import java.util.*;

/**
 * CWE-407 unit tests for Apache ActiveMQ defects 0002 and 0003.
 *
 * activemq-0002: DemandForwardingBridgeSupport.java duplicateSuppressionIsRequired()
 *   candidateConsumers is an ArrayList; matchFound() calls candidateConsumers.contains()
 *   — O(C) per alias per subscription — O(S×N×C) total per network connect.
 *   Fix: convert candidateConsumers to HashSet before the outer sub-scan loop for O(1) lookup.
 *
 * activemq-0003: TransactionContext.java isInXATransaction()
 *   ENDED_XA_TRANSACTION_CONTEXTS values are ArrayList<TransactionContext>;
 *   transactions.contains(this) — O(C) linear scan per XA txn bucket.
 *   Fix: change values to Set<TransactionContext> for O(1) contains.
 */
public class ActiveMQTest2 {

    // Simulate defect: matchFound with ArrayList candidateConsumers
    static boolean matchFound_list(List<Integer> candidateConsumers, List<Integer> networkConsumers) {
        for (Integer alias : networkConsumers) {
            if (candidateConsumers.contains(alias)) return true;  // O(C) — defect
        }
        return false;
    }

    // Simulate fix: matchFound with HashSet candidateConsumers
    static boolean matchFound_set(Set<Integer> candidateSet, List<Integer> networkConsumers) {
        for (Integer alias : networkConsumers) {
            if (candidateSet.contains(alias)) return true;  // O(1)
        }
        return false;
    }

    static void testActiveMQ0002() throws Exception {
        int C = 500;   // candidateConsumers per remote subscription
        int S = 2000;  // current subscriptions in the region
        int N = 3;     // networkConsumerIds per existing sub (small, 1–3)

        List<Integer> candidateList = new ArrayList<>(C);
        for (int i = 0; i < C; i++) candidateList.add(i);
        Set<Integer> candidateSet = new HashSet<>(candidateList);

        // Build S existing subs, each with N networkConsumerIds (not overlapping — full scan)
        List<List<Integer>> subs = new ArrayList<>(S);
        for (int s = 0; s < S; s++) {
            List<Integer> nc = new ArrayList<>(N);
            for (int n = 0; n < N; n++) nc.add(C + s * N + n);  // no overlap → full C scan each time
            subs.add(nc);
        }

        // correctness: last sub has a matching id → find it
        subs.get(S - 1).set(0, candidateList.get(0));
        boolean r1 = false, r2 = false;
        for (List<Integer> nc : subs) {
            if (matchFound_list(candidateList, nc)) { r1 = true; break; }
        }
        for (List<Integer> nc : subs) {
            if (matchFound_set(candidateSet, nc)) { r2 = true; break; }
        }
        assert r1 == r2 : "list and set must agree: " + r1 + " vs " + r2;

        // Reset: no match case (worst case — full scan)
        subs.get(S - 1).set(0, C + S * N + 99);
        int REPS = 20;

        long t0 = System.nanoTime();
        for (int r = 0; r < REPS; r++) {
            for (List<Integer> nc : subs) matchFound_list(candidateList, nc);
        }
        long tList = System.nanoTime() - t0;

        t0 = System.nanoTime();
        for (int r = 0; r < REPS; r++) {
            for (List<Integer> nc : subs) matchFound_set(candidateSet, nc);
        }
        long tSet = System.nanoTime() - t0;

        double ratio = (double) tList / tSet;
        System.out.printf("activemq-0002: list=%.3fs set=%.3fs ratio=%.1f×%n",
                tList / 1e9, tSet / 1e9, ratio);
        assert ratio > 4 : "Expected >4× speedup, got " + ratio;
        System.out.println("PASS activemq-0002");
    }

    // Simulate defect: isInXATransaction with List values
    static boolean isInXATransaction_list(Map<Integer, List<Integer>> endedContexts, int self) {
        for (List<Integer> transactions : endedContexts.values()) {
            if (transactions.contains(self)) return true;  // O(C) — defect
        }
        return false;
    }

    // Simulate fix: isInXATransaction with Set values
    static boolean isInXATransaction_set(Map<Integer, Set<Integer>> endedContexts, int self) {
        for (Set<Integer> transactions : endedContexts.values()) {
            if (transactions.contains(self)) return true;  // O(1)
        }
        return false;
    }

    static void testActiveMQ0003() throws Exception {
        int T = 50;    // ended XA transaction buckets
        int C = 200;   // contexts per bucket

        Map<Integer, List<Integer>> listMap = new LinkedHashMap<>();
        Map<Integer, Set<Integer>> setMap = new LinkedHashMap<>();
        for (int t = 0; t < T; t++) {
            List<Integer> lst = new ArrayList<>(C);
            Set<Integer> set = new LinkedHashSet<>(C);
            for (int c = 0; c < C; c++) {
                int ctx = t * C + c;
                lst.add(ctx);
                set.add(ctx);
            }
            listMap.put(t, lst);
            setMap.put(t, set);
        }

        // self not in any bucket → worst case (full scan)
        int self = T * C + 999;

        // correctness: not present
        assert !isInXATransaction_list(listMap, self);
        assert !isInXATransaction_set(setMap, self);

        int REPS = 10_000;
        long t0 = System.nanoTime();
        for (int r = 0; r < REPS; r++) isInXATransaction_list(listMap, self);
        long tList = System.nanoTime() - t0;

        t0 = System.nanoTime();
        for (int r = 0; r < REPS; r++) isInXATransaction_set(setMap, self);
        long tSet = System.nanoTime() - t0;

        double ratio = (double) tList / tSet;
        System.out.printf("activemq-0003: list=%.3fs set=%.3fs ratio=%.1f×%n",
                tList / 1e9, tSet / 1e9, ratio);
        assert ratio > 5 : "Expected >5× speedup, got " + ratio;
        System.out.println("PASS activemq-0003");
    }

    public static void main(String[] args) throws Exception {
        testActiveMQ0002();
        testActiveMQ0003();
        System.out.println("ALL PASS");
    }
}