package rechargereward

import (
	"strings"
	"time"
)

type rechargeRewardPeriod struct {
	CycleKey     string
	RechargeDate int
	StartAt      time.Time
	EndAt        time.Time
}

func (s *Service) currentPeriod(now time.Time, location *time.Location) (rechargeRewardPeriod, bool) {
	startAt := rechargeRewardStartAt(s.cfg.RechargeReward.StartDate, location)
	return currentRechargeRewardPeriod(now, startAt, location)
}

func (s *Service) displayPeriod(now time.Time, location *time.Location) rechargeRewardPeriod {
	startAt := rechargeRewardStartAt(s.cfg.RechargeReward.StartDate, location)
	period, ok := currentRechargeRewardPeriod(now, startAt, location)
	if ok {
		return period
	}
	monthStart := time.Date(startAt.Year(), startAt.Month(), 1, 0, 0, 0, 0, location)
	return rechargeRewardPeriod{
		CycleKey:     startAt.Format("20060102"),
		RechargeDate: startAt.Year()*100 + int(startAt.Month()),
		StartAt:      startAt,
		EndAt:        monthStart.AddDate(0, 1, 0),
	}
}

func currentRechargeRewardPeriod(now time.Time, startAt time.Time, location *time.Location) (rechargeRewardPeriod, bool) {
	local := now.In(location)
	start := startAt.In(location)
	if local.Before(start) {
		return rechargeRewardPeriod{}, false
	}
	monthStart := time.Date(local.Year(), local.Month(), 1, 0, 0, 0, 0, location)
	periodStart := monthStart
	if periodStart.Before(start) {
		periodStart = start
	}
	periodEnd := monthStart.AddDate(0, 1, 0)
	if !local.Before(periodEnd) {
		return rechargeRewardPeriod{}, false
	}
	return rechargeRewardPeriod{
		CycleKey:     periodStart.Format("20060102"),
		RechargeDate: periodStart.Year()*100 + int(periodStart.Month()),
		StartAt:      periodStart,
		EndAt:        periodEnd,
	}, true
}

func rechargeRewardStartAt(raw string, location *time.Location) time.Time {
	value := strings.TrimSpace(raw)
	if value == "" {
		value = "2026-05-21"
	}
	parsed, err := time.ParseInLocation("2006-01-02", value, location)
	if err != nil {
		parsed, _ = time.ParseInLocation("2006-01-02", "2026-05-21", location)
	}
	return time.Date(parsed.Year(), parsed.Month(), parsed.Day(), 0, 0, 0, 0, location)
}

func rechargeRewardStorageTime(t time.Time, storageLocation *time.Location) string {
	if storageLocation == nil {
		storageLocation = t.Location()
	}
	return t.In(storageLocation).Format("2006-01-02 15:04:05")
}