karsher 0.5.0

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

impl CacheManager {
    pub fn get_mut_or_insert(&mut self, key: &str) -> &mut Cache {
        self.caches.entry(key.to_string()).or_insert(Default::default())
    }
    pub fn get_default_cache(&self) -> &Option<String> {
        &self.default_cache
    }

    pub fn get_mut_pair(
        &mut self,
        key_1: &str,
        key_2: &str,
    ) -> Option<(&mut Cache, &mut Cache)> {
        if let Some([c1, c2]) = self.caches.get_many_mut([key_1, key_2]) {
            Some((c1, c2))
        } else {
            None
        }
    }

    pub fn set_default_cache(&mut self, default_cache: &str) {
        self.default_cache = Some(String::from(default_cache));
    }

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

    pub fn get_cache_names(&self) -> Vec<&String> {
        self.caches.keys().into_iter().collect()
    }

    pub fn remove_cache(&mut self, cache_name: &str) -> Option<Cache> {
        self.caches.remove(cache_name)
    }

    pub fn clear_values(&mut self, cache_name: &str) -> bool {
        if let Some(cache) = self.caches.get_mut(cache_name) {
            cache.cache.clear();
            cache.cache_aliases.clear();
            return true;
        }
        false
    }
}

impl Cache {
    pub fn concat(&mut self, other: &Cache) {
        self.cache = self
            .cache
            .iter()
            .chain(other.cache.iter())
            .map(|(k, v)| (*k, v.clone()))
            .collect();
        self.cache_aliases = self
            .cache_aliases
            .iter()
            .chain(other.cache_aliases.iter())
            .map(|(k, v)| (k.clone(), *v))
            .collect();
    }

    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<&str> = aliases
            .iter()
            .filter_map(|alias| {
                if !self.cache_aliases.contains_key(*alias) {
                    Some(*alias)
                } else {
                    None
                }
            })
            .collect();

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

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

        if let Some(value) = parsed_key.and_then(|key| self.cache.get(&key)) {
            Some(value)
        } else {
            None
        }
    }

    pub fn list(&self) -> Vec<(&u64, &String, Vec<&String>)> {
        self.cache
            .iter()
            .map(|(key, value)| {
                (
                    key,
                    value,
                    self.cache_aliases
                        .iter()
                        .filter_map(
                            move |(alias, k)| {
                                if key == k {
                                    Some(alias)
                                } else {
                                    None
                                }
                            },
                        )
                        .collect(),
                )
            })
            .collect()
    }
    pub fn remove(&mut self, key: &str) -> Option<String> {
        let key = {
            if let Some(actual_key) = self.cache_aliases.remove(key) {
                Some(actual_key)
            } else {
                key.parse::<u64>().ok()
            }
        };

        if let Some((key, v)) =
            key.and_then(|key| self.cache.remove(&key).map(|v| (key, v)))
        {
            self.cache_aliases = self
                .cache_aliases
                .iter()
                .filter_map(|(k, v)| {
                    if v != &key {
                        Some((k.clone(), *v))
                    } else {
                        None
                    }
                })
                .collect();
            Some(v)
        } else {
            None
        }
    }
}