Refactor Api-Client

Add Exceptionhandler, AlertService JSON-Converter
AppSettings via DI

Reformat Code

Jugenddienst Stunden/Infrastructure/ApiClient.cs

@@ -0,0 +1,111 @@
+using System.Net.Http.Headers;
+using System.Text;
+using System.Text.Json;
+using System.Net.Http.Json;
+using Jugenddienst_Stunden.Interfaces;
+
+namespace Jugenddienst_Stunden.Infrastructure;
+
+internal sealed class ApiClient : IApiClient {
+	private readonly HttpClient _http;
+	private readonly JsonSerializerOptions _json;
+	private readonly ApiOptions _options;
+	private readonly IAppSettings _settings;
+
+	public ApiClient(HttpClient http, ApiOptions options, ITokenProvider tokenProvider, IAppSettings settings) {
+		_http = http;
+		_options = options;
+		_settings = settings;
+
+		_http.Timeout = options.Timeout;
+		if (!_http.DefaultRequestHeaders.Accept.Any())
+			_http.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
+
+		var token = tokenProvider.GetToken();
+		if (!string.IsNullOrWhiteSpace(token))
+			_http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
+
+		_json = new JsonSerializerOptions {
+			PropertyNameCaseInsensitive = true,
+			WriteIndented = false,
+			DefaultIgnoreCondition = System.Text.Json.Serialization.JsonIgnoreCondition.WhenWritingNull
+		};
+
+		// Globale Converter: erlauben numerische Felder auch als Strings (z.B. user.id)
+		_json.Converters.Add(new Jugenddienst_Stunden.Models.JsonFlexibleInt32Converter());
+		_json.Converters.Add(new Jugenddienst_Stunden.Models.JsonFlexibleNullableInt32Converter());
+
+		// Stelle sicher, dass die BaseAddress sofort aus den aktuellen Settings (Preferences) gesetzt wird
+		// und nicht erst beim ersten Request. Dadurch steht die ApiUrl ab Initialisierung zur Verfügung.
+		EnsureBaseAddress();
+	}
+
+	public Task<T> GetAsync<T>(string path, IDictionary<string, string?>? query = null, CancellationToken ct = default)
+		=> SendAsync<T>(HttpMethod.Get, path, null, query, ct);
+
+	public async Task<T> SendAsync<T>(HttpMethod method, string path, object? body = null,
+		IDictionary<string, string?>? query = null, CancellationToken ct = default) {
+		// Vor jedem Request sicherstellen, dass die (ggf. geänderte) BaseAddress gesetzt ist
+		EnsureBaseAddress();
+		var uri = BuildUri(path, query);
+		using var req = new HttpRequestMessage(method, uri) {
+			Content = body is null ? null : JsonContent.Create(body, options: _json)
+		};
+
+		using var res = await _http.SendAsync(req, HttpCompletionOption.ResponseHeadersRead, ct).ConfigureAwait(false);
+		var text = await res.Content.ReadAsStringAsync(ct).ConfigureAwait(false);
+		if (!res.IsSuccessStatusCode)
+			throw ApiException.From(res.StatusCode, TryGetMessage(text), text);
+
+		if (typeof(T) == typeof(void) || typeof(T) == typeof(object) || string.IsNullOrWhiteSpace(text))
+			return default!;
+
+		var obj = System.Text.Json.JsonSerializer.Deserialize<T>(text, _json);
+		if (obj is null)
+			throw new ApiException("Fehler beim Deserialisieren der Daten.");
+		return obj;
+	}
+
+	public Task DeleteAsync(string path, IDictionary<string, string?>? query = null, CancellationToken ct = default)
+		=> SendAsync<object>(HttpMethod.Delete, path, null, query, ct);
+
+	private void EnsureBaseAddress() {
+		var baseUrl = _settings.ApiUrl;
+
+		if (string.IsNullOrWhiteSpace(baseUrl)) {
+			throw new InvalidOperationException(
+				"ApiUrl ist leer. Bitte zuerst eine gültige Server-URL setzen (Preferences key 'apiUrl'), " +
+				"z.B. im Login/Setup, bevor API-Aufrufe stattfinden."
+			);
+		}
+
+		// nur setzen, wenn nötig (damit spätere Änderungen nach Login greifen)
+		if (_http.BaseAddress is null || !Uri.Equals(_http.BaseAddress, new Uri(baseUrl, UriKind.Absolute))) {
+			_http.BaseAddress = new Uri(baseUrl, UriKind.Absolute);
+			_http.Timeout = _options.Timeout;
+		}
+	}
+
+	private static string TryGetMessage(string text) {
+		try {
+			using var doc = JsonDocument.Parse(text);
+			if (doc.RootElement.TryGetProperty("message", out var m) && m.ValueKind == JsonValueKind.String)
+				return m.GetString() ?? text;
+		} catch {
+		}
+
+		return text;
+	}
+
+	private static Uri BuildUri(string path, IDictionary<string, string?>? query) {
+		if (query is null || query.Count == 0)
+			return new Uri(path, UriKind.Relative);
+
+		var sb = new StringBuilder(path);
+		sb.Append(path.Contains('?') ? '&' : '?');
+		sb.Append(string.Join('&', query
+			.Where(kv => kv.Value is not null)
+			.Select(kv => $"{Uri.EscapeDataString(kv.Key)}={Uri.EscapeDataString(kv.Value!)}")));
+		return new Uri(sb.ToString(), UriKind.Relative);
+	}
+}