# VBA Module Knowledge Base

**Scope:** `VBA/` directory - Core automation logic

## OVERVIEW

VBA modules for BOM extraction: ClassModules (domain logic), Modules (workflows), DocumentModules (sheet events).

## STRUCTURE

```
VBA/
├── ClassModules/         # 4 classes: BomExtractor, BomItem, ProductModelParser, ConditionEvaluator
├── Modules/              # 4 modules: MainModule, BIPUploadModule, ComponentInventoryCheckModule, TestModule
├── DocumentModules/      # Sheet9.cls (event handlers)
└── vba_metadata.json     # Module metadata
```

## WHERE TO LOOK

| Task | Location | Notes |
|------|----------|-------|
| Main entry point | `Modules/MainModule.bas` | `ProcessProductModels()` |
| BOM extraction | `ClassModules/BomExtractor.cls` | `ExtractBom()` with assembly logic |
| Model parsing | `ClassModules/ProductModelParser.cls` | `Parse()` extracts 6 conditions |
| Condition logic | `ClassModules/ConditionEvaluator.cls` | Expression evaluation |
| BIP upload | `Modules/BIPUploadModule.bas` | Upload to BIP system |
| Inventory check | `Modules/ComponentInventoryCheckModule.bas` | Component verification |

## CODE MAP

| Symbol | Type | Location | Role |
|--------|------|----------|------|
| `ProcessProductModels()` | Sub | `MainModule.bas` | Main entry point |
| `ExtractBom()` | Function | `BomExtractor.cls` | Core matching logic |
| `Parse()` | Function | `ProductModelParser.cls` | Model string parser |
| `Evaluate()` | Function | `ConditionEvaluator.cls` | Condition evaluator |
| `LoadFromRow()` | Sub | `BomItem.cls` | Row data loader |

## CONVENTIONS

### Module Organization
- **ClassModules**: `*.cls` files with `Option Explicit`, public methods, private state
- **Modules**: `*.bas` files with public subs, helper functions
- **DocumentModules**: Sheet-specific event handlers (e.g., `Sheet9.cls`)

### Error Handling Pattern
```vba
On Error GoTo ErrorHandler
' ... logic ...
Exit Sub
ErrorHandler:
    ' Handle error
```

### Data Loading
- `BomExtractor.LoadBomData()` starts at row 4 (row 3 is header)
- `BomItem.LoadFromRow()` uses `On Error Resume Next` for type conversions

## ANTI-PATTERNS (THIS PROJECT)

- **NEVER** change row indexing in `LoadBomData()` — hardcoded to start at row 4
- **NEVER** reorder `BomItem` fields — column mapping is hardcoded (11 fields)
- **NEVER** remove `On Error Resume Next` in `LoadFromRow()` — handles type conversion
- **NEVER** bypass `ApplyAssemblyLogic()` — parent/child override is critical
- **NEVER** hardcode workbook names — always use `ThisWorkbook`

## UNIQUE STYLES

### Assembly Logic (总成逻辑)
Parent category overrides children if:
1. Parent matches exactly 1 item
2. All children match at least 1 item
3. Result: parent output, children hidden

### Batch Output Pattern
```vba
' Collect in Collection
' Convert to 2D array
' Single Range.Value write
```

### Condition Syntax
- Format: `"field=value|field2=value2"` (pipe = OR)
- Example: `"azxs=M|azxs=L"` (vertical OR horizontal installation)

## NOTES

### Scripting.Dictionary Dependency
All classes use `CreateObject("Scripting.Dictionary")` - Windows only, not Mac-compatible.

### Workbook Sheets Required
- `产品订单` - Input orders
- `平台配置清单` - BOM configuration (starts at row 4)
- `BOM 提取结果` - Auto-created output