feat(api): add workspace member management endpoints (#556)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/api/src/workspaces/workspaces.service.ts

@@ -1,7 +1,22 @@
-import { Injectable, Logger } from "@nestjs/common";
-import { WorkspaceMemberRole } from "@prisma/client";
+import {
+  BadRequestException,
+  ConflictException,
+  ForbiddenException,
+  Injectable,
+  Logger,
+  NotFoundException,
+} from "@nestjs/common";
+import { Prisma, WorkspaceMemberRole } from "@prisma/client";
+import type { WorkspaceMember } from "@prisma/client";
 import { PrismaService } from "../prisma/prisma.service";
-import type { WorkspaceResponseDto } from "./dto";
+import type { AddMemberDto, UpdateMemberRoleDto, WorkspaceResponseDto } from "./dto";
+
+const WORKSPACE_ROLE_RANK: Record<WorkspaceMemberRole, number> = {
+  [WorkspaceMemberRole.GUEST]: 1,
+  [WorkspaceMemberRole.MEMBER]: 2,
+  [WorkspaceMemberRole.ADMIN]: 3,
+  [WorkspaceMemberRole.OWNER]: 4,
+};
 
 @Injectable()
 export class WorkspacesService {
@@ -94,4 +109,237 @@ export class WorkspacesService {
       },
     ];
   }
+
+  /**
+   * Add a member to a workspace.
+   */
+  async addMember(
+    workspaceId: string,
+    actorUserId: string,
+    addMemberDto: AddMemberDto
+  ): Promise<WorkspaceMember> {
+    const actorMembership = await this.prisma.workspaceMember.findUnique({
+      where: {
+        workspaceId_userId: {
+          workspaceId,
+          userId: actorUserId,
+        },
+      },
+      select: {
+        role: true,
+      },
+    });
+
+    if (!actorMembership) {
+      throw new ForbiddenException("You are not a member of this workspace");
+    }
+
+    this.assertCanAssignRole(actorMembership.role, addMemberDto.role);
+
+    const user = await this.prisma.user.findUnique({
+      where: { id: addMemberDto.userId },
+      select: { id: true },
+    });
+
+    if (!user) {
+      throw new NotFoundException(`User with ID ${addMemberDto.userId} not found`);
+    }
+
+    const existingMembership = await this.prisma.workspaceMember.findUnique({
+      where: {
+        workspaceId_userId: {
+          workspaceId,
+          userId: addMemberDto.userId,
+        },
+      },
+      select: {
+        workspaceId: true,
+        userId: true,
+      },
+    });
+
+    if (existingMembership) {
+      throw new ConflictException("User is already a member of this workspace");
+    }
+
+    try {
+      return await this.prisma.workspaceMember.create({
+        data: {
+          workspaceId,
+          userId: addMemberDto.userId,
+          role: addMemberDto.role,
+        },
+      });
+    } catch (error) {
+      if (this.isUniqueConstraintError(error)) {
+        throw new ConflictException("User is already a member of this workspace");
+      }
+      throw error;
+    }
+  }
+
+  /**
+   * Update the role of an existing workspace member.
+   */
+  async updateMemberRole(
+    workspaceId: string,
+    actorUserId: string,
+    targetUserId: string,
+    updateMemberRoleDto: UpdateMemberRoleDto
+  ): Promise<WorkspaceMember> {
+    return this.prisma.$transaction(async (tx) => {
+      const actorMembership = await tx.workspaceMember.findUnique({
+        where: {
+          workspaceId_userId: {
+            workspaceId,
+            userId: actorUserId,
+          },
+        },
+        select: {
+          role: true,
+        },
+      });
+
+      if (!actorMembership) {
+        throw new ForbiddenException("You are not a member of this workspace");
+      }
+
+      const targetMembership = await tx.workspaceMember.findUnique({
+        where: {
+          workspaceId_userId: {
+            workspaceId,
+            userId: targetUserId,
+          },
+        },
+        select: {
+          role: true,
+        },
+      });
+
+      if (!targetMembership) {
+        throw new NotFoundException(`User ${targetUserId} is not a member of this workspace`);
+      }
+
+      this.assertCanManageTargetMember(actorMembership.role, targetMembership.role);
+      this.assertCanAssignRole(actorMembership.role, updateMemberRoleDto.role);
+
+      if (targetMembership.role === WorkspaceMemberRole.OWNER) {
+        const isDemotion = updateMemberRoleDto.role !== WorkspaceMemberRole.OWNER;
+        if (isDemotion) {
+          const ownerCount = await tx.workspaceMember.count({
+            where: {
+              workspaceId,
+              role: WorkspaceMemberRole.OWNER,
+            },
+          });
+          if (ownerCount <= 1) {
+            if (actorUserId === targetUserId) {
+              throw new BadRequestException("Cannot self-demote if you are the sole owner");
+            }
+            throw new BadRequestException("Cannot remove the last owner from a workspace");
+          }
+        }
+      }
+
+      return tx.workspaceMember.update({
+        where: {
+          workspaceId_userId: {
+            workspaceId,
+            userId: targetUserId,
+          },
+        },
+        data: {
+          role: updateMemberRoleDto.role,
+        },
+      });
+    });
+  }
+
+  /**
+   * Remove a member from a workspace.
+   */
+  async removeMember(
+    workspaceId: string,
+    actorUserId: string,
+    targetUserId: string
+  ): Promise<void> {
+    await this.prisma.$transaction(async (tx) => {
+      const actorMembership = await tx.workspaceMember.findUnique({
+        where: {
+          workspaceId_userId: {
+            workspaceId,
+            userId: actorUserId,
+          },
+        },
+        select: {
+          role: true,
+        },
+      });
+
+      if (!actorMembership) {
+        throw new ForbiddenException("You are not a member of this workspace");
+      }
+
+      const targetMembership = await tx.workspaceMember.findUnique({
+        where: {
+          workspaceId_userId: {
+            workspaceId,
+            userId: targetUserId,
+          },
+        },
+        select: {
+          role: true,
+        },
+      });
+
+      if (!targetMembership) {
+        throw new NotFoundException(`User ${targetUserId} is not a member of this workspace`);
+      }
+
+      this.assertCanManageTargetMember(actorMembership.role, targetMembership.role);
+
+      if (targetMembership.role === WorkspaceMemberRole.OWNER) {
+        const ownerCount = await tx.workspaceMember.count({
+          where: {
+            workspaceId,
+            role: WorkspaceMemberRole.OWNER,
+          },
+        });
+        if (ownerCount <= 1) {
+          throw new BadRequestException("Cannot remove the last owner from a workspace");
+        }
+      }
+
+      await tx.workspaceMember.delete({
+        where: {
+          workspaceId_userId: {
+            workspaceId,
+            userId: targetUserId,
+          },
+        },
+      });
+    });
+  }
+
+  private assertCanAssignRole(
+    actorRole: WorkspaceMemberRole,
+    requestedRole: WorkspaceMemberRole
+  ): void {
+    if (WORKSPACE_ROLE_RANK[actorRole] < WORKSPACE_ROLE_RANK[requestedRole]) {
+      throw new ForbiddenException("You cannot assign a role higher than your own");
+    }
+  }
+
+  private assertCanManageTargetMember(
+    actorRole: WorkspaceMemberRole,
+    targetRole: WorkspaceMemberRole
+  ): void {
+    if (WORKSPACE_ROLE_RANK[actorRole] < WORKSPACE_ROLE_RANK[targetRole]) {
+      throw new ForbiddenException("You cannot manage a member with a higher role");
+    }
+  }
+
+  private isUniqueConstraintError(error: unknown): error is Prisma.PrismaClientKnownRequestError {
+    return error instanceof Prisma.PrismaClientKnownRequestError && error.code === "P2002";
+  }
 }