import { PageDataFetcher } from '@/lib/page/PageDataFetcher';
import { DRIVER_SERVICE_TOKEN } from '@/lib/di/tokens';
import { DriverService } from '@/lib/services/drivers/DriverService';
import type { DriverProfileViewModelData } from '@/lib/view-models/DriverProfileViewModel';

// ============================================================================
// TYPES
// ============================================================================

export type PageQueryResult = 
  | { status: 'ok'; dto: DriverProfileViewModelData }
  | { status: 'notFound' }
  | { status: 'redirect'; to: string }
  | { status: 'error'; errorId: string };

// ============================================================================
// SERVER QUERY CLASS
// ============================================================================

/**
 * ProfilePageQuery
 *
 * Server-side data fetcher for the profile page.
 * Returns a discriminated union with all possible page states.
 * Ensures JSON-serializable DTO with no null leakage.
 */
export class ProfilePageQuery {
  /**
   * Execute the profile page query
   * 
   * @param driverId - The driver ID to fetch profile for
   * @returns PageQueryResult with discriminated union of states
   */
  static async execute(driverId: string | null): Promise<PageQueryResult> {
    // Handle missing driver ID
    if (!driverId) {
      return { status: 'notFound' };
    }

    try {
      // Fetch using PageDataFetcher to avoid direct DI in page
      const driverService = await PageDataFetcher.fetchManual(async () => {
        const container = (await import('@/lib/di/container')).ContainerManager.getInstance().getContainer();
        return container.get<DriverService>(DRIVER_SERVICE_TOKEN);
      });

      if (!driverService) {
        return { status: 'error', errorId: 'SERVICE_UNAVAILABLE' };
      }

      const viewModel = await driverService.getDriverProfile(driverId);

      // Convert to DTO and ensure JSON-serializable
      const dto = this.toSerializableDTO(viewModel.toDTO());

      if (!dto.currentDriver) {
        return { status: 'notFound' };
      }

      return { status: 'ok', dto };

    } catch (error) {
      console.error('ProfilePageQuery failed:', error);
      return { status: 'error', errorId: 'FETCH_FAILED' };
    }
  }

  /**
   * Convert DTO to ensure JSON-serializability
   * - Dates become ISO strings
   * - Undefined becomes null
   * - No Date objects remain
   */
  private static toSerializableDTO(dto: DriverProfileViewModelData): DriverProfileViewModelData {
    return {
      currentDriver: dto.currentDriver ? {
        ...dto.currentDriver,
        joinedAt: dto.currentDriver.joinedAt, // Already ISO string
      } : null,
      stats: dto.stats ? {
        ...dto.stats,
        // Ensure all nullable numbers are properly handled
        avgFinish: dto.stats.avgFinish ?? null,
        bestFinish: dto.stats.bestFinish ?? null,
        worstFinish: dto.stats.worstFinish ?? null,
        finishRate: dto.stats.finishRate ?? null,
        winRate: dto.stats.winRate ?? null,
        podiumRate: dto.stats.podiumRate ?? null,
        percentile: dto.stats.percentile ?? null,
        rating: dto.stats.rating ?? null,
        consistency: dto.stats.consistency ?? null,
        overallRank: dto.stats.overallRank ?? null,
      } : null,
      finishDistribution: dto.finishDistribution ? { ...dto.finishDistribution } : null,
      teamMemberships: dto.teamMemberships.map(m => ({
        ...m,
        joinedAt: m.joinedAt, // Already ISO string
      })),
      socialSummary: {
        friendsCount: dto.socialSummary.friendsCount,
        friends: dto.socialSummary.friends.map(f => ({
          ...f,
        })),
      },
      extendedProfile: dto.extendedProfile ? {
        ...dto.extendedProfile,
        achievements: dto.extendedProfile.achievements.map(a => ({
          ...a,
          earnedAt: a.earnedAt, // Already ISO string
        })),
      } : null,
    };
  }
}