feat: config auto-generation

`cheat` now attempts to auto-generate a config file if one cannot be
found on the filesystem.

cmd/cheat/main.go

@@ -31,13 +31,35 @@ func main() {
 		os.Exit(0)
 	}
 
-	// load the config file
-	confpath, err := config.Path(runtime.GOOS)
+	// load the os-specifc paths at which the config file may be located
+	confpaths, err := config.Paths(runtime.GOOS)
 	if err != nil {
-		fmt.Fprintln(os.Stderr, "could not locate config file")
+		fmt.Fprintf(os.Stderr, "failed to load config: %v\n", err)
 		os.Exit(1)
 	}
 
+	// search for the config file in the above paths
+	confpath, err := config.Path(confpaths)
+	if err != nil {
+
+		// the config file does not exist, so we'll try to create one
+		if err = config.Init(confpaths[0], configs()); err != nil {
+			fmt.Fprintf(
+				os.Stderr,
+				"failed to create config file: %s: %v\n",
+				confpaths[0],
+				err,
+			)
+			os.Exit(1)
+		}
+
+		confpath = confpaths[0]
+
+		fmt.Printf("Created config file: %s\n", confpath)
+		fmt.Println("Please edit this file now to configure cheat.")
+		os.Exit(0)
+	}
+
 	// initialize the configs
 	conf, err := config.New(opts, confpath, true)
 	if err != nil {

internal/config/init.go

@@ -0,0 +1,24 @@
+package config
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+// Init initializes a config file
+func Init(confpath string, configs string) error {
+
+	// assert that the config directory exists
+	if err := os.MkdirAll(filepath.Dir(confpath), 0755); err != nil {
+		return fmt.Errorf("failed to create directory: %v", err)
+	}
+
+	// write the config file
+	if err := ioutil.WriteFile(confpath, []byte(configs), 0644); err != nil {
+		return fmt.Errorf("failed to create file: %v", err)
+	}
+
+	return nil
+}

internal/config/path.go

@@ -3,43 +3,10 @@ package config
 import (
 	"fmt"
 	"os"
-	"path"
-
-	"github.com/mitchellh/go-homedir"
 )
 
 // Path returns the config file path
-func Path(sys string) (string, error) {
-
-	var paths []string
-
-	// if CHEAT_CONFIG_PATH is set, return it
-	if os.Getenv("CHEAT_CONFIG_PATH") != "" {
-
-		// expand ~
-		expanded, err := homedir.Expand(os.Getenv("CHEAT_CONFIG_PATH"))
-		if err != nil {
-			return "", fmt.Errorf("failed to expand ~: %v", err)
-		}
-
-		return expanded, nil
-	}
-
-	switch sys {
-	case "darwin", "linux", "freebsd":
-		paths = []string{
-			path.Join(os.Getenv("XDG_CONFIG_HOME"), "/cheat/conf.yml"),
-			path.Join(os.Getenv("HOME"), ".config/cheat/conf.yml"),
-			path.Join(os.Getenv("HOME"), ".cheat/conf.yml"),
-		}
-	case "windows":
-		paths = []string{
-			fmt.Sprintf("%s/cheat/conf.yml", os.Getenv("APPDATA")),
-			fmt.Sprintf("%s/cheat/conf.yml", os.Getenv("PROGRAMDATA")),
-		}
-	default:
-		return "", fmt.Errorf("unsupported os: %s", sys)
-	}
+func Path(paths []string) (string, error) {
 
 	// check if the config file exists on any paths
 	for _, p := range paths {

internal/config/paths.go

@@ -0,0 +1,42 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"path"
+
+	"github.com/mitchellh/go-homedir"
+)
+
+// Paths returns config file paths that are appropriate for the operating
+// system
+func Paths(sys string) ([]string, error) {
+
+	// if CHEAT_CONFIG_PATH is set, return it
+	if os.Getenv("CHEAT_CONFIG_PATH") != "" {
+
+		// expand ~
+		expanded, err := homedir.Expand(os.Getenv("CHEAT_CONFIG_PATH"))
+		if err != nil {
+			return []string{}, fmt.Errorf("failed to expand ~: %v", err)
+		}
+
+		return []string{expanded}, nil
+	}
+
+	switch sys {
+	case "darwin", "linux", "freebsd":
+		return []string{
+			path.Join(os.Getenv("XDG_CONFIG_HOME"), "/cheat/conf.yml"),
+			path.Join(os.Getenv("HOME"), ".config/cheat/conf.yml"),
+			path.Join(os.Getenv("HOME"), ".cheat/conf.yml"),
+		}, nil
+	case "windows":
+		return []string{
+			fmt.Sprintf("%s/cheat/conf.yml", os.Getenv("APPDATA")),
+			fmt.Sprintf("%s/cheat/conf.yml", os.Getenv("PROGRAMDATA")),
+		}, nil
+	default:
+		return []string{}, fmt.Errorf("unsupported os: %s", sys)
+	}
+}