package server

import (
	"fmt"
	"github.com/gin-gonic/gin"
	"os"
	"path/filepath"
	"strings"
)

func validateWebUIDir(dir string) error {
	info, e := os.Stat(filepath.Join(dir, "index.html"))
	if e != nil || info.IsDir() {
		return fmt.Errorf("WEBUI_DIR must contain index.html")
	}
	return nil
}
func within(root, path string) bool {
	rel, e := filepath.Rel(root, path)
	return e == nil && rel != ".." && !strings.HasPrefix(rel, ".."+string(os.PathSeparator))
}
func (s *Server) staticFallback(c *gin.Context) {
	if c.Request.URL.Path == "/api" || strings.HasPrefix(c.Request.URL.Path, "/api/") || s.WebUIDir == "" || c.Request.Method != "GET" && c.Request.Method != "HEAD" {
		reply(c, 404, "接口不存在", nil)
		return
	}
	root, e := filepath.EvalSymlinks(s.WebUIDir)
	if e != nil {
		reply(c, 404, "页面不存在", nil)
		return
	}
	root, e = filepath.Abs(root)
	if e != nil {
		reply(c, 404, "页面不存在", nil)
		return
	}
	candidate := filepath.Join(root, filepath.FromSlash(strings.TrimPrefix(c.Request.URL.Path, "/")))
	if !within(root, candidate) {
		reply(c, 404, "页面不存在", nil)
		return
	}
	if resolved, e := filepath.EvalSymlinks(candidate); e == nil {
		if !within(root, resolved) {
			reply(c, 404, "页面不存在", nil)
			return
		}
		if info, e := os.Stat(resolved); e == nil && !info.IsDir() {
			c.File(resolved)
			return
		}
	}
	index, e := filepath.EvalSymlinks(filepath.Join(root, "index.html"))
	if e != nil || !within(root, index) {
		reply(c, 404, "页面不存在", nil)
		return
	}
	c.Header("Cache-Control", "no-cache")
	c.File(index)
}