add RandomCard and String to PoC interface

1 files changed, 15 insertions, 2 deletions

diff --git a/go/game/pileOfCards.go b/go/game/pileOfCards.go
index 88a3c750..27ecb09d 100644
--- a/go/game/pileOfCards.go
+++ b/go/game/pileOfCards.go
@@ -17,9 +17,11 @@ type PileOfCards interface {
 	AddCards(cards []*Card)
 	AddCard(card *Card)
 	RemoveCard(card *Card)
+	RandomCard() *Card
 	MoveCard(card *Card, into PileOfCards)
 	MoveInto(into PileOfCards)
 	ToList() string
+	String() string
 }
 
 type PileOfCardsBase struct {
@@ -39,13 +41,13 @@ func (poc *PileOfCardsBase) String() string {
 	return fmt.Sprintf("[%s]", strings.Join(cardNames, ", "))
 }
 
-var InvalidPocString = errors.New("Invalid PileOfCards format")
+var ErrInvalidPocString = errors.New("Invalid PileOfCards format")
 
 // Initialise a PileOfCard from a string.
 // Return InvalidPocString on error.
 func (poc *PileOfCardsBase) FromString(in string) error {
 	if in[0] != '[' || in[len(in)-1] != ']' {
-		return InvalidPocString
+		return ErrInvalidPocString
 	}
 
 	in = in[1 : len(in)-1]
@@ -106,6 +108,17 @@ func (poc *PileOfCardsBase) RemoveCard(card *Card) {
 	}
 }
 
+func (poc *PileOfCardsBase) RandomCard() *Card {
+	availCards := poc.Cards()
+	var pick int
+	if n := len(availCards); n > 1 {
+		pick = rand.Intn(n - 1)
+	} else {
+		pick = 0
+	}
+	return availCards[pick]
+}
+
 func (poc *PileOfCardsBase) MoveCard(c *Card, into PileOfCards) {
 	poc.RemoveCard(c)
 	into.AddCard(c)