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using System.Globalization;
using Costasdev.Busurbano.Backend.Configuration;
using Costasdev.Busurbano.Backend.Types.Nominatim;
using Costasdev.Busurbano.Backend.Types.Planner;
using Microsoft.Extensions.Caching.Memory;
using Microsoft.Extensions.Options;
namespace Costasdev.Busurbano.Backend.Services;
public class NominatimGeocodingService : IGeocodingService
{
private readonly HttpClient _httpClient;
private readonly IMemoryCache _cache;
private readonly ILogger<NominatimGeocodingService> _logger;
private readonly AppConfiguration _config;
private const string GaliciaBounds = "-9.3,43.8,-6.7,41.7";
public NominatimGeocodingService(HttpClient httpClient, IMemoryCache cache, ILogger<NominatimGeocodingService> logger, IOptions<AppConfiguration> config)
{
_httpClient = httpClient;
_cache = cache;
_logger = logger;
_config = config.Value;
// Nominatim requires a User-Agent
if (!_httpClient.DefaultRequestHeaders.Contains("User-Agent"))
{
_httpClient.DefaultRequestHeaders.Add("User-Agent", "Busurbano/1.0 (https://github.com/arielcostas/Busurbano)");
}
}
public async Task<List<PlannerSearchResult>> GetAutocompleteAsync(string query)
{
if (string.IsNullOrWhiteSpace(query)) return new List<PlannerSearchResult>();
var cacheKey = $"nominatim_autocomplete_{query.ToLowerInvariant()}";
if (_cache.TryGetValue(cacheKey, out List<PlannerSearchResult>? cachedResults) && cachedResults != null)
{
return cachedResults;
}
try
{
var url = $"{_config.NominatimBaseUrl}/search?q={Uri.EscapeDataString(query)}&format=jsonv2&viewbox={GaliciaBounds}&bounded=1&countrycodes=es&addressdetails=1";
var response = await _httpClient.GetFromJsonAsync<List<NominatimSearchResult>>(url);
var results = response?.Select(MapToPlannerSearchResult).ToList() ?? new List<PlannerSearchResult>();
_cache.Set(cacheKey, results, TimeSpan.FromMinutes(30));
return results;
}
catch (Exception ex)
{
_logger.LogError(ex, "Error fetching Nominatim autocomplete results from {Url}", _config.NominatimBaseUrl);
return new List<PlannerSearchResult>();
}
}
public async Task<PlannerSearchResult?> GetReverseGeocodeAsync(double lat, double lon)
{
var cacheKey = $"nominatim_reverse_{lat:F5}_{lon:F5}";
if (_cache.TryGetValue(cacheKey, out PlannerSearchResult? cachedResult) && cachedResult != null)
{
return cachedResult;
}
try
{
var url = $"{_config.NominatimBaseUrl}/reverse?lat={lat.ToString(CultureInfo.InvariantCulture)}&lon={lon.ToString(CultureInfo.InvariantCulture)}&format=jsonv2&addressdetails=1";
var response = await _httpClient.GetFromJsonAsync<NominatimSearchResult>(url);
if (response == null) return null;
var result = MapToPlannerSearchResult(response);
_cache.Set(cacheKey, result, TimeSpan.FromMinutes(60));
return result;
}
catch (Exception ex)
{
_logger.LogError(ex, "Error fetching Nominatim reverse geocode results from {Url}", _config.NominatimBaseUrl);
return null;
}
}
private PlannerSearchResult MapToPlannerSearchResult(NominatimSearchResult result)
{
var name = result.Address?.Road ?? result.DisplayName?.Split(',').FirstOrDefault();
var label = result.DisplayName;
return new PlannerSearchResult
{
Name = name,
Label = label,
Lat = double.TryParse(result.Lat, CultureInfo.InvariantCulture, out var lat) ? lat : 0,
Lon = double.TryParse(result.Lon, CultureInfo.InvariantCulture, out var lon) ? lon : 0,
Layer = result.Type
};
}
}
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