adding revenue

internal/model/revenue.go

@@ -0,0 +1,69 @@
+package model
+
+import "time"
+
+// PeriodType defines the granularity of the revenue entry
+type PeriodType string
+
+const (
+	PeriodQuarter  PeriodType = "Q"
+	PeriodHalfYear PeriodType = "H"
+	PeriodYear     PeriodType = "Y"
+)
+
+// Period holds the actual time range for a revenue entry
+type Period struct {
+	Type  PeriodType
+	Year  int
+	Index int // Q1=1 Q2=2 Q3=3 Q4=4 | H1=1 H2=2 | FY=1
+	Start time.Time
+	End   time.Time
+}
+
+// RevenueCategory is what the revenue is broken down by
+type RevenueCategory string
+
+const (
+	CategoryProduct  RevenueCategory = "product"
+	CategoryLocation RevenueCategory = "location"
+	CategoryTotal    RevenueCategory = "total"
+)
+
+// Revenue is a single line in a financial report
+type Revenue struct {
+	ID       int
+	Company  *Company
+	Currency *Currency
+	Category RevenueCategory
+	Label    string // e.g. "North America", "iPhone", "Total"
+	Value    float64
+	Period   Period
+}
+
+// RevenueReport groups revenue lines for a company/period
+// and verifies that sub-categories sum to total
+type RevenueReport struct {
+	Company *Company
+	Period  Period
+	Entries []Revenue
+}
+
+// Total returns the sum of all entries matching a category
+func (r *RevenueReport) Total(category RevenueCategory) float64 {
+	var sum float64
+	for _, e := range r.Entries {
+		if e.Category == category {
+			sum += e.Value
+		}
+	}
+	return sum
+}
+
+// Validate checks that product + location sums match the total entry
+func (r *RevenueReport) Validate() (bool, float64, float64) {
+	total := r.Total(CategoryTotal)
+	products := r.Total(CategoryProduct)
+	locations := r.Total(CategoryLocation)
+	// both breakdowns should equal the total
+	return products == total && locations == total, products, locations
+}