/**
 * @ai-summary Business logic for vehicles feature
 * @ai-context Handles VIN decoding, caching, and business rules
 */

import { VehiclesRepository } from '../data/vehicles.repository';
import { vpicClient } from '../external/vpic/vpic.client';
import {
  Vehicle,
  CreateVehicleRequest,
  UpdateVehicleRequest,
  VehicleResponse
} from './vehicles.types';
import { logger } from '../../../core/logging/logger';
import { cacheService } from '../../../core/config/redis';
import { isValidVIN } from '../../../shared-minimal/utils/validators';

export class VehiclesService {
  private readonly cachePrefix = 'vehicles';
  private readonly listCacheTTL = 300; // 5 minutes
  
  constructor(private repository: VehiclesRepository) {}
  
  async createVehicle(data: CreateVehicleRequest, userId: string): Promise<VehicleResponse> {
    logger.info('Creating vehicle', { userId, vin: data.vin });
    
    // Validate VIN
    if (!isValidVIN(data.vin)) {
      throw new Error('Invalid VIN format');
    }
    
    // Check for duplicate
    const existing = await this.repository.findByUserAndVIN(userId, data.vin);
    if (existing) {
      throw new Error('Vehicle with this VIN already exists');
    }
    
    // Decode VIN
    const vinData = await vpicClient.decodeVIN(data.vin);
    
    // Create vehicle with decoded data
    const vehicle = await this.repository.create({
      ...data,
      userId,
      make: vinData?.make,
      model: vinData?.model,
      year: vinData?.year,
    });
    
    // Cache VIN decode result
    if (vinData) {
      await this.repository.cacheVINDecode(data.vin, vinData);
    }
    
    // Invalidate user's vehicle list cache
    await this.invalidateUserCache(userId);
    
    return this.toResponse(vehicle);
  }
  
  async getUserVehicles(userId: string): Promise<VehicleResponse[]> {
    const cacheKey = `${this.cachePrefix}:user:${userId}`;
    
    // Check cache
    const cached = await cacheService.get<VehicleResponse[]>(cacheKey);
    if (cached) {
      logger.debug('Vehicle list cache hit', { userId });
      return cached;
    }
    
    // Get from database
    const vehicles = await this.repository.findByUserId(userId);
    const response = vehicles.map(v => this.toResponse(v));
    
    // Cache result
    await cacheService.set(cacheKey, response, this.listCacheTTL);
    
    return response;
  }
  
  async getVehicle(id: string, userId: string): Promise<VehicleResponse> {
    const vehicle = await this.repository.findById(id);
    
    if (!vehicle) {
      throw new Error('Vehicle not found');
    }
    
    if (vehicle.userId !== userId) {
      throw new Error('Unauthorized');
    }
    
    return this.toResponse(vehicle);
  }
  
  async updateVehicle(
    id: string, 
    data: UpdateVehicleRequest, 
    userId: string
  ): Promise<VehicleResponse> {
    // Verify ownership
    const existing = await this.repository.findById(id);
    if (!existing) {
      throw new Error('Vehicle not found');
    }
    if (existing.userId !== userId) {
      throw new Error('Unauthorized');
    }
    
    // Update vehicle
    const updated = await this.repository.update(id, data);
    if (!updated) {
      throw new Error('Update failed');
    }
    
    // Invalidate cache
    await this.invalidateUserCache(userId);
    
    return this.toResponse(updated);
  }
  
  async deleteVehicle(id: string, userId: string): Promise<void> {
    // Verify ownership
    const existing = await this.repository.findById(id);
    if (!existing) {
      throw new Error('Vehicle not found');
    }
    if (existing.userId !== userId) {
      throw new Error('Unauthorized');
    }
    
    // Soft delete
    await this.repository.softDelete(id);
    
    // Invalidate cache
    await this.invalidateUserCache(userId);
  }
  
  private async invalidateUserCache(userId: string): Promise<void> {
    const cacheKey = `${this.cachePrefix}:user:${userId}`;
    await cacheService.del(cacheKey);
  }
  
  async getDropdownMakes(): Promise<{ id: number; name: string }[]> {
    try {
      logger.info('Getting dropdown makes');
      const makes = await vpicClient.getAllMakes();
      
      return makes.map(make => ({
        id: make.Make_ID,
        name: make.Make_Name
      }));
    } catch (error) {
      logger.error('Failed to get dropdown makes', { error });
      throw new Error('Failed to load makes');
    }
  }

  async getDropdownModels(make: string): Promise<{ id: number; name: string }[]> {
    try {
      logger.info('Getting dropdown models', { make });
      const models = await vpicClient.getModelsForMake(make);
      
      return models.map(model => ({
        id: model.Model_ID,
        name: model.Model_Name
      }));
    } catch (error) {
      logger.error('Failed to get dropdown models', { make, error });
      throw new Error('Failed to load models');
    }
  }

  async getDropdownTransmissions(): Promise<{ id: number; name: string }[]> {
    try {
      logger.info('Getting dropdown transmissions');
      const transmissions = await vpicClient.getTransmissionTypes();
      
      return transmissions.map(transmission => ({
        id: transmission.Id,
        name: transmission.Name
      }));
    } catch (error) {
      logger.error('Failed to get dropdown transmissions', { error });
      throw new Error('Failed to load transmissions');
    }
  }

  async getDropdownEngines(): Promise<{ id: number; name: string }[]> {
    try {
      logger.info('Getting dropdown engines');
      const engines = await vpicClient.getEngineConfigurations();
      
      return engines.map(engine => ({
        id: engine.Id,
        name: engine.Name
      }));
    } catch (error) {
      logger.error('Failed to get dropdown engines', { error });
      throw new Error('Failed to load engines');
    }
  }

  async getDropdownTrims(): Promise<{ id: number; name: string }[]> {
    try {
      logger.info('Getting dropdown trims');
      const trims = await vpicClient.getTrimLevels();
      
      return trims.map(trim => ({
        id: trim.Id,
        name: trim.Name
      }));
    } catch (error) {
      logger.error('Failed to get dropdown trims', { error });
      throw new Error('Failed to load trims');
    }
  }

  private toResponse(vehicle: Vehicle): VehicleResponse {
    return {
      id: vehicle.id,
      userId: vehicle.userId,
      vin: vehicle.vin,
      make: vehicle.make,
      model: vehicle.model,
      year: vehicle.year,
      engine: vehicle.engine,
      transmission: vehicle.transmission,
      trimLevel: vehicle.trimLevel,
      driveType: vehicle.driveType,
      fuelType: vehicle.fuelType,
      nickname: vehicle.nickname,
      color: vehicle.color,
      licensePlate: vehicle.licensePlate,
      odometerReading: vehicle.odometerReading,
      isActive: vehicle.isActive,
      createdAt: vehicle.createdAt.toISOString(),
      updatedAt: vehicle.updatedAt.toISOString(),
    };
  }
}