package embed_static
import (
"bytes"
"encoding/json"
"html"
"net/http"
"strings"
"github.com/gin-gonic/gin"
)
// SPAPageMeta 注入到 SPA 入口 HTML 的 SEO / 社交预览元数据（仅 ，不写 #root，避免刷新闪屏）
type SPAPageMeta struct {
Title string // 完整
Description string
Keywords string // meta keywords
Canonical string
OGType string // 默认 website
OGImage string
SiteName string // og:site_name
Locale string // og:locale，默认 zh_CN
Robots string // 如 noindex,nofollow
JSONLD string // 已序列化的 JSON-LD 对象（不含 script 标签）
Status int // HTTP 状态码，0 视为 200
}
// ServeSPAWithMeta 返回带页面级 meta / JSON-LD 的干净 SPA 入口
func ServeSPAWithMeta(c *gin.Context, meta *SPAPageMeta) {
status := http.StatusOK
if meta != nil && meta.Status != 0 {
status = meta.Status
}
data, err := staticFS.ReadFile("static/spa/index.html")
if err != nil {
c.String(http.StatusNotFound, "前端未构建，请运行: cd frontend && npm run build")
return
}
data = applySPAPageMeta(data, meta)
// 入口 HTML 禁止长期缓存，否则发版后仍引用旧 chunk 哈希
c.Header("Cache-Control", "no-cache")
c.Data(status, "text/html; charset=utf-8", data)
}
func applySPAPageMeta(data []byte, meta *SPAPageMeta) []byte {
if meta == nil {
meta = &SPAPageMeta{}
}
title := strings.TrimSpace(meta.Title)
if title == "" && spaBrandTitleFn != nil {
title = strings.TrimSpace(spaBrandTitleFn())
}
if title != "" {
escaped := html.EscapeString(title)
data = spaTitleRe.ReplaceAll(data, []byte("<title>"+escaped+""))
}
var head strings.Builder
writeMeta(&head, "description", meta.Description)
writeMeta(&head, "keywords", meta.Keywords)
if canonical := strings.TrimSpace(meta.Canonical); canonical != "" {
head.WriteString(``)
}
robots := strings.TrimSpace(meta.Robots)
if robots != "" {
writeMeta(&head, "robots", robots)
}
ogType := strings.TrimSpace(meta.OGType)
if ogType == "" {
ogType = "website"
}
locale := strings.TrimSpace(meta.Locale)
if locale == "" {
locale = "zh_CN"
}
writeProp(&head, "og:type", ogType)
writeProp(&head, "og:site_name", meta.SiteName)
writeProp(&head, "og:locale", locale)
writeProp(&head, "og:title", firstNonEmpty(meta.Title, title))
writeProp(&head, "og:description", meta.Description)
writeProp(&head, "og:url", meta.Canonical)
writeProp(&head, "og:image", meta.OGImage)
writeMetaName(&head, "twitter:card", twitterCard(meta.OGImage))
writeMetaName(&head, "twitter:title", firstNonEmpty(meta.Title, title))
writeMetaName(&head, "twitter:description", meta.Description)
writeMetaName(&head, "twitter:image", meta.OGImage)
if jsonld := strings.TrimSpace(meta.JSONLD); jsonld != "" {
head.WriteString(``)
}
// 同步注入品牌配置，避免 React 首屏用默认名闪一下
if boot := spaBrandingBootScript(); boot != "" {
head.WriteString(boot)
}
if head.Len() > 0 {
data = bytes.Replace(data, []byte(""), []byte(head.String()+""), 1)
}
return data
}
// spaBrandingBootScript 生成 window.__J13_BRANDING__=...; 内联脚本
func spaBrandingBootScript() string {
if spaBrandJSONFn == nil {
return ""
}
raw := bytes.TrimSpace(spaBrandJSONFn())
if len(raw) == 0 || !json.Valid(raw) {
return ""
}
// 防止 JSON 字符串中的 提前闭合标签
safe := bytes.ReplaceAll(raw, []byte("<"), []byte(`\u003c`))
return ""
}
func writeMeta(b *strings.Builder, name, content string) {
content = strings.TrimSpace(content)
if content == "" {
return
}
b.WriteString(``)
}
func writeMetaName(b *strings.Builder, name, content string) {
writeMeta(b, name, content)
}
func writeProp(b *strings.Builder, prop, content string) {
content = strings.TrimSpace(content)
if content == "" {
return
}
b.WriteString(``)
}
func twitterCard(ogImage string) string {
if strings.TrimSpace(ogImage) != "" {
return "summary_large_image"
}
return "summary"
}
func firstNonEmpty(vals ...string) string {
for _, v := range vals {
if s := strings.TrimSpace(v); s != "" {
return s
}
}
return ""
}