package rechargereward

import (
	"fmt"
	"strconv"
	"strings"
)

func parseAmountCents(raw string) (int64, error) {
	raw = strings.TrimSpace(raw)
	if raw == "" {
		return 0, nil
	}
	raw = strings.ReplaceAll(raw, ",", "")
	if strings.HasPrefix(raw, "+") {
		raw = strings.TrimPrefix(raw, "+")
	}
	if strings.HasPrefix(raw, "-") {
		return 0, fmt.Errorf("amount must be non-negative")
	}

	parts := strings.Split(raw, ".")
	if len(parts) > 2 {
		return 0, fmt.Errorf("invalid amount")
	}
	integerPart := strings.TrimSpace(parts[0])
	if integerPart == "" {
		integerPart = "0"
	}
	for _, ch := range integerPart {
		if ch < '0' || ch > '9' {
			return 0, fmt.Errorf("invalid amount")
		}
	}
	dollars, err := strconv.ParseInt(integerPart, 10, 64)
	if err != nil {
		return 0, err
	}
	centsPart := "00"
	if len(parts) == 2 {
		fraction := strings.TrimSpace(parts[1])
		for _, ch := range fraction {
			if ch < '0' || ch > '9' {
				return 0, fmt.Errorf("invalid amount")
			}
		}
		if len(fraction) == 1 {
			centsPart = fraction + "0"
		} else if len(fraction) >= 2 {
			centsPart = fraction[:2]
		}
	}
	cents, err := strconv.ParseInt(centsPart, 10, 64)
	if err != nil {
		return 0, err
	}
	return dollars*100 + cents, nil
}

func parseIntegrationAmountCents(value integrationAmount) int64 {
	cents, err := parseAmountCents(string(value))
	if err != nil {
		return 0
	}
	return cents
}

func formatAmountCents(cents int64) string {
	if cents < 0 {
		cents = 0
	}
	return fmt.Sprintf("%d.%02d", cents/100, cents%100)
}

type integrationAmount string