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
}