import {
    AbstractFactory,
    DependencyRequirement,
    PropertyDependency,
    isInstantiable,
    DEPENDENCY_KEYS_METADATA_KEY,
    DEPENDENCY_KEYS_PROPERTY_METADATA_KEY, Instantiable, Injectable, Inject, FactoryProducer,
} from '../../di'
import {Collection, ErrorWithContext} from '../../util'
import {Logging} from '../../service/Logging'
import {Config} from '../../service/Config'
import {Migrator} from './Migrator'
import {DatabaseMigrator} from './DatabaseMigrator'

/**
 * A dependency injection factory that matches the abstract Migrator class
 * and produces an instance of the configured session driver implementation.
 */
@Injectable()
@FactoryProducer()
export class MigratorFactory extends AbstractFactory<Migrator> {
    @Inject()
    protected readonly logging!: Logging

    @Inject()
    protected readonly config!: Config

    constructor() {
        super({})
    }

    produce(): Migrator {
        return new (this.getMigratorClass())()
    }

    match(something: unknown): boolean {
        return something === Migrator
    }

    getDependencyKeys(): Collection<DependencyRequirement> {
        const meta = Reflect.getMetadata(DEPENDENCY_KEYS_METADATA_KEY, this.getMigratorClass())
        if ( meta ) {
            return meta
        }

        return new Collection<DependencyRequirement>()
    }

    getInjectedProperties(): Collection<PropertyDependency> {
        const meta = new Collection<PropertyDependency>()
        let currentToken = this.getMigratorClass()

        do {
            const loadedMeta = Reflect.getMetadata(DEPENDENCY_KEYS_PROPERTY_METADATA_KEY, currentToken)
            if ( loadedMeta ) {
                meta.concat(loadedMeta)
            }
            currentToken = Object.getPrototypeOf(currentToken)
        } while (Object.getPrototypeOf(currentToken) !== Function.prototype && Object.getPrototypeOf(currentToken) !== Object.prototype)

        return meta
    }

    /**
     * Return the instantiable class of the configured migrator backend.
     * @protected
     * @return Instantiable<Migrator>
     */
    protected getMigratorClass(): Instantiable<Migrator> {
        const MigratorClass = this.config.get('database.migrations.driver', DatabaseMigrator)

        if ( !isInstantiable(MigratorClass) || !(MigratorClass.prototype instanceof Migrator) ) {
            const e = new ErrorWithContext('Provided migration driver class does not extend from @extollo/lib.Migrator')
            e.context = {
                configKey: 'database.migrations.driver',
                class: MigratorClass.toString(),
            }
        }

        return MigratorClass
    }
}