use std::sync::Arc;

use async_trait::async_trait;

use crate::{RuntimeCacheConfig, RuntimeCacheStoreInitError, RuntimeCacheStores};

#[async_trait]
pub trait CacheBackendFactory: Send + Sync {
    async fn build(
        &self,
        config: &RuntimeCacheConfig,
    ) -> Result<RuntimeCacheStores, RuntimeCacheStoreInitError>;
}

pub type SharedCacheBackendFactory = Arc<dyn CacheBackendFactory>;

#[derive(Clone, Copy, Debug, Default)]
pub struct BuiltinCacheBackendFactory;

#[async_trait]
impl CacheBackendFactory for BuiltinCacheBackendFactory {
    async fn build(
        &self,
        config: &RuntimeCacheConfig,
    ) -> Result<RuntimeCacheStores, RuntimeCacheStoreInitError> {
        RuntimeCacheStores::from_config(config).await
    }
}

#[cfg(test)]
mod tests {
    use crate::{CacheBackendFactory, RuntimeCacheConfig};

    use super::BuiltinCacheBackendFactory;

    #[tokio::test]
    async fn builtin_factory_builds_default_memory_stores() {
        let stores = BuiltinCacheBackendFactory
            .build(&RuntimeCacheConfig::default())
            .await
            .unwrap();

        assert_eq!(stores.backend, crank_core::CacheBackend::Memory);
    }
}