feat(backend): Activate domain events for user login, role assignment, and tenant removal

Implemented domain event raising in command handlers to enable audit logging and event-driven architecture for key Identity module operations.

Changes:
- Updated LoginCommand to include IpAddress and UserAgent fields for audit trail
- Updated AuthController to extract and pass IP address and user agent from HTTP context
- Modified LoginCommandHandler to raise UserLoggedInEvent on successful login
- Updated AssignUserRoleCommand to include AssignedBy field for audit purposes
- Modified AssignUserRoleCommandHandler to raise UserRoleAssignedEvent with previous role tracking
- Updated RemoveUserFromTenantCommand to include RemovedBy and Reason fields
- Modified RemoveUserFromTenantCommandHandler to raise UserRemovedFromTenantEvent before deletion
- Added domain methods to User aggregate: RecordLoginWithEvent, RaiseRoleAssignedEvent, RaiseRemovedFromTenantEvent
- Updated TenantUsersController to extract current user ID from JWT claims and pass to commands

Technical Details:
- All event raising follows aggregate root encapsulation pattern
- Domain events are persisted through repository UpdateAsync calls
- Event handlers will automatically log these events for audit trail
- Maintains backward compatibility with existing login flow

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

colaflow-api/src/ColaFlow.API/Controllers/AuthController.cs

@@ -31,8 +31,19 @@ public class AuthController : ControllerBase
     /// Login with email and password
     /// </summary>
     [HttpPost("login")]
-    public async Task<IActionResult> Login([FromBody] LoginCommand command)
+    public async Task<IActionResult> Login([FromBody] LoginRequest request)
     {
+        var ipAddress = HttpContext.Connection.RemoteIpAddress?.ToString();
+        var userAgent = HttpContext.Request.Headers["User-Agent"].ToString();
+
+        var command = new LoginCommand(
+            request.TenantSlug,
+            request.Email,
+            request.Password,
+            ipAddress,
+            userAgent
+        );
+
         var result = await _mediator.Send(command);
         return Ok(result);
     }
@@ -148,3 +159,9 @@ public class AuthController : ControllerBase
         }
     }
 }
+
+public record LoginRequest(
+    string TenantSlug,
+    string Email,
+    string Password
+);

colaflow-api/src/ColaFlow.API/Controllers/TenantUsersController.cs

@@ -64,7 +64,14 @@ public class TenantUsersController : ControllerBase
         if (userTenantId != tenantId)
             return StatusCode(403, new { error = "Access denied: You can only manage users in your own tenant" });
 
-        var command = new AssignUserRoleCommand(tenantId, userId, request.Role);
+        // Extract current user ID from claims
+        var currentUserIdClaim = User.FindFirst("user_id")?.Value;
+        if (currentUserIdClaim == null)
+            return Unauthorized(new { error = "User ID not found in token" });
+
+        var currentUserId = Guid.Parse(currentUserIdClaim);
+
+        var command = new AssignUserRoleCommand(tenantId, userId, request.Role, currentUserId);
         await _mediator.Send(command);
         return Ok(new { Message = "Role assigned successfully" });
     }
@@ -87,7 +94,14 @@ public class TenantUsersController : ControllerBase
         if (userTenantId != tenantId)
             return StatusCode(403, new { error = "Access denied: You can only manage users in your own tenant" });
 
-        var command = new RemoveUserFromTenantCommand(tenantId, userId);
+        // Extract current user ID from claims
+        var currentUserIdClaim = User.FindFirst("user_id")?.Value;
+        if (currentUserIdClaim == null)
+            return Unauthorized(new { error = "User ID not found in token" });
+
+        var currentUserId = Guid.Parse(currentUserIdClaim);
+
+        var command = new RemoveUserFromTenantCommand(tenantId, userId, currentUserId, null);
         await _mediator.Send(command);
         return Ok(new { Message = "User removed from tenant successfully" });
     }

colaflow-api/src/Modules/Identity/ColaFlow.Modules.Identity.Application/Commands/AssignUserRole/AssignUserRoleCommand.cs

@@ -5,4 +5,5 @@ namespace ColaFlow.Modules.Identity.Application.Commands.AssignUserRole;
 public record AssignUserRoleCommand(
     Guid TenantId,
     Guid UserId,
-    string Role) : IRequest<Unit>;
+    string Role,
+    Guid AssignedBy) : IRequest<Unit>;

colaflow-api/src/Modules/Identity/ColaFlow.Modules.Identity.Application/Commands/AssignUserRole/AssignUserRoleCommandHandler.cs

@@ -1,4 +1,5 @@
 using ColaFlow.Modules.Identity.Domain.Aggregates.Users;
+using ColaFlow.Modules.Identity.Domain.Aggregates.Users.Events;
 using ColaFlow.Modules.Identity.Domain.Aggregates.Tenants;
 using ColaFlow.Modules.Identity.Domain.Repositories;
 using MediatR;
@@ -47,10 +48,12 @@ public class AssignUserRoleCommandHandler : IRequestHandler<AssignUserRoleComman
             request.TenantId,
             cancellationToken);
 
+        TenantRole? previousRole = existingRole?.Role;
+
         if (existingRole != null)
         {
             // Update existing role
-            existingRole.UpdateRole(role, Guid.Empty); // OperatorUserId can be set from HttpContext in controller
+            existingRole.UpdateRole(role, request.AssignedBy);
             await _userTenantRoleRepository.UpdateAsync(existingRole, cancellationToken);
         }
         else
@@ -60,11 +63,22 @@ public class AssignUserRoleCommandHandler : IRequestHandler<AssignUserRoleComman
                 UserId.Create(request.UserId),
                 TenantId.Create(request.TenantId),
                 role,
-                null); // AssignedByUserId can be set from HttpContext in controller
+                UserId.Create(request.AssignedBy));
 
             await _userTenantRoleRepository.AddAsync(userTenantRole, cancellationToken);
         }
 
+        // Raise domain event for role assignment
+        user.RaiseRoleAssignedEvent(
+            TenantId.Create(request.TenantId),
+            role,
+            previousRole,
+            request.AssignedBy
+        );
+
+        // Save changes to persist event
+        await _userRepository.UpdateAsync(user, cancellationToken);
+
         return Unit.Value;
     }
 }

colaflow-api/src/Modules/Identity/ColaFlow.Modules.Identity.Application/Commands/Login/LoginCommand.cs

@@ -6,5 +6,7 @@ namespace ColaFlow.Modules.Identity.Application.Commands.Login;
 public record LoginCommand(
     string TenantSlug,
     string Email,
-    string Password
+    string Password,
+    string? IpAddress,
+    string? UserAgent
 ) : IRequest<LoginResponseDto>;

colaflow-api/src/Modules/Identity/ColaFlow.Modules.Identity.Application/Commands/Login/LoginCommandHandler.cs

@@ -2,6 +2,7 @@ using ColaFlow.Modules.Identity.Application.Dtos;
 using ColaFlow.Modules.Identity.Application.Services;
 using ColaFlow.Modules.Identity.Domain.Aggregates.Tenants;
 using ColaFlow.Modules.Identity.Domain.Aggregates.Users;
+using ColaFlow.Modules.Identity.Domain.Aggregates.Users.Events;
 using ColaFlow.Modules.Identity.Domain.Repositories;
 using MediatR;
 
@@ -67,18 +68,24 @@ public class LoginCommandHandler : IRequestHandler<LoginCommand, LoginResponseDt
             throw new InvalidOperationException($"User {user.Id} has no role assigned for tenant {tenant.Id}");
         }
 
+        // 4.5. Record login and raise domain event
+        user.RecordLoginWithEvent(
+            TenantId.Create(tenant.Id),
+            request.IpAddress ?? "unknown",
+            request.UserAgent ?? "unknown"
+        );
+
         // 5. Generate JWT token with role
         var accessToken = _jwtService.GenerateToken(user, tenant, userTenantRole.Role);
 
         // 6. Generate refresh token
         var refreshToken = await _refreshTokenService.GenerateRefreshTokenAsync(
             user,
-            ipAddress: null,
+            ipAddress: request.IpAddress,
-            userAgent: null,
+            userAgent: request.UserAgent,
             cancellationToken);
 
-        // 7. Update last login time
+        // 7. Save user changes (including domain event)
-        user.RecordLogin();
         await _userRepository.UpdateAsync(user, cancellationToken);
 
         // 8. Return result

colaflow-api/src/Modules/Identity/ColaFlow.Modules.Identity.Application/Commands/RemoveUserFromTenant/RemoveUserFromTenantCommand.cs

@@ -4,4 +4,6 @@ namespace ColaFlow.Modules.Identity.Application.Commands.RemoveUserFromTenant;
 
 public record RemoveUserFromTenantCommand(
     Guid TenantId,
-    Guid UserId) : IRequest<Unit>;
+    Guid UserId,
+    Guid RemovedBy,
+    string? Reason) : IRequest<Unit>;

colaflow-api/src/Modules/Identity/ColaFlow.Modules.Identity.Application/Commands/RemoveUserFromTenant/RemoveUserFromTenantCommandHandler.cs

@@ -1,4 +1,6 @@
 using ColaFlow.Modules.Identity.Domain.Aggregates.Users;
+using ColaFlow.Modules.Identity.Domain.Aggregates.Users.Events;
+using ColaFlow.Modules.Identity.Domain.Aggregates.Tenants;
 using ColaFlow.Modules.Identity.Domain.Repositories;
 using MediatR;
 
@@ -8,13 +10,16 @@ public class RemoveUserFromTenantCommandHandler : IRequestHandler<RemoveUserFrom
 {
     private readonly IUserTenantRoleRepository _userTenantRoleRepository;
     private readonly IRefreshTokenRepository _refreshTokenRepository;
+    private readonly IUserRepository _userRepository;
 
     public RemoveUserFromTenantCommandHandler(
         IUserTenantRoleRepository userTenantRoleRepository,
-        IRefreshTokenRepository refreshTokenRepository)
+        IRefreshTokenRepository refreshTokenRepository,
+        IUserRepository userRepository)
     {
         _userTenantRoleRepository = userTenantRoleRepository;
         _refreshTokenRepository = refreshTokenRepository;
+        _userRepository = userRepository;
     }
 
     public async Task<Unit> Handle(RemoveUserFromTenantCommand request, CancellationToken cancellationToken)
@@ -42,7 +47,7 @@ public class RemoveUserFromTenantCommandHandler : IRequestHandler<RemoveUserFrom
 
         foreach (var token in userTokens.Where(t => !t.RevokedAt.HasValue))
         {
-            token.Revoke("User removed from tenant");
+            token.Revoke(request.Reason ?? "User removed from tenant");
         }
 
         if (userTokens.Any())
@@ -50,6 +55,19 @@ public class RemoveUserFromTenantCommandHandler : IRequestHandler<RemoveUserFrom
             await _refreshTokenRepository.UpdateRangeAsync(userTokens, cancellationToken);
         }
 
+        // Raise domain event before deletion
+        var user = await _userRepository.GetByIdAsync(request.UserId, cancellationToken);
+        if (user != null)
+        {
+            user.RaiseRemovedFromTenantEvent(
+                TenantId.Create(request.TenantId),
+                request.RemovedBy,
+                request.Reason ?? "User removed from tenant"
+            );
+
+            await _userRepository.UpdateAsync(user, cancellationToken);
+        }
+
         // Remove user's role
         await _userTenantRoleRepository.DeleteAsync(userTenantRole, cancellationToken);
 

colaflow-api/src/Modules/Identity/ColaFlow.Modules.Identity.Domain/Aggregates/Users/User.cs

@@ -139,6 +139,24 @@ public sealed class User : AggregateRoot
         UpdatedAt = DateTime.UtcNow;
     }
 
+    public void RecordLoginWithEvent(TenantId tenantId, string ipAddress, string userAgent)
+    {
+        LastLoginAt = DateTime.UtcNow;
+        UpdatedAt = DateTime.UtcNow;
+
+        AddDomainEvent(new UserLoggedInEvent(Id, tenantId, ipAddress, userAgent));
+    }
+
+    public void RaiseRoleAssignedEvent(TenantId tenantId, TenantRole role, TenantRole? previousRole, Guid assignedBy)
+    {
+        AddDomainEvent(new UserRoleAssignedEvent(Id, tenantId, role, previousRole, assignedBy));
+    }
+
+    public void RaiseRemovedFromTenantEvent(TenantId tenantId, Guid removedBy, string reason)
+    {
+        AddDomainEvent(new UserRemovedFromTenantEvent(Id, tenantId, removedBy, reason));
+    }
+
     public void VerifyEmail()
     {
         EmailVerifiedAt = DateTime.UtcNow;