# StdDev Ranges Implementation Checklist

## 📋 Quick Implementation Guide

### Phase 1: Add JavaScript Modules (2 files)

```bash
# Copy to your static folder:
cp .code/rollcalc-stddev-ranges.js /path/to/flask/static/
cp .code/rollcalc-stddev-integration.js /path/to/flask/static/
```

### Phase 2: Update HTML (3 lines changed)

In `roll_calculator.html`, find the section where scripts are loaded (around line ~2370):

**Add after the other script tags:**
```html
<script src="/static/rollcalc-stddev-ranges.js"></script>
<script src="/static/rollcalc-stddev-integration.js"></script>
```

### Phase 3: Update JavaScript - Article Selection

In `rollcalc_improvements.js`, find the `populateArticleDropdowns_v14()` function.

In the "DirectCalc-Article" section (~line 2340), after the existing article fill code:

**ADD THESE LINES:**
```javascript
// NEW: Store stddev values for later use
document.getElementById('d-th').dataset.stddev = match.thickness_stddev || 0;
document.getElementById('d-aw').dataset.stddev = match.area_weight_stddev || 0;

console.log('[StdDev] Stored:', {
  thickness_stddev: match.thickness_stddev,
  area_weight_stddev: match.area_weight_stddev
});
```

### Phase 4: Update Direct Calc Button Handler

**FIND:** The diameter calculation section in the `d-calc` click handler (~line 2380)

**Replace this block:**
```javascript
if (mode === 'diameter') {
  if (!d_mm || !t_mm || !L_m) { alert('Please enter d, t and L.'); return; }
  const D_nom = Math.sqrt(d_mm*d_mm + (4*L_m*1000*t_mm)/Math.PI);
  resLabel.textContent = 'Roll Diameter (D)';
  resVal.textContent   = D_nom.toFixed(1) + ' mm';
  if (tol) {
    const D_min = Math.sqrt(d_mm*d_mm + (4*L_m*1000*(t_mm-tol))/Math.PI);
    const D_max = Math.sqrt(d_mm*d_mm + (4*L_m*1000*(t_mm+tol))/Math.PI);
    resRange.textContent = 'Min: ' + D_min.toFixed(1) + ' mm  |  Max: ' + D_max.toFixed(1) + ' mm';
  } else { resRange.textContent = ''; }
  document.getElementById('d-di').value = D_nom.toFixed(1);
  calculatedLength = L_m;
}
```

**WITH THIS:**
```javascript
if (mode === 'diameter') {
  const result = window.StdDevIntegration.calculateDiameterWithStddev(d_mm, t_mm, null, L_m, tol);
  if (!result) return;
  
  calculatedLength = result.calculatedLength;
  
  // Calculate weight with stddev ranges
  const weightRanges = window.StdDevIntegration.calcWeightWithStddev(calculatedLength);
  
  // Forklift check uses worst-case weight
  window.StdDevIntegration.evaluateForkliftWithWorstCase(d_mm, category);
}
```

### Phase 5: Update Weight Calculation

**FIND:** The `calcWeight()` function (~line 2410)

**Replace:**
```javascript
function calcWeight(length) {
  const wi = parseFloat(document.getElementById('de-wi').value) || 0;
  const aw = parseFloat(document.getElementById('d-aw').value) || 0;
  if (wi > 0 && aw > 0 && length > 0) {
    const w = (aw * length * wi / 1000).toFixed(1);
    document.getElementById('d-wo').value = w;
    return parseFloat(w);
  }
  document.getElementById('d-wo').value = '';
  return null;
}
```

**WITH:**
```javascript
function calcWeight(length) {
  return window.StdDevIntegration.calcWeightWithStddev(length);
}
```

### Phase 6: Update Forklift Check Call

**FIND:** The line that calls `ForkliftChecker.evaluate()` (~line 2420)

**Change from:**
```javascript
const allowed = runForkliftCheck(weight);
```

**TO:**
```javascript
const allowed = window.StdDevIntegration.evaluateForkliftWithWorstCase(d_mm, category);
```

---

## ✅ Testing Checklist

### Test 1: Article with StdDev Data
```
Action: Select "180005" from dropdown
Expected:
  ✓ thickness_stddev loaded (0.379181)
  ✓ area_weight_stddev loaded (133.240428)
  ✓ Console shows [StdDev] Stored message
```

### Test 2: Diameter Calculation
```
Action: 
  - Select "180005"
  - Length: 50 m
  - Click Calculate
Expected:
  ✓ Result shows nominal: 502.8 mm
  ✓ Range shows: ±2σ: 491.2 – 514.4 mm
  ✓ Console shows diameter ranges
```

### Test 3: Weight Calculation
```
Action: Same as Test 2
Expected:
  ✓ Weight field shows: 974.8 kg
  ✓ Data attributes set: weight_nom, weight_min, weight_max
  ✓ Worst-case weight: 1041.4 kg
```

### Test 4: Forklift Checker
```
Action: Same as Test 2
Expected:
  ✓ Forklift checker uses worst-case (1041.4 kg)
  ✓ Shows appropriate warning/OK status
  ✓ Console shows [StdDev-Forklift] message
```

### Test 5: Load Optimizer
```
Action: Same as Test 2, then open Load Optimizer
Expected:
  ✓ Pre-filled with nominal weight (974.8 kg)
  ✓ NOT using worst-case weight
  ✓ Calculations correct
```

### Test 6: Backward Compatibility
```
Action: Manually enter values (no article selection)
Expected:
  ✓ System works as before
  ✓ Shows only nominal values
  ✓ No errors in console
```

---

## 🐛 Debugging

If something doesn't work:

1. **Open DevTools (F12) → Console**
2. **Look for these logs:**
   - `[StdDev] Stored:` - Article stddev loaded?
   - `[StdDev-Calc] Diameter with ranges:` - Calculation done?
   - `[StdDev-Weight] Calculated ranges:` - Weight ranges set?
   - `[StdDev-Forklift] Using worst-case weight:` - Forklift using right value?

3. **Common issues:**
   - Missing script tags → Add to HTML `<head>`
   - Article without stddev → Should default to 0
   - Functions undefined → Check script load order
   - Wrong values → Check browser cache (Ctrl+Shift+Delete)

---

## 📊 Expected Results (Example Article 180005)

| Field | Value |
|-------|-------|
| Thickness | 6.228 ± 0.758 mm (±2σ) |
| Area Weight | 3899.02 ± 266.48 g/m² (±2σ) |
| Diameter @ 50m | 502.8 mm (491.2–514.4 mm range) |
| Weight @ 5m width | 974.8 kg (908.1–1041.4 kg range) |
| Forklift Check | Uses 1041.4 kg (worst-case) |
| Load Optimizer | Uses 974.8 kg (nominal) |

---

## 📁 Files Modified

| File | Changes |
|------|---------|
| roll_calculator.html | Add 2 `<script>` tags |
| rollcalc_improvements.js | Add 6 lines (stddev storage) |
| d-calc handler | Replace diameter & weight code (~15 lines) |
| calcWeight() | Replace with 1-liner call |
| Forklift call | Change 1 line |

**Total changes: ~25 lines in 2 files**

---

## 🎯 Rollback

If you need to revert:

1. **Remove script tags from HTML**
2. **Restore original d-calc handler code** (keep v14 base)
3. **Restore original calcWeight() function**
4. **Delete stddev JavaScript files**

Everything is backward compatible - no data format changes.

---

## ✨ You're All Set!

Follow the 6 phases above and you'll have StdDev ranges implemented in ~15 minutes! 🚀

**Questions?** Check `STDDEV_RANGES_DOCS.md` for detailed docs.