// Copyright 2022 tison <wander4096@gmail.com>.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use anyhow::Result;
use aredis::{command::SetOption, Client};

struct Lock {
    client: Client,
    key: Vec<u8>,
}

impl Lock {
    const VALUE_ON_LOCK: &'static [u8] = b"locking";

    pub fn new<K: Into<Vec<u8>>>(client: Client, key: K) -> Self {
        Self {
            client,
            key: key.into(),
        }
    }

    pub async fn acquire(&mut self) -> Result<bool> {
        let result = self
            .client
            .set(
                self.key.clone(),
                Self::VALUE_ON_LOCK,
                SetOption::default().nx(),
            )
            .await?;
        Ok(result)
    }

    pub async fn release(&mut self) -> Result<bool> {
        let result = self.client.del(vec![self.key.clone()]).await?;
        Ok(result == 1)
    }
}

#[tokio::test]
#[serial_test::serial]
async fn test_lock() -> Result<()> {
    let client = crate::client().await?;
    let mut lock = Lock::new(client, "test-lock");

    let got = lock.acquire().await?;
    assert!(got);

    let got = lock.acquire().await?;
    assert!(!got);

    let got = lock.release().await?;
    assert!(got);

    let got = lock.acquire().await?;
    assert!(got);
    Ok(())
}