package notify

import (
	"context"
	"encoding/json"
	"strconv"
	"strings"

	iapmodel "github.com/perfect-panel/server/internal/model/iap/apple"
	"github.com/perfect-panel/server/internal/model/subscribe"
	"github.com/perfect-panel/server/internal/svc"
	"github.com/perfect-panel/server/internal/types"
	iapapple "github.com/perfect-panel/server/pkg/iap/apple"
	"github.com/perfect-panel/server/pkg/logger"
	"gorm.io/gorm"
)

// AppleIAPNotifyLogic 用于处理 App Store Server Notifications V2 的苹果内购通知
// 负责：JWS 验签、事务记录写入/撤销更新、订阅生命周期同步（续期/撤销等）
type AppleIAPNotifyLogic struct {
	logger.Logger
	ctx    context.Context
	svcCtx *svc.ServiceContext
}

// NewAppleIAPNotifyLogic 创建通知处理逻辑实例
// 参数：
// - ctx: 请求上下文
// - svcCtx: 服务上下文，包含 DB/Redis/配置 等
// 返回：
// - *AppleIAPNotifyLogic: 通知处理逻辑对象
func NewAppleIAPNotifyLogic(ctx context.Context, svcCtx *svc.ServiceContext) *AppleIAPNotifyLogic {
	return &AppleIAPNotifyLogic{
		Logger: logger.WithContext(ctx),
		ctx:    ctx,
		svcCtx: svcCtx,
	}
}

// Handle 处理苹果内购通知
// 流程：
// 1. 验签通知信封，解析得到交易 JWS 并再次验签；
// 2. 写入或更新事务记录（幂等按 OriginalTransactionId）；
// 3. 依据产品映射更新订阅到期时间或撤销状态；
// 4. 全流程关键节点输出详细中文日志，便于定位问题。
// 参数：
// - signedPayload: 通知信封的 JWS（包含 data.signedTransactionInfo）
// 返回：
// - error: 处理失败错误，成功返回 nil
func (l *AppleIAPNotifyLogic) Handle(signedPayload string) error {
	txPayload, ntype, err := iapapple.VerifyNotificationSignedPayload(signedPayload)
	if err != nil {
		// 验签失败，记录错误以便排查（通常为 JWS 格式/证书链问题）
		l.Errorw("iap notify verify failed", logger.Field("error", err.Error()))
		return err
	}
	// 验签通过，记录通知类型与关键交易标识
	l.Infow("iap notify verified", logger.Field("type", ntype), logger.Field("productId", txPayload.ProductId), logger.Field("originalTransactionId", txPayload.OriginalTransactionId))
	return l.svcCtx.DB.Transaction(func(db *gorm.DB) error {
		var existing *iapmodel.Transaction
		existing, _ = iapmodel.NewModel(l.svcCtx.DB, l.svcCtx.Redis).FindByOriginalId(l.ctx, txPayload.OriginalTransactionId)
		if existing == nil || existing.Id == 0 {
			// 首次出现该事务，写入记录
			rec := &iapmodel.Transaction{
				UserId:                0,
				OriginalTransactionId: txPayload.OriginalTransactionId,
				TransactionId:         txPayload.TransactionId,
				ProductId:             txPayload.ProductId,
				PurchaseAt:            txPayload.PurchaseDate,
				RevocationAt:          txPayload.RevocationDate,
				JWSHash:               "",
			}
			if e := db.Model(&iapmodel.Transaction{}).Create(rec).Error; e != nil {
				// 事务写入失败（唯一约束/字段问题），输出详细日志
				l.Errorw("iap notify insert transaction error", logger.Field("error", e.Error()), logger.Field("productId", txPayload.ProductId), logger.Field("originalTransactionId", txPayload.OriginalTransactionId))
				return e
			}
		} else {
			if txPayload.RevocationDate != nil {
				// 撤销场景：更新 revocation_at
				if e := db.Model(&iapmodel.Transaction{}).
					Where("original_transaction_id = ?", txPayload.OriginalTransactionId).
					Update("revocation_at", txPayload.RevocationDate).Error; e != nil {
					// 撤销更新失败，记录日志
					l.Errorw("iap notify update revocation error", logger.Field("error", e.Error()), logger.Field("originalTransactionId", txPayload.OriginalTransactionId))
					return e
				}
			}
		}
		var days int64
		{
			pid := strings.ToLower(txPayload.ProductId)
			parts := strings.Split(pid, ".")
			for i := len(parts) - 1; i >= 0; i-- {
				p := parts[i]
				var unit string
				if strings.HasPrefix(p, "day") {
					unit = "Day"
					p = p[len("day"):]
				} else if strings.HasPrefix(p, "month") {
					unit = "Month"
					p = p[len("month"):]
				} else if strings.HasPrefix(p, "year") {
					unit = "Year"
					p = p[len("year"):]
				}
				if unit != "" {
					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 {
						switch unit {
						case "Day":
							days = q
						case "Month":
							days = q * 30
						case "Year":
							days = q * 365
						}
						break
					}
				}
			}
		}
		if days == 0 {
			_, subs, e := l.svcCtx.SubscribeModel.FilterList(l.ctx, &subscribe.FilterParams{
				Page:            1,
				Size:            9999,
				Show:            true,
				Sell:            true,
				DefaultLanguage: true,
			})
			if e == nil && len(subs) > 0 {
				for _, item := range subs {
					var discounts []types.SubscribeDiscount
					if item.Discount != "" {
						_ = json.Unmarshal([]byte(item.Discount), &discounts)
					}
					for _, d := range discounts {
						if strings.Contains(strings.ToLower(txPayload.ProductId), strings.ToLower(item.UnitTime)) && d.Quantity > 0 {
							// fallback not strict
							if item.UnitTime == "Day" {
								days = int64(d.Quantity)
							} else if item.UnitTime == "Month" {
								days = int64(d.Quantity) * 30
							} else if item.UnitTime == "Year" {
								days = int64(d.Quantity) * 365
							}
							break
						}
					}
					if days > 0 {
						break
					}
				}
			}
		}
		if days == 0 {
			l.Errorw("iap notify product mapping missing", logger.Field("productId", txPayload.ProductId))
		}
		token := "iap:" + txPayload.OriginalTransactionId
		sub, e := l.svcCtx.UserModel.FindOneSubscribeByToken(l.ctx, token)
		if e == nil && sub != nil && sub.Id != 0 {
			if txPayload.RevocationDate != nil {
				// 撤销：订阅置为过期并记录完成时间
				sub.Status = 3
				t := *txPayload.RevocationDate
				sub.FinishedAt = &t
				sub.ExpireTime = t
			} else if days > 0 {
				// 正常：根据映射天数续期
				exp := iapapple.CalcExpire(txPayload.PurchaseDate, days)
				sub.ExpireTime = exp
				sub.Status = 1
			}
			if e := l.svcCtx.UserModel.UpdateSubscribe(l.ctx, sub, db); e != nil {
				// 订阅更新失败，记录日志
				l.Errorw("iap notify update subscribe error", logger.Field("error", e.Error()), logger.Field("userSubscribeId", sub.Id))
				return e
			}
			// 更新成功，输出订阅状态
			l.Infow("iap notify updated subscribe", logger.Field("userSubscribeId", sub.Id), logger.Field("status", sub.Status))
		}
		return nil
	})
}