Add artist members and multiple writers

library.json

@@ -1,21 +1,47 @@
 {
-  "Taylor Swift": [
+  "artists": [
     {
-      "title": "Love Story",
-      "composer": "Taylor Swift",
-      "performer": "Taylor Swift"
-    }
-  ],
-  "black midi": [
-    {
-      "title": "Love Story",
-      "composer": "Taylor Swift",
-      "performer": "black midi"
+      "name": "Taylor Swift",
+      "members": [
+        "Taylor Swift"
+      ],
+      "catalog": [
+        {
+          "title": "Love Story",
+          "writers": [
+            "Taylor Swift"
+          ],
+          "performer": "Taylor Swift"
+        }
+      ]
     },
     {
-      "title": "Love Story",
-      "composer": "black midi",
-      "performer": "black midi"
+      "name": "black midi",
+      "members": [
+        "Cameron Picton",
+        "Matt Kelvin",
+        "Morgan Simpson",
+        "Geordie Greep"
+      ],
+      "catalog": [
+        {
+          "title": "Love Story",
+          "writers": [
+            "Taylor Swift"
+          ],
+          "performer": "black midi"
+        },
+        {
+          "title": "Love Story",
+          "writers": [
+            "Cameron Picton",
+            "Matt Kelvin",
+            "Morgan Simpson",
+            "Geordie Greep"
+          ],
+          "performer": "black midi"
+        }
+      ]
     }
   ]
 }

src/library.rs

@@ -1,32 +1,16 @@
 use nanoserde::DeJson;
 use std::{
-    collections::{HashMap, HashSet},
-    hash::Hash,
+    collections::HashSet,
+    hash::{Hash, Hasher},
 };
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, DeJson)]
 pub struct Library {
     artists: HashSet<Artist>,
 }
 
 impl Library {
-    pub fn new(json: HashMap<String, Vec<Song>>) -> Self {
-        let artists = json
-            .into_iter()
-            .map(|(name, catalog)| Artist {
-                name,
-                catalog: catalog.into_iter().collect(),
-            })
-            .collect();
-        Library { artists }
-    }
-
     pub fn find_covers(&self) -> HashSet<&Song> {
-        let names = self
-            .artists
-            .iter()
-            .map(|artist| artist.name.clone())
-            .collect::<HashSet<_>>();
         self.artists
             .iter()
             .fold(HashSet::new(), |mut covers, artist| {
@@ -34,19 +18,20 @@ impl Library {
                 covers
             })
             .into_iter()
-            .filter(|song| names.contains(&song.composer))
+            .filter(|song| song.is_library_cover(self))
             .collect()
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq, DeJson)]
 struct Artist {
     name: String,
+    members: HashSet<String>,
     catalog: HashSet<Song>,
 }
 
 impl Hash for Artist {
-    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
+    fn hash<H: Hasher>(&self, state: &mut H) {
         self.name.hash(state);
     }
 }
@@ -55,27 +40,61 @@ impl Artist {
     fn covered_songs(&self) -> HashSet<&Song> {
         self.catalog
             .iter()
-            .filter(|song| song.composer != self.name)
+            .filter(|song| song.is_covered_by(self))
             .collect()
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Eq, Hash, DeJson)]
+#[derive(Debug, Clone, PartialEq, Eq, DeJson)]
 pub struct Song {
     pub title: String,
     pub performer: String,
-    pub composer: String,
+    pub writers: HashSet<String>,
+}
+
+impl Hash for Song {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.title.hash(state);
+        self.performer.hash(state);
+    }
+}
+
+impl Song {
+    fn is_library_cover(&self, library: &Library) -> bool {
+        library
+            .artists
+            .iter()
+            .any(|artist| self.is_cover_of(artist))
+    }
+
+    fn is_covered_by(&self, artist: &Artist) -> bool {
+        self.performer == artist.name && self.writers.is_disjoint(&artist.members)
+    }
+
+    fn is_cover_of(&self, artist: &Artist) -> bool {
+        self.performer != artist.name && !self.writers.is_disjoint(&artist.members)
+    }
 }
 
 #[cfg(test)]
 mod tests {
     use super::*;
 
+    fn bm_members() -> HashSet<String> {
+        [
+            "Cameron Picton".to_string(),
+            "Matt Kelvin".to_string(),
+            "Morgan Simpson".to_string(),
+            "Geordie Greep".to_string(),
+        ]
+        .into()
+    }
+
     fn bmbmbm() -> Song {
         Song {
             title: "bmbmbm".to_string(),
             performer: "black midi".to_string(),
-            composer: "black midi".to_string(),
+            writers: bm_members(),
         }
     }
 
@@ -83,7 +102,7 @@ mod tests {
         Song {
             title: "Love Story".to_string(),
             performer: performer.to_string(),
-            composer: "Taylor Swift".to_string(),
+            writers: ["Taylor Swift".to_string()].into(),
         }
     }
 
@@ -91,28 +110,75 @@ mod tests {
         Song {
             title: "21st Century Schizoid Man".to_string(),
             performer: "black midi".to_string(),
-            composer: "Greg Lake, Ian McDonald, Michael Giles, Peter Sinfield & Robert Fripp"
-                .to_string(),
+            writers: [
+                "Greg Lake".to_string(),
+                "Ian McDonald".to_string(),
+                "Michael Giles".to_string(),
+                "Peter Sinfield".to_string(),
+                "Robert Fripp".to_string(),
+            ]
+            .into(),
+        }
+    }
+
+    fn exile() -> Song {
+        Song {
+            title: "Exile".to_string(),
+            performer: "Taylor Swift".to_string(),
+            writers: [
+                "Taylor Swift".to_string(),
+                "William Bowery".to_string(),
+                "Justin Vernon".to_string(),
+            ]
+            .into(),
         }
     }
 
     fn bm() -> Artist {
         Artist {
             name: "black midi".to_string(),
-            catalog: HashSet::from([bmbmbm(), love_story("black midi"), schizoid_man()]),
+            members: bm_members(),
+            catalog: [bmbmbm(), love_story("black midi"), schizoid_man()].into(),
         }
     }
 
     fn ts() -> Artist {
         Artist {
             name: "Taylor Swift".to_string(),
-            catalog: HashSet::from([love_story("Taylor Swift")]),
+            members: ["Taylor Swift".to_string()].into(),
+            catalog: [love_story("Taylor Swift"), exile()].into(),
+        }
+    }
+
+    fn bon_iver() -> Artist {
+        Artist {
+            name: "Bon Iver".to_string(),
+            members: [
+                "Justin Vernon".to_string(),
+                "Sean Carey".to_string(),
+                "Michael Noyce".to_string(),
+                "Matthew McCaughan".to_string(),
+            ]
+            .into(),
+            catalog: [
+                Song {
+                    title: "Skinny Love".to_string(),
+                    performer: "Bon Iver".to_string(),
+                    writers: ["Justin Vernon".to_string()].into(),
+                },
+                Song {
+                    title: "Holocene".to_string(),
+                    performer: "Bon Iver".to_string(),
+                    writers: ["Justin Vernon".to_string()].into(),
+                },
+            ]
+            .into(),
         }
     }
 
     fn library() -> Library {
         Library {
-            artists: HashSet::from([bm(), ts()]),
+            artists: HashSet::from([bm(), ts(), bon_iver()]),
         }
     }
 
@@ -121,8 +187,22 @@ mod tests {
         assert!(bm().covered_songs() == HashSet::from([&love_story("black midi"), &schizoid_man()]))
     }
 
+    #[test]
+    fn test_covered_songs_no_covers() {
+        assert!(bon_iver().covered_songs().is_empty())
+    }
+
     #[test]
     fn test_find_covers() {
         assert!(library().find_covers() == HashSet::from([&love_story("black midi")]))
     }
+
+    #[test]
+    fn test_find_covers_one_artist() {
+        assert!(Library {
+            artists: [bon_iver()].into()
+        }
+        .find_covers()
+        .is_empty())
+    }
 }

src/main.rs

@@ -1,22 +1,20 @@
 use nanoserde::DeJson;
-use std::{collections::HashMap, env, fs};
+use std::{env, fs};
 
 mod library;
-use crate::library::{Library, Song};
 
 fn main() {
     let file_path = env::args()
         .nth(1)
         .expect("Usage: cover path/to/library.json");
-    let data = fs::read_to_string(file_path).expect("Failed to open library file");
-    let json: HashMap<String, Vec<Song>> =
-        DeJson::deserialize_json(&data).expect("Failed to deserialize library");
-    let library = Library::new(json);
+    let json = fs::read_to_string(file_path).expect("Failed to open library file");
+    let library: library::Library =
+        DeJson::deserialize_json(&json).expect("Failed to deserialize library file");
     for cover in library.find_covers() {
         println!("Found cover!");
         println!(
-            "{}, by {}, covered by {}",
-            cover.title, cover.composer, cover.performer
+            "{}, by {:?}, covered by {}",
+            cover.title, cover.writers, cover.performer
         )
     }
 }