plans.gno

 1package engine
 2
 3// LegalPlans lists every plan side can play from deck in state s: costs summing to 3,
 4// basics any number of times, each unspent special of deck at most once. Plans come in
 5// card order, depth first.
 6func (rs *Ruleset) LegalPlans(s State, side Side, deck uint64) []Plan {
 7	var buf [beatsPerRound]CardID
 8	return rs.extendPlans(nil, buf[:0], 0, deck&^s.Gnomes[side].Spent, 0)
 9}
10
11func (rs *Ruleset) extendPlans(out []Plan, plan Plan, beats int, available, used uint64) []Plan {
12	if beats == beatsPerRound {
13		done := make(Plan, len(plan))
14		copy(done, plan)
15		return append(out, done)
16	}
17	for i := range rs.Cards {
18		c := &rs.Cards[i]
19		if beats+c.Cost > beatsPerRound {
20			continue
21		}
22		bit := uint64(1) << uint(i)
23		if c.Special && (available&bit == 0 || used&bit != 0) {
24			continue
25		}
26		out = rs.extendPlans(out, append(plan, CardID(i)), beats+c.Cost, available, used|bit)
27	}
28	return out
29}