package apple

import (
	"encoding/json"
	"strconv"
	"strings"
	"time"
)

type ProductMapping struct {
	DurationDays int64  `json:"durationDays"`
	Tier         string `json:"tier"`
	Description  string `json:"description"`
	PriceText    string `json:"priceText"`
	SubscribeId  int64  `json:"subscribeId"`
}

type ProductMap struct {
	Items map[string]ProductMapping `json:"iapProductMap"`
}

func ParseProductMap(customData string) (*ProductMap, error) {
	if customData == "" {
		return &ProductMap{Items: map[string]ProductMapping{}}, nil
	}
	var obj ProductMap
	if err := json.Unmarshal([]byte(customData), &obj); err != nil {
		return &ProductMap{Items: map[string]ProductMapping{}}, nil
	}
	if obj.Items == nil {
		obj.Items = map[string]ProductMapping{}
	}
	return &obj, nil
}

func CalcExpire(start time.Time, days int64) time.Time {
	if days <= 0 {
		return time.UnixMilli(0)
	}
	return start.Add(time.Duration(days) * 24 * time.Hour)
}

// ParsedProduct holds the result of parsing an Apple product ID.
type ParsedProduct struct {
	Unit     string // "Day", "Month", "Year"
	Quantity int64
}

// ParseProductIdDuration extracts time unit and quantity from Apple product IDs.
// e.g. "com.app.vip.day30" -> {Unit: "Day", Quantity: 30}
func ParseProductIdDuration(productId string) *ParsedProduct {
	pid := strings.ToLower(productId)
	parts := strings.Split(pid, ".")
	for i := len(parts) - 1; i >= 0; i-- {
		p := parts[i]
		var unit string
		switch {
		case strings.HasPrefix(p, "day"):
			unit = "Day"
			p = p[len("day"):]
		case strings.HasPrefix(p, "month"):
			unit = "Month"
			p = p[len("month"):]
		case strings.HasPrefix(p, "year"):
			unit = "Year"
			p = p[len("year"):]
		default:
			continue
		}
		digits := p
		for j := 0; j < len(digits); j++ {
			if digits[j] < '0' || digits[j] > '9' {
				digits = digits[:j]
				break
			}
		}
		if q, e := strconv.ParseInt(digits, 10, 64); e == nil && q > 0 {
			return &ParsedProduct{Unit: unit, Quantity: q}
		}
	}
	return nil
}