package ana

import (
	"maps"
	"math"
	"regexp"
	"time"

	"gogs.inhome.blapointe.com/ana-ledger/ledger"
)

type Predictor func(ledger.Balances, time.Duration) ledger.Balances

func NewInterestPredictor(namePattern string, currencyPattern string, apy float64) Predictor {
	nameMatcher := regexp.MustCompile(namePattern)
	currencyMatcher := regexp.MustCompile(currencyPattern)
	return func(given ledger.Balances, delta time.Duration) ledger.Balances {
		result := maps.Clone(given)
		for k, v := range result {
			result[k] = maps.Clone(v)
		}

		for name := range result {
			if !nameMatcher.MatchString(name) {
				continue
			}
			for currency := range result[name] {
				if !currencyMatcher.MatchString(string(currency)) {
					continue
				}
				percentOfYearPassed := float64(delta) / float64(time.Hour*365)
				result[name][currency] *= math.Pow(1.0+apy/12.0, percentOfYearPassed)
			}
		}
		return result
	}
}