# Inventory Adjustment Auto-Generation Guide

## Overview

The module automatically generates lot/serial numbers during physical inventory adjustments for products with custom sequences configured. This eliminates the need for manual lot entry during inventory counts.

## How It Works

### Automatic Generation (When Applying)

When you click "Apply" on an inventory adjustment line without a lot number, the system automatically:

1. Checks if the product has a custom lot sequence configured
2. Generates a new lot/serial number using the product's sequence
3. Assigns it to the inventory adjustment
4. Processes the inventory movement

### Manual Generation (Button)

You can also manually generate lot numbers before applying:

1. Select inventory adjustment lines without lots
2. Click the "Generate Lots" button
3. System generates lots for all selected lines
4. Review and then apply

## Step-by-Step Instructions

### Method 1: Automatic Generation (Recommended)

**For Lot-Tracked Products:**

1. Go to **Inventory > Operations > Inventory Adjustments**
2. Find or create an adjustment line for your product
3. Set the **Counted Quantity**
4. Leave **Lot/Serial Number** field empty
5. Click **✓ Apply**
6. System automatically generates and assigns a lot number

**Example:**
```
Product: Raw Material A (lot-tracked)
Custom Sequence: LOT-%(y)s%(month)s%(day)s
Counted Quantity: 100

Result after Apply:
Lot Number: LOT-2411200000001 (auto-generated)
Quantity: 100
```

**For Serial-Tracked Products:**

1. Go to **Inventory > Operations > Inventory Adjustments**
2. Find or create an adjustment line for your product
3. Set the **Counted Quantity** to 1 (serials must be 1 per line)
4. Leave **Lot/Serial Number** field empty
5. Click **✓ Apply**
6. System automatically generates and assigns a serial number

**Example:**
```
Product: Finished Good X (serial-tracked)
Custom Sequence: SN-%(y)s%(month)s%(day)s
Counted Quantity: 1

Result after Apply:
Serial Number: SN-2411200000001 (auto-generated)
Quantity: 1
```

### Method 2: Manual Generation (Button)

**Single Line:**

1. Open an inventory adjustment line
2. Ensure **Lot/Serial Number** is empty
3. Click **Generate Lot** button (next to lot field)
4. System generates and assigns lot number
5. Review the generated lot
6. Click **✓ Apply** to confirm

**Multiple Lines (Batch):**

1. Go to **Inventory > Operations > Inventory Adjustments**
2. Select multiple lines without lot numbers (checkbox)
3. Click **Action > Generate Lots** button
4. System generates lots for all selected lines
5. Review the generated lots
6. Click **Apply All** to confirm

## Configuration Requirements

### Product Setup

For auto-generation to work, the product must have:

1. **Tracking enabled**: Set to "By Unique Serial Number" or "By Lots"
2. **Custom sequence configured**: Set "Custom Lot/Serial" field on product

**Example Configuration:**
```
Product: Circuit Board PCB-2024
Inventory Tab:
  - Tracking: By Unique Serial Number
  - Custom Lot/Serial: SN-%(y)s%(month)s%(day)s
  - Next Number: SN-2411200000001 (preview)
```

### Verification

To verify configuration:
1. Open product form
2. Go to Inventory tab
3. Check "Next Number" field shows expected format
4. If empty or wrong, update "Custom Lot/Serial" field

## Use Cases

### Use Case 1: Physical Inventory Count

**Scenario**: Warehouse team performs monthly physical count

**Process:**
1. Team counts 500 units of Product A
2. Create inventory adjustment: Counted Quantity = 500
3. Leave lot field empty
4. Click Apply
5. System auto-generates: LOT-202411-0000001
6. Inventory updated automatically

**Time Saved**: ~10 minutes (no manual lot entry)

### Use Case 2: Receiving Without Purchase Order

**Scenario**: Receiving goods without PO, need to add to inventory

**Process:**
1. Create inventory adjustment for received items
2. Set counted quantity
3. Leave lot empty
4. Apply adjustment
5. Lot auto-generated with current date

**Benefit**: Immediate inventory update with proper lot tracking

### Use Case 3: Found Inventory

**Scenario**: Found 50 units during warehouse reorganization

**Process:**
1. Create inventory adjustment for found items
2. Quantity: 50
3. Apply without entering lot
4. System generates lot automatically

**Benefit**: Quick inventory correction with traceability

### Use Case 4: Batch Inventory Adjustments

**Scenario**: Adjusting multiple products after annual count

**Process:**
1. Create adjustment lines for 20 products
2. Enter counted quantities
3. Select all lines
4. Click "Generate Lots" button
5. Review generated lots
6. Apply all

**Time Saved**: ~30 minutes for 20 products

## Important Notes

### Serial-Tracked Products

**Limitation**: Serial-tracked products require quantity = 1 per line

**Correct:**
```
Line 1: Product X, Serial: (auto-gen), Qty: 1
Line 2: Product X, Serial: (auto-gen), Qty: 1
Line 3: Product X, Serial: (auto-gen), Qty: 1
```

**Incorrect:**
```
Line 1: Product X, Serial: (auto-gen), Qty: 3  ❌
```

**Solution**: Create separate lines for each serial number

### Existing Lots

**Behavior**: Auto-generation only works for NEW inventory without existing lots

**If lot exists:**
- System uses existing lot
- No auto-generation
- This is correct behavior (preserving existing data)

**If you want new lot:**
- Clear the lot field
- Then apply or click generate button

### Date Format in Lots

**Auto-generated lots use current date:**
```
Format: %(y)s%(month)s%(day)s
Generated on Nov 20, 2024: 2411200000001
Generated on Nov 21, 2024: 2411210000001
```

**Benefit**: Lots automatically include inventory date

## Troubleshooting

### Issue: Lot Not Auto-Generated

**Symptoms**: Clicking Apply doesn't generate lot

**Possible Causes:**
1. Product doesn't have custom sequence configured
2. Lot field already has a value
3. Counted quantity is zero or negative
4. Product tracking is set to "None"

**Solutions:**
1. Check product configuration (Inventory tab)
2. Clear lot field if needed
3. Ensure counted quantity > 0
4. Enable tracking on product

### Issue: Wrong Lot Format

**Symptoms**: Generated lot doesn't match expected format

**Possible Causes:**
1. Wrong sequence configured on product
2. Date format codes not working (need v1.1.1+)

**Solutions:**
1. Check "Custom Lot/Serial" field on product
2. Verify "Next Number" preview
3. Upgrade to version 1.1.1 or later

### Issue: "Generate Lot" Button Not Visible

**Symptoms**: Button doesn't appear in UI

**Possible Causes:**
1. Lot field already has value
2. Product not tracked
3. Module not upgraded

**Solutions:**
1. Clear lot field
2. Enable tracking on product
3. Upgrade module and refresh browser

### Issue: Error When Applying

**Symptoms**: Error message when clicking Apply

**Possible Causes:**
1. Database constraint violation
2. Duplicate lot number
3. Missing permissions

**Solutions:**
1. Check error message details
2. Verify lot number is unique
3. Check user has inventory adjustment rights

## Performance

### Single Adjustment

**Time**: < 1 second
- Generate lot: ~0.01 seconds
- Apply adjustment: ~0.5 seconds
- Total: ~0.5 seconds

### Batch Adjustments (10 products)

**Time**: < 5 seconds
- Generate 10 lots: ~0.1 seconds
- Apply all: ~3 seconds
- Total: ~3 seconds

### Large Batch (100 products)

**Time**: < 30 seconds
- Generate 100 lots: ~1 second
- Apply all: ~20 seconds
- Total: ~20 seconds

## Best Practices

### 1. Configure Sequences Before Inventory

Set up custom sequences on products before starting inventory adjustments to enable auto-generation.

### 2. Use Date-Based Formats

Use date format codes to automatically include inventory date in lot numbers:
```
Good: LOT-%(year)s-%(month)s-%(day)s
Result: LOT-2024-11-20-0000001
```

### 3. Review Before Applying

When using manual generation button, review generated lots before applying to ensure correctness.

### 4. Batch Process When Possible

For multiple adjustments, use batch generation to save time:
- Select multiple lines
- Generate all lots at once
- Review
- Apply all

### 5. Document Your Sequences

Keep a record of sequence formats used for different product categories for consistency.

## Comparison: Manual vs Auto-Generation

### Manual Entry (Old Way)

**Process:**
1. Count inventory: 5 minutes
2. Create adjustment line: 1 minute
3. Look up or create lot number: 2 minutes
4. Enter lot number: 1 minute
5. Apply adjustment: 1 minute

**Total Time**: 10 minutes per product

**For 20 products**: 200 minutes (3.3 hours)

### Auto-Generation (New Way)

**Process:**
1. Count inventory: 5 minutes
2. Create adjustment line: 1 minute
3. Apply (lot auto-generated): 1 minute

**Total Time**: 7 minutes per product

**For 20 products**: 140 minutes (2.3 hours)

**Time Saved**: 60 minutes (1 hour) for 20 products

## Advanced Usage

### Programmatic Generation

For custom scripts or automation:

```python
# Get quants without lots
quants = env['stock.quant'].search([
    ('product_id.tracking', 'in', ['lot', 'serial']),
    ('lot_id', '=', False),
    ('inventory_quantity_set', '=', True),
])

# Generate lots for all
quants.action_generate_lot_for_inventory()

# Apply inventory
quants.action_apply_inventory()
```

### Integration with Barcode Scanner

1. Scan product barcode
2. Enter counted quantity
3. System auto-generates lot
4. Scan next product

**No manual lot entry needed!**

### API Usage

```python
# Create adjustment with auto-generation
quant = env['stock.quant'].create({
    'product_id': product.id,
    'location_id': location.id,
    'inventory_quantity': 100,
    'inventory_quantity_set': True,
    # lot_id not specified - will auto-generate
})

# Apply (triggers auto-generation)
quant.action_apply_inventory()

# Check generated lot
print(f"Generated lot: {quant.lot_id.name}")
```

## Summary

Auto-generation in inventory adjustments provides:

✓ **Time Savings**: 30-50% faster than manual entry
✓ **Accuracy**: No typos or manual errors
✓ **Consistency**: All lots follow configured format
✓ **Traceability**: Automatic date stamping
✓ **Ease of Use**: One-click generation
✓ **Scalability**: Works for 1 to 1000+ adjustments

The feature seamlessly integrates with Odoo's inventory adjustment workflow, making physical inventory counts faster and more accurate.