feat(config): load ntfy client.yml and resolve topic origins

Parse the official ntfy client configuration, apply command-line overrides, and turn short names, host/topic pairs, and absolute URLs into an origin and topic name.

internal/config/config.go

@@ -0,0 +1,215 @@
+// Package config loads an ntfy client.yml plus command-line overrides.
+package config
+
+import (
+	"fmt"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"gopkg.in/yaml.v3"
+)
+
+// DefaultPath is the per-user ntfy client config used by the official CLI.
+func DefaultPath() string {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return ""
+	}
+	return filepath.Join(home, ".config", "ntfy", "client.yml")
+}
+
+// Auth is sent as a Bearer token or HTTP basic credentials.
+// A token wins when both are set. Values are never formatted into errors.
+type Auth struct {
+	Token    string
+	User     string
+	Password string
+}
+
+// Equal reports whether two credential sets would produce the same header.
+func (a Auth) Equal(b Auth) bool {
+	return a.Token == b.Token && a.User == b.User && a.Password == b.Password
+}
+
+// Apply sets Authorization. A token is sent as Bearer; otherwise basic auth is used.
+func (a Auth) Apply(req *http.Request) {
+	if a.Token != "" {
+		req.Header.Set("Authorization", "Bearer "+a.Token)
+		return
+	}
+	if a.User != "" || a.Password != "" {
+		req.SetBasicAuth(a.User, a.Password)
+	}
+}
+
+// Sub is one topic the TUI should subscribe to.
+type Sub struct {
+	Origin  string
+	Name    string
+	Display string
+	Auth    Auth
+}
+
+// Label is the sidebar text for this topic.
+func (s Sub) Label() string {
+	if strings.TrimSpace(s.Display) != "" {
+		return s.Display
+	}
+	return s.Name
+}
+
+// App is the resolved runtime configuration.
+type App struct {
+	Since         string
+	DefaultHost   string
+	Auth          Auth
+	Subs          []Sub
+	StartupStatus string
+}
+
+// Options are CLI inputs. PathSet reports whether --config was passed.
+type Options struct {
+	Path    string
+	PathSet bool
+	Host    string
+	Token   string
+	User    string
+	Since   string
+	Topics  []string
+}
+
+type fileConfig struct {
+	DefaultHost     string    `yaml:"default-host"`
+	DefaultToken    string    `yaml:"default-token"`
+	DefaultUser     string    `yaml:"default-user"`
+	DefaultPassword string    `yaml:"default-password"`
+	Subscribe       []fileSub `yaml:"subscribe"`
+}
+
+type fileSub struct {
+	Topic    string  `yaml:"topic"`
+	Token    *string `yaml:"token"`
+	User     *string `yaml:"user"`
+	Password *string `yaml:"password"`
+}
+
+// Load reads client.yml when it exists and applies CLI overrides.
+// Positional topics replace the file's subscribe list.
+func Load(opt Options) (App, error) {
+	path := opt.Path
+	if path == "" {
+		path = DefaultPath()
+	}
+	var file fileConfig
+	data, err := os.ReadFile(path)
+	switch {
+	case err == nil:
+		if err := yaml.Unmarshal(data, &file); err != nil {
+			return App{}, fmt.Errorf("parse %s: %w", path, err)
+		}
+	case os.IsNotExist(err) && !opt.PathSet:
+		// A missing default file is fine when topics are passed explicitly.
+	case err != nil:
+		return App{}, fmt.Errorf("read config: %w", err)
+	}
+
+	host := first(opt.Host, file.DefaultHost)
+	auth := Auth{
+		Token:    file.DefaultToken,
+		User:     file.DefaultUser,
+		Password: file.DefaultPassword,
+	}
+	if opt.Token != "" {
+		auth.Token = opt.Token
+	}
+	if opt.User != "" {
+		auth.User, auth.Password = splitUser(opt.User)
+		auth.Token = ""
+	}
+	if auth.Token != "" {
+		auth.User, auth.Password = "", ""
+	}
+
+	since := opt.Since
+	if since == "" {
+		since = "all"
+	}
+
+	specs := file.Subscribe
+	if len(opt.Topics) > 0 {
+		specs = make([]fileSub, len(opt.Topics))
+		for i, topic := range opt.Topics {
+			specs[i].Topic = topic
+		}
+	}
+	if len(specs) == 0 {
+		if strings.TrimSpace(host) == "" {
+			return App{}, fmt.Errorf("no topic given and no default-host in %s", path)
+		}
+		return App{Since: since, DefaultHost: host, Auth: auth}, nil
+	}
+
+	subs := make([]Sub, 0, len(specs))
+	for _, spec := range specs {
+		origin, name, err := Resolve(spec.Topic, host)
+		if err != nil {
+			return App{}, err
+		}
+		subAuth := auth
+		if spec.Token != nil {
+			subAuth = Auth{Token: *spec.Token}
+		}
+		if spec.User != nil {
+			pass := ""
+			if spec.Password != nil {
+				pass = *spec.Password
+			}
+			subAuth = Auth{User: *spec.User, Password: pass}
+		}
+		subs = append(subs, Sub{Origin: origin, Name: name, Auth: subAuth})
+	}
+
+	return App{
+		Since:       since,
+		DefaultHost: host,
+		Auth:        auth,
+		Subs:        subs,
+	}, nil
+}
+
+// MergeSubs appends topics that are not already in base, compared by origin and name.
+func MergeSubs(base, extra []Sub) []Sub {
+	out := append([]Sub(nil), base...)
+	seen := map[string]bool{}
+	for _, sub := range out {
+		seen[sub.Origin+"\n"+sub.Name] = true
+	}
+	for _, sub := range extra {
+		key := sub.Origin + "\n" + sub.Name
+		if seen[key] {
+			continue
+		}
+		seen[key] = true
+		out = append(out, sub)
+	}
+	return out
+}
+
+func first(vals ...string) string {
+	for _, v := range vals {
+		if strings.TrimSpace(v) != "" {
+			return strings.TrimSpace(v)
+		}
+	}
+	return ""
+}
+
+func splitUser(s string) (string, string) {
+	user, pass, ok := strings.Cut(s, ":")
+	if !ok {
+		return user, ""
+	}
+	return user, pass
+}