feat: add picker component

picker/intstate.go

@@ -0,0 +1,82 @@
+package picker
+
+type IntState struct {
+	min       int
+	max       int
+	selection int
+	ignoreMin bool
+	ignoreMax bool
+}
+
+func NewIntState(min, max, selection int, ignoreMin, ignoreMax bool) *IntState {
+	switch {
+	case selection < min && !ignoreMin:
+		selection = min
+	case selection > max && !ignoreMax:
+		selection = max
+	}
+
+	return &IntState{
+		min:       min,
+		max:       max,
+		ignoreMin: ignoreMin,
+		ignoreMax: ignoreMax,
+		selection: selection,
+	}
+}
+
+func (s *IntState) GetValue() interface{} {
+	return s.selection
+}
+
+func (s *IntState) NextExists() bool {
+	return s.ignoreMax ||
+		s.selection < s.max
+}
+
+func (s *IntState) PrevExists() bool {
+	return s.ignoreMin ||
+		s.selection > s.min
+}
+
+func (s *IntState) Next(canCycle bool) {
+	switch {
+	case s.NextExists():
+		s.selection++
+
+	case canCycle:
+		s.selection = s.min
+	}
+}
+
+func (s *IntState) Prev(canCycle bool) {
+	switch {
+	case s.PrevExists():
+		s.selection--
+
+	case canCycle:
+		s.selection = s.max
+	}
+}
+
+func (s *IntState) StepForward(size int) {
+	s.selection += size
+	if s.selection > s.max && !s.ignoreMax {
+		s.selection = s.max
+	}
+}
+
+func (s *IntState) StepBackward(size int) {
+	s.selection -= size
+	if s.selection < s.min && !s.ignoreMin {
+		s.selection = s.min
+	}
+}
+
+func (s *IntState) JumpForward() {
+	s.selection = s.max
+}
+
+func (s *IntState) JumpBackward() {
+	s.selection = s.min
+}