From f8737684ef9795dcd3bdd174fe74d9be601d966e Mon Sep 17 00:00:00 2001
From: wood chen <wood@czl.net>
Date: Sun, 13 Oct 2024 11:57:07 +0800
Subject: [PATCH] =?UTF-8?q?=E5=8E=BB=E9=87=8D,=20=E6=97=A0=E9=87=8D?=
 =?UTF-8?q?=E5=A4=8D=E9=80=89=E6=8B=A9(3=E6=AC=A1=E5=86=85),=20=E6=B4=97?=
 =?UTF-8?q?=E7=89=8C=E7=AE=97=E6=B3=95?=
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Content-Transfer-Encoding: 8bit

---
 main.go | 75 +++++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 62 insertions(+), 13 deletions(-)

diff --git a/main.go b/main.go
index b6b7442..5ac4598 100644
--- a/main.go
+++ b/main.go
@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"math/rand"
 	"net"
@@ -20,16 +19,62 @@ const (
 	port           = ":5003"
 	cacheDuration  = 24 * time.Hour
 	requestTimeout = 10 * time.Second
+	noRepeatCount  = 3 // 在这个次数内不重复选择
 )
 
 var (
 	csvPathsCache map[string]map[string]string
 	lastFetchTime time.Time
-	csvCache      = make(map[string][]string)
+	csvCache      = make(map[string]*URLSelector)
 	mu            sync.RWMutex
 	rng           *rand.Rand
 )
 
+type URLSelector struct {
+	URLs         []string
+	CurrentIndex int
+	RecentUsed   map[string]int
+}
+
+func NewURLSelector(urls []string) *URLSelector {
+	return &URLSelector{
+		URLs:         urls,
+		CurrentIndex: 0,
+		RecentUsed:   make(map[string]int),
+	}
+}
+
+func (us *URLSelector) ShuffleURLs() {
+	for i := len(us.URLs) - 1; i > 0; i-- {
+		j := rng.Intn(i + 1)
+		us.URLs[i], us.URLs[j] = us.URLs[j], us.URLs[i]
+	}
+}
+
+func (us *URLSelector) GetRandomURL() string {
+	if us.CurrentIndex == 0 {
+		us.ShuffleURLs()
+	}
+
+	for i := 0; i < len(us.URLs); i++ {
+		url := us.URLs[us.CurrentIndex]
+		us.CurrentIndex = (us.CurrentIndex + 1) % len(us.URLs)
+
+		if us.RecentUsed[url] < noRepeatCount {
+			us.RecentUsed[url]++
+			// 如果某个URL使用次数达到上限，从RecentUsed中移除
+			if us.RecentUsed[url] == noRepeatCount {
+				delete(us.RecentUsed, url)
+			}
+			return url
+		}
+	}
+
+	// 如果所有URL都被最近使用过，重置RecentUsed并返回第一个URL
+	us.RecentUsed = make(map[string]int)
+	return us.URLs[0]
+}
+
 func main() {
 	source := rand.NewSource(time.Now().UnixNano())
 	rng = rand.New(source)
@@ -89,7 +134,7 @@ func loadCSVPaths() error {
 	jsonPath := filepath.Join("public", "url.json")
 	log.Printf("Attempting to read file: %s", jsonPath)
 
-	data, err := ioutil.ReadFile(jsonPath)
+	data, err := os.ReadFile(jsonPath)
 	if err != nil {
 		return fmt.Errorf("failed to read url.json: %w", err)
 	}
@@ -108,36 +153,40 @@ func loadCSVPaths() error {
 	return nil
 }
 
-func getCSVContent(path string) ([]string, error) {
+func getCSVContent(path string) (*URLSelector, error) {
 	mu.RLock()
-	content, exists := csvCache[path]
+	selector, exists := csvCache[path]
 	mu.RUnlock()
 	if exists {
-		return content, nil
+		return selector, nil
 	}
 
 	fullPath := filepath.Join("public", path)
 	log.Printf("Attempting to read file: %s", fullPath)
 
-	fileContent, err := ioutil.ReadFile(fullPath)
+	fileContent, err := os.ReadFile(fullPath)
 	if err != nil {
 		return nil, fmt.Errorf("error reading CSV content: %w", err)
 	}
 
 	lines := strings.Split(string(fileContent), "\n")
+	uniqueURLs := make(map[string]bool)
 	var fileArray []string
 	for _, line := range lines {
 		trimmed := strings.TrimSpace(line)
-		if trimmed != "" && !strings.HasPrefix(trimmed, "#") {
+		if trimmed != "" && !strings.HasPrefix(trimmed, "#") && !uniqueURLs[trimmed] {
 			fileArray = append(fileArray, trimmed)
+			uniqueURLs[trimmed] = true
 		}
 	}
 
+	selector = NewURLSelector(fileArray)
+
 	mu.Lock()
-	csvCache[path] = fileArray
+	csvCache[path] = selector
 	mu.Unlock()
 
-	return fileArray, nil
+	return selector, nil
 }
 
 func handleAPIRequest(w http.ResponseWriter, r *http.Request) {
@@ -172,19 +221,19 @@ func handleAPIRequest(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	fileArray, err := getCSVContent(csvPath)
+	selector, err := getCSVContent(csvPath)
 	if err != nil {
 		http.Error(w, "Failed to fetch CSV content", http.StatusInternalServerError)
 		log.Println("Error fetching CSV content:", err)
 		return
 	}
 
-	if len(fileArray) == 0 {
+	if len(selector.URLs) == 0 {
 		http.Error(w, "No content available", http.StatusNotFound)
 		return
 	}
 
-	randomURL := fileArray[rng.Intn(len(fileArray))]
+	randomURL := selector.GetRandomURL()
 
 	duration := time.Since(start)
 	log.Printf("Request: %s %s from %s - Duration: %v - Redirecting to: %s\n",