implement reporters if there exist possible target options

1 files changed, 29 insertions, 4 deletions

diff --git a/go/game/targets.go b/go/game/targets.go
index b33b8895..236b4850 100644
--- a/go/game/targets.go
+++ b/go/game/targets.go
@@ -222,6 +222,16 @@ func (t *Target) Options() (options []interface{}) {
 	return options
 }
 
+// HasOptions reports if there is at least one possible target.
+func (t *Target) HasOptions() bool {
+	for _, candidate := range t.candidates() {
+		if err := t.constraint(candidate); err == nil {
+			return true
+		}
+	}
+	return false
+}
+
 func (t *Target) CheckSelection(s *LocalState) error {
 	if t.RequireSelection() {
 		return fmt.Errorf("Number of selected targets and required ones does not match")
@@ -267,10 +277,23 @@ func (t *Targets) NoSelections() bool {
 	}
 	return true
 }
-func (t *Targets) Options() (options []interface{}) { return t.ts[t.idx].Options() }
-func (t *Targets) Cur() *Target                     { return t.ts[t.idx] }
-func (t *Targets) Next()                            { t.idx++ }
-func (t *Targets) Targets() []*Target               { return t.ts }
+
+// Options returns the options of the current target.
+func (t *Targets) Options() (options []any) { return t.ts[t.idx].Options() }
+
+// HasOptions reports if each target has at least one possible target option.
+func (ts *Targets) HasOptions() bool {
+	for _, t := range ts.ts {
+		if !t.HasOptions() {
+			return false
+		}
+	}
+	return true
+}
+
+func (t *Targets) Cur() *Target       { return t.ts[t.idx] }
+func (t *Targets) Next()              { t.idx++ }
+func (t *Targets) Targets() []*Target { return t.ts }
 
 func (t *Targets) CheckTargets(s *LocalState) error {
 	for _, target := range t.ts {
@@ -282,6 +305,7 @@ func (t *Targets) CheckTargets(s *LocalState) error {
 	return nil
 }
 
+// RequireSelection reports if any of the targets require a selection.
 func (targets *Targets) RequireSelection() bool {
 	for _, t := range targets.ts {
 		if t.RequireSelection() {
@@ -292,6 +316,7 @@ func (targets *Targets) RequireSelection() bool {
 	return false
 }
 
+// AllowSelection reports if any of the targets allow a selection.
 func (targets *Targets) AllowSelection() bool {
 	for _, t := range targets.ts {
 		if t.AllowSelection() {