use crate::error::unexpected::Mappable;
use crate::{origin, util};

pub struct Store<F, S>
where
    S: origin::Store + Sync + Send + 'static,
    F: Fn(&origin::Descr) -> Option<S> + Sync + Send,
{
    mapping_fn: F,
    stores: Vec<S>,
}

impl<F, S> Store<F, S>
where
    S: origin::Store + Sync + Send + 'static,
    F: Fn(&origin::Descr) -> Option<S> + Sync + Send,
{
    pub fn new(mapping_fn: F, stores: Vec<S>) -> Store<F, S> {
        Store { mapping_fn, stores }
    }
}

impl<F, S> origin::Store for Store<F, S>
where
    S: origin::Store + Sync + Send + 'static,
    F: Fn(&origin::Descr) -> Option<S> + Sync + Send,
{
    fn sync(&self, descr: &origin::Descr) -> util::BoxFuture<'_, Result<(), origin::SyncError>> {
        let descr = descr.clone();
        Box::pin(async move {
            (self.mapping_fn)(&descr)
                .or_unexpected_while(format!("mapping {:?} to store", &descr))?
                .sync(&descr)
                .await
        })
    }

    fn all_descrs(&self) -> Result<Vec<origin::Descr>, origin::AllDescrsError> {
        let mut res = Vec::<origin::Descr>::new();

        for store in self.stores.iter() {
            store.all_descrs()?.into_iter().collect_into(&mut res);
        }

        Ok(res)
    }

    fn get_file(
        &self,
        descr: &origin::Descr,
        path: &str,
    ) -> Result<util::BoxByteStream, origin::GetFileError> {
        (self.mapping_fn)(descr)
            .or_unexpected_while(format!("mapping {:?} to store", &descr))?
            .get_file(descr, path)
    }
}