printedparts stage 9: reports - stock w/ reconcile, consumption, by-person

Three jwt-optional endpoints with ?format=csv, merged into the reports
hub via get_reports while the plugin is enabled. The stock report's
ledgerdelta column is the reconcile check: 0 for every item whose
stock moved through the ledger, nonzero for anything that bypassed it
(the hand-seeded dev rows demonstrate the catch). MySQL SUM returns
Decimal - cast to int or the delta serializes as a string.

plugins/printedparts/api/routes.py

@@ -346,3 +346,113 @@ def kiosk_take():
     _ledger_write(item, 'take', -quantity, sso, name)
     return success_response(item.to_dict(),
                             message=f'Took {quantity}, {item.quantityonhand} left')
+
+
+# --- reports (merged into GET /api/reports while the plugin is enabled) ------
+
+import csv
+import io
+
+from flask import Response
+from sqlalchemy import func
+
+
+def _csv_response(rows, columns, filename):
+    """CSV download; local helper because generate_csv is not on the
+    contract surface (shopdb.api)."""
+    output = io.StringIO()
+    writer = csv.writer(output)
+    writer.writerow(columns)
+    for row in rows:
+        writer.writerow([row.get(column, '') for column in columns])
+    return Response(
+        output.getvalue(), mimetype='text/csv',
+        headers={'Content-Disposition': f'attachment; filename={filename}'})
+
+
+@printedparts_bp.route('/reports/stock', methods=['GET'])
+@jwt_required(optional=True)
+def report_stock():
+    """Stock levels with low-stock flags and the cache-vs-ledger reconcile.
+
+    ledgerdelta should always be 0; anything else means a write path
+    bypassed the single-commit rule and needs finding.
+    """
+    # int() the sums: MySQL SUM returns Decimal, which JSON-serializes as a
+    # string and breaks the delta arithmetic's type.
+    ledger = {itemid: int(total) for itemid, total in
+              db.session.query(
+                  PrintedItemTransaction.printeditemid,
+                  func.coalesce(func.sum(PrintedItemTransaction.quantitychange), 0))
+              .group_by(PrintedItemTransaction.printeditemid).all()}
+    rows = []
+    for item in PrintedItem.query.filter_by(isactive=True).order_by(
+            PrintedItem.itemname).all():
+        rows.append({
+            'itemcode': item.itemcode,
+            'itemname': item.itemname,
+            'binlocation': item.binlocation or '',
+            'quantityonhand': item.quantityonhand,
+            'lowstockthreshold': item.lowstockthreshold,
+            'islowstock': item.islowstock,
+            'ledgerdelta': item.quantityonhand - ledger.get(item.printeditemid, 0),
+        })
+    columns = ['itemcode', 'itemname', 'binlocation', 'quantityonhand',
+               'lowstockthreshold', 'islowstock', 'ledgerdelta']
+    if request.args.get('format') == 'csv':
+        return _csv_response(rows, columns, 'printedparts-stock.csv')
+    return success_response({'columns': columns, 'rows': rows})
+
+
+@printedparts_bp.route('/reports/consumption', methods=['GET'])
+@jwt_required(optional=True)
+def report_consumption():
+    """Takes per item, optionally bounded by ?days=<n> (default 30)."""
+    days = request.args.get('days', 30, type=int)
+    query = (db.session.query(
+                PrintedItem.itemcode,
+                PrintedItem.itemname,
+                func.count(PrintedItemTransaction.transactionid),
+                func.coalesce(func.sum(-PrintedItemTransaction.quantitychange), 0))
+             .join(PrintedItemTransaction,
+                   PrintedItemTransaction.printeditemid == PrintedItem.printeditemid)
+             .filter(PrintedItemTransaction.transactiontype == 'take'))
+    if days > 0:
+        from datetime import datetime, timedelta, timezone
+        cutoff = datetime.now(timezone.utc).replace(tzinfo=None) - timedelta(days=days)
+        query = query.filter(PrintedItemTransaction.transactiondate >= cutoff)
+    query = query.group_by(PrintedItem.itemcode, PrintedItem.itemname)
+    rows = [{'itemcode': code, 'itemname': name, 'takes': takes,
+             'quantitytaken': int(taken)}
+            for code, name, takes, taken in query.all()]
+    rows.sort(key=lambda row: row['quantitytaken'], reverse=True)
+    columns = ['itemcode', 'itemname', 'takes', 'quantitytaken']
+    if request.args.get('format') == 'csv':
+        return _csv_response(rows, columns, 'printedparts-consumption.csv')
+    return success_response({'columns': columns, 'rows': rows, 'days': days})
+
+
+@printedparts_bp.route('/reports/by-person', methods=['GET'])
+@jwt_required(optional=True)
+def report_by_person():
+    """Takes grouped by employee, optionally bounded by ?days=<n> (default 30)."""
+    days = request.args.get('days', 30, type=int)
+    query = (db.session.query(
+                PrintedItemTransaction.employeesso,
+                func.max(PrintedItemTransaction.employeename),
+                func.count(PrintedItemTransaction.transactionid),
+                func.coalesce(func.sum(-PrintedItemTransaction.quantitychange), 0))
+             .filter(PrintedItemTransaction.transactiontype == 'take'))
+    if days > 0:
+        from datetime import datetime, timedelta, timezone
+        cutoff = datetime.now(timezone.utc).replace(tzinfo=None) - timedelta(days=days)
+        query = query.filter(PrintedItemTransaction.transactiondate >= cutoff)
+    query = query.group_by(PrintedItemTransaction.employeesso)
+    rows = [{'employeesso': sso, 'employeename': name or '', 'takes': takes,
+             'quantitytaken': int(taken)}
+            for sso, name, takes, taken in query.all()]
+    rows.sort(key=lambda row: row['quantitytaken'], reverse=True)
+    columns = ['employeesso', 'employeename', 'takes', 'quantitytaken']
+    if request.args.get('format') == 'csv':
+        return _csv_response(rows, columns, 'printedparts-by-person.csv')
+    return success_response({'columns': columns, 'rows': rows, 'days': days})

plugins/printedparts/plugin.py

@@ -62,6 +62,32 @@ class PrintedpartsPlugin(BasePlugin):
              'printedparts'),
         ]
 
+    def get_reports(self) -> List[dict]:
+        return [
+            {
+                'id': 'printedparts-stock',
+                'name': '3D Parts Stock',
+                'description': 'Stock levels with low-stock flags and the '
+                               'cache-vs-ledger reconcile check',
+                'category': 'inventory',
+                'endpoint': '/api/printedparts/reports/stock',
+            },
+            {
+                'id': 'printedparts-consumption',
+                'name': '3D Parts Consumption',
+                'description': 'Takes per item over a date range',
+                'category': 'usage',
+                'endpoint': '/api/printedparts/reports/consumption',
+            },
+            {
+                'id': 'printedparts-by-person',
+                'name': '3D Parts by Person',
+                'description': 'Takes grouped by employee',
+                'category': 'usage',
+                'endpoint': '/api/printedparts/reports/by-person',
+            },
+        ]
+
     def get_navigation_items(self) -> List[dict]:
         return [
             {