Moved logic of collapsing songs into albums to model package

(it should really be called domain.... maybe will rename it later)

utils/gravatar/gravatar.go

@@ -5,7 +5,7 @@ import (
 	"fmt"
 	"strings"
 
-	"github.com/navidrome/navidrome/utils/math2"
+	"github.com/navidrome/navidrome/utils/number"
 )
 
 const baseUrl = "https://www.gravatar.com/avatar"
@@ -19,7 +19,7 @@ func Url(email string, size int) string {
 	if size < 1 {
 		size = defaultSize
 	}
-	size = math2.Min(maxSize, size)
+	size = number.Min(maxSize, size)
 
 	return fmt.Sprintf("%s/%x?s=%d", baseUrl, hash, size)
 }

utils/number/number.go

@@ -1,4 +1,4 @@
-package math2
+package number
 
 import "golang.org/x/exp/constraints"
 

utils/number/number_test.go

@@ -1,38 +1,38 @@
-package math2_test
+package number_test
 
 import (
 	"testing"
 
-	"github.com/navidrome/navidrome/utils/math2"
+	"github.com/navidrome/navidrome/utils/number"
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 )
 
-func TestMath2(t *testing.T) {
+func TestNumber(t *testing.T) {
 	RegisterFailHandler(Fail)
-	RunSpecs(t, "Math2 Suite")
+	RunSpecs(t, "Number Suite")
 }
 
 var _ = Describe("Min", func() {
 	It("returns zero value if no arguments are passed", func() {
-		Expect(math2.Min[int]()).To(BeZero())
+		Expect(number.Min[int]()).To(BeZero())
 	})
 	It("returns the smallest int", func() {
-		Expect(math2.Min(1, 2)).To(Equal(1))
+		Expect(number.Min(1, 2)).To(Equal(1))
 	})
 	It("returns the smallest float", func() {
-		Expect(math2.Min(-4.1, -4.2, -4.0)).To(Equal(-4.2))
+		Expect(number.Min(-4.1, -4.2, -4.0)).To(Equal(-4.2))
 	})
 })
 
 var _ = Describe("Max", func() {
 	It("returns zero value if no arguments are passed", func() {
-		Expect(math2.Max[int]()).To(BeZero())
+		Expect(number.Max[int]()).To(BeZero())
 	})
 	It("returns the biggest int", func() {
-		Expect(math2.Max(1, 2)).To(Equal(2))
+		Expect(number.Max(1, 2)).To(Equal(2))
 	})
 	It("returns the biggest float", func() {
-		Expect(math2.Max(-4.1, -4.2, -4.0)).To(Equal(-4.0))
+		Expect(number.Max(-4.1, -4.2, -4.0)).To(Equal(-4.0))
 	})
 })

utils/slice/slice.go

@@ -0,0 +1,35 @@
+package slice
+
+func Group[T any, K comparable](s []T, keyFunc func(T) K) map[K][]T {
+	m := map[K][]T{}
+	for _, item := range s {
+		k := keyFunc(item)
+		m[k] = append(m[k], item)
+	}
+	return m
+}
+
+func MostFrequent[T comparable](list []T) T {
+	if len(list) == 0 {
+		var zero T
+		return zero
+	}
+	var topItem T
+	var topCount int
+	counters := map[T]int{}
+
+	if len(list) == 1 {
+		topItem = list[0]
+	} else {
+		for _, id := range list {
+			c := counters[id] + 1
+			counters[id] = c
+			if c > topCount {
+				topItem = id
+				topCount = c
+			}
+		}
+	}
+
+	return topItem
+}

utils/slice/slice_test.go

@@ -0,0 +1,43 @@
+package slice_test
+
+import (
+	"testing"
+
+	"github.com/navidrome/navidrome/utils/slice"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestSlice(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Slice Suite")
+}
+
+var _ = Describe("Group", func() {
+	It("returns empty map for an empty input", func() {
+		keyFunc := func(v int) int { return v % 2 }
+		result := slice.Group([]int{}, keyFunc)
+		Expect(result).To(BeEmpty())
+	})
+
+	It("groups by the result of the key function", func() {
+		keyFunc := func(v int) int { return v % 2 }
+		result := slice.Group([]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}, keyFunc)
+		Expect(result).To(HaveLen(2))
+		Expect(result[0]).To(ConsistOf(2, 4, 6, 8, 10))
+		Expect(result[1]).To(ConsistOf(1, 3, 5, 7, 9, 11))
+	})
+})
+
+var _ = Describe("MostFrequent", func() {
+	It("returns zero value if no arguments are passed", func() {
+		Expect(slice.MostFrequent([]int{})).To(BeZero())
+	})
+
+	It("returns the single item", func() {
+		Expect(slice.MostFrequent([]string{"123"})).To(Equal("123"))
+	})
+	It("returns the item that appeared more times", func() {
+		Expect(slice.MostFrequent([]string{"1", "2", "1", "2", "3", "2"})).To(Equal("2"))
+	})
+})