Add configuration

config.go

@@ -0,0 +1,136 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/BurntSushi/toml"
+)
+
+type configDuration struct {
+	time.Duration
+}
+
+func (d *configDuration) UnmarshalText(text []byte) error {
+	value, err := time.ParseDuration(string(text))
+	if err != nil {
+		return err
+	}
+	d.Duration = value
+	return nil
+}
+
+type Config struct {
+	Theme           string         `toml:"theme"`
+	RefreshInterval configDuration `toml:"refresh_interval"`
+	Repository      string         `toml:"repository"`
+	ShowAll         bool           `toml:"show_all"`
+	Limit           int            `toml:"limit"`
+	Endpoint        string         `toml:"endpoint"`
+	Display         DisplayConfig  `toml:"display"`
+	Paths           PathConfig     `toml:"paths"`
+}
+
+type DisplayConfig struct {
+	FoldResolved           bool `toml:"fold_resolved"`
+	ThreadListWidthPercent int  `toml:"thread_list_width_percent"`
+}
+
+type PathConfig struct {
+	Scroll         bool           `toml:"scroll"`
+	ScrollInterval configDuration `toml:"scroll_interval"`
+}
+
+func defaultConfig() Config {
+	return Config{
+		Theme:           "dark",
+		RefreshInterval: configDuration{10 * time.Second},
+		Limit:           50,
+		Endpoint:        "https://api.github.com/graphql",
+		Display: DisplayConfig{
+			FoldResolved:           true,
+			ThreadListWidthPercent: 33,
+		},
+		Paths: PathConfig{
+			Scroll:         false,
+			ScrollInterval: configDuration{350 * time.Millisecond},
+		},
+	}
+}
+
+func configPath() (string, error) {
+	if path := os.Getenv("GH_THREADS_CONFIG"); path != "" {
+		return path, nil
+	}
+	if base := os.Getenv("XDG_CONFIG_HOME"); base != "" {
+		return filepath.Join(base, "gh-threads", "config.toml"), nil
+	}
+	base, err := os.UserConfigDir()
+	if err != nil {
+		return "", fmt.Errorf("find user config directory: %w", err)
+	}
+	preferred := filepath.Join(base, "gh-threads", "config.toml")
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return "", fmt.Errorf("find home directory: %w", err)
+	}
+	fallback := filepath.Join(home, ".config", "gh-threads", "config.toml")
+	return existingConfigPath(preferred, fallback), nil
+}
+
+func existingConfigPath(preferred, fallback string) string {
+	if _, err := os.Stat(preferred); err == nil || !errors.Is(err, os.ErrNotExist) {
+		return preferred
+	}
+	if _, err := os.Stat(fallback); err == nil {
+		return fallback
+	}
+	return preferred
+}
+
+func loadConfig(path string, required bool) (Config, error) {
+	config := defaultConfig()
+	metadata, err := toml.DecodeFile(path, &config)
+	if err != nil {
+		if !required && errors.Is(err, os.ErrNotExist) {
+			return config, nil
+		}
+		return Config{}, fmt.Errorf("read config %s: %w", path, err)
+	}
+	if undecoded := metadata.Undecoded(); len(undecoded) > 0 {
+		keys := make([]string, len(undecoded))
+		for i, key := range undecoded {
+			keys[i] = key.String()
+		}
+		return Config{}, fmt.Errorf("config %s contains unknown settings: %s", path, strings.Join(keys, ", "))
+	}
+	return config, nil
+}
+
+func validateConfig(config Config) error {
+	switch config.Theme {
+	case "dark", "light":
+	default:
+		return fmt.Errorf("theme must be dark or light")
+	}
+	if config.RefreshInterval.Duration < 2*time.Second {
+		return fmt.Errorf("refresh_interval must be at least 2s")
+	}
+	if config.Limit < 1 || config.Limit > 100 {
+		return fmt.Errorf("limit must be between 1 and 100")
+	}
+	if config.Paths.ScrollInterval.Duration < 50*time.Millisecond {
+		return fmt.Errorf("paths.scroll_interval must be at least 50ms")
+	}
+	if config.Display.ThreadListWidthPercent < 20 || config.Display.ThreadListWidthPercent > 60 {
+		return fmt.Errorf("display.thread_list_width_percent must be between 20 and 60")
+	}
+	if config.ShowAll && config.Repository == "" {
+		return fmt.Errorf("show_all requires repository")
+	}
+	return nil
+}