be a XDG-friendly tool

- respect `$XDG_CONFIG_HOME` environment variable
- search for config in common paths on initialisation

fix tests for exercism.paths on systems with `$XDG_CONFIG_HOME`

In case `$XDG_CONFIG_HOME` is set, tests of `paths` package fail as
config home was not mocked properly.

Author: Vladimir Varankin

cmd/debug.go

@@ -70,7 +70,7 @@ func Debug(ctx *cli.Context) error {
 			fmt.Println("API Key: Please set your API Key to access all of the CLI features")
 		}
 	} else {
-		fmt.Println("Config file: <not configured>")
+		fmt.Printf("Config file: %s (not configured)\n", c.File)
 		fmt.Println("API Key: Please set your API Key to access all of the CLI features")
 	}
 	fmt.Printf("Exercises Directory: %s\n", c.Dir)

config/config.go

@@ -34,8 +34,20 @@ type Config struct {
 
 // New returns a configuration struct with content from the exercism.json file
 func New(path string) (*Config, error) {
-	c := &Config{}
-	err := c.load(paths.Config(path))
+	configPath := paths.Config(path)
+	_, err := os.Stat(configPath)
+	if err != nil && os.IsNotExist(err) {
+		if path == "" {
+			configPath = paths.DefaultConfig
+		}
+	} else if err != nil {
+		return nil, err
+	}
+
+	c := &Config{
+		File: configPath,
+	}
+	err = c.load()
 	return c, err
 }
 
@@ -84,9 +96,7 @@ func (c *Config) Write() error {
 	return nil
 }
 
-func (c *Config) load(argPath string) error {
-	c.File = argPath
-
+func (c *Config) load() error {
 	if err := c.read(); err != nil {
 		return err
 	}

config/config_test.go

@@ -17,15 +17,19 @@ func TestLoad(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	configPath := filepath.Join(tmpDir, "config.json")
+
+	paths.Home = tmpDir
+	paths.ConfigHome = tmpDir
+	paths.DefaultConfig = filepath.Join(tmpDir, "default.json")
+
+	configPath := filepath.Join(paths.ConfigHome, "config.json")
 	if err := os.Link(fixturePath(t, "config.json"), configPath); err != nil {
 		t.Fatal(err)
 	}
-	dirtyPath := filepath.Join(tmpDir, "dirty.json")
+	dirtyPath := filepath.Join(paths.ConfigHome, "dirty.json")
 	if err := os.Link(fixturePath(t, "dirty.json"), dirtyPath); err != nil {
 		t.Fatal(err)
 	}
-	paths.Home = tmpDir
 
 	testCases := []struct {
 		desc                string
@@ -36,7 +40,7 @@ func TestLoad(t *testing.T) {
 		{
 			desc: "defaults",
 			in:   "",
-			out:  paths.Config(""),
+			out:  paths.DefaultConfig,
 			dir:  paths.Exercises(""),
 			key:  "",
 			api:  hostAPI,

paths/paths.go

@@ -11,7 +11,7 @@ import (
 const (
 	// File is the default name of the JSON file where the config written.
 	// The user can pass an alternate filename when using the CLI.
-	File = ".exercism.json"
+	File = "exercism.json"
 	// DirExercises is the default name of the directory for active users.
 	// Make this non-exported when handlers.Login is deleted.
 	DirExercises = "exercism"
@@ -20,31 +20,37 @@ const (
 var (
 	// Home by default will contact the location of your home directory.
 	Home string
+	// ConfigHome will contain $XDG_CONFIG_HOME if it is set or default config home directory.
+	ConfigHome string
+	// DefaultConfig will contain default path to config, according to Home
+	DefaultConfig string
 
-	// XDGConfigHome will contain $XDG_CONFIG_HOME if it exists.
-	XDGConfigHome   string
 	errHomeNotFound = errors.New("unable to locate home directory")
 )
 
 func init() {
-	// on startup set default values
-	Recalculate()
+	var err error
+	Home, err = findHome()
+	if err != nil {
+		panic(err)
+	}
+	ConfigHome = os.Getenv("XDG_CONFIG_HOME")
+	if ConfigHome == "" {
+		ConfigHome = filepath.Join(Home, ".config")
+	}
+	DefaultConfig = filepath.Join(Home, "." + File)
 }
 
 // Config will return the correct input path given any input.
-// Blank input will return the default configuration location.
+// Blank input will return the default configuration location based
+// on ConfigHome.
 // Non-blank input will expand home to be an absolute path.
 // If the target is known to be a directory, the config filename
 // will be appended.
 func Config(path string) string {
 	if path == "" {
-		if XDGConfigHome == "" {
-			return filepath.Join(Home, File)
-		}
-
-		return filepath.Join(XDGConfigHome, File)
+		return filepath.Join(ConfigHome, File)
 	}
-
 	expandedPath := expandPath(path)
 	if IsDir(path) {
 		expandedPath = filepath.Join(expandedPath, File)
@@ -62,18 +68,6 @@ func Exercises(path string) string {
 	return expandPath(path)
 }
 
-// Recalculate sets exercism paths based on Home.
-func Recalculate() {
-	if Home == "" {
-		home, err := findHome()
-		if err != nil {
-			panic(err)
-		}
-		Home = home
-	}
-	XDGConfigHome = os.Getenv("XDG_CONFIG_HOME")
-}
-
 // IsDir determines whether the given path is a valid directory path.
 func IsDir(path string) bool {
 	fi, _ := os.Stat(path)
@@ -114,7 +108,7 @@ func makeAbsolute(path string) string {
 }
 
 func expandHome(path string) string {
-	if path[:2] == "~"+string(os.PathSeparator) {
+	if strings.HasPrefix(path, "~"+string(os.PathSeparator)) {
 		return strings.Replace(path, "~", Home, 1)
 	}
 	return path

paths/paths_test.go

@@ -12,11 +12,19 @@ func TestHome(t *testing.T) {
 	assert.Equal(t, os.Getenv("HOME"), Home)
 }
 
+func TestConfigHome(t *testing.T) {
+	xdgConfigHome := os.Getenv("XDG_CONFIG_HOME")
+	if xdgConfigHome == "" {
+		assert.Equal(t, filepath.Join(Home, ".config"), ConfigHome)
+	} else {
+		assert.Equal(t, xdgConfigHome, ConfigHome)
+	}
+}
+
 func TestExercises(t *testing.T) {
 	dir, err := os.Getwd()
 	assert.NoError(t, err)
 	Home = "/test/home"
-	Recalculate()
 
 	testCases := []struct {
 		givenPath    string
@@ -40,7 +48,7 @@ func TestConfig(t *testing.T) {
 	assert.NoError(t, err)
 
 	Home = dir
-	Recalculate()
+	ConfigHome = dir
 
 	testCases := []struct {
 		desc         string
@@ -50,7 +58,7 @@ func TestConfig(t *testing.T) {
 		{
 			"blank path",
 			"",
-			filepath.Join(Home, ".exercism.json"),
+			filepath.Join(ConfigHome, File),
 		},
 		{
 			"unknown path is expanded, but not modified",
@@ -74,10 +82,3 @@ func TestConfig(t *testing.T) {
 		assert.Equal(t, tc.expectedPath, actual, tc.desc)
 	}
 }
-
-func TestXDGConfig(t *testing.T) {
-	XDGConfigHome = "/home/user/.xdg_config"
-
-	assert.Equal(t, filepath.Join(XDGConfigHome, File), Config(""))
-
-}