import { Service } from '../../../../di/src/decorator/Service.ts'
import {Collection} from '../../collection/Collection.ts'
import Session from './Session.ts'
import SessionManager, {InvalidSessionKeyError} from './SessionManager.ts'
import Utility from '../../service/utility/Utility.ts'
import SessionInterface from './SessionInterface.ts'

/**
 * Type denoting a memory-stored session.
 */
export type SessionRegistrant = { key: string, session: SessionInterface }

/**
 * Session manager object for memory-based sessions.
 * @extends SessionManager
 */
@Service()
export default class MemorySessionManager extends SessionManager {
    /**
     * Collection of registered, in-memory sessions.
     * @type Collection<SessionRegistrant>
     */
    private _sessions: Collection<SessionRegistrant> = new Collection<SessionRegistrant>()

    public async has_session(key: string): Promise<boolean> {
        return !!this._sessions.firstWhere('key', '=', key)
    }

    public async get_session(key?: string): Promise<SessionInterface> {
        if ( !key ) {
            const utility: Utility = this.make(Utility)
            const session_key: string = key || utility.uuid()
            const session = this.make(Session)

            session.set_key(session_key)
            await session.persist()
            this._sessions.push({ key: session_key, session })

            return session
        }

        const session = this._sessions.firstWhere('key', '=', key)
        if ( !session ) throw new InvalidSessionKeyError(key)
        return session.session
    }

    public async purge(key?: string) {
        if ( key ) {
            this._sessions = this._sessions.filter(session => session.key !== key)
        } else {
            this._sessions = new Collection<SessionRegistrant>()
        }
    }
}