soul-yongping/soul-api/internal/handler/db_book.go

package handler

import (
	"context"
	"encoding/json"
	"net/http"
	"sort"
	"strconv"
	"strings"
	"time"

	"soul-api/internal/cache"
	"soul-api/internal/database"
	"soul-api/internal/model"

	"github.com/gin-gonic/gin"
	"gorm.io/gorm"
)

// naturalLessSectionID 对章节 id（如 9.1、9.2、9.10）做自然排序，避免 9.1 < 9.10 < 9.2 的字典序问题
func naturalLessSectionID(a, b string) bool {
	partsA := strings.Split(a, ".")
	partsB := strings.Split(b, ".")
	for i := 0; i < len(partsA) && i < len(partsB); i++ {
		na, errA := strconv.Atoi(partsA[i])
		nb, errB := strconv.Atoi(partsB[i])
		if errA != nil || errB != nil {
			if partsA[i] != partsB[i] {
				return partsA[i] < partsB[i]
			}
			continue
		}
		if na != nb {
			return na < nb
		}
	}
	return len(partsA) < len(partsB)
}

// listSelectCols 列表/导出不加载 content，大幅加速
var listSelectCols = []string{
	"id", "mid", "section_title", "price", "is_free", "is_new",
	"part_id", "part_title", "chapter_id", "chapter_title", "sort_order",
	"hot_score", "updated_at",
}

// sectionListItem 与前端 SectionListItem 一致（小写驼峰）
type sectionListItem struct {
	ID           string   `json:"id"`
	MID          int      `json:"mid,omitempty"` // 自增主键，小程序跳转用
	Title        string   `json:"title"`
	Price        float64  `json:"price"`
	IsFree       *bool    `json:"isFree,omitempty"`
	IsNew        *bool    `json:"isNew,omitempty"` // stitch_soul：标记最新新增
	PartID       string   `json:"partId"`
	PartTitle    string   `json:"partTitle"`
	ChapterID    string   `json:"chapterId"`
	ChapterTitle string   `json:"chapterTitle"`
	FilePath     *string  `json:"filePath,omitempty"`
	ClickCount   int64    `json:"clickCount"`          // 阅读次数（reading_progress）
	PayCount     int64    `json:"payCount"`            // 付款笔数（orders.product_type=section）
	HotScore     float64  `json:"hotScore"`            // 热度积分（加权计算）
	IsPinned     bool     `json:"isPinned,omitempty"`  // 是否置顶（仅 ranking 返回）
}

// computeSectionListWithHotScore 计算章节列表（含 hotScore），保持 sort_order 顺序，供 章节管理 树使用
func computeSectionListWithHotScore(db *gorm.DB) ([]sectionListItem, error) {
	sections, err := computeSectionsWithHotScore(db, false)
	if err != nil {
		return nil, err
	}
	return sections, nil
}

// computeArticleRankingSections 统一计算内容排行榜：置顶优先 + 按 hotScore 降序
// 供管理端内容排行榜页与小程序首页精选推荐共用，排序与置顶均在后端计算
func computeArticleRankingSections(db *gorm.DB) ([]sectionListItem, error) {
	sections, err := computeSectionsWithHotScore(db, true)
	if err != nil {
		return nil, err
	}
	// 读取置顶配置 pinned_section_ids
	pinnedIDs := []string{}
	var cfg model.SystemConfig
	if err := db.Where("config_key = ?", "pinned_section_ids").First(&cfg).Error; err == nil && len(cfg.ConfigValue) > 0 {
		_ = json.Unmarshal(cfg.ConfigValue, &pinnedIDs)
	}
	pinnedSet := make(map[string]int) // id -> 置顶顺序
	for i, id := range pinnedIDs {
		if id != "" {
			pinnedSet[id] = i
		}
	}
	// 排序：置顶优先（按置顶顺序），其次按 hotScore 降序
	sort.Slice(sections, func(i, j int) bool {
		pi, pj := pinnedSet[sections[i].ID], pinnedSet[sections[j].ID]
		piOk, pjOk := sections[i].IsPinned, sections[j].IsPinned
		if piOk && !pjOk {
			return true
		}
		if !piOk && pjOk {
			return false
		}
		if piOk && pjOk {
			return pi < pj
		}
		return sections[i].HotScore > sections[j].HotScore
	})
	return sections, nil
}

// computeSectionsWithHotScore 内部：按排名分算法计算 hotScore
// 热度积分 = 阅读权重×阅读排名分 + 新度权重×新度排名分 + 付款权重×付款排名分
// 阅读量前20名: 第1名=20分...第20名=1分；最近更新前30篇: 第1名=30分...第30名=1分；付款数前20名: 第1名=20分...第20名=1分
func computeSectionsWithHotScore(db *gorm.DB, setPinned bool) ([]sectionListItem, error) {
	var rows []model.Chapter
	if err := db.Select(listSelectCols).Order("COALESCE(sort_order, 999999) ASC, id ASC").Find(&rows).Error; err != nil {
		return nil, err
	}
	// 同 sort_order 时按 id 自然排序（9.1 < 9.2 < 9.10），避免字典序 9.1 < 9.10 < 9.2
	sort.Slice(rows, func(i, j int) bool {
		soI, soJ := 999999, 999999
		if rows[i].SortOrder != nil {
			soI = *rows[i].SortOrder
		}
		if rows[j].SortOrder != nil {
			soJ = *rows[j].SortOrder
		}
		if soI != soJ {
			return soI < soJ
		}
		return naturalLessSectionID(rows[i].ID, rows[j].ID)
	})
	ids := make([]string, 0, len(rows))
	for _, r := range rows {
		ids = append(ids, r.ID)
	}
	readCountMap := make(map[string]int64)
	if len(ids) > 0 {
		var rp []struct {
			SectionID string `gorm:"column:section_id"`
			Cnt       int64  `gorm:"column:cnt"`
		}
		db.Table("reading_progress").Select("section_id, COUNT(*) as cnt").
			Where("section_id IN ?", ids).Group("section_id").Scan(&rp)
		for _, r := range rp {
			readCountMap[r.SectionID] = r.Cnt
		}
	}
	payCountMap := make(map[string]int64)
	if len(ids) > 0 {
		var op []struct {
			ProductID string `gorm:"column:product_id"`
			Cnt       int64  `gorm:"column:cnt"`
		}
		db.Model(&model.Order{}).
			Select("product_id, COUNT(*) as cnt").
			Where("product_type = ? AND product_id IN ? AND status IN ?", "section", ids, []string{"paid", "completed", "success"}).
			Group("product_id").Scan(&op)
		for _, r := range op {
			payCountMap[r.ProductID] = r.Cnt
		}
	}
	readWeight, payWeight, recencyWeight := 0.1, 0.4, 0.5 // 默认与截图一致
	var cfg model.SystemConfig
	if err := db.Where("config_key = ?", "article_ranking_weights").First(&cfg).Error; err == nil && len(cfg.ConfigValue) > 0 {
		var v struct {
			ReadWeight    float64 `json:"readWeight"`
			RecencyWeight float64 `json:"recencyWeight"`
			PayWeight     float64 `json:"payWeight"`
		}
		if err := json.Unmarshal(cfg.ConfigValue, &v); err == nil {
			if v.ReadWeight >= 0 {
				readWeight = v.ReadWeight
			}
			if v.PayWeight >= 0 {
				payWeight = v.PayWeight
			}
			if v.RecencyWeight >= 0 {
				recencyWeight = v.RecencyWeight
			}
		}
	}
	pinnedIDs := []string{}
	if setPinned {
		var cfg2 model.SystemConfig
		if err := db.Where("config_key = ?", "pinned_section_ids").First(&cfg2).Error; err == nil && len(cfg2.ConfigValue) > 0 {
			_ = json.Unmarshal(cfg2.ConfigValue, &pinnedIDs)
		}
	}
	pinnedSet := make(map[string]bool)
	for _, id := range pinnedIDs {
		if id != "" {
			pinnedSet[id] = true
		}
	}

	// 1. 阅读量排名：按 readCount 降序，前20名得 20~1 分
	type idCnt struct {
		id  string
		cnt int64
	}
	readRank := make([]idCnt, 0, len(rows))
	for _, r := range rows {
		readRank = append(readRank, idCnt{r.ID, readCountMap[r.ID]})
	}
	sort.Slice(readRank, func(i, j int) bool { return readRank[i].cnt > readRank[j].cnt })
	readRankScoreMap := make(map[string]float64)
	for i := 0; i < len(readRank) && i < 20; i++ {
		readRankScoreMap[readRank[i].id] = float64(20 - i)
	}

	// 2. 新度排名：按 updated_at 降序（最近更新在前），前30篇得 30~1 分
	recencyRank := make([]struct {
		id        string
		updatedAt time.Time
	}, 0, len(rows))
	for _, r := range rows {
		recencyRank = append(recencyRank, struct {
			id        string
			updatedAt time.Time
		}{r.ID, r.UpdatedAt})
	}
	sort.Slice(recencyRank, func(i, j int) bool {
		return recencyRank[i].updatedAt.After(recencyRank[j].updatedAt)
	})
	recencyRankScoreMap := make(map[string]float64)
	for i := 0; i < len(recencyRank) && i < 30; i++ {
		recencyRankScoreMap[recencyRank[i].id] = float64(30 - i)
	}

	// 3. 付款数排名：按 payCount 降序，前20名得 20~1 分
	payRank := make([]idCnt, 0, len(rows))
	for _, r := range rows {
		payRank = append(payRank, idCnt{r.ID, payCountMap[r.ID]})
	}
	sort.Slice(payRank, func(i, j int) bool { return payRank[i].cnt > payRank[j].cnt })
	payRankScoreMap := make(map[string]float64)
	for i := 0; i < len(payRank) && i < 20; i++ {
		payRankScoreMap[payRank[i].id] = float64(20 - i)
	}

	sections := make([]sectionListItem, 0, len(rows))
	for _, r := range rows {
		price := 1.0
		if r.Price != nil {
			price = *r.Price
		}
		readCnt := readCountMap[r.ID]
		payCnt := payCountMap[r.ID]
		readRankScore := readRankScoreMap[r.ID]
		recencyRankScore := recencyRankScoreMap[r.ID]
		payRankScore := payRankScoreMap[r.ID]
		// 热度积分 = 阅读权重×阅读排名分 + 新度权重×新度排名分 + 付款权重×付款排名分
		hot := readWeight*readRankScore + recencyWeight*recencyRankScore + payWeight*payRankScore
		// 若章节有手动覆盖的 hot_score（>0），则优先使用
		if r.HotScore > 0 {
			hot = float64(r.HotScore)
		}
		item := sectionListItem{
			ID:           r.ID,
			MID:          r.MID,
			Title:        r.SectionTitle,
			Price:        price,
			IsFree:       r.IsFree,
			IsNew:        r.IsNew,
			PartID:       r.PartID,
			PartTitle:    r.PartTitle,
			ChapterID:    r.ChapterID,
			ChapterTitle: r.ChapterTitle,
			ClickCount:   readCnt,
			PayCount:     payCnt,
			HotScore:     hot,
		}
		if setPinned {
			item.IsPinned = pinnedSet[r.ID]
		}
		sections = append(sections, item)
	}
	return sections, nil
}

// DBBookAction GET/POST/PUT /api/db/book
func DBBookAction(c *gin.Context) {
	db := database.DB()
	switch c.Request.Method {
	case http.MethodGet:
		action := c.Query("action")
		id := c.Query("id")
		switch action {
		case "list":
			// 章节管理树：按 sort_order 顺序，含 hotScore
			sections, err := computeSectionListWithHotScore(db)
			if err != nil {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error(), "sections": []sectionListItem{}})
				return
			}
			c.JSON(http.StatusOK, gin.H{"success": true, "sections": sections, "total": len(sections)})
			return
		case "ranking":
			// 内容排行榜：置顶优先 + hotScore 降序，排序由后端统一计算，前端只展示
			sections, err := computeArticleRankingSections(db)
			if err != nil {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error(), "sections": []sectionListItem{}})
				return
			}
			c.JSON(http.StatusOK, gin.H{"success": true, "sections": sections, "total": len(sections)})
			return
		case "read":
			midStr := c.Query("mid")
			if midStr != "" {
				// 优先用 mid 获取（管理端编辑、小程序跳转推荐）
				mid, err := strconv.Atoi(midStr)
				if err != nil || mid < 1 {
					c.JSON(http.StatusOK, gin.H{"success": false, "error": "mid 必须为正整数"})
					return
				}
				var ch model.Chapter
				if err := db.Where("mid = ?", mid).First(&ch).Error; err != nil {
					if err == gorm.ErrRecordNotFound {
						c.JSON(http.StatusOK, gin.H{"success": false, "error": "章节不存在"})
						return
					}
					c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error()})
					return
				}
				price := 1.0
				if ch.Price != nil {
					price = *ch.Price
				}
				c.JSON(http.StatusOK, gin.H{
					"success": true,
					"section": gin.H{
						"id":               ch.ID,
						"title":            ch.SectionTitle,
						"price":            price,
						"content":          ch.Content,
						"isNew":            ch.IsNew,
						"partId":           ch.PartID,
						"partTitle":        ch.PartTitle,
						"chapterId":        ch.ChapterID,
						"chapterTitle":     ch.ChapterTitle,
						"editionStandard":  ch.EditionStandard,
						"editionPremium":   ch.EditionPremium,
					},
				})
				return
			}
			if id == "" {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": "缺少 id 或 mid"})
				return
			}
			var ch model.Chapter
			if err := db.Where("id = ?", id).First(&ch).Error; err != nil {
				if err == gorm.ErrRecordNotFound {
					c.JSON(http.StatusOK, gin.H{"success": false, "error": "章节不存在"})
					return
				}
				c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error()})
				return
			}
			price := 1.0
			if ch.Price != nil {
				price = *ch.Price
			}
			c.JSON(http.StatusOK, gin.H{
				"success": true,
				"section": gin.H{
					"id":               ch.ID,
					"title":            ch.SectionTitle,
					"price":            price,
					"content":          ch.Content,
					"isNew":            ch.IsNew,
					"partId":           ch.PartID,
					"partTitle":        ch.PartTitle,
					"chapterId":        ch.ChapterID,
					"chapterTitle":     ch.ChapterTitle,
					"editionStandard":  ch.EditionStandard,
					"editionPremium":   ch.EditionPremium,
				},
			})
			return
		case "section-orders":
			// 某章节的付款记录（管理端展示）
			if id == "" {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": "缺少 id"})
				return
			}
			var orders []model.Order
			if err := db.Where("product_type = ? AND product_id = ? AND status IN ?", "section", id, []string{"paid", "completed", "success"}).
				Order("pay_time DESC, created_at DESC").Limit(200).Find(&orders).Error; err != nil {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error(), "orders": []model.Order{}})
				return
			}
			c.JSON(http.StatusOK, gin.H{"success": true, "orders": orders})
			return
		case "export":
			var rows []model.Chapter
			if err := db.Select(listSelectCols).Order("COALESCE(sort_order, 999999) ASC, id ASC").Find(&rows).Error; err != nil {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error()})
				return
			}
			sort.Slice(rows, func(i, j int) bool {
				soI, soJ := 999999, 999999
				if rows[i].SortOrder != nil {
					soI = *rows[i].SortOrder
				}
				if rows[j].SortOrder != nil {
					soJ = *rows[j].SortOrder
				}
				if soI != soJ {
					return soI < soJ
				}
				return naturalLessSectionID(rows[i].ID, rows[j].ID)
			})
			sections := make([]sectionListItem, 0, len(rows))
			for _, r := range rows {
				price := 1.0
				if r.Price != nil {
					price = *r.Price
				}
				sections = append(sections, sectionListItem{
					ID: r.ID, Title: r.SectionTitle, Price: price, IsFree: r.IsFree, IsNew: r.IsNew,
					PartID: r.PartID, PartTitle: r.PartTitle, ChapterID: r.ChapterID, ChapterTitle: r.ChapterTitle,
				})
			}
			c.JSON(http.StatusOK, gin.H{"success": true, "sections": sections})
			return
		default:
			c.JSON(http.StatusOK, gin.H{"success": false, "error": "无效的 action"})
			return
		}
	case http.MethodPost:
		var body struct {
			Action string        `json:"action"`
			Data   []importItem  `json:"data"`
		}
		if err := c.ShouldBindJSON(&body); err != nil {
			c.JSON(http.StatusOK, gin.H{"success": false, "error": "请求体无效"})
			return
		}
		switch body.Action {
		case "sync":
			cache.InvalidateBookParts()
			cache.InvalidateBookCache()
			c.JSON(http.StatusOK, gin.H{"success": true, "message": "同步完成（Gin 无文件源时可从 DB 已存在数据视为已同步）"})
			return
		case "import":
			imported, failed := 0, 0
			for _, item := range body.Data {
				price := 1.0
				if item.Price != nil {
					price = *item.Price
				}
				isFree := false
				if item.IsFree != nil {
					isFree = *item.IsFree
				}
				processed, _ := ParseAutoLinkContent(item.Content)
				wordCount := len(processed)
				status := "published"
				editionStandard, editionPremium := true, false
				ch := model.Chapter{
					ID:              item.ID,
					PartID:          strPtr(item.PartID, "part-1"),
					PartTitle:       strPtr(item.PartTitle, "未分类"),
					ChapterID:       strPtr(item.ChapterID, "chapter-1"),
					ChapterTitle:    strPtr(item.ChapterTitle, "未分类"),
					SectionTitle:    item.Title,
					Content:         processed,
					WordCount:       &wordCount,
					IsFree:          &isFree,
					Price:           &price,
					Status:          &status,
					EditionStandard: &editionStandard,
					EditionPremium:  &editionPremium,
				}
				err := db.Where("id = ?", item.ID).First(&model.Chapter{}).Error
				if err == gorm.ErrRecordNotFound {
					err = db.Create(&ch).Error
				} else if err == nil {
					err = db.Model(&model.Chapter{}).Where("id = ?", item.ID).Updates(map[string]interface{}{
						"section_title": ch.SectionTitle,
						"content":       ch.Content,
						"word_count":   ch.WordCount,
						"is_free":      ch.IsFree,
						"price":        ch.Price,
					}).Error
				}
				if err != nil {
					failed++
					continue
				}
				cache.InvalidateChapterContentByID(item.ID)
				imported++
			}
			cache.InvalidateBookParts()
			cache.InvalidateBookCache()
			c.JSON(http.StatusOK, gin.H{"success": true, "message": "导入完成", "imported": imported, "failed": failed})
			return
		default:
			c.JSON(http.StatusOK, gin.H{"success": false, "error": "无效的 action"})
			return
		}
	case http.MethodPut:
		var body struct {
			Action string `json:"action"`
			// reorder：新顺序，支持跨篇跨章时附带 partId/chapterId
			IDs  []string      `json:"ids"`
			Items []reorderItem `json:"items"`
			// move-sections：批量移动节到目标篇/章
			SectionIds         []string `json:"sectionIds"`
			TargetPartID       string   `json:"targetPartId"`
			TargetChapterID    string   `json:"targetChapterId"`
			TargetPartTitle    string   `json:"targetPartTitle"`
			TargetChapterTitle string   `json:"targetChapterTitle"`
			ID                 string   `json:"id"`
			Title              string   `json:"title"`
			Content            string   `json:"content"`
			Price              *float64 `json:"price"`
			IsFree             *bool    `json:"isFree"`
			IsNew              *bool    `json:"isNew"` // stitch_soul：标记最新新增
			EditionStandard    *bool    `json:"editionStandard"` // 是否属于普通版
			EditionPremium     *bool    `json:"editionPremium"`  // 是否属于增值版
			PartID             string   `json:"partId"`
			PartTitle          string   `json:"partTitle"`
			ChapterID          string   `json:"chapterId"`
			ChapterTitle       string   `json:"chapterTitle"`
			HotScore           *float64 `json:"hotScore"`
		}
		if err := c.ShouldBindJSON(&body); err != nil {
			c.JSON(http.StatusOK, gin.H{"success": false, "error": "请求体无效"})
			return
		}
		if body.Action == "reorder" {
			// 立即返回成功，后台异步执行排序更新
			if len(body.Items) > 0 {
				items := make([]reorderItem, len(body.Items))
				copy(items, body.Items)
				c.JSON(http.StatusOK, gin.H{"success": true})
				go func() {
					db := database.DB()
					for i, it := range items {
						if it.ID == "" {
							continue
						}
						up := map[string]interface{}{"sort_order": i}
						if it.PartID != "" {
							up["part_id"] = it.PartID
						}
						if it.PartTitle != "" {
							up["part_title"] = it.PartTitle
						}
						if it.ChapterID != "" {
							up["chapter_id"] = it.ChapterID
						}
						if it.ChapterTitle != "" {
							up["chapter_title"] = it.ChapterTitle
						}
						_ = db.WithContext(context.Background()).Model(&model.Chapter{}).Where("id = ?", it.ID).Updates(up).Error
					}
					cache.InvalidateBookParts()
					cache.InvalidateBookCache()
				}()
				return
			}
			if len(body.IDs) > 0 {
				ids := make([]string, len(body.IDs))
				copy(ids, body.IDs)
				c.JSON(http.StatusOK, gin.H{"success": true})
				go func() {
					db := database.DB()
					for i, id := range ids {
						if id != "" {
							_ = db.WithContext(context.Background()).Model(&model.Chapter{}).Where("id = ?", id).Update("sort_order", i).Error
						}
					}
					cache.InvalidateBookParts()
					cache.InvalidateBookCache()
				}()
				return
			}
		}
		if body.Action == "move-sections" {
			if len(body.SectionIds) == 0 {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": "批量移动缺少 sectionIds（请先勾选要移动的节）"})
				return
			}
			if body.TargetPartID == "" || body.TargetChapterID == "" {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": "批量移动缺少目标篇或目标章（targetPartId、targetChapterId）"})
				return
			}
			up := map[string]interface{}{
				"part_id":       body.TargetPartID,
				"chapter_id":    body.TargetChapterID,
				"part_title":    body.TargetPartTitle,
				"chapter_title": body.TargetChapterTitle,
			}
			if err := db.Model(&model.Chapter{}).Where("id IN ?", body.SectionIds).Updates(up).Error; err != nil {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error()})
				return
			}
			cache.InvalidateBookParts()
			cache.InvalidateBookCache()
			c.JSON(http.StatusOK, gin.H{"success": true, "message": "已移动", "count": len(body.SectionIds)})
			return
		}
		if body.ID == "" {
			c.JSON(http.StatusOK, gin.H{"success": false, "error": "缺少 id"})
			return
		}
		price := 1.0
		if body.Price != nil {
			price = *body.Price
		}
		isFree := false
		if body.IsFree != nil {
			isFree = *body.IsFree
		}
		// 后端统一解析 @/# 并转为带 data-id 的 span
		processedContent, err := ParseAutoLinkContent(body.Content)
		if err != nil {
			c.JSON(http.StatusOK, gin.H{"success": false, "error": "解析 @/# 失败: " + err.Error()})
			return
		}
		wordCount := len(processedContent)
		updates := map[string]interface{}{
			"section_title": body.Title,
			"content":       processedContent,
			"word_count":    wordCount,
			"price":         price,
			"is_free":       isFree,
		}
		if body.IsNew != nil {
			updates["is_new"] = *body.IsNew
		}
		// 默认普通版：未传时按普通版处理
		if body.EditionStandard != nil {
			updates["edition_standard"] = *body.EditionStandard
		} else if body.EditionPremium == nil {
			updates["edition_standard"] = true
			updates["edition_premium"] = false
		}
		if body.EditionPremium != nil {
			updates["edition_premium"] = *body.EditionPremium
		}
		if body.HotScore != nil {
			updates["hot_score"] = *body.HotScore
		}
		if body.PartID != "" {
			updates["part_id"] = body.PartID
		}
		if body.PartTitle != "" {
			updates["part_title"] = body.PartTitle
		}
		if body.ChapterID != "" {
			updates["chapter_id"] = body.ChapterID
		}
		if body.ChapterTitle != "" {
			updates["chapter_title"] = body.ChapterTitle
		}
		var existing model.Chapter
		err = db.Where("id = ?", body.ID).First(&existing).Error
		if err == gorm.ErrRecordNotFound {
			// 新建：Create
			partID := body.PartID
			if partID == "" {
				partID = "part-1"
			}
			partTitle := body.PartTitle
			if partTitle == "" {
				partTitle = "未分类"
			}
			chapterID := body.ChapterID
			if chapterID == "" {
				chapterID = "chapter-1"
			}
			chapterTitle := body.ChapterTitle
			if chapterTitle == "" {
				chapterTitle = "未分类"
			}
			editionStandard, editionPremium := true, false
			if body.EditionPremium != nil && *body.EditionPremium {
				editionStandard, editionPremium = false, true
			} else if body.EditionStandard != nil {
				editionStandard = *body.EditionStandard
			}
			status := "published"
			ch := model.Chapter{
				ID:              body.ID,
				PartID:          partID,
				PartTitle:       partTitle,
				ChapterID:       chapterID,
				ChapterTitle:    chapterTitle,
				SectionTitle:    body.Title,
				Content:         processedContent,
				WordCount:       &wordCount,
				IsFree:          &isFree,
				Price:           &price,
				Status:          &status,
				EditionStandard: &editionStandard,
				EditionPremium:  &editionPremium,
			}
			if body.IsNew != nil {
				ch.IsNew = body.IsNew
			}
			if err := db.Create(&ch).Error; err != nil {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error()})
				return
			}
			cache.InvalidateChapterContent(ch.MID)
			cache.InvalidateBookParts()
			cache.InvalidateBookCache()
			c.JSON(http.StatusOK, gin.H{"success": true})
			return
		}
		if err != nil {
			c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error()})
			return
		}
		err = db.Model(&model.Chapter{}).Where("id = ?", body.ID).Updates(updates).Error
		if err != nil {
			c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error()})
			return
		}
		cache.InvalidateChapterContentByID(body.ID)
		cache.InvalidateBookParts()
		cache.InvalidateBookCache()
		c.JSON(http.StatusOK, gin.H{"success": true})
		return
	}
	c.JSON(http.StatusOK, gin.H{"success": false, "error": "不支持的请求方法"})
}

type reorderItem struct {
	ID           string `json:"id"`
	PartID       string `json:"partId"`
	PartTitle    string `json:"partTitle"`
	ChapterID    string `json:"chapterId"`
	ChapterTitle string `json:"chapterTitle"`
}

type importItem struct {
	ID           string   `json:"id"`
	Title        string   `json:"title"`
	Content      string   `json:"content"`
	Price        *float64 `json:"price"`
	IsFree       *bool    `json:"isFree"`
	PartID       *string  `json:"partId"`
	PartTitle    *string  `json:"partTitle"`
	ChapterID    *string  `json:"chapterId"`
	ChapterTitle *string  `json:"chapterTitle"`
}

func strPtr(s *string, def string) string {
	if s != nil && *s != "" {
		return *s
	}
	return def
}

// DBBookDelete DELETE /api/db/book
func DBBookDelete(c *gin.Context) {
	id := c.Query("id")
	if id == "" {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": "缺少 id"})
		return
	}
	cache.InvalidateChapterContentByID(id)
	if err := database.DB().Where("id = ?", id).Delete(&model.Chapter{}).Error; err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error()})
		return
	}
	cache.InvalidateBookParts()
	cache.InvalidateBookCache()
	c.JSON(http.StatusOK, gin.H{"success": true})
}