package productser

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"errors"
	"fmt"
	"strings"
	"time"

	"91porn-server/app/appg"
	"91porn-server/app/service/mediacontentser"

	"91porn-server/common/db"
	"91porn-server/common/log"
	redisutil "91porn-server/common/redis"
	"91porn-server/common/stderr"
	"91porn-server/middleware/ua"
	"91porn-server/models/v/media_buy_record_mod"
	"91porn-server/models/v/mediacontentmod"
	"91porn-server/models/v/mediamod"
	"91porn-server/models/v/txnmod"
	"91porn-server/models/v/usermod"
	"91porn-server/models/v/walletmod"

	"go.mongodb.org/mongo-driver/bson/primitive"
)

const (
	dramaBuyRequestTTL = 24 * time.Hour
	dramaBuyLockTTL    = 2 * time.Minute
)

var errDramaAlreadyBought = errors.New("drama episode already bought")

var releaseDramaBuyLockScript = redisutil.NewScript(`
if redis.call('GET', KEYS[1]) ~= ARGV[1] then
  return 0
end
return redis.call('DEL', KEYS[1])
`)

type BuyDramaEpisodeResponse struct {
	OrderID     primitive.ObjectID `json:"orderId"`
	MediaID     primitive.ObjectID `json:"mediaId"`
	ContentID   primitive.ObjectID `json:"contentId"`
	AccessType  string             `json:"accessType"`
	CanPlay     bool               `json:"canPlay"`
	PaidCoin    int64              `json:"paidCoin"`
	CoinBalance int64              `json:"coinBalance"`
}

func BuyDramaEpisode(
	uid uint64,
	mediaID, contentID primitive.ObjectID,
	checkoutContextID, requestID string,
	uaInfo ua.UA,
	ip string,
) (BuyDramaEpisodeResponse, stderr.Code) {
	requestID = strings.TrimSpace(requestID)
	checkoutContextID = strings.TrimSpace(checkoutContextID)
	if requestID == "" || len(requestID) > 128 || contentID.IsZero() || mediaID.IsZero() ||
		!strings.HasPrefix(checkoutContextID, "drama-checkout-") {
		return BuyDramaEpisodeResponse{}, stderr.ErrParamError
	}
	media, err := mediamod.GetInfo(mediaID)
	if err != nil || media.ID.IsZero() || media.MediaType != mediamod.MediaTypeDrama || media.Status != 1 || media.IsDelete {
		return BuyDramaEpisodeResponse{}, stderr.InvalidProduct
	}
	content, err := mediacontentmod.GetInfo(contentID, true)
	if err != nil || content.ID.IsZero() || content.MediaID != mediaID || content.MediaType != mediamod.MediaTypeDrama || content.IsDelete {
		return BuyDramaEpisodeResponse{}, stderr.InvalidProduct
	}
	if bought, buyErr := media_buy_record_mod.IsBuy(uid, mediaID, contentID); buyErr != nil {
		return BuyDramaEpisodeResponse{}, stderr.PayBusy
	} else if bought {
		return BuyDramaEpisodeResponse{}, stderr.RepeatPurchase
	}
	hasCard, cardErr := mediacontentser.ActiveDramaCardStatus(uid)
	if cardErr != nil {
		return BuyDramaEpisodeResponse{}, stderr.PayBusy
	}
	isFree, canPlay, accessType := mediacontentser.ResolveDramaAccess(content, media, false, hasCard)
	if isFree || (canPlay && accessType == "card") {
		return BuyDramaEpisodeResponse{}, stderr.RepeatPurchase
	}
	if content.Price <= 0 {
		return BuyDramaEpisodeResponse{}, stderr.InvalidProduct
	}
	wallet, err := walletmod.GetWallet(uid)
	if err != nil || wallet == nil || wallet.ID.IsZero() {
		return BuyDramaEpisodeResponse{}, stderr.PayBusy
	}
	plan := debitPlan(wallet, content.Price)
	if plan == nil {
		return BuyDramaEpisodeResponse{}, stderr.InsufficientBalance
	}
	user, err := usermod.FindUserByUID(uid)
	if err != nil || user == nil {
		return BuyDramaEpisodeResponse{}, stderr.PayBusy
	}
	if appg.Redis == nil {
		return BuyDramaEpisodeResponse{}, stderr.PayBusy
	}
	requestKey := dramaBuyKey("request", uid, requestID)
	requestAcquired, err := appg.Redis.SetNX(requestKey, "1", dramaBuyRequestTTL)
	if err != nil {
		return BuyDramaEpisodeResponse{}, stderr.PayBusy
	}
	if !requestAcquired {
		if bought, _ := media_buy_record_mod.IsBuy(uid, mediaID, contentID); bought {
			return BuyDramaEpisodeResponse{}, stderr.RepeatPurchase
		}
		return BuyDramaEpisodeResponse{}, stderr.PayBusy
	}
	lockKey := dramaBuyKey("episode", uid, contentID.Hex())
	lockAcquired, err := appg.Redis.SetNX(lockKey, requestID, dramaBuyLockTTL)
	if err != nil || !lockAcquired {
		_, _ = appg.Redis.Del(requestKey)
		return BuyDramaEpisodeResponse{}, stderr.PayBusy
	}
	defer releaseDramaBuyLock(lockKey, requestID)

	orderID := primitive.NewObjectID()
	createdAt := time.Now()
	balanceBefore := wallet.Amount + wallet.Income
	balanceAfter := balanceBefore
	err = appg.VideoDB.Trans(func(t *db.MongoTool) error {
		alreadyBought, checkErr := media_buy_record_mod.IsBuyWithTool(t, uid, mediaID, contentID)
		if checkErr != nil {
			return checkErr
		}
		if alreadyBought {
			return errDramaAlreadyBought
		}
		updatedWallet, debitErr := walletmod.Debit(t, plan, uid)
		if debitErr != nil {
			return debitErr
		}
		balanceAfter = updatedWallet.Amount + updatedWallet.Income
		record := &media_buy_record_mod.MediaBuyRecord{
			ID: orderID, MediaId: mediaID, MediaType: mediamod.MediaTypeDrama,
			Uid: uid, Type: 0, ContentId: contentID, Coins: content.Price,
			PayMoney: content.Price, CreatedAt: createdAt, UpdateTime: createdAt,
		}
		if createErr := media_buy_record_mod.Create(t, record); createErr != nil {
			return createErr
		}
		transaction := txnmod.TransactionLog{
			TransNo: orderID, UID: uid, Amount: -content.Price, ActualAmount: float64(-content.Price),
			TranType: txnmod.BuyAcg.Key(), TranTypeInt: int64(txnmod.BuyAcg),
			Desc:    fmt.Sprintf("短剧-单集购买-%s-第%d集", media.Title, content.EpisodeNumber),
			DiscDoc: user.DiscDoc, SysType: user.SysType,
			RealAmount: walletmod.GetRealAmount(updatedWallet),
		}
		if logErr := txnmod.InsertTransactionLog(t, &transaction); logErr != nil {
			return logErr
		}
		if countErr := mediamod.IncPurchasesCountWithTool(t, mediaID, 1); countErr != nil {
			return countErr
		}
		if countErr := mediacontentmod.IncCountPurchasesWithTool(t, contentID, 1); countErr != nil {
			return countErr
		}
		return nil
	})
	if err != nil {
		_, _ = appg.Redis.Del(requestKey)
		if errors.Is(err, errDramaAlreadyBought) {
			return BuyDramaEpisodeResponse{}, stderr.RepeatPurchase
		}
		log.Error("buy drama episode transaction failed", log.E(err), log.Any("uid", uid), log.Any("contentID", contentID))
		return BuyDramaEpisodeResponse{}, stderr.BuyFailed
	}
	return BuyDramaEpisodeResponse{
		OrderID: orderID, MediaID: mediaID, ContentID: contentID,
		AccessType: "bought", CanPlay: true, PaidCoin: content.Price, CoinBalance: balanceAfter,
	}, stderr.Success
}

func dramaBuyKey(scope string, uid uint64, value string) string {
	sum := sha256.Sum256([]byte(fmt.Sprintf("%s:%d:%s", scope, uid, value)))
	return "drama:buy:" + scope + ":" + hex.EncodeToString(sum[:])
}

func releaseDramaBuyLock(key, token string) {
	if appg.Redis == nil || key == "" || token == "" {
		return
	}
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()
	if _, err := appg.Redis.RunScriptContext(ctx, releaseDramaBuyLockScript, []string{key}, token); err != nil {
		log.Error("release drama buy lock failed", log.E(err), log.Any("key", key))
	}
}