/// The parsed chain block representation
pub type ParsedBlock = pallas::MultiEraBlock;

/// The action that indicates what to do next when scanning the chain
pub enum ChainBlockNextAction {
    /// RollForward event (we are still on the correct fork)
    RollForward {
        /// The next point in the chain to read
        next_point: ChainPoint,
        /// The parsed block 
        block: ParsedBlock,
    },
    /// RollBackward event (we are on an incorrect fork, we need to get back a point to roll forward again)
    RollBackward {
        /// The rollback point in the chain to read (as a new valid point to read from on the main chain, which has already been seen)
        rollback_point: ChainPoint,
    },
}

/// The trait that reads events to either:
/// - read next block on the chain
/// - rollback to another point in case of rollback
/// - do nothing
pub trait ChainBlockReader {
    //// Get next chain block action
    async fn get_next_chain_block(&self, point: &ChainPoint) -> StdResult<Option<ChainBlockNextAction>>;
}