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//! Module providing a map implementation based on [`alloc::collections::BTreeMap`].

extern crate alloc;

use crate::map::Map;
use alloc::collections::BTreeMap;

/// A [`Map`] implementation based on [`alloc::collections::BTreeMap`].
pub struct AllocBTreeMap<K, V> {
    btree_map: BTreeMap<K, V>,
}

impl<K, V> Default for AllocBTreeMap<K, V> {
    fn default() -> Self {
        Self::new()
    }
}

impl<K, V> AllocBTreeMap<K, V> {
    /// Creates a new [`AllocBTreeMap`] with the given [`BTreeMap`].
    pub fn with_btree_map(btree_map: BTreeMap<K, V>) -> Self {
        Self { btree_map }
    }

    /// Creates a new empty [`AllocBTreeMap`].
    pub fn new() -> Self {
        Self {
            btree_map: BTreeMap::new(),
        }
    }
}

impl<K: Ord, V> Map<K, V> for AllocBTreeMap<K, V> {
    type Error = core::convert::Infallible;

    fn insert(&mut self, key: K, value: V) -> Result<Option<V>, Self::Error> {
        Ok(self.btree_map.insert(key, value))
    }

    fn get(&self, key: &K) -> Option<&V> {
        self.btree_map.get(key)
    }

    fn get_mut(&mut self, key: &K) -> Option<&mut V> {
        self.btree_map.get_mut(key)
    }

    fn remove(&mut self, key: &K) -> Option<V> {
        self.btree_map.remove(key)
    }

    fn clear(&mut self) -> Result<(), Self::Error> {
        self.btree_map.clear();

        Ok(())
    }

    fn is_empty(&self) -> bool {
        self.btree_map.is_empty()
    }

    fn capacity(&self) -> Option<usize> {
        None
    }

    fn len(&self) -> usize {
        self.btree_map.len()
    }
}