package ledger

import (
	"time"

	"github.com/howeyc/ledger"
)

type Currency string

const (
	USD = Currency("$")
)

type Delta struct {
	Date     time.Time
	Account  string
	Value    float64
	Currency Currency
}

func newDeltas(t *ledger.Transaction) []Delta {
	result := make([]Delta, len(t.AccountChanges))
	for i, a := range t.AccountChanges {
		result[i] = newDelta(t.Date, a)
	}
	return result
}

func newDelta(d time.Time, a ledger.Account) Delta {
	value, _ := a.Balance.Float64()
	return Delta{
		Date:     d,
		Account:  a.Name,
		Value:    value,
		Currency: USD, // TODO
	}
}

func (delta Delta) Plus(other Delta) Delta {
	return Delta{
		Date:     other.Date,
		Account:  delta.Account,
		Value:    delta.Value + other.Value,
		Currency: other.Currency,
	}
}