/**
 * CWE-407 simulation: OBS Studio push_audio_tree da_find O(N²) per audio frame.
 *
 * Simulates the defect in libobs/obs-audio.c where push_audio_tree()
 * and push_audio_tree2() use da_find(audio->render_order, &source, 0)
 * — a linear scan — to check if a source is already in the render order.
 * Called once per source during audio tree traversal, this is O(N²) per
 * audio frame (~47 Hz). With complex scenes (many sources), this causes
 * measurable audio processing overhead.
 *
 * Fix: use a HashSet alongside the render_order list for O(1) membership.
 */
import java.util.*;

public class ObsStudioTest {

    /* --- Defective path: linear scan per source (da_find) --- */
    static int buildRenderOrderDefective(Object[] sources) {
        int ops = 0;
        List<Object> renderOrder = new ArrayList<>();
        for (Object source : sources) {
            // da_find: linear scan of render_order
            boolean found = false;
            for (int i = 0; i < renderOrder.size(); i++) {
                ops++;
                if (renderOrder.get(i) == source) {
                    found = true;
                    break;
                }
            }
            if (!found) {
                renderOrder.add(source);
            }
        }
        return ops;
    }

    /* --- Fixed path: hash set for O(1) membership --- */
    static int buildRenderOrderFixed(Object[] sources) {
        int ops = 0;
        List<Object> renderOrder = new ArrayList<>();
        Set<Object> seen = new HashSet<>();
        for (Object source : sources) {
            ops++; // HashSet.contains is O(1)
            if (seen.add(source)) {
                renderOrder.add(source);
            }
        }
        return ops;
    }

    public static void main(String[] args) {
        int[] sizes = {100, 500, 1000};
        boolean allPass = true;

        System.out.println("=== OBS Studio push_audio_tree CWE-407 Test ===");
        System.out.printf("%-8s %-12s %-12s %-8s %-6s%n",
                "N", "Defective", "Fixed", "Ratio", "Pass");

        for (int N : sizes) {
            // Simulate N unique sources being added to render order
            Object[] sources = new Object[N];
            for (int i = 0; i < N; i++) sources[i] = new Object();

            int opsDefective = buildRenderOrderDefective(sources);
            int opsFixed = buildRenderOrderFixed(sources);

            double ratio = (double) opsDefective / opsFixed;
            boolean pass = ratio > 2.0;
            if (!pass) allPass = false;

            System.out.printf("%-8d %-12d %-12d %-8.1fx %-6s%n",
                    N, opsDefective, opsFixed, ratio, pass ? "PASS" : "FAIL");
        }

        // Simulate repeated frames (the defect runs every audio frame)
        System.out.println("\n--- Per-second overhead at 47 frames/sec ---");
        int N = 200; // realistic complex scene
        Object[] sources = new Object[N];
        for (int i = 0; i < N; i++) sources[i] = new Object();
        int perFrameDefective = buildRenderOrderDefective(sources);
        int perFrameFixed = buildRenderOrderFixed(sources);
        System.out.printf("N=%d: defective=%d ops/frame × 47 = %d ops/sec%n",
                N, perFrameDefective, perFrameDefective * 47);
        System.out.printf("N=%d: fixed=%d ops/frame × 47 = %d ops/sec%n",
                N, perFrameFixed, perFrameFixed * 47);

        System.out.println();
        if (allPass) {
            System.out.println("ALL PASS — defective path is quadratic, fixed path is linear");
        } else {
            System.out.println("FAIL — ratio not demonstrated");
            System.exit(1);
        }
    }
}