Base.vn Prep

Specific clarify (ngoài Universal):

• Attachment lưu ở đâu? (S3 vs DB blob)
• Sub-task / dependency có support?
• Recurring task (daily/weekly)?
• Time tracking integrated?

Data model:

tenants(id, name, plan)
users(id, tenant_id, email, role)
projects(id, tenant_id, name)
tasks(id, tenant_id, project_id, assignee_id, title, status, due_date)
comments(id, task_id, author_id, body, created_at)
attachments(id, task_id, s3_key, mime, size)

idx_tasks_assignee_status (assignee_id, status)
idx_tasks_project_created (project_id, created_at DESC)

API:

• POST /tasks · GET /tasks?projectId · PATCH /tasks/:id
• POST /tasks/:id/comments · GET /tasks/:id/comments
• POST /attachments/sign → presigned S3 URL

Architecture:

Client → API (NestJS) → Postgres. Redis cache cho task list. BullMQ cho notification. Worker push WebSocket nếu cần real-time comment.

Trade-offs:

• Multi-tenant: shared schema + tenant_id + RLS — balance cost vs isolation
• Notification dùng queue để không block POST
• Attachment qua presigned URL — không proxy qua API

Specific clarify:

• Templating ai làm? (admin GUI hay code-defined)
• Localization i18n?
• Provider: SaaS (SendGrid, FCM) hay self-host?
• Unsubscribe management UI?

Data model:

notifications(id, tenant_id, user_id, type, payload_json, channel, status, retry_count)
user_preferences(user_id, channel, type, enabled, frequency)
templates(id, type, channel, subject, body_html, body_text)

idx_notif_user_status (user_id, status, created_at DESC)
idx_notif_retry       (status, retry_count) WHERE status='failed'

Flow:

App emit event → Notification Service → check preferences
→ write DB (pending) → enqueue BullMQ per channel
→ Worker render template → send via provider
→ update status, retry exponential backoff nếu fail

Trade-offs:

• Write DB trước khi enqueue → audit + retry sau crash
• Queue per channel → email chậm không block push
• Digest batch cho low-priority → tránh spam
• Provider fail → fallback (SendGrid → SES)

Specific clarify:

• Loại leave? (annual, sick, unpaid)
• Balance tracking tự động?
• Approval chain config per-tenant?
• Calendar: Google/Outlook hay built-in?

Data model:

leave_types(id, tenant_id, name, paid, max_days_per_year)
leave_balances(user_id, leave_type_id, year, allocated, used)
leave_requests(id, tenant_id, user_id, type_id, start_date, end_date, days, status)
approvals(id, request_id, approver_id, level, status, decided_at)
approval_rules(tenant_id, type_id, min_days, approver_role)

State machine:

draft → submitted → manager_pending → director_pending → approved
                                  ↓                ↓
                              rejected         rejected

Trade-offs:

• State machine tường minh > boolean flag → audit dễ
• Approval rules data-driven → per-tenant config
• Balance update khi approved, không khi submitted → tránh rollback
• Lock pessimistic khi update balance → tránh double-deduct