Refactor API handlers and proxy logic

- Centralized `getClient` logic into a dedicated function to reduce redundancy.
- Moved proxy initialization to a new utility function `SetProxy` in `internal/util/proxy.go`.
- Replaced `Internal` handler with `CLIHandler` in `server.go` for improved clarity and consistency.
- Removed unused functions and redundant HTTP client setup across the codebase for better maintainability.

internal/cmd/run.go

@@ -7,12 +7,10 @@ import (
 	"github.com/luispater/CLIProxyAPI/internal/auth"
 	"github.com/luispater/CLIProxyAPI/internal/client"
 	"github.com/luispater/CLIProxyAPI/internal/config"
+	"github.com/luispater/CLIProxyAPI/internal/util"
 	log "github.com/sirupsen/logrus"
-	"golang.org/x/net/proxy"
 	"io/fs"
-	"net"
 	"net/http"
-	"net/url"
 	"os"
 	"os/signal"
 	"path/filepath"
@@ -69,33 +67,12 @@ func StartService(cfg *config.Config) {
 	}
 
 	if len(cfg.GlAPIKey) > 0 {
-		var transport *http.Transport
-		proxyURL, errParse := url.Parse(cfg.ProxyUrl)
-		if errParse == nil {
-			if proxyURL.Scheme == "socks5" {
-				username := proxyURL.User.Username()
-				password, _ := proxyURL.User.Password()
-				proxyAuth := &proxy.Auth{User: username, Password: password}
-				dialer, errSOCKS5 := proxy.SOCKS5("tcp", proxyURL.Host, proxyAuth, proxy.Direct)
-				if errSOCKS5 != nil {
-					log.Fatalf("create SOCKS5 dialer failed: %v", errSOCKS5)
-				}
-				transport = &http.Transport{
-					DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
-						return dialer.Dial(network, addr)
-					},
-				}
-			} else if proxyURL.Scheme == "http" || proxyURL.Scheme == "https" {
-				// Handle HTTP/HTTPS proxy.
-				transport = &http.Transport{Proxy: http.ProxyURL(proxyURL)}
-			}
-		}
-
 		for i := 0; i < len(cfg.GlAPIKey); i++ {
-			httpClient := &http.Client{}
-			if transport != nil {
-				httpClient.Transport = transport
+			httpClient, errSetProxy := util.SetProxy(cfg, &http.Client{})
+			if errSetProxy != nil {
+				log.Fatalf("set proxy failed: %v", errSetProxy)
 			}
+
 			log.Debug("Initializing with Generative Language API key...")
 			cliClient := client.NewClient(httpClient, nil, cfg, cfg.GlAPIKey[i])
 			cliClients = append(cliClients, cliClient)