import {Event} from '../../../event/Event'
import {Migration} from '../Migration'
import {Inject, Injectable} from '../../../di'
import {Migrations} from '../../services/Migrations'
import {ErrorWithContext} from '../../../util'

/**
 * Generic base-class for migration-related events.
 */
@Injectable()
export abstract class MigrationEvent extends Event {
    @Inject()
    protected readonly migrations!: Migrations

    /** The migration relevant to this event. */
    private internalMigration: Migration

    /**
     * Get the relevant migration.
     */
    public get migration(): Migration {
        return this.internalMigration
    }

    constructor(
        migration: Migration,
    ) {
        super()
        this.internalMigration = migration
    }

    dehydrate(): {identifier: string} {
        return {
            identifier: this.migration.identifier,
        }
    }

    rehydrate(state: {identifier: string}): void {
        const migration = this.migrations.get(state.identifier)

        if ( !migration ) {
            throw new ErrorWithContext(`Unable to find migration with identifier: ${state.identifier}`, {
                identifier: state.identifier,
            })
        }

        this.internalMigration = migration
    }
}