amnesia 0.2.0 

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use super::{Driver, Error as CacheError};
use async_trait::async_trait;
use redis::AsyncCommands;
use std::{fmt::Debug, time::Duration};

#[derive(Clone)]
pub struct Config {
	pub prefix: String,
	pub redis_url: String,
}

impl Default for Config {
	fn default() -> Self {
		Self {
			prefix: String::new(),
			redis_url: "redis://localhost".to_string(),
		}
	}
}

#[allow(clippy::module_name_repetitions)]
#[derive(Debug)]
/// A driver that uses Redis.
pub struct RedisDriver {
	prefix: String,
	client: redis::Client,
}

impl RedisDriver {
	/// Create a new Redis driver.
	///
	/// # Errors
	///
	/// Returns an error if the Redis URL is invalid.
	pub fn new(config: Config) -> Result<Self, redis::RedisError> {
		Ok(Self {
			prefix: config.prefix,
			client: redis::Client::open(config.redis_url)?,
		})
	}

	fn prefixed_key(&self, key: &str) -> String {
		format!("{}{key}", self.prefix)
	}
}

fn map_redis_err(e: redis::RedisError) -> CacheError {
	CacheError::Other(Box::new(e))
}

#[async_trait]
impl Driver for RedisDriver {
	async fn get(&self, key: &str) -> Result<Option<Vec<u8>>, CacheError> {
		let mut conn = self
			.client
			.get_async_connection()
			.await
			.map_err(map_redis_err)?;

		conn.get(self.prefixed_key(key))
			.await
			.map_err(map_redis_err)
	}

	async fn has(&self, key: &str) -> Result<bool, CacheError> {
		let mut conn = self
			.client
			.get_async_connection()
			.await
			.map_err(map_redis_err)?;

		conn.exists(self.prefixed_key(key))
			.await
			.map_err(map_redis_err)
	}

	async fn put(
		&self,
		key: &str,
		value: Vec<u8>,
		expiry: Option<Duration>,
	) -> Result<(), CacheError> {
		let mut conn = self
			.client
			.get_async_connection()
			.await
			.map_err(map_redis_err)?;

		if let Some(expiry) = expiry {
			conn.set_ex::<_, _, ()>(self.prefixed_key(key), value, expiry.as_secs())
				.await
				.map_err(map_redis_err)?;
		} else {
			conn.set::<_, _, ()>(self.prefixed_key(key), value)
				.await
				.map_err(map_redis_err)?;
		}

		Ok(())
	}

	async fn forget(&self, key: &str) -> Result<(), CacheError> {
		let mut conn = self
			.client
			.get_async_connection()
			.await
			.map_err(map_redis_err)?;

		conn.del::<_, ()>(self.prefixed_key(key))
			.await
			.map_err(map_redis_err)
	}

	async fn flush(&self) -> Result<(), CacheError> {
		let mut conn = self
			.client
			.get_async_connection()
			.await
			.map_err(map_redis_err)?;

		redis::cmd("FLUSHDB")
			.query_async::<()>(&mut conn)
			.await
			.map_err(map_redis_err)
	}
}

#[cfg(test)]
mod tests {
	use std::env;

	use super::*;
	use crate::Cache;

	#[tokio::test]
	async fn test_redis_driver() {
		let cache = Cache::new(
			RedisDriver::new(Config {
				redis_url: env::var("REDIS_URL").expect("REDIS_URL not set"),
				..Default::default()
			})
			.unwrap(),
		);

		assert_eq!(cache.get::<String>("foo").await.unwrap(), None);
		assert!(!cache.has("foo").await.unwrap());

		cache
			.put("foo", &"bar", Duration::from_secs(1))
			.await
			.unwrap();

		assert_eq!(
			cache.get::<String>("foo").await.unwrap(),
			Some("bar".to_string())
		);
		assert!(cache.has("foo").await.unwrap());

		cache.forget("foo").await.unwrap();

		assert_eq!(cache.get::<String>("foo").await.unwrap(), None);
		assert!(!cache.has("foo").await.unwrap());
	}
}