package service

import (
	"context"
	"net/url"
	"strconv"
	"strings"
	"time"

	"affiliate_dash/internal/model"
)

type rockRefreshCacheItem struct {
	response *RockRefreshResponse
	cachedAt time.Time
}

// 腾讯「查询绑定」按链接里的 timestamp 验签，大约 10 分钟后返回「签名已过期」。
// 从签名时间起满 8 分钟就换一条，留出余量，买家不会扫到已经失效的码。
const rockBindLinkMaxAge = 8 * time.Minute

// 上游若仍返回同一条旧签名，不要每个轮询都再打一次。
const rockBindLinkRetryGap = 15 * time.Second

type rockBindLinkCacheItem struct {
	bindURL   string
	qrURL     string
	cachedAt  time.Time // 链接上没有 timestamp 时，用写入时间代替签名时间
	fetchedAt time.Time
}

func rockBindLinkIssuedAt(bindURL string) (time.Time, bool) {
	parsed, err := url.Parse(strings.TrimSpace(bindURL))
	if err != nil {
		return time.Time{}, false
	}
	raw := strings.TrimSpace(parsed.Query().Get("timestamp"))
	if raw == "" {
		return time.Time{}, false
	}
	value, err := strconv.ParseInt(raw, 10, 64)
	if err != nil || value <= 0 {
		return time.Time{}, false
	}
	if value >= 1_000_000_000_000 {
		return time.UnixMilli(value), true
	}
	return time.Unix(value, 0), true
}

func rockBindLinkStillFresh(item rockBindLinkCacheItem, now time.Time) bool {
	if strings.TrimSpace(item.bindURL) == "" {
		return false
	}
	issued, ok := rockBindLinkIssuedAt(item.bindURL)
	if !ok {
		issued = item.cachedAt
	}
	if issued.IsZero() {
		return false
	}
	return now.Sub(issued) < rockBindLinkMaxAge
}

func (s *RockService) rememberBindLink(tokenID uint, bindURL, qrURL string) {
	bindURL = strings.TrimSpace(bindURL)
	if s == nil || tokenID == 0 || bindURL == "" {
		return
	}
	qrURL = strings.TrimSpace(qrURL)
	if qrURL == "" {
		qrURL = qrCodeURL(bindURL)
	}
	now := time.Now()
	s.bindLinkCache.Store(tokenID, rockBindLinkCacheItem{
		bindURL:   bindURL,
		qrURL:     qrURL,
		cachedAt:  now,
		fetchedAt: now,
	})
}

// freshBindLink 只为仍在扫码的同一提货号重取活动链接。过期前复用缓存，避免每轮轮询都打 0666。
func (s *RockService) freshBindLink(ctx context.Context, tokenID uint, orderNo string) (string, string) {
	if s == nil || s.client == nil || tokenID == 0 {
		return "", ""
	}
	var token model.RockToken
	if err := s.db.WithContext(ctx).Unscoped().First(&token, tokenID).Error; err != nil {
		return "", ""
	}
	if token.Status != model.RockStatusUsing || strings.TrimSpace(token.RedeemCode) == "" {
		return "", ""
	}
	if orderNo = strings.TrimSpace(orderNo); orderNo != "" && token.AssignedOrderNo != "" && token.AssignedOrderNo != orderNo {
		return "", ""
	}
	if item, ok := s.bindLinkCache.Load(token.ID); ok {
		cached := item.(rockBindLinkCacheItem)
		if rockBindLinkStillFresh(cached, time.Now()) {
			return cached.bindURL, cached.qrURL
		}
		if !cached.fetchedAt.IsZero() && time.Since(cached.fetchedAt) < rockBindLinkRetryGap {
			return cached.bindURL, cached.qrURL
		}
	}
	detail, err := s.client.GetRedeemDetail(ctx, token.RedeemCode)
	if err != nil || detail == nil || strings.TrimSpace(detail.BindURL) == "" {
		if item, ok := s.bindLinkCache.Load(token.ID); ok {
			cached := item.(rockBindLinkCacheItem)
			return cached.bindURL, cached.qrURL
		}
		return "", ""
	}
	bindURL := strings.TrimSpace(detail.BindURL)
	qrURL := strings.TrimSpace(detail.QRURL)
	s.rememberBindLink(token.ID, bindURL, qrURL)
	if qrURL == "" {
		qrURL = qrCodeURL(bindURL)
	}
	return bindURL, qrURL
}