Merge pull request #201 from invopop/rounding-simplified

Removing total calculator option, increasing accuracy in line calculations

bill/invoice.go

@@ -420,9 +420,6 @@ func (inv *Invoice) calculate(r *tax.Regime, tID *tax.Identity) error {
 		Lines:    tls,
 		Includes: pit,
 	}
-	if inv.Tax != nil {
-		tc.Calculator = inv.Tax.Calculator
-	}
 	if err := tc.Calculate(t.Taxes); err != nil {
 		return err
 	}

bill/invoice_test.go

@@ -165,7 +165,6 @@ func TestRemoveIncludedTax2(t *testing.T) {
 		Code: "123TEST",
 		Tax: &bill.Tax{
 			PricesInclude: common.TaxCategoryVAT,
-			Calculator:    tax.TotalCalculatorLine,
 		},
 		Supplier: &org.Party{
 			TaxID: &tax.Identity{
@@ -230,7 +229,6 @@ func TestRemoveIncludedTax3(t *testing.T) {
 		Code: "123TEST",
 		Tax: &bill.Tax{
 			PricesInclude: common.TaxCategoryVAT,
-			Calculator:    tax.TotalCalculatorLine,
 		},
 		Supplier: &org.Party{
 			TaxID: &tax.Identity{
@@ -496,7 +494,6 @@ func TestRemoveIncludedTaxDeep(t *testing.T) {
 		Code: "123TEST",
 		Tax: &bill.Tax{
 			PricesInclude: common.TaxCategoryVAT,
-			Calculator:    tax.TotalCalculatorLine,
 		},
 		Supplier: &org.Party{
 			TaxID: &tax.Identity{
@@ -628,6 +625,63 @@ func TestRemoveIncludedTaxDeep2(t *testing.T) {
 	assert.Equal(t, i.Totals.Payable.String(), i2.Totals.Payable.String())
 }
 
+func TestCalculateTotalsWithFractions(t *testing.T) {
+	i := &bill.Invoice{
+		Code: "123TEST",
+		Supplier: &org.Party{
+			TaxID: &tax.Identity{
+				Country: l10n.ES,
+				Code:    "B98602642",
+			},
+		},
+		Customer: &org.Party{
+			TaxID: &tax.Identity{
+				Country: l10n.ES,
+				Code:    "54387763P",
+			},
+		},
+		IssueDate: cal.MakeDate(2022, 6, 13),
+		Lines: []*bill.Line{
+			{
+				Quantity: num.MakeAmount(2010, 2),
+				Item: &org.Item{
+					Name:  "Test Item",
+					Price: num.MakeAmount(305, 2),
+				},
+				Taxes: tax.Set{
+					{
+						Category: "VAT",
+						Percent:  num.NewPercentage(230, 3),
+					},
+				},
+			},
+			{
+				Quantity: num.MakeAmount(2010, 2),
+				Item: &org.Item{
+					Name:  "Test Item 2",
+					Price: num.MakeAmount(305, 2),
+				},
+				Taxes: tax.Set{
+					{
+						Category: "VAT",
+						Percent:  num.NewPercentage(230, 3),
+					},
+				},
+			},
+		},
+	}
+
+	require.NoError(t, i.Calculate())
+
+	//data, _ := json.MarshalIndent(i, "", "  ")
+	//t.Log(string(data))
+
+	l0 := i.Lines[0]
+	assert.Equal(t, "3.05", l0.Item.Price.String())
+	assert.Equal(t, "61.31", l0.Sum.String())
+	assert.Equal(t, "122.61", i.Totals.Total.String())
+}
+
 func TestCalculate(t *testing.T) {
 	i := &bill.Invoice{
 		Code: "123TEST",
@@ -753,7 +807,6 @@ func baseInvoice(t *testing.T, lines ...*bill.Line) *bill.Invoice {
 		Code: "123TEST",
 		Tax: &bill.Tax{
 			PricesInclude: common.TaxCategoryVAT,
-			Calculator:    tax.TotalCalculatorLine,
 		},
 		Supplier: &org.Party{
 			TaxID: &tax.Identity{

bill/line.go

@@ -35,6 +35,9 @@ type Line struct {
 	// Set of specific notes for this line that may be required for
 	// clarification.
 	Notes []*cbc.Note `json:"notes,omitempty" jsonschema:"title=Notes"`
+
+	// internal amount provided with greater precision
+	total num.Amount
 }
 
 // GetTaxes responds with the array of tax rates applied to this line.
@@ -44,7 +47,7 @@ func (l *Line) GetTaxes() tax.Set {
 
 // GetTotal provides the final total for this line, excluding any tax calculations.
 func (l *Line) GetTotal() num.Amount {
-	return l.Total
+	return l.total
 }
 
 // ValidateWithContext ensures the line contains everything required using
@@ -79,26 +82,34 @@ func (l *Line) calculate(r *tax.Regime, zero num.Amount) error {
 
 	// Ensure the Price precision is set correctly according to the currency
 	l.Item.Price = l.Item.Price.MatchPrecision(zero)
+	price := l.Item.Price.RescaleUp(zero.Exp() + 2)
 
 	// Calculate the line sum and total
-	l.Sum = l.Item.Price.Multiply(l.Quantity)
-	l.Total = l.Sum
+	l.Sum = price.Multiply(l.Quantity)
+	l.total = l.Sum
 
 	for _, d := range l.Discounts {
 		if d.Percent != nil && !d.Percent.IsZero() {
 			d.Amount = d.Percent.Of(l.Sum) // always override
 		}
 		d.Amount = d.Amount.MatchPrecision(zero)
-		l.Total = l.Total.Subtract(d.Amount)
+		l.total = l.total.Subtract(d.Amount)
+		d.Amount = d.Amount.Rescale(l.Item.Price.Exp())
 	}
 
 	for _, c := range l.Charges {
 		if c.Percent != nil && !c.Percent.IsZero() {
 			c.Amount = c.Percent.Of(l.Sum) // always override
 		}
 		c.Amount = c.Amount.MatchPrecision(zero)
-		l.Total = l.Total.Add(c.Amount)
+		l.total = l.total.Add(c.Amount)
+		c.Amount = c.Amount.Rescale(l.Item.Price.Exp())
 	}
+
+	// Rescale the final sum and total
+	l.Sum = l.Sum.Rescale(l.Item.Price.Exp())
+	l.Total = l.total.Rescale(l.Item.Price.Exp())
+
 	return nil
 }
 
@@ -152,8 +163,8 @@ func calculateLines(r *tax.Regime, zero num.Amount, lines []*Line) error {
 func calculateLineSum(zero num.Amount, lines []*Line) num.Amount {
 	sum := zero
 	for _, l := range lines {
-		sum = sum.MatchPrecision(l.Total)
-		sum = sum.Add(l.Total)
+		sum = sum.MatchPrecision(l.total)
+		sum = sum.Add(l.total)
 	}
 	return sum
 }

bill/payment.go

@@ -54,6 +54,7 @@ func (p *Payment) totalAdvance(zero num.Amount) *num.Amount {
 	sum := zero
 	for _, a := range p.Advances {
 		sum = sum.Add(a.Amount)
+		a.Amount = a.Amount.Rescale(zero.Exp())
 	}
 	return &sum
 }

bill/payment_test.go

@@ -33,6 +33,8 @@ func TestPaymentCalculations(t *testing.T) {
 	assert.Equal(t, "10", p.Advances[0].Amount.String())
 	p.calculateAdvances(zero, total)
 	assert.Equal(t, "10.00", p.Advances[0].Amount.String())
+	ta := p.totalAdvance(zero)
+	assert.Equal(t, "10.00", ta.String())
 
 	p = &Payment{
 		Advances: []*pay.Advance{

bill/tax.go

@@ -5,9 +5,7 @@ import (
 	"errors"
 
 	"github.com/invopop/gobl/cbc"
-	"github.com/invopop/gobl/i18n"
 	"github.com/invopop/gobl/tax"
-	"github.com/invopop/jsonschema"
 	"github.com/invopop/validation"
 )
 
@@ -25,10 +23,6 @@ type Tax struct {
 	// Special tax tags that apply to this invoice according to local requirements.
 	Tags []cbc.Key `json:"tags,omitempty" jsonschema:"title=Tags"`
 
-	// Calculator defines the rule to use when calculating the taxes.
-	// Currently supported options: `line`, or `total` (default).
-	Calculator cbc.Key `json:"calculator,omitempty" jsonschema:"title=Calculator"`
-
 	// Any additional data that may be required for processing, but should never
 	// be relied upon by recipients.
 	Meta cbc.Meta `json:"meta,omitempty" jsonschema:"title=Meta"`
@@ -51,23 +45,6 @@ func (t *Tax) ValidateWithContext(ctx context.Context) error {
 	return validation.ValidateStructWithContext(ctx, t,
 		validation.Field(&t.PricesInclude),
 		validation.Field(&t.Tags, validation.Each(r.InTags())),
-		validation.Field(&t.Calculator, tax.InKeyDefs(tax.TotalCalculatorDefs)),
 		validation.Field(&t.Meta),
 	)
 }
-
-// JSONSchemaExtend extends the schema with additional property details
-func (Tax) JSONSchemaExtend(schema *jsonschema.Schema) {
-	props := schema.Properties
-	if val, ok := props.Get("calculator"); ok {
-		its := val.(*jsonschema.Schema)
-		its.OneOf = make([]*jsonschema.Schema, len(tax.TotalCalculatorDefs))
-		for i, v := range tax.TotalCalculatorDefs {
-			its.OneOf[i] = &jsonschema.Schema{
-				Const:       v.Key.String(),
-				Title:       v.Name.String(i18n.EN),
-				Description: v.Desc.String(i18n.EN),
-			}
-		}
-	}
-}

bill/tax_test.go

@@ -25,15 +25,4 @@ func TestTaxValidation(t *testing.T) {
 	err = tx.ValidateWithContext(ctx)
 	require.Error(t, err)
 	assert.Contains(t, err.Error(), "must be a valid value")
-
-	tx = &bill.Tax{
-		Calculator: "line",
-	}
-	err = tx.ValidateWithContext(ctx)
-	require.NoError(t, err)
-
-	tx.Calculator = "invalid"
-	err = tx.ValidateWithContext(ctx)
-	require.Error(t, err)
-	assert.Contains(t, err.Error(), "calculator: must be a valid value")
 }

pay/terms.go

@@ -105,7 +105,7 @@ func (t *Terms) CalculateDues(zero num.Amount, sum num.Amount) {
 		if dd.Percent != nil && !dd.Percent.IsZero() {
 			dd.Amount = dd.Percent.Of(sum)
 		}
-		dd.Amount = dd.Amount.MatchPrecision(zero)
+		dd.Amount = dd.Amount.Rescale(zero.Exp())
 	}
 }
 

regimes/co/co.go

@@ -44,6 +44,7 @@ func New() *tax.Regime {
 			`),
 		},
 		TimeZone:         "America/Bogota",
+		Tags:             invoiceTags,
 		Validator:        Validate,
 		Calculator:       Calculate,
 		IdentityTypeKeys: taxIdentityTypeDefs, // see tax_identity.go

regimes/co/examples/out/simplified.json

@@ -0,0 +1,85 @@
+{
+	"$schema": "https://gobl.org/draft-0/envelope",
+	"head": {
+		"uuid": "8a51fd30-2a27-11ee-be56-0242ac120002",
+		"dig": {
+			"alg": "sha256",
+			"val": "2346991aab5ee704bd2b0ad14a06260aaf81fa7baca32c2bcd211cbc177aa6a2"
+		},
+		"draft": true
+	},
+	"doc": {
+		"$schema": "https://gobl.org/draft-0/bill/invoice",
+		"type": "standard",
+		"series": "SETT",
+		"code": "1234",
+		"issue_date": "2021-01-01",
+		"currency": "COP",
+		"tax": {
+			"tags": [
+				"simplified"
+			]
+		},
+		"supplier": {
+			"name": "EXAMPLE SUPPLIER S.A.S.",
+			"tax_id": {
+				"country": "CO",
+				"zone": "11001",
+				"type": "tin",
+				"code": "9014514812"
+			}
+		},
+		"lines": [
+			{
+				"i": 1,
+				"quantity": "1",
+				"item": {
+					"name": "Useful service",
+					"price": "200000.00"
+				},
+				"sum": "200000.00",
+				"taxes": [
+					{
+						"cat": "VAT",
+						"percent": "19%"
+					}
+				],
+				"total": "200000.00"
+			}
+		],
+		"payment": {
+			"advances": [
+				{
+					"desc": "Prepaid",
+					"percent": "100%",
+					"amount": "238000.00"
+				}
+			]
+		},
+		"totals": {
+			"sum": "200000.00",
+			"total": "200000.00",
+			"taxes": {
+				"categories": [
+					{
+						"code": "VAT",
+						"rates": [
+							{
+								"base": "200000.00",
+								"percent": "19%",
+								"amount": "38000.00"
+							}
+						],
+						"amount": "38000.00"
+					}
+				],
+				"sum": "38000.00"
+			},
+			"tax": "38000.00",
+			"total_with_tax": "238000.00",
+			"payable": "238000.00",
+			"advance": "238000.00",
+			"due": "0.00"
+		}
+	}
+}

regimes/co/examples/simplified.json

@@ -0,0 +1,41 @@
+{
+  "$schema": "https://gobl.org/draft-0/bill/invoice",
+  "code": "1234",
+  "series": "SETT",
+  "currency": "COP",
+  "issue_date": "2021-01-01",
+  "tax": {
+    "tags": ["simplified"]
+  },
+  "supplier": {
+    "tax_id": {
+      "country": "CO",
+      "code": "9014514812",
+      "zone": "11001"
+    },
+    "name": "EXAMPLE SUPPLIER S.A.S."
+  },
+  "lines": [
+    {
+      "quantity": "1",
+      "item": {
+        "name": "Useful service",
+        "price": "200000.00"
+      },
+      "taxes": [
+        {
+          "cat": "VAT",
+          "percent": "19%"
+        }
+      ]
+    }
+  ],
+  "payment": {
+    "advances": [
+      {
+        "desc": "Prepaid",
+        "percent": "100%"
+      }
+    ]
+  }
+}