/**
 * Infrastructure Adapter: InMemoryRaceRegistrationRepository
 *
 * In-memory implementation of IRaceRegistrationRepository.
 * Stores race registrations in Maps keyed by raceId and driverId.
 */

import type { RaceRegistration } from '@gridpilot/racing/domain/entities/RaceRegistration';
import type { IRaceRegistrationRepository } from '@gridpilot/racing/domain/repositories/IRaceRegistrationRepository';

type RaceRegistrationSeed = Pick<RaceRegistration, 'raceId' | 'driverId' | 'registeredAt'>;

export class InMemoryRaceRegistrationRepository implements IRaceRegistrationRepository {
  private registrationsByRace: Map<string, Set<string>>;
  private registrationsByDriver: Map<string, Set<string>>;

  constructor(seedRegistrations?: RaceRegistrationSeed[]) {
    this.registrationsByRace = new Map();
    this.registrationsByDriver = new Map();

    if (seedRegistrations) {
      seedRegistrations.forEach((registration) => {
        this.addToIndexes(registration.raceId, registration.driverId, registration.registeredAt);
      });
    }
  }

  private addToIndexes(raceId: string, driverId: string, _registeredAt: Date): void {
    let raceSet = this.registrationsByRace.get(raceId);
    if (!raceSet) {
      raceSet = new Set();
      this.registrationsByRace.set(raceId, raceSet);
    }
    raceSet.add(driverId);

    let driverSet = this.registrationsByDriver.get(driverId);
    if (!driverSet) {
      driverSet = new Set();
      this.registrationsByDriver.set(driverId, driverSet);
    }
    driverSet.add(raceId);
  }

  private removeFromIndexes(raceId: string, driverId: string): void {
    const raceSet = this.registrationsByRace.get(raceId);
    if (raceSet) {
      raceSet.delete(driverId);
      if (raceSet.size === 0) {
        this.registrationsByRace.delete(raceId);
      }
    }

    const driverSet = this.registrationsByDriver.get(driverId);
    if (driverSet) {
      driverSet.delete(raceId);
      if (driverSet.size === 0) {
        this.registrationsByDriver.delete(driverId);
      }
    }
  }

  async isRegistered(raceId: string, driverId: string): Promise<boolean> {
    const raceSet = this.registrationsByRace.get(raceId);
    if (!raceSet) return false;
    return raceSet.has(driverId);
  }

  async getRegisteredDrivers(raceId: string): Promise<string[]> {
    const raceSet = this.registrationsByRace.get(raceId);
    if (!raceSet) return [];
    return Array.from(raceSet.values());
  }

  async getRegistrationCount(raceId: string): Promise<number> {
    const raceSet = this.registrationsByRace.get(raceId);
    return raceSet ? raceSet.size : 0;
  }

  async register(registration: RaceRegistration): Promise<void> {
    const alreadyRegistered = await this.isRegistered(registration.raceId, registration.driverId);
    if (alreadyRegistered) {
      throw new Error('Already registered for this race');
    }
    this.addToIndexes(registration.raceId, registration.driverId, registration.registeredAt);
  }

  async withdraw(raceId: string, driverId: string): Promise<void> {
    const alreadyRegistered = await this.isRegistered(raceId, driverId);
    if (!alreadyRegistered) {
      throw new Error('Not registered for this race');
    }
    this.removeFromIndexes(raceId, driverId);
  }

  async getDriverRegistrations(driverId: string): Promise<string[]> {
    const driverSet = this.registrationsByDriver.get(driverId);
    if (!driverSet) return [];
    return Array.from(driverSet.values());
  }

  async clearRaceRegistrations(raceId: string): Promise<void> {
    const raceSet = this.registrationsByRace.get(raceId);
    if (!raceSet) return;

    for (const driverId of raceSet.values()) {
      const driverSet = this.registrationsByDriver.get(driverId);
      if (driverSet) {
        driverSet.delete(raceId);
        if (driverSet.size === 0) {
          this.registrationsByDriver.delete(driverId);
        }
      }
    }

    this.registrationsByRace.delete(raceId);
  }
}