feat(domain): add StoredSong, SongSummary, SongRepositoryPort

crates/domain/src/song.rs

@@ -60,6 +60,40 @@ pub struct Song {
     pub sections: Vec<Section>,
 }
 
+use uuid::Uuid;
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct StoredSong {
+    pub id: Uuid,
+    pub song: Song,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct SongSummary {
+    pub id: Uuid,
+    pub meta: SongMeta,
+    pub preview_chords: Vec<String>,
+}
+
+pub fn song_preview_chords(song: &Song) -> Vec<String> {
+    let mut seen = std::collections::HashSet::new();
+    let mut result = Vec::new();
+    'outer: for section in &song.sections {
+        for line in &section.lines {
+            for cp in &line.chords {
+                let name = cp.chord.name(true);
+                if seen.insert(name.clone()) {
+                    result.push(name);
+                    if result.len() >= 5 {
+                        break 'outer;
+                    }
+                }
+            }
+        }
+    }
+    result
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;