using System.Net.Http.Json;
using System.Text.Json.Serialization;
using Microsoft.Maui.Networking;

namespace LMEMappeCatastaliApp.Services;

public sealed class NetworkLocationService
{
    private readonly HttpClient httpClient = new()
    {
        Timeout = TimeSpan.FromSeconds(6)
    };

    public NetworkLocationService()
    {
        httpClient.DefaultRequestHeaders.UserAgent.ParseAdd("LMEMappeCatastali/0.2.15");
    }

    public async Task<NetworkLocationSnapshot?> GetApproximateLocationAsync(
        CancellationToken cancellationToken = default)
    {
        if (Connectivity.Current.NetworkAccess != NetworkAccess.Internet)
        {
            return null;
        }

        using var response = await httpClient.GetAsync("https://ipapi.co/json/", cancellationToken);
        if (!response.IsSuccessStatusCode)
        {
            return null;
        }

        var result = await response.Content.ReadFromJsonAsync<IpLocationResponse>(cancellationToken);
        if (result is null
            || result.Error == true
            || !result.Latitude.HasValue
            || !result.Longitude.HasValue
            || Math.Abs(result.Latitude.Value) > 90
            || Math.Abs(result.Longitude.Value) > 180)
        {
            return null;
        }

        var labelParts = new[] { result.City, result.Region, result.CountryName }
            .Where(value => !string.IsNullOrWhiteSpace(value));
        return new NetworkLocationSnapshot(
            result.Latitude.Value,
            result.Longitude.Value,
            string.Join(", ", labelParts));
    }

    private sealed class IpLocationResponse
    {
        [JsonPropertyName("latitude")]
        public double? Latitude { get; init; }

        [JsonPropertyName("longitude")]
        public double? Longitude { get; init; }

        [JsonPropertyName("city")]
        public string? City { get; init; }

        [JsonPropertyName("region")]
        public string? Region { get; init; }

        [JsonPropertyName("country_name")]
        public string? CountryName { get; init; }

        [JsonPropertyName("error")]
        public bool? Error { get; init; }
    }
}

public sealed record NetworkLocationSnapshot(double Latitude, double Longitude, string Label);