GODT-1815: Combined/Split mode

internal/user/map.go

@@ -0,0 +1,89 @@
+package user
+
+import (
+	"github.com/bradenaw/juniper/xslices"
+	"golang.org/x/exp/slices"
+)
+
+type ordMap[Key comparable, Val, Data any] struct {
+	data  map[Key]Data
+	order []Key
+
+	toKey  func(Data) Key
+	toVal  func(Data) Val
+	isLess func(Data, Data) bool
+}
+
+func newOrdMap[Key comparable, Val, Data any](
+	key func(Data) Key,
+	value func(Data) Val,
+	less func(Data, Data) bool,
+	data ...Data,
+) ordMap[Key, Val, Data] {
+	m := ordMap[Key, Val, Data]{
+		data: make(map[Key]Data),
+
+		toKey:  key,
+		toVal:  value,
+		isLess: less,
+	}
+
+	for _, d := range data {
+		m.insert(d)
+	}
+
+	return m
+}
+
+func (set *ordMap[Key, Val, Data]) insert(data Data) {
+	if _, ok := set.data[set.toKey(data)]; ok {
+		set.delete(set.toKey(data))
+	}
+
+	set.data[set.toKey(data)] = data
+
+	set.order = append(set.order, set.toKey(data))
+
+	slices.SortFunc(set.order, func(a, b Key) bool {
+		return set.isLess(set.data[a], set.data[b])
+	})
+}
+
+func (set *ordMap[Key, Val, Data]) delete(key Key) Val {
+	data, ok := set.data[key]
+	if !ok {
+		return *new(Val)
+	}
+
+	delete(set.data, key)
+
+	set.order = xslices.Filter(set.order, func(otherKey Key) bool {
+		return otherKey != key
+	})
+
+	return set.toVal(data)
+}
+
+func (set *ordMap[Key, Val, Data]) get(key Key) Val {
+	return set.toVal(set.data[key])
+}
+
+func (set *ordMap[Key, Val, Data]) keys() []Key {
+	return set.order
+}
+
+func (set *ordMap[Key, Val, Data]) values() []Val {
+	return xslices.Map(set.order, func(key Key) Val {
+		return set.toVal(set.data[key])
+	})
+}
+
+func (set *ordMap[Key, Val, Data]) toMap() map[Key]Val {
+	m := make(map[Key]Val)
+
+	for _, key := range set.order {
+		m[key] = set.toVal(set.data[key])
+	}
+
+	return m
+}