Add a bunch of logging.

cardsim/player.go

@@ -463,3 +463,10 @@ func (p *Player[C]) ReportError(e error) {
 func (p *Player[C]) CanAct() bool {
 	return p.ActionsRemaining > 0 && (len(p.Hand) > 0 || len(p.PermanentActions) > 0)
 }
+
+func (p *Player[C]) Debug(minLevel int, msg Message) {
+	if p.DebugLevel < minLevel {
+		return
+	}
+	p.TemporaryMessages = append(p.TemporaryMessages, msg)
+}

cardsim/rules.go

@@ -334,18 +334,21 @@ func (r *RuleCollection[C]) Run(p *Player[C]) error {
 		r.steps = steps
 	}
 
+	p.Debug(2, Msgf("Executing steps: %v", steps))
+
 	var errs ErrorCollector
 	for _, step := range steps {
 		stepRules := r.byStep[step]
-		p.Rand.Shuffle(len(stepRules), func(i, j int) {
-			stepRules[i], stepRules[j] = stepRules[j], stepRules[i]
-		})
+		p.Debug(3, Msgf("Executing step %d; length %d", step, len(stepRules)))
+		ShuffleAll(stepRules, p.Rand)
 		var remove []RuleID
 		halt := false
 		for _, id := range stepRules {
 			rule := r.rules[id]
+			p.Debug(4, Msgf("Executing rule %x (labeled %q)", id, rule.Label()))
 			err := rule.Enact(p)
 			if err != nil {
+				p.Debug(2, Msgf("Rule %x (%q): error: %v", id, rule.Label(), err))
 				ignore := false
 				if errors.Is(err, ErrDeleteRule) {
 					remove = append(remove, id)
@@ -377,10 +380,14 @@ func (r *RuleCollection[C]) Run(p *Player[C]) error {
 			}
 		}
 		if halt {
-			return errs.Emit()
+			ret := errs.Emit()
+			p.Debug(2, Msgf("Rules stopping early. Result: %v", ret))
+			return ret
 		}
 	}
-	return errs.Emit()
+	ret := errs.Emit()
+	p.Debug(2, Msgf("Rules complete. Result: %v", ret))
+	return ret
 }
 
 func (r *RuleCollection[C]) applyDelayedUpdates() {