import type { League } from '@gridpilot/racing/domain/entities/League';
import type { Protest } from '@gridpilot/racing/domain/entities/Protest';
import type { Race } from '@gridpilot/racing/domain/entities/Race';
import type { DriverDTO } from '@gridpilot/racing/application/dto/DriverDTO';
import type { LeagueConfigFormModel } from '@gridpilot/racing/application';
import type { MembershipRole } from '@/lib/leagueMembership';
import { EntityMappers } from '@gridpilot/racing/application/mappers/EntityMappers';
import {
  getLeagueMembershipRepository,
  getDriverRepository,
  getGetLeagueFullConfigUseCase,
  getRaceRepository,
  getProtestRepository,
  getDriverStats,
  getAllDriverRankings,
} from '@/lib/di-container';

export interface LeagueJoinRequestViewModel {
  id: string;
  leagueId: string;
  driverId: string;
  requestedAt: Date;
  message?: string;
  driver?: DriverDTO;
}

export interface ProtestDriverSummary {
  [driverId: string]: DriverDTO;
}

export interface ProtestRaceSummary {
  [raceId: string]: Race;
}

export interface LeagueOwnerSummaryViewModel {
  driver: DriverDTO;
  rating: number | null;
  rank: number | null;
}

export interface LeagueAdminProtestsViewModel {
  protests: Protest[];
  racesById: ProtestRaceSummary;
  driversById: ProtestDriverSummary;
}

export interface LeagueAdminConfigViewModel {
  form: LeagueConfigFormModel | null;
}

export interface LeagueAdminPermissionsViewModel {
  canRemoveMember: boolean;
  canUpdateRoles: boolean;
}

export interface LeagueAdminViewModel {
  joinRequests: LeagueJoinRequestViewModel[];
  ownerSummary: LeagueOwnerSummaryViewModel | null;
  config: LeagueAdminConfigViewModel;
  protests: LeagueAdminProtestsViewModel;
}

/**
 * Load join requests plus requester driver DTOs for a league.
 */
export async function loadLeagueJoinRequests(leagueId: string): Promise<LeagueJoinRequestViewModel[]> {
  const membershipRepo = getLeagueMembershipRepository();
  const requests = await membershipRepo.getJoinRequests(leagueId);

  const driverRepo = getDriverRepository();
  const uniqueDriverIds = Array.from(new Set(requests.map((r) => r.driverId)));
  const driverEntities = await Promise.all(uniqueDriverIds.map((id) => driverRepo.findById(id)));
  const driverDtos = driverEntities
    .map((driver) => (driver ? EntityMappers.toDriverDTO(driver) : null))
    .filter((dto): dto is DriverDTO => dto !== null);

  const driversById: Record<string, DriverDTO> = {};
  for (const dto of driverDtos) {
    driversById[dto.id] = dto;
  }

  return requests.map((request) => ({
    id: request.id,
    leagueId: request.leagueId,
    driverId: request.driverId,
    requestedAt: request.requestedAt,
    message: request.message,
    driver: driversById[request.driverId],
  }));
}

/**
 * Approve a league join request and return updated join requests.
 */
export async function approveLeagueJoinRequest(
  leagueId: string,
  requestId: string
): Promise<LeagueJoinRequestViewModel[]> {
  const membershipRepo = getLeagueMembershipRepository();
  const requests = await membershipRepo.getJoinRequests(leagueId);
  const request = requests.find((r) => r.id === requestId);
  if (!request) {
    throw new Error('Join request not found');
  }

  await membershipRepo.saveMembership({
    leagueId: request.leagueId,
    driverId: request.driverId,
    role: 'member',
    status: 'active',
    joinedAt: new Date(),
  });
  await membershipRepo.removeJoinRequest(requestId);

  return loadLeagueJoinRequests(leagueId);
}

/**
 * Reject a league join request (alpha: just remove).
 */
export async function rejectLeagueJoinRequest(
  leagueId: string,
  requestId: string
): Promise<LeagueJoinRequestViewModel[]> {
  const membershipRepo = getLeagueMembershipRepository();
  await membershipRepo.removeJoinRequest(requestId);
  return loadLeagueJoinRequests(leagueId);
}

/**
 * Compute permissions for a performer on league membership actions.
 */
export async function getLeagueAdminPermissions(
  leagueId: string,
  performerDriverId: string
): Promise<LeagueAdminPermissionsViewModel> {
  const membershipRepo = getLeagueMembershipRepository();
  const performer = await membershipRepo.getMembership(leagueId, performerDriverId);

  const isOwner = performer?.role === 'owner';
  const isAdmin = performer?.role === 'admin';

  return {
    canRemoveMember: Boolean(isOwner || isAdmin),
    canUpdateRoles: Boolean(isOwner),
  };
}

/**
 * Remove a member from the league, enforcing simple role rules.
 */
export async function removeLeagueMember(
  leagueId: string,
  performerDriverId: string,
  targetDriverId: string
): Promise<void> {
  const membershipRepo = getLeagueMembershipRepository();
  const performer = await membershipRepo.getMembership(leagueId, performerDriverId);
  if (!performer || (performer.role !== 'owner' && performer.role !== 'admin')) {
    throw new Error('Only owners or admins can remove members');
  }

  const membership = await membershipRepo.getMembership(leagueId, targetDriverId);
  if (!membership) {
    throw new Error('Member not found');
  }
  if (membership.role === 'owner') {
    throw new Error('Cannot remove the league owner');
  }

  await membershipRepo.removeMembership(leagueId, targetDriverId);
}

/**
 * Update a member's role, enforcing simple owner-only rules.
 */
export async function updateLeagueMemberRole(
  leagueId: string,
  performerDriverId: string,
  targetDriverId: string,
  newRole: MembershipRole
): Promise<void> {
  const membershipRepo = getLeagueMembershipRepository();
  const performer = await membershipRepo.getMembership(leagueId, performerDriverId);
  if (!performer || performer.role !== 'owner') {
    throw new Error('Only the league owner can update roles');
  }

  const membership = await membershipRepo.getMembership(leagueId, targetDriverId);
  if (!membership) {
    throw new Error('Member not found');
  }
  if (membership.role === 'owner') {
    throw new Error('Cannot change the owner role');
  }

  await membershipRepo.saveMembership({
    ...membership,
    role: newRole,
  });
}

/**
 * Load owner summary (DTO + rating/rank) for a league.
 */
export async function loadLeagueOwnerSummary(league: League): Promise<LeagueOwnerSummaryViewModel | null> {
  const driverRepo = getDriverRepository();
  const entity = await driverRepo.findById(league.ownerId);
  if (!entity) return null;

  const ownerDriver = EntityMappers.toDriverDTO(entity);
  const stats = getDriverStats(ownerDriver.id);
  const allRankings = getAllDriverRankings();

  let rating: number | null = stats?.rating ?? null;
  let rank: number | null = null;

  if (stats) {
    if (typeof stats.overallRank === 'number' && stats.overallRank > 0) {
      rank = stats.overallRank;
    } else {
      const indexInGlobal = allRankings.findIndex((stat) => stat.driverId === stats.driverId);
      if (indexInGlobal !== -1) {
        rank = indexInGlobal + 1;
      }
    }

    if (rating === null) {
      const globalEntry = allRankings.find((stat) => stat.driverId === stats.driverId);
      if (globalEntry) {
        rating = globalEntry.rating;
      }
    }
  }

  return {
    driver: ownerDriver,
    rating,
    rank,
  };
}

/**
 * Load league full config form.
 */
export async function loadLeagueConfig(leagueId: string): Promise<LeagueAdminConfigViewModel> {
  const useCase = getGetLeagueFullConfigUseCase();
  const form = await useCase.execute({ leagueId });
  return { form };
}

/**
 * Load protests, related races and driver DTOs for a league.
 */
export async function loadLeagueProtests(leagueId: string): Promise<LeagueAdminProtestsViewModel> {
  const raceRepo = getRaceRepository();
  const protestRepo = getProtestRepository();
  const driverRepo = getDriverRepository();

  const leagueRaces = await raceRepo.findByLeagueId(leagueId);

  const allProtests: Protest[] = [];
  const racesById: Record<string, Race> = {};

  for (const race of leagueRaces) {
    racesById[race.id] = race;
    const raceProtests = await protestRepo.findByRaceId(race.id);
    allProtests.push(...raceProtests);
  }

  const driverIds = new Set<string>();
  allProtests.forEach((p) => {
    driverIds.add(p.protestingDriverId);
    driverIds.add(p.accusedDriverId);
  });

  const driverEntities = await Promise.all(Array.from(driverIds).map((id) => driverRepo.findById(id)));
  const driverDtos = driverEntities
    .map((driver) => (driver ? EntityMappers.toDriverDTO(driver) : null))
    .filter((dto): dto is DriverDTO => dto !== null);

  const driversById: Record<string, DriverDTO> = {};
  for (const dto of driverDtos) {
    driversById[dto.id] = dto;
  }

  return {
    protests: allProtests,
    racesById,
    driversById,
  };
}