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)
		}

		monthsPassed := float64(delta) / float64(time.Hour*24.0*365.0/12.0)
		scalar := math.Pow(1.0+apy/12.0, monthsPassed)
		for name := range result {
			if !nameMatcher.MatchString(name) {
				continue
			}
			for currency := range result[name] {
				if !currencyMatcher.MatchString(string(currency)) {
					continue
				}
				result[name][currency] *= scalar
			}
		}
		return result
	}
}

func NewContributionPredictor(reg ledger.Register) Predictor {
	monthlyRate := getMonthlyContributionRate(reg)
	_ = monthlyRate
	return func(given ledger.Balances, delta time.Duration) ledger.Balances {
		panic(nil)
	}
}

func getMonthlyContributionRate(reg ledger.Register) map[string]ledger.Balance {
	panic(nil)
}

func getRecentContributions(reg ledger.Register) map[string][]ledger.Balance {
	return getContributions(reg.Between(time.Now().Add(-1*time.Hour*365/2), time.Now()))
}

func getContributions(reg ledger.Register) map[string][]ledger.Balance {
	contributions := make(map[string][]ledger.Balance)
	for _, date := range reg.Dates() {
		for name := range reg[date] {
			contributions[name] = append(contributions[name], maps.Clone(reg[date][name]))
			if a := contributions[name]; len(a) > 1 {
				for k := range a[len(a)-2] {
					a[len(a)-1][k] -= a[len(a)-2][k]
				}
			}
		}
	}
	return contributions
}