use std::io::Cursor;

use crate::{
    Result,
    buffer::{ArchiveBuf as _, ArchiveBufMut},
    connection::Connection,
    database::Database,
    errors::AppError,
};
use bytes::BytesMut;

use super::get::Get;

#[derive(Debug, Clone)]
pub struct MGet {
    gets: Vec<Get>,
}

impl MGet {
    pub fn new(gets: Vec<Get>) -> Self {
        Self { gets }
    }

    pub async fn execute(self, db: &Database, connection: &mut Connection) -> Result<()> {
        let mut values = Vec::with_capacity(self.gets.len());

        for get in self.gets {
            values.push(db.get(&get.key).await);
        }

        let mut buf = BytesMut::new();

        buf.try_put_vec(values, |data, buf| {
            buf.put_option(data.as_deref(), ArchiveBufMut::put_bytes_with_length);

            Ok::<(), AppError>(())
        })?;

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

        Ok(())
    }

    pub fn parse(buf: &mut Cursor<&[u8]>) -> Result<Self> {
        let gets = buf.try_get_vec(Get::parse)?;

        Ok(Self { gets })
    }

    pub fn put(&self, buf: &mut BytesMut) -> Result<()> {
        buf.put_short_string("mget")?;
        self.put_without_cmd_name(buf)
    }

    pub fn put_without_cmd_name(&self, buf: &mut BytesMut) -> Result<()> {
        buf.try_put_vec(&self.gets, Get::put_without_cmd_name)?;

        Ok(())
    }
}