use std::io::Cursor;

use bytes::{Buf as _, BufMut, Bytes, BytesMut};

use crate::{Result, connection::Connection, database::Database, errors::AppError};

#[derive(Debug, Clone)]
pub struct Ttl {
    key: String,
}

impl Ttl {
    pub async fn execute(self, db: &Database, connection: &mut Connection) -> Result<()> {
        let ttl = db.ttl(&self.key).await;

        let Some(ttl) = ttl else {
            connection.write(Bytes::from_static(&[0])).await?;
            return Ok(());
        };

        let mut buf = BytesMut::new();

        buf.put_u8(1);
        buf.put_u64(ttl);

        connection.write(buf.into()).await?;

        Ok(())
    }

    pub fn parse(bytes: &mut Cursor<&[u8]>) -> Result<Self> {
        let key_length = bytes.try_get_u16()? as usize;

        if bytes.remaining() < key_length {
            return Err(AppError::IncompleteCommandBuffer);
        }

        let key = String::from_utf8(bytes.copy_to_bytes(key_length).to_vec())?;

        Ok(Self { key })
    }
}