feat(config): add PathManager interface for XDG-compliant path computation

pkg/config/pathmanager.go

@@ -0,0 +1,344 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"sync"
+)
+
+// PathManager centralises all filesystem path computation for the Devsy CLI.
+// Per-OS implementations supply the five top-level directory methods; every
+// sub-path is derived from those by the shared basePathManager.
+type PathManager interface {
+	// Top-level XDG category directories.
+	ConfigDir() (string, error)
+	DataDir() (string, error)
+	CacheDir() (string, error)
+	StateDir() (string, error)
+	RuntimeDir() (string, error)
+
+	// Config paths.
+	ConfigFilePath() (string, error)
+
+	// Data sub-paths (context-relative).
+	ContextDir(context string) (string, error)
+	WorkspacesDir(context string) (string, error)
+	WorkspaceDir(context, workspaceID string) (string, error)
+	MachinesDir(context string) (string, error)
+	MachineDir(context, machineID string) (string, error)
+	ProvidersDir(context string) (string, error)
+	ProviderDir(context, providerName string) (string, error)
+	ProviderBinariesDir(context, providerName string) (string, error)
+	ProviderDaemonDir(context, providerName string) (string, error)
+	ProInstancesDir(context string) (string, error)
+	ProInstanceDir(context, proInstanceHost string) (string, error)
+	LocksDir(context string) (string, error)
+
+	// Cache sub-paths.
+	AgentCacheDir() (string, error)
+	ProviderDownloadCacheDir() (string, error)
+	FeatureCacheDir(hashedID string) (string, error)
+	PlatformCacheDir() (string, error)
+	SSHKeysDir() (string, error)
+
+	// Runtime sub-paths.
+	DaemonPIDFile() (string, error)
+	DaemonLockFile() (string, error)
+	DaemonStreamsFile() (string, error)
+	ProcessPIDFile(name string) (string, error)
+	ProcessLockFile(name string) (string, error)
+	ProcessStreamsFile(name string) (string, error)
+
+	// State sub-paths.
+	LogDir() (string, error)
+}
+
+// basePathManager implements every sub-path method by delegating the top-level
+// directory resolution to the embedded pm field (the concrete per-OS struct).
+type basePathManager struct {
+	pm PathManager // self-reference wired after construction
+}
+
+// --- Config paths ---
+
+func (b *basePathManager) ConfigFilePath() (string, error) {
+	if p := os.Getenv(EnvConfig); p != "" {
+		return p, nil
+	}
+
+	dir, err := b.pm.ConfigDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, ConfigFile), nil
+}
+
+// --- Data sub-paths (context-relative) ---
+
+func (b *basePathManager) ContextDir(context string) (string, error) {
+	dir, err := b.pm.DataDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "contexts", context), nil
+}
+
+func (b *basePathManager) WorkspacesDir(context string) (string, error) {
+	dir, err := b.ContextDir(context)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "workspaces"), nil
+}
+
+func (b *basePathManager) WorkspaceDir(context, workspaceID string) (string, error) {
+	dir, err := b.WorkspacesDir(context)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, workspaceID), nil
+}
+
+func (b *basePathManager) MachinesDir(context string) (string, error) {
+	dir, err := b.ContextDir(context)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "machines"), nil
+}
+
+func (b *basePathManager) MachineDir(context, machineID string) (string, error) {
+	dir, err := b.MachinesDir(context)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, machineID), nil
+}
+
+func (b *basePathManager) ProvidersDir(context string) (string, error) {
+	dir, err := b.ContextDir(context)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "providers"), nil
+}
+
+func (b *basePathManager) ProviderDir(context, providerName string) (string, error) {
+	dir, err := b.ProvidersDir(context)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, providerName), nil
+}
+
+func (b *basePathManager) ProviderBinariesDir(context, providerName string) (string, error) {
+	dir, err := b.ProviderDir(context, providerName)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "binaries"), nil
+}
+
+func (b *basePathManager) ProviderDaemonDir(context, providerName string) (string, error) {
+	dir, err := b.ProviderDir(context, providerName)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "daemon"), nil
+}
+
+func (b *basePathManager) ProInstancesDir(context string) (string, error) {
+	dir, err := b.ContextDir(context)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "pro_instances"), nil
+}
+
+func (b *basePathManager) ProInstanceDir(context, proInstanceHost string) (string, error) {
+	dir, err := b.ProInstancesDir(context)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, proInstanceHost), nil
+}
+
+func (b *basePathManager) LocksDir(context string) (string, error) {
+	dir, err := b.ContextDir(context)
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "locks"), nil
+}
+
+// --- Cache sub-paths ---
+
+func (b *basePathManager) AgentCacheDir() (string, error) {
+	dir, err := b.pm.CacheDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "agents"), nil
+}
+
+func (b *basePathManager) ProviderDownloadCacheDir() (string, error) {
+	dir, err := b.pm.CacheDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "providers"), nil
+}
+
+func (b *basePathManager) FeatureCacheDir(hashedID string) (string, error) {
+	dir, err := b.pm.CacheDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "features", hashedID), nil
+}
+
+func (b *basePathManager) PlatformCacheDir() (string, error) {
+	dir, err := b.pm.CacheDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "platform"), nil
+}
+
+func (b *basePathManager) SSHKeysDir() (string, error) {
+	dir, err := b.pm.CacheDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "keys"), nil
+}
+
+// --- Runtime sub-paths ---
+
+func (b *basePathManager) DaemonPIDFile() (string, error) {
+	dir, err := b.pm.RuntimeDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, DaemonProcessName+".pid"), nil
+}
+
+func (b *basePathManager) DaemonLockFile() (string, error) {
+	dir, err := b.pm.RuntimeDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, DaemonProcessName+".lock"), nil
+}
+
+func (b *basePathManager) DaemonStreamsFile() (string, error) {
+	dir, err := b.pm.RuntimeDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, DaemonProcessName+".streams"), nil
+}
+
+func (b *basePathManager) ProcessPIDFile(name string) (string, error) {
+	dir, err := b.pm.RuntimeDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, name+".pid"), nil
+}
+
+func (b *basePathManager) ProcessLockFile(name string) (string, error) {
+	dir, err := b.pm.RuntimeDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, name+".lock"), nil
+}
+
+func (b *basePathManager) ProcessStreamsFile(name string) (string, error) {
+	dir, err := b.pm.RuntimeDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, name+".streams"), nil
+}
+
+// --- State sub-paths ---
+
+func (b *basePathManager) LogDir() (string, error) {
+	dir, err := b.pm.StateDir()
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Join(dir, "logs"), nil
+}
+
+// --- Singleton management ---
+
+var (
+	defaultPM     PathManager
+	defaultPMOnce sync.Once
+	defaultPMMu   sync.Mutex
+)
+
+// NewPathManager returns a new PathManager for the current platform.
+func NewPathManager() PathManager {
+	return newPlatformPathManager()
+}
+
+// DefaultPathManager returns the process-wide singleton PathManager.
+func DefaultPathManager() PathManager {
+	defaultPMMu.Lock()
+	defer defaultPMMu.Unlock()
+
+	defaultPMOnce.Do(func() {
+		defaultPM = NewPathManager()
+	})
+
+	return defaultPM
+}
+
+// SetPathManager replaces the singleton PathManager (for testing).
+func SetPathManager(pm PathManager) {
+	defaultPMMu.Lock()
+	defer defaultPMMu.Unlock()
+
+	defaultPM = pm
+	// Mark the Once as done so future DefaultPathManager() calls return pm.
+	defaultPMOnce.Do(func() {})
+}
+
+// ResetPathManager clears the singleton so the next DefaultPathManager call
+// creates a fresh instance. Intended for tests only.
+func ResetPathManager() {
+	defaultPMMu.Lock()
+	defer defaultPMMu.Unlock()
+
+	defaultPM = nil
+	defaultPMOnce = sync.Once{}
+}