feat: config implementation and testing

internal/client/config/config.go

@@ -0,0 +1,212 @@
+package config
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/fs"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+var ErrNotFound = errors.New("config: not initialised, run `potok init`")
+
+const maxVaultNameLen = 64
+const invalidNameChars = `/\:*?"<>|` + " "
+
+type Config struct {
+	ServerURL string  `json:"server_url"`
+	Vaults    []Vault `json:"vaults"`
+}
+
+type Vault struct {
+	Name         string     `json:"name"`
+	Path         string     `json:"path"`
+	RemoteID     string     `json:"remote_id,omitempty"`
+	LastSyncedAt *time.Time `json:"last_synced_at,omitempty"`
+}
+
+type Store interface {
+	Load() (*Config, error)
+	Save(cfg *Config) error
+	Path() string
+}
+
+type FileStore struct {
+	Dir string
+}
+
+var _ Store = (*FileStore)(nil)
+
+func Dir() (string, error) {
+	if dir := os.Getenv("POTOK_CONFIG_DIR"); dir != "" {
+		return dir, nil
+	}
+	if dir := os.Getenv("XDG_CONFIG_HOME"); dir != "" {
+		return filepath.Join(dir, "potok"), nil
+	}
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return "", fmt.Errorf("config: locate home directory: %w", err)
+	}
+	return filepath.Join(home, ".potok"), nil
+}
+
+func (s *FileStore) Path() string {
+	dir := s.Dir
+	if dir == "" {
+		resolved, err := Dir()
+		if err != nil {
+			return "config.json"
+		}
+		dir = resolved
+	}
+	return filepath.Join(dir, "config.json")
+}
+
+func (s *FileStore) Load() (*Config, error) {
+	path := s.Path()
+	data, err := os.ReadFile(path)
+	if errors.Is(err, fs.ErrNotExist) {
+		return nil, ErrNotFound
+	}
+	if err != nil {
+		return nil, fmt.Errorf("config: read %s: %w", path, err)
+	}
+
+	var cfg Config
+	if err := json.Unmarshal(data, &cfg); err != nil {
+		return nil, fmt.Errorf("config: parse %s: %w", path, err)
+	}
+	return &cfg, nil
+}
+
+func (s *FileStore) Save(cfg *Config) error {
+	if err := cfg.Validate(); err != nil {
+		return err
+	}
+
+	data, err := json.MarshalIndent(cfg, "", "  ")
+	if err != nil {
+		return fmt.Errorf("config: encode: %w", err)
+	}
+	data = append(data, '\n')
+
+	path := s.Path()
+	dir := filepath.Dir(path)
+	if err := os.MkdirAll(dir, 0o700); err != nil {
+		return fmt.Errorf("config: create %s: %w", dir, err)
+	}
+
+	tmp, err := os.CreateTemp(dir, ".config-*.json")
+	if err != nil {
+		return fmt.Errorf("config: create temp file: %w", err)
+	}
+	tmpName := tmp.Name()
+	defer func() {
+
+		_ = tmp.Close()
+		_ = os.Remove(tmpName)
+	}()
+
+	if err := tmp.Chmod(0o600); err != nil {
+		return fmt.Errorf("config: set permissions on temp file: %w", err)
+	}
+	if _, err := tmp.Write(data); err != nil {
+		return fmt.Errorf("config: write temp file: %w", err)
+	}
+
+	if err := tmp.Sync(); err != nil {
+		return fmt.Errorf("config: sync temp file: %w", err)
+	}
+	if err := tmp.Close(); err != nil {
+		return fmt.Errorf("config: close temp file: %w", err)
+	}
+	if err := os.Rename(tmpName, path); err != nil {
+		return fmt.Errorf("config: replace %s: %w", path, err)
+	}
+	return nil
+}
+
+func (c *Config) Validate() error {
+	if c.ServerURL != "" {
+		u, err := url.Parse(c.ServerURL)
+		if err != nil {
+			return fmt.Errorf("config: invalid server_url %q: %w", c.ServerURL, err)
+		}
+		if u.Scheme != "http" && u.Scheme != "https" {
+			return fmt.Errorf("config: server_url must use http or https, got %q", u.Scheme)
+		}
+		if u.Host == "" {
+			return fmt.Errorf("config: server_url %q is missing a host", c.ServerURL)
+		}
+	}
+
+	seen := make(map[string]struct{}, len(c.Vaults))
+	for _, v := range c.Vaults {
+		if err := ValidateVaultName(v.Name); err != nil {
+			return err
+		}
+		if _, dup := seen[v.Name]; dup {
+			return fmt.Errorf("config: vault %q is registered twice", v.Name)
+		}
+		seen[v.Name] = struct{}{}
+
+		if !filepath.IsAbs(v.Path) {
+			return fmt.Errorf("config: vault %q needs an absolute path, got %q", v.Name, v.Path)
+		}
+	}
+	return nil
+}
+
+func ValidateVaultName(name string) error {
+	switch {
+	case name == "":
+		return errors.New("config: vault name is empty")
+	case len(name) > maxVaultNameLen:
+		return fmt.Errorf("config: vault name %q is longer than %d characters", name, maxVaultNameLen)
+	case strings.ContainsAny(name, invalidNameChars):
+		return fmt.Errorf("config: vault name %q contains a space or one of %s", name, invalidNameChars)
+	case strings.HasPrefix(name, "-"):
+		return fmt.Errorf("config: vault name %q may not start with a dash", name)
+	case strings.HasPrefix(name, "."):
+		return fmt.Errorf("config: vault name %q may not start with a dot", name)
+	}
+	return nil
+}
+
+func (c *Config) Vault(name string) (*Vault, bool) {
+	for i := range c.Vaults {
+		if c.Vaults[i].Name == name {
+			return &c.Vaults[i], true
+		}
+	}
+	return nil, false
+}
+
+func (c *Config) AddVault(v Vault) error {
+	if err := ValidateVaultName(v.Name); err != nil {
+		return err
+	}
+	if _, exists := c.Vault(v.Name); exists {
+		return fmt.Errorf("config: vault %q is already registered", v.Name)
+	}
+	if !filepath.IsAbs(v.Path) {
+		return fmt.Errorf("config: vault %q needs an absolute path, got %q", v.Name, v.Path)
+	}
+	c.Vaults = append(c.Vaults, v)
+	return nil
+}
+
+func (c *Config) RemoveVault(name string) bool {
+	for i := range c.Vaults {
+		if c.Vaults[i].Name == name {
+			c.Vaults = append(c.Vaults[:i], c.Vaults[i+1:]...)
+			return true
+		}
+	}
+	return false
+}