完善采购审批流程、企业微信通知和采购专用章

po_app/money.py

@@ -0,0 +1,37 @@
+"""Exact fixed point arithmetic shared by persistence, forms and PDF output."""
+from decimal import Decimal, InvalidOperation, ROUND_HALF_UP
+
+ZERO = Decimal('0')
+CENT = Decimal('0.01')
+UNIT = Decimal('0.0001')
+MAX_VALUE = Decimal('999999999')
+MAX_TOTAL = Decimal('999999999999.99')
+
+
+def number(value, label='数值', allow_zero=True):
+    try:
+        result = Decimal(str(value if value not in (None, '') else 0).strip())
+    except (InvalidOperation, ValueError):
+        raise ValueError('%s必须是有效数字' % label)
+    if not result.is_finite() or result < 0 or result > MAX_VALUE:
+        raise ValueError('%s必须在 0 到 %s 之间' % (label, MAX_VALUE))
+    if result != result.quantize(UNIT):
+        raise ValueError('%s最多保留四位小数' % label)
+    if not allow_zero and result == 0:
+        raise ValueError('%s必须大于零' % label)
+    return result.quantize(UNIT)
+
+
+def money(value):
+    return Decimal(str(value or 0)).quantize(CENT, rounding=ROUND_HALF_UP)
+
+
+def line_amount(qty, price):
+    amount = money(number(qty, '数量') * number(price, '单价'))
+    if amount > MAX_TOTAL:
+        raise ValueError('明细金额过大')
+    return amount
+
+
+def format_price(value):
+    return format(Decimal(str(value or 0)), '.4f').rstrip('0').rstrip('.') or '0'