commit bd3457a0bbd05d0fd60d98a0f35442c26dc4d5fe
Author: XOF <xofine@noreply.localhost>
Date:   Wed Dec 17 00:39:24 2025 +0800

    添加 main.go

diff --git a/main.go b/main.go
new file mode 100644
index 0000000..5f94ce1
--- /dev/null
+++ b/main.go
@@ -0,0 +1,200 @@
+package main
+
+import (
+	"crypto/md5"
+	"crypto/subtle"
+	"fmt"
+	"html/template"
+	"io"
+	"log"
+	"math/rand"
+	"net/http"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const (
+	downloadDir   = "./chrome_versions"
+	checkInterval = 24 * time.Hour
+	maxRetries    = 3
+)
+
+var (
+	authToken      string
+	authEnabled    bool
+	port           string
+	keepVersions   int
+	chromeURL      string
+)
+
+type Version struct {
+	Filename string
+	Size     int64
+	Time     time.Time
+}
+
+func init() {
+	authToken = getEnv("AUTH_TOKEN", "")
+	authEnabled = getEnv("AUTH_ENABLED", "false") == "true" || authToken != ""
+	port = getEnv("PORT", "8080")
+	keepVersions, _ = strconv.Atoi(getEnv("KEEP_VERSIONS", "3"))
+	chromeURL = getEnv("CHROME_URL", "https://www.google.cn/chrome?standalone=1&platform=win64")
+}
+
+func getEnv(key, defaultValue string) string {
+	if value := os.Getenv(key); value != "" {
+		return value
+	}
+	return defaultValue
+}
+
+func main() {
+	os.MkdirAll(downloadDir, 0755)
+	log.Printf("Auth enabled: %v, Port: %s, Keep versions: %d", authEnabled, port, keepVersions)
+
+	go monitor()
+
+	http.HandleFunc("/", authMiddleware(serveIndex))
+	http.Handle("/download/", authMiddleware(http.StripPrefix("/download/", http.FileServer(http.Dir(downloadDir))).ServeHTTP))
+
+	log.Printf("Server started on :%s", port)
+	log.Fatal(http.ListenAndServe(":"+port, nil))
+}
+
+func monitor() {
+	for {
+		delay := time.Duration(rand.Intn(3600)) * time.Second
+		time.Sleep(delay)
+
+		checkAndDownload()
+		time.Sleep(checkInterval)
+	}
+}
+
+func checkAndDownload() {
+	var data []byte
+	var err error
+
+	for i := 0; i < maxRetries; i++ {
+		resp, err := http.Get(chromeURL)
+		if err != nil {
+			log.Printf("Attempt %d failed: %v", i+1, err)
+			time.Sleep(time.Duration(i+1) * 10 * time.Second)
+			continue
+		}
+
+		data, err = io.ReadAll(resp.Body)
+		resp.Body.Close()
+
+		if err == nil {
+			break
+		}
+		log.Printf("Attempt %d read failed: %v", i+1, err)
+	}
+
+	if err != nil {
+		log.Println("All retries failed")
+		return
+	}
+
+	hash := fmt.Sprintf("%x", md5.Sum(data))
+	filename := fmt.Sprintf("chrome_%s_%s.exe", time.Now().Format("20060102"), hash[:8])
+	filepath := filepath.Join(downloadDir, filename)
+
+	if _, err := os.Stat(filepath); err == nil {
+		log.Println("File already exists, skipping")
+		return
+	}
+
+	if err := os.WriteFile(filepath, data, 0644); err != nil {
+		log.Printf("Error saving file: %v", err)
+		return
+	}
+
+	log.Printf("Downloaded: %s", filename)
+	cleanupOldVersions()
+}
+
+func cleanupOldVersions() {
+	files, _ := os.ReadDir(downloadDir)
+	if len(files) <= keepVersions {
+		return
+	}
+
+	var versions []Version
+	for _, f := range files {
+		if strings.HasSuffix(f.Name(), ".exe") {
+			info, _ := f.Info()
+			versions = append(versions, Version{
+				Filename: f.Name(),
+				Time:     info.ModTime(),
+				Size:     info.Size(),
+			})
+		}
+	}
+
+	sort.Slice(versions, func(i, j int) bool {
+		return versions[i].Time.After(versions[j].Time)
+	})
+
+	for i := keepVersions; i < len(versions); i++ {
+		os.Remove(filepath.Join(downloadDir, versions[i].Filename))
+	}
+}
+
+func authMiddleware(next http.HandlerFunc) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if authEnabled {
+			token := r.URL.Query().Get("token")
+			if subtle.ConstantTimeCompare([]byte(token), []byte(authToken)) != 1 {
+				http.Error(w, "Unauthorized", http.StatusUnauthorized)
+				return
+			}
+		}
+		next(w, r)
+	}
+}
+
+func serveIndex(w http.ResponseWriter, r *http.Request) {
+	files, _ := os.ReadDir(downloadDir)
+	var versions []Version
+
+	for _, f := range files {
+		if strings.HasSuffix(f.Name(), ".exe") {
+			info, _ := f.Info()
+			versions = append(versions, Version{
+				Filename: f.Name(),
+				Time:     info.ModTime(),
+				Size:     info.Size(),
+			})
+		}
+	}
+
+	sort.Slice(versions, func(i, j int) bool {
+		return versions[i].Time.After(versions[j].Time)
+	})
+
+	token := r.URL.Query().Get("token")
+	tmpl := template.Must(template.New("index").Parse(`
+<!DOCTYPE html>
+<html>
+<head><title>Chrome Offline Installer</title></head>
+<body>
+<h1>Chrome Offline Versions</h1>
+<ul>
+{{range .Versions}}
+<li><a href="/download/{{.Filename}}{{if $.Token}}?token={{$.Token}}{{end}}">{{.Filename}}</a> ({{.Size}} bytes, {{.Time.Format "2006-01-02 15:04"}})</li>
+{{end}}
+</ul>
+</body>
+</html>
+`))
+	tmpl.Execute(w, struct {
+		Versions []Version
+		Token    string
+	}{versions, token})
+}