package utils

import (
	"errors"
	"strings"
	"time"
)

// ParseDateString mengubah string "YYYY-MM-DD" menjadi time.Time
func ParseDateString(dateStr string) (time.Time, error) {
	if dateStr == "" {
		return time.Time{}, errors.New("date string is empty")
	}

	parsed, err := time.Parse("2006-01-02", dateStr)
	if err != nil {
		return time.Time{}, errors.New("invalid date format, expected YYYY-MM-DD")
	}

	return parsed, nil
}

// FormatDate mengubah time.Time menjadi string "YYYY-MM-DD"
func FormatDate(t time.Time) string {
	return t.Format("2006-01-02")
}

// ParseDateRangeForQuery parses optional YYYY-MM-DD from/to strings for list filters.
// It returns a start pointer (inclusive) and an end pointer advanced by one day
// so callers can safely use "< end" to achieve an inclusive upper bound.
func ParseDateRangeForQuery(fromStr, toStr string) (*time.Time, *time.Time, error) {
	var fromPtr *time.Time
	var toPtr *time.Time

	if strings.TrimSpace(fromStr) != "" {
		parsed, err := ParseDateString(strings.TrimSpace(fromStr))
		if err != nil {
			return nil, nil, errors.New("created_from must use format YYYY-MM-DD")
		}
		fromValue := parsed
		fromPtr = &fromValue
	}

	if strings.TrimSpace(toStr) != "" {
		parsed, err := ParseDateString(strings.TrimSpace(toStr))
		if err != nil {
			return nil, nil, errors.New("created_to must use format YYYY-MM-DD")
		}
		nextDay := parsed.AddDate(0, 0, 1)
		toPtr = &nextDay
	}

	if fromPtr != nil && toPtr != nil && fromPtr.After(*toPtr) {
		return nil, nil, errors.New("created_from must be earlier than created_to")
	}

	return fromPtr, toPtr, nil
}