1 files changed, 120 insertions, 0 deletions
diff --git a/pkg/config/yaml.go b/pkg/config/yaml.go
new file mode 100644
index 0000000..53d4d98
--- /dev/null
+++ b/pkg/config/yaml.go
@@ -0,0 +1,120 @@
+package config
+
+import (
+	"fmt"
+
+	"gopkg.in/yaml.v3"
+)
+
+type config struct {
+	*Config      `yaml:",inline"`
+	GlobalConfig Map `yaml:",inline"` // need to be duplicated, because the Map in Config is not filled
+	Feeds        []configGroupFeed
+}
+
+type group struct {
+	Group string
+	Feeds []configGroupFeed
+}
+
+type configGroupFeed struct {
+	Target *string
+	Feed   Feed  `yaml:",inline"`
+	Group  group `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 {
+	if grpFeed.Target != nil {
+		return *grpFeed.Target
+	}
+	if grpFeed.Feed.Name != "" {
+		return grpFeed.Feed.Name
+	}
+
+	return grpFeed.Group.Group
+}
+
+func unmarshal(buf []byte, cfg *Config) (config, error) {
+	parsedCfg := config{Config: cfg}
+
+	if err := yaml.Unmarshal(buf, &parsedCfg); err != nil {
+		return config{}, err
+	}
+	//fmt.Printf("--- parsedCfg:\n%+v\n\n", parsedCfg)
+
+	if parsedCfg.GlobalConfig == nil {
+		cfg.GlobalConfig = Map{}
+	} else {
+		cfg.GlobalConfig = parsedCfg.GlobalConfig // need to copy the map explicitly
+	}
+
+	return parsedCfg, nil
+}
+
+func (cfg *Config) parse(buf []byte) error {
+	var (
+		err       error
+		parsedCfg config
+	)
+
+	if parsedCfg, err = unmarshal(buf, cfg); err != nil {
+		return fmt.Errorf("while unmarshalling: %w", err)
+	}
+
+	if err := buildFeeds(parsedCfg.Feeds, []string{}, cfg.Feeds); 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)
+	}
+}
+
+// Fetch the group structure and populate the `Target` fields in the feeds
+func buildFeeds(cfg []configGroupFeed, target []string, feeds Feeds) error {
+	for _, f := range cfg {
+		target := appTarget(target, f.target())
+		switch {
+		case f.isFeed() && f.isGroup():
+			return fmt.Errorf("Entry with Target %s is both a Feed and a group", target)
+
+		case f.isFeed():
+			name := f.Feed.Name
+			if name == "" {
+				return fmt.Errorf("Unnamed feed")
+			}
+
+			if _, ok := feeds[name]; ok {
+				return fmt.Errorf("Duplicate Feed Name '%s'", name)
+			}
+			f.Feed.Target = target
+			feeds[name] = f.Feed
+
+		case f.isGroup():
+			if err := buildFeeds(f.Group.Feeds, target, feeds); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}