package parse;

import java.util.HashMap;
import java.util.Objects;
import org.javatuples.Pair;

public class AuParser {

    private final static String libraryName = "au";

    static {
        System.loadLibrary(libraryName);
    }

    private long address;

    public AuParser() {
    }

    private native int firstField();
    private native int firstRecord();
    private native int nextField();
    private native int reset();
    private native int getMilliSeconds();
    private native long getSerial();
    private native long getSeconds();
    private native long init(String log);
    private native String getHost();
    private native String getFieldName();
    private native String getFieldStr();
    private native String findField(String name);
    private native String interpretField();

    public HashMap parseEvent(String log) {
        HashMap<String, Object> event = new HashMap<>();
        Pair<String, String> parsedLine = parseFlumeLine(log);
        String line = parsedLine.getValue0();
        String host = parsedLine.getValue1();
        address = init(line);
        firstRecord();
        firstField();
        while (true) {
            String field = getFieldName();
            String fieldValue = getFieldStr();
            if (Objects.equals(field, "hostname")) {
                fieldValue = fieldValue.substring(1, fieldValue.length());
            }
            event.put(field, fieldValue);
            if (nextField() == 0)
                break;
        }
        reset();
        firstRecord();
        if (!event.containsKey("type")) {
            event.put("type", "TRASH");
        }
        if (event.get("type").equals("SYSCALL")) {
            findField("syscall");
            event.put("syscall", interpretField());
        }
        int milliSeconds = getMilliSeconds();
        long seconds = getSeconds();
        int timestamp = (int)(1000*seconds + (float)milliSeconds);
        event.put("timestamp", timestamp);
        event.put("event_id", getSerial());
        event.putIfAbsent("hostname", host);
        return event;
    }

    private Pair<String, String> parseFlumeLine(String log) {
        char tenth = log.charAt(10);
        int ord = (int) tenth;
        int hostIndex= 11 + ord/2;
        int k = 3;
        if (log.charAt(hostIndex + 2) == 't') {
            k = 2;
        }
        int logLength = log.length();
        String line = log.substring(hostIndex + k, logLength);
        String host = log.substring(11, hostIndex);
        return new Pair<>(line, host);
    }
}