feature: Add support to windows setup command

 * Add windows setup suport (cristianoliveira#30)

README.md

@@ -67,12 +67,14 @@ Ergo comes with a setup command that can configure that for you. The current sys
 
  - osx
  - linux-gnome
+ - windows
 
 (Contributions are welcomed)
 
 ```bash
 ergo setup <operation-system>
 ```
+
 In case of errors or if it doesn't work please take a look on detailed config session below.
 
 ### Showtime

commands/setup.go

@@ -2,21 +2,24 @@ package commands
 
 import (
 	"fmt"
-	"github.com/cristianoliveira/ergo/proxy"
 	"log"
 	"os/exec"
 	"runtime"
 	"strings"
+
+	"github.com/cristianoliveira/ergo/proxy"
 )
 
 // Setup command tries set ergo as the proxy on networking settings.
 // For now, this feature is only supported for:
 //   - OSX
 //   - Linux-gnome
+//   - Windows
 //
 // Usage:
 // `ergo setup osx`
 func Setup(system string, remove bool, config *proxy.Config) {
+
 	fmt.Println("Current detected system: " + runtime.GOOS)
 	proxyURL := "http://127.0.0.1:" + config.Port + "/proxy.pac"
 	script := ""
@@ -60,12 +63,24 @@ func Setup(system string, remove bool, config *proxy.Config) {
 			log.Fatal(err)
 		}
 
+	case "windows":
+		if remove {
+			cmd = exec.Command("reg", "delete", `HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings`, "/v", "AutoConfigURL", "/f")
+		} else {
+			cmd = exec.Command("reg", "add", `HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings`, "/v", "AutoConfigURL", "/t", "REG_SZ", "/d", proxyURL, "/f")
+		}
+		if err := cmd.Run(); err != nil {
+			log.Fatal(err)
+		}
+		//this is because windows needs to be told about the change
+		InetRefresh()
 	default:
 		fmt.Println(`
 List of supported system
 
 -linux-gnome
 -osx
+-windows
 
 For more support please open an issue on: https://github.com/cristianoliveira/ergo
 		`)

commands/setup_hlp.go

@@ -0,0 +1,10 @@
+// +build linux darwin
+
+package commands
+
+//ShowInternetOptions is just a dummy for now 
+//this is only used for Windows
+func ShowInternetOptions() {}
+//InetRefresh is just a dummy. It only has functionality
+//in Windows
+func InetRefresh()         {}

commands/setup_hlp_win.go

@@ -0,0 +1,57 @@
+// +build windows
+
+package commands
+
+import (
+	"fmt"
+	"log"
+	"os/exec"
+	"syscall"
+)
+
+//ShowInternetOptions will display the Internet Options
+//control panel. If the user clicks OK here, then the modifications
+//will be visible without a restart
+//this is just a fallback for the InetRefresh function
+func ShowInternetOptions() {
+	cmd := exec.Command("control", "inetcpl.cpl,Connections,4")
+	fmt.Println("Starting the Internet Options control panel")
+	err := cmd.Run()
+	if err != nil {
+		log.Printf("Internet Options control panel could not be started.\r\n%s\r\n", err.Error())
+	}
+}
+
+//InetRefresh will inform windows that a proxy change was performed.
+//if windows is not informed about the change, then the modification will only be noticed
+//after a restart
+func InetRefresh() {
+	wininet := syscall.MustLoadDLL("wininet.dll")
+	inetsetoption := wininet.MustFindProc("InternetSetOptionW")
+	//Option 39 is INTERNET_OPTION_SETTINGS_CHANGED
+	ret, _, callErr := inetsetoption.Call(0, 39, 0, 0)
+
+	if ret == 0 {
+		log.Printf(`
+			Could not auto refresh the proxy settings. 
+			Step 1
+			The received error is: %s
+			Please press OK on the next dialog.\r\n`,
+			callErr.Error())
+
+		ShowInternetOptions()
+	}
+	//Option 37 is INTERNET_OPTION_REFRESH
+	ret, _, callErr = inetsetoption.Call(0, 37, 0, 0)
+	if ret == 0 {
+		log.Printf(`
+			Could not auto refresh the proxy settings. 
+			Step 2
+			The received error is: %s
+			Please press OK on the next dialog.\r\n`,
+			callErr.Error())
+		ShowInternetOptions()
+	}
+
+	return
+}

main.go

@@ -3,9 +3,10 @@ package main
 import (
 	"flag"
 	"fmt"
+	"os"
+
 	"github.com/cristianoliveira/ergo/commands"
 	"github.com/cristianoliveira/ergo/proxy"
-	"os"
 )
 
 //VERSION of ergo.
@@ -21,7 +22,7 @@ Usage:
   ergo list
   ergo list-names
   ergo url <name>
-  ergo setup [linux-gnome|osx]
+  ergo setup [linux-gnome|osx|windows]
 
 Options:
   -h      Shows this message.