Add Rankable protocol (#803)

- Add extension helpers to Array of Rankable.
- ArtistDigest and VenueDigest are now Rankable, and do not need
specialized extensions on Array anymore.

Sources/Site/Music/ArtistDigest.swift

@@ -30,26 +30,4 @@ extension ArtistDigest: LibraryComparable {
   }
 }
 
-extension Array where Element == ArtistDigest {
-  func ranked(by sort: RankingSort) -> [Ranking: [ArtistDigest]] {
-    self.reduce(into: [Ranking: [ArtistDigest]]()) {
-      let ranking = $1.ranking(for: sort)
-      var arr = ($0[ranking] ?? [])
-      arr.append($1)
-      $0[ranking] = arr
-    }
-  }
-
-  var firstSeen: [PartialDate: [ArtistDigest]] {
-    self.reduce(into: [PartialDate: [(ArtistDigest, FirstSet)]]()) {
-      let firstSet = $1.firstSet
-      var arr = ($0[firstSet.date] ?? [])
-      arr.append(($1, firstSet))
-      $0[firstSet.date] = arr
-    }.reduce(into: [PartialDate: [ArtistDigest]]()) {
-      $0[$1.key] = $1.value.sorted(by: { lhs, rhs in
-        lhs.1.rank < rhs.1.rank
-      }).map { $0.0 }
-    }
-  }
-}
+extension ArtistDigest: Rankable {}

Sources/Site/Music/Rankable.swift

@@ -0,0 +1,37 @@
+//
+//  Rankable.swift
+//
+//
+//  Created by Greg Bolsinga on 6/8/24.
+//
+
+import Foundation
+
+protocol Rankable: LibraryComparable, Hashable, PathRestorable {
+  var firstSet: FirstSet { get }
+  func ranking(for sort: RankingSort) -> Ranking
+}
+
+extension Array where Element: Rankable {
+  func ranked(by sort: RankingSort) -> [Ranking: [Element]] {
+    self.reduce(into: [Ranking: [Element]]()) {
+      let ranking = $1.ranking(for: sort)
+      var arr = ($0[ranking] ?? [])
+      arr.append($1)
+      $0[ranking] = arr
+    }
+  }
+
+  var firstSeen: [PartialDate: [Element]] {
+    self.reduce(into: [PartialDate: [(Element, FirstSet)]]()) {
+      let firstSet = $1.firstSet
+      var arr = ($0[firstSet.date] ?? [])
+      arr.append(($1, firstSet))
+      $0[firstSet.date] = arr
+    }.reduce(into: [PartialDate: [Element]]()) {
+      $0[$1.key] = $1.value.sorted(by: { lhs, rhs in
+        lhs.1.rank < rhs.1.rank
+      }).map { $0.0 }
+    }
+  }
+}

Sources/Site/Music/VenueDigest.swift

@@ -30,26 +30,4 @@ extension VenueDigest: LibraryComparable {
   }
 }
 
-extension Array where Element == VenueDigest {
-  func ranked(by sort: RankingSort) -> [Ranking: [VenueDigest]] {
-    self.reduce(into: [Ranking: [VenueDigest]]()) {
-      let ranking = $1.ranking(for: sort)
-      var arr = ($0[ranking] ?? [])
-      arr.append($1)
-      $0[ranking] = arr
-    }
-  }
-
-  var firstSeen: [PartialDate: [VenueDigest]] {
-    self.reduce(into: [PartialDate: [(VenueDigest, FirstSet)]]()) {
-      let firstSet = $1.firstSet
-      var arr = ($0[firstSet.date] ?? [])
-      arr.append(($1, firstSet))
-      $0[firstSet.date] = arr
-    }.reduce(into: [PartialDate: [VenueDigest]]()) {
-      $0[$1.key] = $1.value.sorted(by: { lhs, rhs in
-        lhs.1.rank < rhs.1.rank
-      }).map { $0.0 }
-    }
-  }
-}
+extension VenueDigest: Rankable {}