package config import ( "fmt" "io" "reflect" "strings" "gopkg.in/yaml.v3" "github.com/Necoro/feed2imap-go/pkg/log" ) const ( strTag = "!!str" nullTag = "!!null" emptyTag = "" ) type config struct { *Config `yaml:",inline"` GlobalConfig Map `yaml:",inline"` Feeds []configGroupFeed } type group struct { Group string Feeds []configGroupFeed } type configGroupFeed struct { Target yaml.Node Feed Feed `yaml:",inline"` Group group `yaml:",inline"` Options Map `yaml:",inline"` } func (grpFeed *configGroupFeed) isGroup() bool { return grpFeed.Group.Group != "" } func (grpFeed *configGroupFeed) isFeed() bool { return grpFeed.Feed.Name != "" || grpFeed.Feed.Url != "" } func (grpFeed *configGroupFeed) target() string { tag := grpFeed.Target.ShortTag() switch tag { case strTag: return grpFeed.Target.Value case nullTag: return "" case emptyTag: // tag not set: continue on default: panic("unexpected tag " + tag + " for target node") } if grpFeed.Feed.Name != "" { return grpFeed.Feed.Name } return grpFeed.Group.Group } func unmarshal(in io.Reader, cfg *Config) (config, error) { parsedCfg := config{Config: cfg} d := yaml.NewDecoder(in) if err := d.Decode(&parsedCfg); err != nil && err != io.EOF { return config{}, err } return parsedCfg, nil } func (cfg *Config) parse(in io.Reader) error { var ( err error parsedCfg config ) if parsedCfg, err = unmarshal(in, cfg); err != nil { return fmt.Errorf("while unmarshalling: %w", err) } if err := buildFeeds(parsedCfg.Feeds, []string{}, cfg.Feeds, &cfg.FeedOptions); err != nil { return fmt.Errorf("while parsing: %w", err) } return nil } func appTarget(target []string, app string) []string { switch { case len(target) == 0 && app == "": return []string{} case len(target) == 0: return []string{app} case app == "": return target default: return append(target, app) } } func buildOptions(globalFeedOptions *Options, options Map) (feedOptions Options, unknownFields []string) { if options == nil { // no options set for the feed: copy global options and be done return *globalFeedOptions, unknownFields } fv := reflect.ValueOf(&feedOptions).Elem() gv := reflect.ValueOf(globalFeedOptions).Elem() n := gv.NumField() for i := 0; i < n; i++ { val := fv.Field(i) f := fv.Type().Field(i) if f.PkgPath != "" && !f.Anonymous { continue } tag := f.Tag.Get("yaml") if tag == "" { continue } name := strings.Split(tag, ",")[0] set, ok := options[name] if ok { // in the map -> copy and delete val.Set(reflect.ValueOf(set)) delete(options, name) } else { // not in the map -> copy from global val.Set(gv.Field(i)) } } // remaining fields are unknown for k := range options { unknownFields = append(unknownFields, k) } return feedOptions, unknownFields } // Fetch the group structure and populate the `targetStr` fields in the feeds func buildFeeds(cfg []configGroupFeed, target []string, feeds Feeds, globalFeedOptions *Options) error { for _, f := range cfg { target := appTarget(target, f.target()) switch { case f.isFeed() && f.isGroup(): return fmt.Errorf("Entry with targetStr %s is both a Feed and a group", target) case f.isFeed(): feedCopy := f.Feed name := f.Feed.Name if name == "" { return fmt.Errorf("Unnamed feed") } if _, ok := feeds[name]; ok { return fmt.Errorf("Duplicate Feed Name '%s'", name) } opt, unknown := buildOptions(globalFeedOptions, f.Options) for _, optName := range unknown { log.Warnf("Unknown option '%s' for feed '%s'. Ignored!", optName, name) } feedCopy.Options = opt feedCopy.Target = target feeds[name] = &feedCopy case f.isGroup(): if err := buildFeeds(f.Group.Feeds, target, feeds, globalFeedOptions); err != nil { return err } for optName := range f.Options { log.Warnf("Unknown option '%s' for group '%s'. Ignored!", optName, f.Group.Group) } } } return nil }