import * as fs from 'fs';
import * as path from 'path';

// Types
export interface GtfsStop {
  stop_id: string;
  stop_code: string;
  stop_name: string;
  stop_lat: number;
  stop_lon: number;
}

export interface GtfsRoute {
  route_id: string;
  route_short_name: string;
  route_long_name: string;
  route_type?: string;
}

// CSV Parser
function parseCSVLine(line: string): string[] {
  const result: string[] = [];
  let current = '';
  let inQuotes = false;
  
  for (let i = 0; i < line.length; i++) {
    const char = line[i];
    if (char === '"') {
      inQuotes = !inQuotes;
    } else if (char === ',' && !inQuotes) {
      result.push(current.trim());
      current = '';
    } else {
      current += char;
    }
  }
  result.push(current.trim());
  return result;
}

// Load GTFS Stops
export function loadGtfsStops(gtfsDir: string = 'gtfs'): Map<string, GtfsStop> {
  const stopsFile = path.join(process.cwd(), gtfsDir, 'stops.txt');
  const content = fs.readFileSync(stopsFile, 'utf-8');
  const lines = content.split('\n').filter(line => line.trim());
  const stops = new Map<string, GtfsStop>();
  
  for (let i = 1; i < lines.length; i++) {
    const values = parseCSVLine(lines[i]);
    if (values.length < 6) continue;
    
    const stop: GtfsStop = {
      stop_id: values[0],
      stop_code: values[1],
      stop_name: values[2],
      stop_lat: parseFloat(values[4]),
      stop_lon: parseFloat(values[5]),
    };
    
    stops.set(stop.stop_id, stop);
  }
  
  return stops;
}

// Load GTFS Routes
export function loadGtfsRoutes(gtfsDir: string = 'gtfs'): Map<string, GtfsRoute> {
  const routesFile = path.join(process.cwd(), gtfsDir, 'routes.txt');
  const content = fs.readFileSync(routesFile, 'utf-8');
  const lines = content.split('\n').filter(line => line.trim());
  const routes = new Map<string, GtfsRoute>();
  
  for (let i = 1; i < lines.length; i++) {
    const values = parseCSVLine(lines[i]);
    if (values.length < 5) continue;
    
    const route: GtfsRoute = {
      route_id: values[0],
      route_short_name: values[2],
      route_long_name: values[3],
      route_type: values[5] || undefined,
    };
    
    routes.set(route.route_id, route);
  }
  
  return routes;
}