chore: Add basic config creation and reading

app/main.go

@@ -0,0 +1,95 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path"
+
+	"github.com/charmbracelet/log"
+	"github.com/goccy/go-yaml"
+	"github.com/kirsle/configdir"
+	"github.com/urfave/cli/v3"
+)
+
+func mainEntrypoint(context.Context, *cli.Command) error {
+	if os.Geteuid() != 0 {
+		return fmt.Errorf("this program must be run as root")
+	}
+
+	log.Info("Initializing UnrealXR")
+
+	// Allow for overriding the config directory
+	configDir := os.Getenv("UNREALXR_CONFIG_PATH")
+
+	if configDir == "" {
+		configDir = configdir.LocalConfig("unrealxr")
+		err := configdir.MakePath(configDir)
+
+		if err != nil {
+			return fmt.Errorf("failed to ensure config directory exists: %w", err)
+		}
+	}
+
+	_, err := os.Stat(path.Join(configDir, "config.yml"))
+
+	if err != nil {
+		log.Debug("Creating default config file")
+		err := os.WriteFile(path.Join(configDir, "config.yml"), InitialConfig, 0644)
+
+		if err != nil {
+			return fmt.Errorf("failed to create initial config file: %w", err)
+		}
+	}
+
+	// Read and parse the config file
+	configBytes, err := os.ReadFile(path.Join(configDir, "config.yml"))
+
+	if err != nil {
+		return fmt.Errorf("failed to read config file: %w", err)
+	}
+
+	config := &Config{}
+	err = yaml.Unmarshal(configBytes, config)
+
+	if err != nil {
+		return fmt.Errorf("failed to parse config file: %w", err)
+	}
+
+	InitializePotentiallyMissingConfigValues(config)
+	return nil
+}
+
+func main() {
+	logLevel := os.Getenv("UNREALXR_LOG_LEVEL")
+
+	if logLevel != "" {
+		switch logLevel {
+		case "debug":
+			log.SetLevel(log.DebugLevel)
+
+		case "info":
+			log.SetLevel(log.InfoLevel)
+
+		case "warn":
+			log.SetLevel(log.WarnLevel)
+
+		case "error":
+			log.SetLevel(log.ErrorLevel)
+
+		case "fatal":
+			log.SetLevel(log.FatalLevel)
+		}
+	}
+
+	// Initialize the CLI
+	cmd := &cli.Command{
+		Name:   "unrealxr",
+		Usage:  "A spatial multi-display renderer for XR devices",
+		Action: mainEntrypoint,
+	}
+
+	if err := cmd.Run(context.Background(), os.Args); err != nil {
+		log.Fatal(err)
+	}
+}