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

package handler

import (
	"net/http"
	"strings"

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

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

// escapeLike 转义 LIKE 中的 % _ \，防止注入与通配符滥用
func escapeLike(s string) string {
	s = strings.ReplaceAll(s, "\\", "\\\\")
	s = strings.ReplaceAll(s, "%", "\\%")
	s = strings.ReplaceAll(s, "_", "\\_")
	return s
}

// SearchGet GET /api/search?q= 从 chapters 表搜索（GORM，参数化）
// 优化：先搜标题（快），再搜内容（慢），不加载完整 content 到内存
func SearchGet(c *gin.Context) {
	q := strings.TrimSpace(c.Query("q"))
	if q == "" {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "error": "请输入搜索关键词"})
		return
	}
	pattern := "%" + escapeLike(q) + "%"
	db := database.DB()

	// 第一步：标题匹配（快速，不加载 content）
	type searchRow struct {
		ID           string   `gorm:"column:id"`
		MID          uint     `gorm:"column:mid"`
		SectionTitle string   `gorm:"column:section_title"`
		PartTitle    string   `gorm:"column:part_title"`
		ChapterTitle string   `gorm:"column:chapter_title"`
		Price        *float64 `gorm:"column:price"`
		IsFree       *bool    `gorm:"column:is_free"`
		Snippet      string   `gorm:"column:snippet"`
	}

	var titleMatches []searchRow
	db.Model(&model.Chapter{}).
		Select("id, mid, section_title, part_title, chapter_title, price, is_free, '' as snippet").
		Where("section_title LIKE ?", pattern).
		Order("sort_order ASC, id ASC").
		Limit(3).
		Find(&titleMatches)

	titleIDs := make(map[string]bool, len(titleMatches))
	for _, m := range titleMatches {
		titleIDs[m.ID] = true
	}

	// 第二步：内容匹配（排除已命中标题的，用 SQL 提取摘要避免加载完整 content）
	remaining := 20 - len(titleMatches)
	var contentMatches []searchRow
	if remaining > 0 {
		contentQ := db.Model(&model.Chapter{}).
			Select("id, mid, section_title, part_title, chapter_title, price, is_free, "+
				"CONCAT(CASE WHEN LOCATE(?, content) > 60 THEN '...' ELSE '' END, "+
				"SUBSTRING(content, GREATEST(1, LOCATE(?, content) - 50), 200), "+
				"CASE WHEN LENGTH(content) > LOCATE(?, content) + 150 THEN '...' ELSE '' END) as snippet",
				q, q, q).
			Where("content LIKE ?", pattern)
		if len(titleIDs) > 0 {
			ids := make([]string, 0, len(titleIDs))
			for id := range titleIDs {
				ids = append(ids, id)
			}
			contentQ = contentQ.Where("id NOT IN ?", ids)
		}
		contentQ.Order("sort_order ASC, id ASC").
			Limit(remaining).
			Find(&contentMatches)
	}

	results := make([]gin.H, 0, len(titleMatches)+len(contentMatches))
	for _, ch := range titleMatches {
		price := 1.0
		if ch.Price != nil {
			price = *ch.Price
		}
		results = append(results, gin.H{
			"id": ch.ID, "title": ch.SectionTitle, "partTitle": ch.PartTitle, "chapterTitle": ch.ChapterTitle,
			"price": price, "isFree": ch.IsFree, "matchType": "title", "score": 10, "snippet": "",
		})
	}
	for _, ch := range contentMatches {
		price := 1.0
		if ch.Price != nil {
			price = *ch.Price
		}
		snippet := ch.Snippet
		if len([]rune(snippet)) > 200 {
			snippet = string([]rune(snippet)[:200]) + "..."
		}
		results = append(results, gin.H{
			"id": ch.ID, "title": ch.SectionTitle, "partTitle": ch.PartTitle, "chapterTitle": ch.ChapterTitle,
			"price": price, "isFree": ch.IsFree, "matchType": "content", "score": 5, "snippet": snippet,
		})
	}
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"data":    gin.H{"keyword": q, "total": len(results), "results": results},
	})
}