package com.termux.shared.data;

import java.util.LinkedHashSet;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class UrlUtils {

    public static Pattern URL_MATCH_REGEX;

    public static Pattern getUrlMatchRegex() {
        if (URL_MATCH_REGEX != null) return URL_MATCH_REGEX;

        StringBuilder regex_sb = new StringBuilder();

        regex_sb.append("(");                       // Begin first matching group.
        regex_sb.append("(?:");                     // Begin scheme group.
        regex_sb.append("dav|");                    // The DAV proto.
        regex_sb.append("dict|");                   // The DICT proto.
        regex_sb.append("dns|");                    // The DNS proto.
        regex_sb.append("file|");                   // File path.
        regex_sb.append("finger|");                 // The Finger proto.
        regex_sb.append("ftp(?:s?)|");              // The FTP proto.
        regex_sb.append("git|");                    // The Git proto.
        regex_sb.append("gemini|");                 // The Gemini proto.
        regex_sb.append("gopher|");                 // The Gopher proto.
        regex_sb.append("http(?:s?)|");             // The HTTP proto.
        regex_sb.append("imap(?:s?)|");             // The IMAP proto.
        regex_sb.append("irc(?:[6s]?)|");           // The IRC proto.
        regex_sb.append("ip[fn]s|");                // The IPFS proto.
        regex_sb.append("ldap(?:s?)|");             // The LDAP proto.
        regex_sb.append("pop3(?:s?)|");             // The POP3 proto.
        regex_sb.append("redis(?:s?)|");            // The Redis proto.
        regex_sb.append("rsync|");                  // The Rsync proto.
        regex_sb.append("rtsp(?:[su]?)|");          // The RTSP proto.
        regex_sb.append("sftp|");                   // The SFTP proto.
        regex_sb.append("smb(?:s?)|");              // The SAMBA proto.
        regex_sb.append("smtp(?:s?)|");             // The SMTP proto.
        regex_sb.append("svn(?:(?:\\+ssh)?)|");     // The Subversion proto.
        regex_sb.append("tcp|");                    // The TCP proto.
        regex_sb.append("telnet|");                 // The Telnet proto.
        regex_sb.append("tftp|");                   // The TFTP proto.
        regex_sb.append("udp|");                    // The UDP proto.
        regex_sb.append("vnc|");                    // The VNC proto.
        regex_sb.append("ws(?:s?)");                // The Websocket proto.
        regex_sb.append(")://");                    // End scheme group.
        regex_sb.append(")");                       // End first matching group.


        // Begin second matching group.
        regex_sb.append("(");

        // User name and/or password in format 'user:pass@'.
        regex_sb.append("(?:\\S+(?::\\S*)?@)?");

        // Begin host group.
        regex_sb.append("(?:");

        // IP address (from http://www.regular-expressions.info/examples.html).
        regex_sb.append("(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)|");

        // Host name or domain.
        regex_sb.append("(?:(?:[a-z\\u00a1-\\uffff0-9]-*)*[a-z\\u00a1-\\uffff0-9]+)(?:(?:\\.(?:[a-z\\u00a1-\\uffff0-9]-*)*[a-z\\u00a1-\\uffff0-9]+)*(?:\\.(?:[a-z\\u00a1-\\uffff]{2,})))?|");

        // Just path. Used in case of 'file://' scheme.
        regex_sb.append("/(?:(?:[a-z\\u00a1-\\uffff0-9]-*)*[a-z\\u00a1-\\uffff0-9]+)");

        // End host group.
        regex_sb.append(")");

        // Port number.
        regex_sb.append("(?::\\d{1,5})?");

        // Resource path with optional query string.
        regex_sb.append("(?:/[a-zA-Z0-9:@%\\-._~!$&()*+,;=?/]*)?");

        // Fragment.
        regex_sb.append("(?:#[a-zA-Z0-9:@%\\-._~!$&()*+,;=?/]*)?");

        // End second matching group.
        regex_sb.append(")");

        URL_MATCH_REGEX = Pattern.compile(
            regex_sb.toString(),
            Pattern.CASE_INSENSITIVE | Pattern.MULTILINE | Pattern.DOTALL);

        return URL_MATCH_REGEX;
    }

    public static LinkedHashSet<CharSequence> extractUrls(String text) {
        LinkedHashSet<CharSequence> urlSet = new LinkedHashSet<>();
        Matcher matcher = getUrlMatchRegex().matcher(text);

        while (matcher.find()) {
            int matchStart = matcher.start(1);
            int matchEnd = matcher.end();
            String url = text.substring(matchStart, matchEnd);
            urlSet.add(url);
        }

        return urlSet;
    }

}