initial commit

internal/config/config.go

@@ -0,0 +1,203 @@
+package config
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+
+	"github.com/spf13/viper"
+)
+
+// Config represents the application configuration
+type Config struct {
+	Defaults DefaultConfig `mapstructure:"defaults"`
+}
+
+// DefaultConfig contains default values for CLI options
+type DefaultConfig struct {
+	Interval     string   `mapstructure:"interval"`
+	Numeric      bool     `mapstructure:"numeric"`
+	Fields       []string `mapstructure:"fields"`
+	Theme        string   `mapstructure:"theme"`
+	Units        string   `mapstructure:"units"`
+	Color        string   `mapstructure:"color"`
+	Resolve      bool     `mapstructure:"resolve"`
+	IPv4         bool     `mapstructure:"ipv4"`
+	IPv6         bool     `mapstructure:"ipv6"`
+	NoHeaders    bool     `mapstructure:"no_headers"`
+	OutputFormat string   `mapstructure:"output_format"`
+	SortBy       string   `mapstructure:"sort_by"`
+}
+
+var globalConfig *Config
+
+// Load loads configuration from file and environment variables
+func Load() (*Config, error) {
+	if globalConfig != nil {
+		return globalConfig, nil
+	}
+
+	v := viper.New()
+	
+	// set config name and file type (auto-detect based on extension)
+	v.SetConfigName("snitch")
+	// don't set config type - let viper auto-detect based on file extension
+	// this allows both .toml and .yaml files to work
+	v.AddConfigPath("$HOME/.config/snitch")
+	v.AddConfigPath("$HOME/.snitch")
+	v.AddConfigPath("/etc/snitch")
+
+	// Environment variables
+	v.SetEnvPrefix("SNITCH")
+	v.AutomaticEnv()
+	
+	// environment variable bindings for readme-documented variables
+	_ = v.BindEnv("config", "SNITCH_CONFIG")
+	_ = v.BindEnv("defaults.resolve", "SNITCH_RESOLVE")
+	_ = v.BindEnv("defaults.theme", "SNITCH_THEME")
+	_ = v.BindEnv("defaults.color", "SNITCH_NO_COLOR")
+	
+	// Set defaults
+	setDefaults(v)
+	
+	// Handle SNITCH_CONFIG environment variable for custom config path
+	if configPath := os.Getenv("SNITCH_CONFIG"); configPath != "" {
+		v.SetConfigFile(configPath)
+	}
+	
+	// Try to read config file
+	if err := v.ReadInConfig(); err != nil {
+		// It's OK if config file doesn't exist
+		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
+			return nil, fmt.Errorf("error reading config file: %w", err)
+		}
+	}
+	
+	// Handle special environment variables
+	handleSpecialEnvVars(v)
+	
+	// Unmarshal into config struct
+	config := &Config{}
+	if err := v.Unmarshal(config); err != nil {
+		return nil, fmt.Errorf("error unmarshaling config: %w", err)
+	}
+	
+	globalConfig = config
+	return config, nil
+}
+
+func setDefaults(v *viper.Viper) {
+	// Set default values matching the README specification
+	v.SetDefault("defaults.interval", "1s")
+	v.SetDefault("defaults.numeric", false)
+	v.SetDefault("defaults.fields", []string{"pid", "process", "user", "proto", "state", "laddr", "lport", "raddr", "rport"})
+	v.SetDefault("defaults.theme", "auto")
+	v.SetDefault("defaults.units", "auto")
+	v.SetDefault("defaults.color", "auto")
+	v.SetDefault("defaults.resolve", true)
+	v.SetDefault("defaults.ipv4", false)
+	v.SetDefault("defaults.ipv6", false)
+	v.SetDefault("defaults.no_headers", false)
+	v.SetDefault("defaults.output_format", "table")
+	v.SetDefault("defaults.sort_by", "")
+}
+
+func handleSpecialEnvVars(v *viper.Viper) {
+	// Handle SNITCH_NO_COLOR - if set to "1", disable color
+	if os.Getenv("SNITCH_NO_COLOR") == "1" {
+		v.Set("defaults.color", "never")
+	}
+	
+	// Handle SNITCH_RESOLVE - if set to "0", disable resolution
+	if os.Getenv("SNITCH_RESOLVE") == "0" {
+		v.Set("defaults.resolve", false)
+		v.Set("defaults.numeric", true)
+	}
+}
+
+// Get returns the global configuration, loading it if necessary
+func Get() *Config {
+	if globalConfig == nil {
+		config, err := Load()
+		if err != nil {
+			// Return default config on error
+			return &Config{
+				Defaults: DefaultConfig{
+					Interval:     "1s",
+					Numeric:      false,
+					Fields:       []string{"pid", "process", "user", "proto", "state", "laddr", "lport", "raddr", "rport"},
+					Theme:        "auto",
+					Units:        "auto",
+					Color:        "auto",
+					Resolve:      true,
+					IPv4:         false,
+					IPv6:         false,
+					NoHeaders:    false,
+					OutputFormat: "table",
+					SortBy:       "",
+				},
+			}
+		}
+		return config
+	}
+	return globalConfig
+}
+
+// GetInterval returns the configured interval as a duration
+func (c *Config) GetInterval() time.Duration {
+	if duration, err := time.ParseDuration(c.Defaults.Interval); err == nil {
+		return duration
+	}
+	return time.Second // default fallback
+}
+
+// CreateExampleConfig creates an example configuration file
+func CreateExampleConfig(path string) error {
+	exampleConfig := `# snitch configuration file
+# See https://github.com/you/snitch for full documentation
+
+[defaults]
+# Default refresh interval for watch/stats/trace commands
+interval = "1s"
+
+# Disable name/service resolution by default
+numeric = false
+
+# Default fields to display (comma-separated list)
+fields = ["pid", "process", "user", "proto", "state", "laddr", "lport", "raddr", "rport"]
+
+# Default theme for TUI (dark, light, mono, auto)
+theme = "auto"
+
+# Default units for byte display (auto, si, iec)
+units = "auto"
+
+# Default color mode (auto, always, never)
+color = "auto"
+
+# Enable name resolution by default
+resolve = true
+
+# Filter options
+ipv4 = false
+ipv6 = false
+
+# Output options
+no_headers = false
+output_format = "table"
+sort_by = ""
+`
+
+	// Ensure directory exists
+	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
+		return fmt.Errorf("failed to create config directory: %w", err)
+	}
+	
+	// Write config file
+	if err := os.WriteFile(path, []byte(exampleConfig), 0644); err != nil {
+		return fmt.Errorf("failed to write config file: %w", err)
+	}
+	
+	return nil
+}