karsher 0.1.1

karsher is a dumb cache written in rust
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use serde::{Deserialize, Serialize};

pub use crate::prelude::*;
use crate::utils::calculate_hash;

#[derive(Default, Serialize, Deserialize)]
pub struct Cache {
    cache: BTreeMap<u64, String>,
    cache_aliases: BTreeMap<u64, u64>,
}
#[derive(Default, Serialize, Deserialize)]
pub struct CacheManager {
    caches: HashMap<String, Cache>,
}

impl CacheManager {
    pub fn get_mut_or_insert(&mut self, key: &str) -> Option<&mut Cache> {
        if !self.caches.contains_key(key) {
            let _ = self.caches.insert(key.into(), Default::default());
        }
        self.caches.get_mut(key)
    }

    pub fn get(&self, key: &str) -> Option<&Cache> {
        self.caches.get(key)
    }
}

impl Cache {
    pub fn insert(&mut self, aliases: Vec<&str>, value: &str) -> u64 {
        let key = calculate_hash(&value);
        self.cache.insert(key, value.to_owned());

        let aliases: Vec<(u64, &str)> = aliases
            .iter()
            .filter_map(|alias| {
                let k = calculate_hash(alias);
                if !self.cache_aliases.contains_key(&k) {
                    Some((k, *alias))
                } else {
                    None
                }
            })
            .collect();

        for (hash_alias, _) in &aliases {
            self.cache_aliases.insert(*hash_alias, key);
        }
        key
    }

    pub fn get(&self, key: &str) -> Option<&str> {
        let parsed_key = {
            if let Some(actual_key) = self.cache_aliases.get(&calculate_hash(&key)) {
                Some(*actual_key)
            } else {
                key.parse::<u64>().ok()
            }
        };

        if let Some(key) = parsed_key && let Some(value) = self.cache.get(&key) {
            Some(value)
        } else {
            None
        }
    }
    pub fn remove(&mut self, key: &str) -> Option<String> {
        let key = {
            if let Some(actual_key) = self.cache_aliases.remove(&calculate_hash(&key)) {
                Some(actual_key)
            } else {
                key.parse::<u64>().ok()
            }
        };

        if let Some(key) = key && let Some(v) = self.cache.remove(&key) {
            self.cache_aliases = self.cache_aliases.drain_filter(|_, v| v != &key)
            .collect();
            Some(v)
        }else {
            None
        }
    }
}