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WORK ORDER PERSISTENCE - IMPLEMENTATION SUMMARY
Implementation Date: November 29, 2025
Node-RED Location: /home/mdares/.node-red/
Backup Location: flows.json.backup_ALL_PHASES_COMPLETE
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OVERVIEW
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Successfully implemented all 7 phases of the work order persistence system.
The system now ensures work order progress is preserved across Node-RED restarts,
provides resume/restart functionality, and maintains database as source of truth.


PHASES IMPLEMENTED
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✅ PHASE 1: Database Schema Verification & Updates
   - Verified work_orders table has required columns
   - Confirmed: cycle_count, good_parts, scrap_parts, progress_percent columns exist
   - Status: COMPLETE (already had correct schema)

✅ PHASE 2: Add Cycle Persistence to work_orders Table
   - Added 4th output to Machine Cycles function
   - Initially implemented with 5-second throttling
   - UPDATED: Changed to immediate write (every cycle) for accuracy
   - SQL: UPDATE work_orders SET cycle_count, good_parts, scrap_parts, progress_percent
   - Database now updates on EVERY cycle (no lag)
   - Files Modified: flows.json (Machine cycles function)

✅ PHASE 3: Implement Resume/Restart Prompt on Load
   - Modified start-work-order to query DB for existing progress
   - Added Progress Check Handler node to evaluate progress
   - Created resume-work-order action handler
   - Created restart-work-order action handler
   - Added Resume/Restart prompt dialog to Home template UI
   - Fixed: Added scrap_parts to queries and resume logic
   - Files Modified: flows.json (Work Order buttons, Progress Check Handler, Home Template)

✅ PHASE 4: Fix Complete Button to Persist Final Counts
   - Modified complete-work-order handler to capture final values
   - SQL: UPDATE work_orders SET status='DONE', cycle_count, good_parts, scrap_parts, progress_percent=100
   - Final production counts now permanently saved before marking DONE
   - Files Modified: flows.json (Work Order buttons)

✅ PHASE 5: Update Session Restore to Set RUNNING Status
   - Modified restore-query handler in Back to UI
   - Automatically sets work order status back to RUNNING on Node-RED restart
   - User must still click Start button to begin counting (safety feature)
   - Fixed: Corrected start handler bug (removed undefined dbMsg reference)
   - Files Modified: flows.json (Back to UI function)

✅ PHASE 6: Load Work Order Data from Database (Not Session)
   - Updated Progress Check Handler to use DB values as source of truth
   - Even when progress is 0, values are loaded from database (not hardcoded)
   - activeWorkOrder object now includes all DB fields (cycle_count, good_parts, scrap)
   - Files Modified: flows.json (Progress Check Handler)

✅ PHASE 7: Add Tab Switch State Refresh (Optional Enhancement)
   - Added tab refresh polling (every 2 seconds when Home tab visible)
   - Added currentState message handler to Home template
   - UI now refreshes with latest data when switching back to Home tab
   - Files Modified: flows.json (Home Template)


KEY IMPROVEMENTS & FIXES
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1. SCRAP TRACKING FIX
   - Issue: Resume showed wrong good_parts count (calculation: cycles × cavities - scrap)
   - Root Cause: scrap value not loaded from database on resume
   - Fix: Added scrap_parts to all DB queries and resume/restart handlers
   - Result: Resume now shows accurate good_parts count

2. DATABASE LAG FIX
   - Issue: Database was one cycle behind (5-second throttle)
   - User Feedback: Loading work order showed stale data
   - Fix: Removed throttle, now writes to DB on every cycle
   - Result: Database always current, Load shows exact progress

3. LOAD BUTTON BUG FIX
   - Issue: After Phase 5, Load button stopped working (no UI update, no RUNNING status)
   - Root Cause: start handler referenced undefined dbMsg variable
   - Fix: Changed return [dbMsg, homeMsg, null, null] to [null, homeMsg, null, null]
   - Result: Load button works perfectly


TECHNICAL DETAILS
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Modified Nodes:
1. Machine cycles (function) - Immediate DB persistence
2. Work Order buttons (function) - start/resume/restart/complete handlers
3. Progress Check Handler (function) - NEW node for progress evaluation
4. Back to UI (function) - resume-prompt and restore-query handlers
5. Home Template (ui_template) - Resume/Restart dialog and tab refresh

Database Updates:
- work_orders table: cycle_count, good_parts, scrap_parts, progress_percent updated on every cycle
- Status transitions: PENDING → RUNNING → DONE
- Session restore sets status back to RUNNING

Flow Connections:
- Machine cycles → Output 4 → DB Guard (Cycles) → mariaDB
- Work Order buttons → Progress Check Handler → Back to UI → Home Template
- All database writes use parameterized queries (SQL injection safe)


USER WORKFLOWS
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1. START NEW WORK ORDER
   - Click Load on work order with no progress
   - Status changes to RUNNING in database
   - Click Start button to begin production
   - Each cycle updates database immediately
   - Progress visible in UI and database

2. RESUME EXISTING WORK ORDER
   - Click Load on work order with progress (e.g., 60/200 parts)
   - Resume/Restart prompt appears
   - Click "Resume from 60 parts"
   - Status changes to RUNNING
   - Production continues from 60 parts
   - Click Start to begin counting

3. RESTART WORK ORDER
   - Click Load on work order with progress
   - Resume/Restart prompt appears
   - Click "Restart from 0"
   - Confirmation dialog appears
   - After confirm: cycle_count, good_parts, scrap_parts reset to 0
   - Status changes to RUNNING
   - Click Start to begin counting from 0

4. COMPLETE WORK ORDER
   - Click Done button
   - Final cycle_count, good_parts, scrap_parts persisted to database
   - progress_percent set to 100
   - Status changes to DONE
   - All state cleared

5. NODE-RED RESTART (SESSION RESTORE)
   - Node-RED restarts (crash or maintenance)
   - System queries for work orders with status='RUNNING'
   - Restores activeWorkOrder with cycle_count, good_parts, scrap
   - Status remains RUNNING (or is set back to RUNNING)
   - UI shows work order loaded
   - User must click Start to resume production

6. TAB SWITCHING
   - User on Home tab with production running
   - Switches to Graphs tab
   - Production continues in background
   - Switches back to Home tab
   - Within 2 seconds, UI refreshes with latest data


TESTING CHECKLIST
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✓ New work order start (0 progress)
✓ Resume existing work order (with progress)
✓ Restart existing work order (with progress)
✓ Complete work order (final counts persisted)
✓ Node-RED restart with running work order
✓ Tab switching shows fresh data
✓ Database updates on every cycle
✓ Load button shows current progress (not stale)
✓ Scrap tracking accurate on resume
✓ Resume/Restart prompt appears when expected
✓ Start button enabled/disabled correctly


BACKUP FILES
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flows.json.backup_phase3              - After Phase 3 (Resume/Restart)
flows.json.backup_phase3_complete     - Phase 3 complete with scrap fix
flows.json.backup_phase5_complete     - After Phase 5 (Session Restore)
flows.json.backup_phase6_complete     - After Phase 6 (DB source of truth)
flows.json.backup_phase7_complete     - After Phase 7 (Tab refresh)
flows.json.backup_ALL_PHASES_COMPLETE - FINAL BACKUP (all phases complete)

To restore a backup:
cd /home/mdares/.node-red
cp flows.json.backup_ALL_PHASES_COMPLETE flows.json
# Restart Node-RED


KNOWN BEHAVIOR
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1. Production must be started manually (safety feature)
   - After Load: Status = RUNNING, but production not started
   - User must click Start button
   - This prevents accidental production during debugging

2. Database writes on every cycle
   - Originally throttled to 5 seconds
   - Changed to immediate for accuracy
   - Performance impact: negligible (1 query per cycle ~30-120s)

3. Maximum data loss on crash: 1 incomplete cycle
   - Database updates after each complete cycle
   - If Node-RED crashes mid-cycle, that cycle is lost
   - Session restore recovers all complete cycles

4. Tab refresh polls every 2 seconds
   - Only when Home tab is visible
   - Minimal performance impact
   - Ensures UI stays fresh


SUCCESS CRITERIA MET
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✅ Work orders persist progress across Node-RED restarts
✅ Resume/Restart prompt prevents accidental data loss
✅ work_orders table always reflects current production state
✅ Tab switches don't lose data
✅ Multi-day work orders can be interrupted and resumed
✅ Maximum data loss: 1 cycle on crash (acceptable)
✅ Database is single source of truth
✅ UI always shows current, accurate data


IMPLEMENTATION NOTES
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- All SQL queries use parameterized statements (safe from SQL injection)
- Database is source of truth (not session/memory)
- UI updates use Angular scope watchers
- Error handling includes node.warn() logging for debugging
- Flow connections verified and tested
- No backwards compatibility issues


FINAL STATUS: ✅ ALL PHASES COMPLETE AND TESTED
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