import { Injectable } from '@nestjs/common';
import { readFileSync } from 'fs';
import path, { join } from 'path';
import { City, Geo, State } from 'src/models/server.model.js';
import { fileURLToPath } from 'url';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

@Injectable()
export class GeoService {
    geo:Geo;
    constructor() {
        this.loadGeo();
      }
      private loadGeo(): void {
        const filePath = join(__dirname,'..', 'assets', 'geo.json');
        const rawData = readFileSync(filePath, 'utf8');
        this.geo = JSON.parse(rawData);
      }
      
      findCitiesStartingWith( prefix: string, state?:string): { city: string; state: string; state_code: string }[] {
        const result: { city: string; state: string; state_code: string }[] = [];
    
        this.geo.states.forEach((state: State) => {
            state.cities.forEach((city: City) => {
                if (city.name.toLowerCase().startsWith(prefix.toLowerCase())) {
                    result.push({
                        city: city.name,
                        state: state.name,
                        state_code: state.state_code
                    });
                }
            });
        });
        
        return state ? result.filter(e=>e.state_code.toLowerCase()===state.toLowerCase()) :result;
    }
}