//! Utilities for managing database schema changes.
use crate::beacon_chain::BeaconChainTypes;
use std::sync::Arc;
use store::Error as StoreError;
use store::hot_cold_store::{HotColdDB, HotColdDBError};
use store::metadata::{CURRENT_SCHEMA_VERSION, SchemaVersion};

/// Migrate the database from one schema version to another, applying all requisite mutations.
///
/// All migrations for schema versions up to and including v28 have been removed. Nodes on live
/// networks are already running v28, so only the current version check remains.
pub fn migrate_schema<T: BeaconChainTypes>(
    _db: Arc<HotColdDB<T::EthSpec, T::HotStore, T::ColdStore>>,
    from: SchemaVersion,
    to: SchemaVersion,
) -> Result<(), StoreError> {
    match (from, to) {
        // Migrating from the current schema version to itself is always OK, a no-op.
        (_, _) if from == to && to == CURRENT_SCHEMA_VERSION => Ok(()),
        // Anything else is an error.
        (_, _) => Err(HotColdDBError::UnsupportedSchemaVersion {
            target_version: to,
            current_version: from,
        }
        .into()),
    }
}