1 files changed, 130 insertions, 0 deletions
diff --git a/internal/yaml/yaml.go b/internal/yaml/yaml.go
new file mode 100644
index 0000000..8cbace7
--- /dev/null
+++ b/internal/yaml/yaml.go
@@ -0,0 +1,130 @@
+package yaml
+
+import (
+	"fmt"
+	"io/ioutil"
+
+	"gopkg.in/yaml.v3"
+
+	C "github.com/Necoro/feed2imap-go/internal/config"
+	F "github.com/Necoro/feed2imap-go/internal/feed"
+)
+
+type config struct {
+	GlobalConfig C.Map `yaml:",inline"`
+	Feeds        []configGroupFeed
+}
+
+type group struct {
+	Group string
+	Feeds []configGroupFeed
+}
+
+type feed struct {
+	Name      string
+	Url       string
+	C.Options `yaml:",inline"`
+}
+
+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 parse(buf []byte) (config, error) {
+	var parsedCfg config
+	if err := yaml.Unmarshal(buf, &parsedCfg); err != nil {
+		return parsedCfg, fmt.Errorf("while unmarshalling: %w", err)
+	}
+	//fmt.Printf("--- parsedCfg:\n%+v\n\n", parsedCfg)
+
+	return parsedCfg, 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)
+	}
+}
+
+// Parse the group structure and populate the `Target` fields in the feeds
+func buildFeeds(cfg []configGroupFeed, target []string, feeds F.Feeds) error {
+	for idx := range cfg {
+		f := &cfg[idx] // cannot use `_, f := range cfg` as it returns copies(!), but we need the originals
+		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)
+			}
+			feeds[name] = &F.Feed{
+				Name:    f.Feed.Name,
+				Target:  target,
+				Url:     f.Feed.Url,
+				Options: f.Feed.Options,
+			}
+
+		case f.isGroup():
+			if err := buildFeeds(f.Group.Feeds, target, feeds); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}
+
+func Load(path string) (C.Config, F.Feeds, error) {
+	buf, err := ioutil.ReadFile(path)
+	if err != nil {
+		return C.Config{}, nil, fmt.Errorf("while reading '%s': %w", path, err)
+	}
+
+	var parsedCfg config
+	if parsedCfg, err = parse(buf); err != nil {
+		return C.Config{}, nil, err
+	}
+
+	feeds := F.Feeds{}
+
+	if err := buildFeeds(parsedCfg.Feeds, []string{}, feeds); err != nil {
+		return C.Config{}, nil, fmt.Errorf("while parsing: %w", err)
+	}
+
+	return C.Config{GlobalConfig: parsedCfg.GlobalConfig}, feeds, nil
+}