package me.chayapak1.chomensbot_mabe.util;

import javax.net.ssl.KeyManager;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.io.*;
import java.net.URL;
import java.net.URLConnection;
import java.security.KeyManagementException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;

public class DownloadUtilities {
    private static class DefaultTrustManager implements X509TrustManager {
        @Override
        public void checkClientTrusted(X509Certificate[] arg0, String arg1) {}

        @Override
        public void checkServerTrusted(X509Certificate[] arg0, String arg1) {}

        @Override
        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }
    }

    public static byte[] DownloadToByteArray(URL url, int maxSize) throws IOException, KeyManagementException, NoSuchAlgorithmException {
        SSLContext ctx = SSLContext.getInstance("TLS");
        ctx.init(new KeyManager[0], new TrustManager[] {new DefaultTrustManager()}, new SecureRandom());
        SSLContext.setDefault(ctx);
        URLConnection conn = url.openConnection();
        conn.setConnectTimeout(5000);
        conn.setReadTimeout(10000);
        // https://www.whatismybrowser.com/guides/the-latest-user-agent/windows
        conn.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/111.0.0.0 Safari/537.36");

        try (BufferedInputStream downloadStream = new BufferedInputStream(conn.getInputStream())) {
            ByteArrayOutputStream byteArrayStream = new ByteArrayOutputStream();
            byte[] buf = new byte[1024];
            int n;
            int tot = 0;
            while ((n = downloadStream.read(buf)) > 0) {
                byteArrayStream.write(buf, 0, n);
                tot += n;
                if (tot > maxSize) {
                    throw new IOException("File is too large");
                }
                if (Thread.interrupted()) {
                    return null;
                }
            }
            return byteArrayStream.toByteArray();
        }
        // Closing a ByteArrayInputStream has no effect, so I do not close it.
    }

    public static InputStream DownloadToInputStream(URL url, int maxSize) throws KeyManagementException, NoSuchAlgorithmException, IOException {
        return new ByteArrayInputStream(DownloadToByteArray(url, maxSize));
    }
}