feat(workspace): add accept and decline invitation use cases

- Implement AcceptInvitationUseCase with validation
- Check invitation status, expiration, and email match
- Auto-create WorkspaceMember on accept
- Handle case when user is already a member
- Implement DeclineInvitationUseCase to reject invitations
- Update invitation status (accepted/declined/expired)
- Add 9 comprehensive unit tests (all passed)

Phase 4 Task 14/68 completed

packages/application/workspace/__init__.py

@@ -9,6 +9,13 @@ from packages.application.workspace.invite_member_use_case import (
     InviteMemberRequest,
     InviteMemberResponse,
 )
+from packages.application.workspace.accept_invitation_use_case import (
+    AcceptInvitationUseCase,
+    AcceptInvitationRequest,
+    AcceptInvitationResponse,
+    DeclineInvitationUseCase,
+    DeclineInvitationRequest,
+)
 
 __all__ = [
     "CreateWorkspaceUseCase",
@@ -17,4 +24,9 @@ __all__ = [
     "InviteMemberUseCase",
     "InviteMemberRequest",
     "InviteMemberResponse",
+    "AcceptInvitationUseCase",
+    "AcceptInvitationRequest",
+    "AcceptInvitationResponse",
+    "DeclineInvitationUseCase",
+    "DeclineInvitationRequest",
 ]

packages/application/workspace/accept_invitation_use_case.py

@@ -0,0 +1,188 @@
+"""
+接受/拒绝邀请 Use Case
+"""
+from datetime import datetime, timezone
+from typing import Optional
+from uuid import uuid4
+
+from packages.domain.entities import (
+    WorkspaceMember,
+    InvitationStatus,
+)
+
+
+class AcceptInvitationRequest:
+    """接受邀请请求"""
+    
+    def __init__(self, invitation_token: str, user_id: str):
+        self.invitation_token = invitation_token
+        self.user_id = user_id
+
+
+class AcceptInvitationResponse:
+    """接受邀请响应"""
+    
+    def __init__(
+        self,
+        workspace_id: str,
+        workspace_name: str,
+        role: str,
+    ):
+        self.workspace_id = workspace_id
+        self.workspace_name = workspace_name
+        self.role = role
+
+
+class AcceptInvitationUseCase:
+    """接受邀请用例"""
+    
+    def __init__(
+        self,
+        workspace_repository,
+        workspace_member_repository,
+        workspace_invitation_repository,
+        user_repository,
+    ):
+        self.workspace_repository = workspace_repository
+        self.workspace_member_repository = workspace_member_repository
+        self.workspace_invitation_repository = workspace_invitation_repository
+        self.user_repository = user_repository
+    
+    def execute(self, request: AcceptInvitationRequest) -> tuple[Optional[AcceptInvitationResponse], Optional[str]]:
+        """
+        执行接受邀请
+        
+        Args:
+            request: 接受请求
+        
+        Returns:
+            (响应, 错误信息)
+        """
+        try:
+            # 1. 验证输入
+            if not request.invitation_token:
+                return None, "Invitation token is required"
+            
+            if not request.user_id:
+                return None, "User ID is required"
+            
+            # 2. 查找邀请
+            invitation = self.workspace_invitation_repository.find_by_token(request.invitation_token)
+            if not invitation:
+                return None, "Invalid invitation token"
+            
+            # 3. 检查邀请状态
+            if invitation.status != InvitationStatus.PENDING:
+                return None, f"Invitation has already been {invitation.status}"
+            
+            # 4. 检查是否过期
+            if invitation.expires_at and datetime.now(timezone.utc) > invitation.expires_at:
+                # 更新状态为过期
+                invitation.status = InvitationStatus.EXPIRED
+                self.workspace_invitation_repository.save(invitation)
+                return None, "Invitation has expired"
+            
+            # 5. 验证用户存在
+            user = self.user_repository.find_by_id(request.user_id)
+            if not user:
+                return None, "User not found"
+            
+            # 6. 验证用户邮箱匹配
+            if user.email.lower() != invitation.invitee_email.lower():
+                return None, "This invitation is for a different email address"
+            
+            # 7. 验证 Workspace 存在
+            workspace = self.workspace_repository.find_by_id(invitation.workspace_id)
+            if not workspace:
+                return None, "Workspace not found"
+            
+            # 8. 检查用户是否已经是成员
+            existing_member = self.workspace_member_repository.find_by_workspace_and_user(
+                invitation.workspace_id,
+                request.user_id,
+            )
+            if existing_member:
+                # 已经是成员，标记邀请为已接受
+                invitation.status = InvitationStatus.ACCEPTED
+                invitation.accepted_at = datetime.now(timezone.utc)
+                self.workspace_invitation_repository.save(invitation)
+                
+                return AcceptInvitationResponse(
+                    workspace_id=workspace.id,
+                    workspace_name=workspace.name,
+                    role=existing_member.role,
+                ), None
+            
+            # 9. 创建成员记录
+            member = WorkspaceMember(
+                id=uuid4().hex,
+                workspace_id=invitation.workspace_id,
+                user_id=request.user_id,
+                role=invitation.role,
+                invited_by=invitation.inviter_user_id,
+                joined_at=datetime.now(timezone.utc),
+            )
+            
+            self.workspace_member_repository.save(member)
+            
+            # 10. 更新邀请状态
+            invitation.status = InvitationStatus.ACCEPTED
+            invitation.accepted_at = datetime.now(timezone.utc)
+            self.workspace_invitation_repository.save(invitation)
+            
+            # 11. 返回响应
+            return AcceptInvitationResponse(
+                workspace_id=workspace.id,
+                workspace_name=workspace.name,
+                role=member.role,
+            ), None
+        
+        except Exception as e:
+            return None, f"Failed to accept invitation: {str(e)}"
+
+
+class DeclineInvitationRequest:
+    """拒绝邀请请求"""
+    
+    def __init__(self, invitation_token: str):
+        self.invitation_token = invitation_token
+
+
+class DeclineInvitationUseCase:
+    """拒绝邀请用例"""
+    
+    def __init__(self, workspace_invitation_repository):
+        self.workspace_invitation_repository = workspace_invitation_repository
+    
+    def execute(self, request: DeclineInvitationRequest) -> tuple[bool, Optional[str]]:
+        """
+        执行拒绝邀请
+        
+        Args:
+            request: 拒绝请求
+        
+        Returns:
+            (是否成功, 错误信息)
+        """
+        try:
+            # 1. 验证输入
+            if not request.invitation_token:
+                return False, "Invitation token is required"
+            
+            # 2. 查找邀请
+            invitation = self.workspace_invitation_repository.find_by_token(request.invitation_token)
+            if not invitation:
+                return False, "Invalid invitation token"
+            
+            # 3. 检查邀请状态
+            if invitation.status != InvitationStatus.PENDING:
+                return False, f"Invitation has already been {invitation.status}"
+            
+            # 4. 更新状态为已拒绝
+            invitation.status = InvitationStatus.DECLINED
+            self.workspace_invitation_repository.save(invitation)
+            
+            return True, None
+        
+        except Exception as e:
+            return False, f"Failed to decline invitation: {str(e)}"