use crate::{amount::AmountCents, asset::AssetId, AccountId, Payment, PaymentId};
use futures::TryStreamExt;

#[derive(thiserror::Error, Debug)]
pub enum Error {
    #[error("Storage error: {0}")]
    Storage(String),

    #[error("No storage update when expecting")]
    NoUpdate,
}

#[async_trait::async_trait]
pub trait Batch {
    async fn spend_payment(
        &mut self,
        payment_id: PaymentId,
        transaction_id: AccountId,
    ) -> Result<(), Error>;

    async fn rollback(self) -> Result<(), Error>;

    async fn commit(self) -> Result<(), Error>;

    async fn store_new_payments(&mut self, outputs: &[Payment]) -> Result<(), Error>;

    async fn store_transaction(&mut self) -> Result<(), Error>;
}

#[async_trait::async_trait]
pub trait Storage<B, I>
where
    B: Batch,
    I: TryStreamExt<Ok = (PaymentId, AmountCents), Error = Error> + Unpin,
{
    async fn get_payment(&self, id: PaymentId) -> Result<Payment, Error>;

    async fn begin(&self) -> Result<B, Error>;

    async fn get_balance(&self, account: AccountId) -> Result<Vec<(AssetId, AmountCents)>, Error>;

    async fn get_unspend_payments(&self, account: AccountId, asset: AssetId) -> Result<I, Error>;
}