feat(cli): discover ThothII projects and installations

tools/tht/cmd/tht/main.go

@@ -22,7 +22,10 @@ import (
 	"github.com/aritmolab/thothii/tools/tht/internal/workspaceops"
 )
 
-const usage = `Usage: tht --installation <absolute-path>/thothii-installation.yaml <command>
+const usage = `Usage: tht [--installation <absolute-path>/thothii-installation.yaml] <command>
+
+When --installation is omitted, tht uses THOTHII_INSTALLATION or discovers one valid
+descriptor in the current project tree.
 
 Commands:
   status              Show the Compose service state.
@@ -78,6 +81,23 @@ func run(ctx context.Context, args []string, stdout, stderr io.Writer) int {
 		fmt.Fprintf(stderr, "tht: %s\n\n%s", err, usage)
 		return 2
 	}
+	if command == "help" && len(commandArgs) == 0 {
+		fmt.Fprint(stdout, usage)
+		return 0
+	}
+	if (command == "version" || command == "setup") && len(commandArgs) == 0 {
+		return commandUsageError(stderr, fmt.Sprintf("unknown command %q", command))
+	}
+	workingDirectory, err := os.Getwd()
+	if err != nil {
+		fmt.Fprintf(stderr, "tht: current directory is unavailable: %s\n", output.Sanitize(err.Error(), nil))
+		return 2
+	}
+	installationPath, err = config.Resolve(installationPath, os.Getenv, workingDirectory)
+	if err != nil {
+		fmt.Fprintf(stderr, "tht: %s\n", output.Sanitize(err.Error(), nil))
+		return 2
+	}
 	installation, err := config.Load(installationPath)
 	if err != nil {
 		fmt.Fprintf(stderr, "tht: %s\n", output.Sanitize(err.Error(), nil))
@@ -588,13 +608,29 @@ func piFailure(stderr io.Writer, err error, secretValues []string) int {
 }
 
 func parseArgs(args []string) (string, string, []string, error) {
-	if len(args) < 3 || args[0] != "--installation" {
-		return "", "", nil, errors.New("--installation <absolute-path> is required before the command")
+	var installation string
+	commandArgs := make([]string, 0, len(args))
+	for index := 0; index < len(args); index++ {
+		if args[index] != "--installation" {
+			commandArgs = append(commandArgs, args[index])
+			continue
+		}
+		if index+1 >= len(args) {
+			return "", "", nil, errors.New("--installation requires an absolute path")
+		}
+		if installation != "" {
+			return "", "", nil, errors.New("--installation may be supplied once")
+		}
+		installation = args[index+1]
+		if !filepath.IsAbs(installation) {
+			return "", "", nil, errors.New("--installation must be an absolute path")
+		}
+		index++
 	}
-	if !filepath.IsAbs(args[1]) {
-		return "", "", nil, errors.New("--installation must be an absolute path")
+	if len(commandArgs) == 0 {
+		return "", "", nil, errors.New("a command is required")
 	}
-	return args[1], args[2], args[3:], nil
+	return installation, commandArgs[0], commandArgs[1:], nil
 }
 
 func logsArgs(args []string) ([]string, error) {