package net.knarcraft.serverlauncher;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.util.Scanner;

/**
 * A holding class for methods shared between classes.
 *
 * @author      Kristian Knarvik <kristian.knarvik@knett.no>
 * @version     1.0.0
 * @since       1.0.0
 */
public class Shared {
    /**
     * Finds a substring between two substrings in a string.
     *
     * @param string The string containing the substrings
     * @param start  The substring before the wanted substring
     * @param end    The substring after the wanted substring
     * @return The wanted substring.
     */
    public static String stringBetween(String string, String start, String end) {
        int startPos = string.indexOf(start) + start.length();
        if (!string.contains(start) || string.indexOf(end, startPos) < startPos) {
            return "";
        }
        return string.substring(startPos, string.indexOf(end, startPos));
    }

    /**
     * Reads a file from a website.
     * This is used to find the newest version of jars and the software.
     *
     * @param path  The full url of the file to read
     * @return      True if successful. False otherwise
     */
    public static String readFile(String path) throws IOException {
        URL url = new URL(path);
        return new Scanner(url.openStream()).useDelimiter("\\Z").next();
    }

    /**
     * Downloads a file from a website.
     *
     * @param path      The full url of the file to download.
     * @param outfile   The file to save to
     * @return          True if successful. False otherwise
     */
    public static boolean downloadFile(String path, Path outfile) {
        try {
            URL url = new URL(path);
            InputStream in = url.openStream();
            Files.copy(in, outfile, StandardCopyOption.REPLACE_EXISTING);
            return true;
        } catch (IOException e) {
            return false;
        }
    }
}