Add autocomplete support for services (#473)

* Add autocomplete support for services

* fix bug with standard completion and add regions

---------

Co-authored-by: Josh Wilkes <[email protected]>

pkg/assume/completion.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/common-fate/clio"
 	"github.com/common-fate/granted/pkg/cfaws"
+	"github.com/common-fate/granted/pkg/console"
 	"github.com/urfave/cli/v2"
 )
 
@@ -16,17 +17,74 @@ import (
 //
 // You can use `assume -c ` + tab to get profile names or `assume -` + tab to get flags
 func Completion(ctx *cli.Context) {
+	var awsRegions = []string{
+		"us-east-1",      // US East (N. Virginia)
+		"us-east-2",      // US East (Ohio)
+		"us-west-1",      // US West (N. California)
+		"us-west-2",      // US West (Oregon)
+		"af-south-1",     // Africa (Cape Town)
+		"ap-east-1",      // Asia Pacific (Hong Kong)
+		"ap-south-1",     // Asia Pacific (Mumbai)
+		"ap-northeast-1", // Asia Pacific (Tokyo)
+		"ap-northeast-2", // Asia Pacific (Seoul)
+		"ap-northeast-3", // Asia Pacific (Osaka)
+		"ap-southeast-1", // Asia Pacific (Singapore)
+		"ap-southeast-2", // Asia Pacific (Sydney)
+		"ca-central-1",   // Canada (Central)
+		"eu-central-1",   // EU (Frankfurt)
+		"eu-west-1",      // EU (Ireland)
+		"eu-west-2",      // EU (London)
+		"eu-west-3",      // EU (Paris)
+		"eu-north-1",     // EU (Stockholm)
+		"eu-south-1",     // EU (Milan)
+		"me-south-1",     // Middle East (Bahrain)
+		"sa-east-1",      // South America (Sao Paulo)
+	}
+
 	clio.SetLevelFromEnv("GRANTED_LOG")
 	if ctx.Bool("verbose") {
 		clio.SetLevelFromString("debug")
 	}
-	if len(os.Args) > 2 && strings.HasPrefix(os.Args[len(os.Args)-2], "-") {
-		// set the ooutput back to std out so that this completion works correctly
-		ctx.App.Writer = os.Stdout
-		cli.DefaultAppComplete(ctx)
-	} else {
-		// Ignore errors from this function. Tab completion handles graceful degradation back to listing files.
-		awsProfiles, _ := cfaws.LoadProfiles()
+
+	// autocompletion for service flag
+	if len(os.Args) > 2 {
+
+		// reduce -- to - to make matching simpler
+		arg := os.Args[len(os.Args)-2]
+		if strings.HasPrefix(arg, "--") {
+			arg = arg[1:]
+		}
+		if arg == "-s" || arg == "-service" {
+			for k := range console.ServiceMap {
+				fmt.Println(k)
+			}
+			return
+		}
+		if arg == "-r" || arg == "-region" {
+			fmt.Println(strings.Join(awsRegions, "\n"))
+			return
+		}
+
+		if strings.HasPrefix(arg, "-") {
+			ctx.App.Writer = os.Stdout
+			cli.DefaultAppComplete(ctx)
+		}
+	}
+
+	awsProfiles, _ := cfaws.LoadProfiles()
+
+	// profileName argument can have any position to the command
+	// this check will help in not showing the profile name again it's already included.
+	hasProfileNameArg := false
+	for _, arg := range os.Args {
+		for _, awsProfile := range awsProfiles.ProfileNames {
+			if arg == awsProfile {
+				hasProfileNameArg = true
+			}
+		}
+	}
+
+	if !hasProfileNameArg {
 		// Tab completion script requires each option to be separated by a newline
 		fmt.Println(strings.Join(awsProfiles.ProfileNames, "\n"))
 	}