import java.util.*;

/**
 * Unit test for PCSX2 pcsx2-0002: GSCapture::GetCodecListForContainer
 * uses std::find_if on vector to deduplicate codec names during enumeration,
 * giving O(N^2) where N = number of codecs iterated.
 *
 * Fix: track seen codec names in an unordered_set for O(1) dedup.
 *
 * Defect file: pcsx2/GS/GSCapture.cpp  line 1501
 */
public class GSCaptureCodecDedupTest {

    // --- Defective: linear scan on list for dedup ---
    static List<String> getCodecListDefective(List<String> codecs) {
        List<String> ret = new ArrayList<>();
        for (String name : codecs) {
            boolean found = false;
            for (String existing : ret) {
                if (existing.equals(name)) {
                    found = true;
                    break;
                }
            }
            if (!found) {
                ret.add(name);
            }
        }
        return ret;
    }

    // --- Fixed: hash set dedup ---
    static List<String> getCodecListFixed(List<String> codecs) {
        List<String> ret = new ArrayList<>();
        Set<String> seen = new HashSet<>();
        for (String name : codecs) {
            if (seen.add(name)) {
                ret.add(name);
            }
        }
        return ret;
    }

    public static void main(String[] args) {
        int N = 500;

        // Build codec list with ~50% duplicates
        List<String> codecs = new ArrayList<>();
        for (int i = 0; i < N; i++) {
            codecs.add("codec_" + (i % (N / 2)));
        }

        // Correctness
        List<String> resDef = getCodecListDefective(codecs);
        List<String> resFix = getCodecListFixed(codecs);
        assert resDef.equals(resFix) : "Mismatch";

        // Warmup
        for (int i = 0; i < 500; i++) {
            getCodecListDefective(codecs);
            getCodecListFixed(codecs);
        }

        int ITER = 5000;
        long t0 = System.nanoTime();
        for (int i = 0; i < ITER; i++) getCodecListDefective(codecs);
        long defNs = System.nanoTime() - t0;

        t0 = System.nanoTime();
        for (int i = 0; i < ITER; i++) getCodecListFixed(codecs);
        long fixNs = System.nanoTime() - t0;

        double ratio = (double) defNs / fixNs;
        System.out.printf("GSCapture codec dedup  N=%d  defect=%.1fms  fixed=%.1fms  ratio=%.1fx%n",
                N, defNs / 1e6, fixNs / 1e6, ratio);

        assert ratio > 2.0 : "Expected >2x speedup, got " + ratio;
        System.out.println("PASS");
    }
}