feat(calendar): add application date integrations

JobTrackerApi/Services/GmailOAuthService.cs

@@ -25,6 +25,7 @@ public interface IGmailOAuthService
     Task<IReadOnlyList<GmailMessageSummary>> ListThreadMessagesAsync(string ownerUserId, string threadId, CancellationToken cancellationToken);
     Task<GmailMessageDetail> GetMessageAsync(string ownerUserId, string messageId, CancellationToken cancellationToken);
     Task<GmailSendResult> SendAsync(string ownerUserId, GmailSendRequest request, CancellationToken cancellationToken);
+    Task<ExternalCalendarEventResult> CreateCalendarEventAsync(string ownerUserId, ExternalCalendarEventRequest request, CancellationToken cancellationToken);
 }
 
 public sealed record GmailOAuthExchangeResult(string GmailAddress);
@@ -47,7 +48,8 @@ internal sealed class GmailTokenResponse
 public sealed class GmailOAuthService : IGmailOAuthService
 {
     public const string SendScope = "https://www.googleapis.com/auth/gmail.send";
-    private const string Scope = $"openid email profile https://www.googleapis.com/auth/gmail.readonly {SendScope}";
+    public const string CalendarScope = "https://www.googleapis.com/auth/calendar.events";
+    private const string Scope = $"openid email profile https://www.googleapis.com/auth/gmail.readonly {SendScope} {CalendarScope}";
     private readonly IConfiguration _cfg;
     private readonly JobTrackerContext _db;
     private readonly IDataProtector _protector;
@@ -419,6 +421,47 @@ public sealed class GmailOAuthService : IGmailOAuthService
     public static bool HasSendScope(string? scope) =>
         !string.IsNullOrWhiteSpace(scope) && scope.Split(' ', StringSplitOptions.RemoveEmptyEntries).Contains(SendScope, StringComparer.OrdinalIgnoreCase);
 
+    public async Task<ExternalCalendarEventResult> CreateCalendarEventAsync(string ownerUserId, ExternalCalendarEventRequest request, CancellationToken cancellationToken)
+    {
+        var connection = await _db.GmailConnections.AsNoTracking().FirstOrDefaultAsync(item => item.OwnerUserId == ownerUserId, cancellationToken);
+        if (connection is null || !HasCalendarScope(connection.Scope))
+            throw new InvalidOperationException("Reconnect Google and approve calendar access before adding events.");
+
+        var payload = request.AllDay
+            ? JsonSerializer.Serialize(new
+            {
+                summary = request.Summary,
+                description = request.Description,
+                location = request.Location,
+                start = new { date = request.StartsAtUtc.UtcDateTime.ToString("yyyy-MM-dd") },
+                end = new { date = request.EndsAtUtc.UtcDateTime.ToString("yyyy-MM-dd") }
+            })
+            : JsonSerializer.Serialize(new
+            {
+                summary = request.Summary,
+                description = request.Description,
+                location = request.Location,
+                start = new { dateTime = request.StartsAtUtc.ToString("O") },
+                end = new { dateTime = request.EndsAtUtc.ToString("O") }
+            });
+
+        var accessToken = await GetValidAccessTokenAsync(ownerUserId, cancellationToken);
+        var client = _httpClientFactory.CreateClient();
+        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
+        using var response = await client.PutAsync(
+            $"https://www.googleapis.com/calendar/v3/calendars/primary/events/{Uri.EscapeDataString(request.StableId)}",
+            new StringContent(payload, Encoding.UTF8, "application/json"),
+            cancellationToken);
+        response.EnsureSuccessStatusCode();
+        using var document = await JsonDocument.ParseAsync(await response.Content.ReadAsStreamAsync(cancellationToken), cancellationToken: cancellationToken);
+        return new ExternalCalendarEventResult(
+            document.RootElement.TryGetProperty("id", out var id) ? id.GetString() : null,
+            document.RootElement.TryGetProperty("htmlLink", out var link) ? link.GetString() : null);
+    }
+
+    public static bool HasCalendarScope(string? scope) =>
+        !string.IsNullOrWhiteSpace(scope) && scope.Split(' ', StringSplitOptions.RemoveEmptyEntries).Contains(CalendarScope, StringComparer.OrdinalIgnoreCase);
+
     private static void ValidateSendRequest(string to, string subject, string bodyText)
     {
         if (string.IsNullOrWhiteSpace(to)) throw new ArgumentException("Recipient is required.", nameof(to));