#![allow(unused_variables)] // TODO(you): remove this lint after implementing this mod
#![allow(dead_code)] // TODO(you): remove this lint after implementing this mod

use std::ops::Bound;
use std::sync::Arc;

use anyhow::Result;
use bytes::Bytes;
use crossbeam_skiplist::SkipMap;
use ouroboros::self_referencing;

use crate::iterators::StorageIterator;
use crate::table::SsTableBuilder;

/// A basic mem-table based on crossbeam-skiplist
pub struct MemTable {
    map: SkipMap<Bytes, Bytes>,
}

impl MemTable {
    /// Create a new mem-table.
    pub fn create() -> Self {
        unimplemented!()
    }

    /// Get a value by key.
    pub fn get(&self, key: &[u8]) -> Option<Bytes> {
        unimplemented!()
    }

    /// Put a key-value pair into the mem-table.
    pub fn put(&self, key: &[u8], value: &[u8]) {
        unimplemented!()
    }

    /// Get an iterator over a range of keys.
    pub fn scan(&self, lower: Bound<&[u8]>, upper: Bound<&[u8]>) -> MemTableIterator {
        unimplemented!()
    }

    /// Flush the mem-table to SSTable.
    pub fn flush(&self, builder: &mut SsTableBuilder) -> Result<()> {
        unimplemented!()
    }
}

type SkipMapRangeIter<'a> =
    crossbeam_skiplist::map::Range<'a, Bytes, (Bound<Bytes>, Bound<Bytes>), Bytes, Bytes>;

/// An iterator over a range of `SkipMap`.
#[self_referencing]
pub struct MemTableIterator {
    map: Arc<SkipMap<Bytes, Bytes>>,
    #[borrows(map)]
    #[not_covariant]
    iter: SkipMapRangeIter<'this>,
    item: (Bytes, Bytes),
}

impl StorageIterator for MemTableIterator {
    fn value(&self) -> &[u8] {
        unimplemented!()
    }

    fn key(&self) -> &[u8] {
        unimplemented!()
    }

    fn is_valid(&self) -> bool {
        unimplemented!()
    }

    fn next(&mut self) -> Result<()> {
        unimplemented!()
    }
}

#[cfg(test)]
mod tests;