refactor(rewrite): reorganize referer rules and remove obsolete mapping

internal/reader/rewrite/referer_override_test.go

@@ -33,11 +33,6 @@ func TestGetRefererForURL(t *testing.T) {
 			url:      "https://scontent-sjc3-1.cdninstagram.com/example.jpg",
 			expected: "https://www.instagram.com",
 		},
-		{
-			name:     "Piokok URL",
-			url:      "https://sp1.piokok.com/example.jpg",
-			expected: "https://sp1.piokok.com",
-		},
 		{
 			name:     "Weibo Video URL",
 			url:      "https://f.video.weibocdn.com/example.mp4",

internal/reader/rewrite/rules.go

@@ -50,31 +50,29 @@ func GetRefererForURL(u string) string {
 	}
 
 	switch parsedUrl.Hostname() {
-	case "moyu.im":
-		return "https://i.jandan.net"
-	case "i.pximg.net":
-		return "https://www.pixiv.net"
-	case "sp1.piokok.com":
-		return "https://sp1.piokok.com"
+	case "appinn.com":
+		return "https://appinn.com"
+	case "bjp.org.cn":
+		return "https://bjp.org.cn"
 	case "cdnfile.sspai.com":
 		return "https://sspai.com"
 	case "f.video.weibocdn.com":
 		return "https://weibo.com"
+	case "i.pximg.net":
+		return "https://www.pixiv.net"
 	case "img.hellogithub.com":
 		return "https://hellogithub.com"
-	case "bjp.org.cn":
-		return "https://bjp.org.cn"
-	case "appinn.com":
-		return "https://appinn.com"
+	case "moyu.im":
+		return "https://i.jandan.net"
 	}
 
 	switch {
-	case strings.HasSuffix(parsedUrl.Hostname(), ".sinaimg.cn"):
-		return "https://weibo.com"
 	case strings.HasSuffix(parsedUrl.Hostname(), ".cdninstagram.com"):
 		return "https://www.instagram.com"
 	case strings.HasSuffix(parsedUrl.Hostname(), ".moyu.im"):
 		return "https://i.jandan.net"
+	case strings.HasSuffix(parsedUrl.Hostname(), ".sinaimg.cn"):
+		return "https://weibo.com"
 	}
 
 	return ""