package handler

import (
	"context"
	"encoding/json"
	"net/http"
	"sort"

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

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

// listSelectCols 列表/导出不加载 content，大幅加速；含 updated_at 用于热度算法
var listSelectCols = []string{
	"id", "section_title", "price", "is_free", "is_new",
	"part_id", "part_title", "chapter_id", "chapter_title", "sort_order", "updated_at",
}

// sectionListItem 与前端 SectionListItem 一致（小写驼峰），含点击、付款与热度排名
type sectionListItem struct {
	ID           string   `json:"id"`
	Title        string   `json:"title"`
	Price        float64  `json:"price"`
	IsFree       *bool    `json:"isFree,omitempty"`
	IsNew        *bool    `json:"isNew,omitempty"`
	PartID       string   `json:"partId"`
	PartTitle    string   `json:"partTitle"`
	ChapterID    string   `json:"chapterId"`
	ChapterTitle string   `json:"chapterTitle"`
	FilePath     *string  `json:"filePath,omitempty"`
	ClickCount   int      `json:"clickCount,omitempty"` // 阅读/点击次数（reading_progress 条数）
	PayCount     int      `json:"payCount,omitempty"`   // 付款笔数（orders 已支付）
	HotScore     float64  `json:"hotScore,omitempty"`   // 热度积分（文章排名算法算出）
	HotRank      int      `json:"hotRank,omitempty"`    // 热度排名（1=最高）
}

// 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":
			var rows []model.Chapter
			if err := db.Select(listSelectCols).Order("sort_order ASC, id ASC").Find(&rows).Error; err != nil {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error(), "sections": []sectionListItem{}})
				return
			}
			ids := make([]string, 0, len(rows))
			for _, r := range rows {
				ids = append(ids, r.ID)
			}
			// 点击量：与 reading_progress 表直接捆绑，按 section_id 计数（小程序打开章节会立即上报一条）
			type readCnt struct{ SectionID string `gorm:"column:section_id"`; Cnt int64 `gorm:"column:cnt"` }
			var readCounts []readCnt
			if len(ids) > 0 {
				db.Table("reading_progress").Select("section_id, COUNT(*) as cnt").Where("section_id IN ?", ids).Group("section_id").Scan(&readCounts)
			}
			readMap := make(map[string]int)
			for _, x := range readCounts {
				readMap[x.SectionID] = int(x.Cnt)
			}
			// 付款笔数：与 orders 表直接捆绑，兼容 paid/completed/success 等已支付状态
			type payCnt struct{ ProductID string `gorm:"column:product_id"`; Cnt int64 `gorm:"column:cnt"` }
			var payCounts []payCnt
			if len(ids) > 0 {
				db.Table("orders").Select("product_id, COUNT(*) as cnt").
					Where("product_type = ? AND status IN ? AND product_id IN ?", "section", []string{"paid", "completed", "success"}, ids).
					Group("product_id").Scan(&payCounts)
			}
			payMap := make(map[string]int)
			for _, x := range payCounts {
				payMap[x.ProductID] = int(x.Cnt)
			}
			// 文章排名算法：权重可从 config article_ranking_weights 读取，默认 阅读50% 新度30% 付款20%
			readWeight, recencyWeight, payWeight := 0.5, 0.3, 0.2
			var cfgRow model.SystemConfig
			if err := db.Where("config_key = ?", "article_ranking_weights").First(&cfgRow).Error; err == nil && len(cfgRow.ConfigValue) > 0 {
				var m map[string]interface{}
				if json.Unmarshal(cfgRow.ConfigValue, &m) == nil {
					if v, ok := m["readWeight"]; ok {
						if f, ok := v.(float64); ok && f >= 0 && f <= 1 {
							readWeight = f
						}
					}
					if v, ok := m["recencyWeight"]; ok {
						if f, ok := v.(float64); ok && f >= 0 && f <= 1 {
							recencyWeight = f
						}
					}
					if v, ok := m["payWeight"]; ok {
						if f, ok := v.(float64); ok && f >= 0 && f <= 1 {
							payWeight = f
						}
					}
				}
			}
			// 热度 = readWeight*阅读排名分 + recencyWeight*新度排名分 + payWeight*付款排名分
			readScore := make(map[string]float64)
			idsByRead := make([]string, len(ids))
			copy(idsByRead, ids)
			sort.Slice(idsByRead, func(i, j int) bool { return readMap[idsByRead[i]] > readMap[idsByRead[j]] })
			for i := 0; i < 20 && i < len(idsByRead); i++ {
				readScore[idsByRead[i]] = float64(20 - i)
			}
			recencyScore := make(map[string]float64)
			sort.Slice(rows, func(i, j int) bool { return rows[i].UpdatedAt.After(rows[j].UpdatedAt) })
			for i := 0; i < 30 && i < len(rows); i++ {
				recencyScore[rows[i].ID] = float64(30 - i)
			}
			payScore := make(map[string]float64)
			idsByPay := make([]string, len(ids))
			copy(idsByPay, ids)
			sort.Slice(idsByPay, func(i, j int) bool { return payMap[idsByPay[i]] > payMap[idsByPay[j]] })
			for i := 0; i < 20 && i < len(idsByPay); i++ {
				payScore[idsByPay[i]] = float64(20 - i)
			}
			type idTotal struct {
				id    string
				total float64
			}
			totals := make([]idTotal, 0, len(rows))
			for _, r := range rows {
				t := readWeight*readScore[r.ID] + recencyWeight*recencyScore[r.ID] + payWeight*payScore[r.ID]
				totals = append(totals, idTotal{r.ID, t})
			}
			sort.Slice(totals, func(i, j int) bool { return totals[i].total > totals[j].total })
			hotRankMap := make(map[string]int)
			for i, t := range totals {
				hotRankMap[t.id] = i + 1
			}
			hotScoreMap := make(map[string]float64)
			for _, t := range totals {
				hotScoreMap[t.id] = t.total
			}
			// 恢复 rows 的 sort_order 顺序（上面 recency 排序打乱了）
			sort.Slice(rows, func(i, j int) bool {
				soi, soj := 0, 0
				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 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,
					ClickCount:   readMap[r.ID],
					PayCount:     payMap[r.ID],
					HotScore:     hotScoreMap[r.ID],
					HotRank:      hotRankMap[r.ID],
				})
			}
			c.JSON(http.StatusOK, gin.H{"success": true, "sections": sections, "total": len(sections)})
			return
		case "read":
			if id == "" {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": "缺少 id"})
				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,
				},
			})
			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("sort_order ASC, id ASC").Find(&rows).Error; err != nil {
				c.JSON(http.StatusOK, gin.H{"success": false, "error": err.Error()})
				return
			}
			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":
			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
				}
				wordCount := len(item.Content)
				status := "published"
				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:      item.Content,
					WordCount:    &wordCount,
					IsFree:       &isFree,
					Price:        &price,
					Status:       &status,
				}
				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
				}
				imported++
			}
			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
		}
		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
					}
				}()
				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
						}
					}
				}()
				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
			}
			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
		}
		wordCount := len(body.Content)
		updates := map[string]interface{}{
			"section_title": body.Title,
			"content":       body.Content,
			"word_count":    wordCount,
			"price":         price,
			"is_free":       isFree,
		}
		if body.IsNew != nil {
			updates["is_new"] = *body.IsNew
		}
		if body.EditionStandard != nil {
			updates["edition_standard"] = *body.EditionStandard
		}
		if body.EditionPremium != nil {
			updates["edition_premium"] = *body.EditionPremium
		}
		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
		}
		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
	}
	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
	}
	c.JSON(http.StatusOK, gin.H{"success": true})
}