/**
 * CWE-407 unit test for WeeChat gui-nicklist.c nick dedup defect.
 *
 * Defect: gui_nicklist_add_nick() calls gui_nicklist_search_nick() which
 *   performs O(N) linear scan through the nick linked list for each add.
 *   When bulk-adding N nicks (e.g., joining a large IRC channel with
 *   thousands of users), this yields O(N^2) total work.
 *
 * Fix: Maintain a hash table (name -> nick) per buffer for O(1) dedup.
 *
 * This test models the defect pattern in Java:
 *   - Defective: LinkedList + contains() for dedup on each add
 *   - Fixed: HashSet for O(1) dedup
 */
import java.util.*;

public class WeechatNicklistDedupTest {

    /** Defective: linear scan through existing nicks for dedup */
    static long defective(String[] nicks) {
        LinkedList<String> nicklist = new LinkedList<>();
        long ops = 0;
        for (String nick : nicks) {
            // gui_nicklist_search_nick_name: linear scan O(N)
            ops += nicklist.size();
            if (!nicklist.contains(nick)) {
                nicklist.add(nick);
            }
        }
        return ops;
    }

    /** Fixed: hash set for O(1) dedup */
    static long fixed(String[] nicks) {
        HashSet<String> nickSet = new HashSet<>();
        LinkedList<String> nicklist = new LinkedList<>();
        long ops = 0;
        for (String nick : nicks) {
            ops++; // O(1) hash lookup
            if (nickSet.add(nick)) {
                nicklist.add(nick);
            }
        }
        return ops;
    }

    public static void main(String[] args) {
        // Simulate joining a large IRC channel with 2000 unique users
        int N = 2000;
        String[] nicks = new String[N];
        for (int i = 0; i < N; i++) {
            nicks[i] = "user_" + i;
        }

        long defOps = defective(nicks);
        long fixOps = fixed(nicks);

        double ratio = (double) defOps / fixOps;

        System.out.println("=== WeeChat gui-nicklist.c Nick Dedup Test ===");
        System.out.println("Nicks added:         " + N);
        System.out.println("Defective ops:       " + defOps);
        System.out.println("Fixed ops:           " + fixOps);
        System.out.printf("Ratio (defective/fixed): %.1fx%n", ratio);

        // Verify: defective should be significantly more expensive
        boolean pass = ratio >= 5.0;
        System.out.println("RESULT: " + (pass ? "PASS" : "FAIL")
            + " (ratio >= 5.0 required)");

        if (!pass) System.exit(1);
    }
}