q>) -> Option<Self::Item<'_>>
  where
    Q: ?Sized + Comparable<KeyPointer<Self::Key>>,
  {
    self.0.upper_bound(version, bound)
  }

  fn upper_bound_versioned<Q>(
    &self,
    version: u64,
    bound: Bound<&Q>,
  ) -> Option<Self::VersionedItem<'_>>
  where
    Q: ?Sized + Comparable<KeyPointer<Self::Key>>,
  {
    self.0.upper_bound_versioned(version, bound)
  }

  fn lower_bound<Q>(&self, version: u64, bound: Bound<&Q>) -> Option<Self::Item<'_>>
  where
    Q: ?Sized + Comparable<KeyPointer<Self::Key>>,
  {
    self.0.lower_bound(version, bound)
  }

  fn lower_bound_versioned<Q>(
    &self,
    version: u64,
    bound: Bound<&Q>,
  ) -> Option<Self::VersionedItem<'_>>
  where
    Q: ?Sized + Comparable<KeyPointer<Self::Key>>,
  {
    self.0.lower_bound_versioned(version, bound)
  }

  fn first(&self, version: u64) -> Option<Self::Item<'_>>
  where
    KeyPointer<Self::Key>: Ord,
  {
    self.0.front(version)
  }

  fn first_versioned(&self, version: u64) -> Option<Self::VersionedItem<'_>>
  where
    KeyPointer<Self::Key>: Ord,
  {
    self.0.front_versioned(version)
  }

  fn last(&self, version: u64) -> Option<Self::Item<'_>>
  where
    KeyPointer<Self::Key>: Ord,
  {
    self.0.back(version)
  }

  fn last_versioned(&self, version: u64) -> Option<Self::VersionedItem<'_>>
  where
    KeyPointer<Self::Key>: Ord,
  {
    self.0.back_versioned(version)
  }

  fn get<Q>(&self, version: u64, key: &Q) -> Option<Self::Item<'_>>
  where
    Q: ?Sized + Comparable<KeyPointer<Self::Key>>,
  {
    self.0.get(version, key)
  }

  fn get_versioned<Q>(&self, version: u64, key: &Q) -> Option<Self::VersionedItem<'_>>
  where
    Q: ?Sized + Comparable<KeyPointer<Self::Key>>,
  {
    self.0.get_versioned(version, key)
  }

  fn contains<Q>(&self, version: u64, key: &Q) -> bool
  where
    Q: ?Sized + Comparable<KeyPointer<Self::Key>>,
  {
    self.0.contains_key(version, key)
  }

  fn contains_versioned<Q>(&self, version: u64, key: &Q) -> bool
  where
    Q: ?Sized + Comparable<KeyPointer<Self::Key>>,
  {
    self.0.contains_key_versioned(version, key)
  }

  fn iter(&self, version: u64) -> Self::Iterator<'_> {
    self.0.iter(version)
  }

  fn iter_all_versions(&self, version: u64) -> Self::IterAll<'_> {
    self.0.iter_all_versions(version)
  }

  fn range<'a, Q, R>(&'a self, version: u64, range: R) -> Self::Range<'a, Q, R>
  where
    R: RangeBounds<Q> + 'a,
    Q: ?Sized + Comparable<KeyPointer<Self::Key>>,
  {
    self.0.range(version, range)
  }

  fn range_all_versions<'a, Q, R>(&'a self, version: u64, range: R) -> Self::RangeAll<'a, Q, R>
  where
    R: RangeBounds<Q> + 'a,
    Q: ?Sized + Comparable<KeyPointer<Self::Key>>,
  {
    self.0.range_all_versions(version, range)
  }
}