package com.it_jaros.jscanner;

import java.util.BitSet;
import java.util.List;
import java.util.stream.Collectors;

public class App {

    private static Thread shutdownHook;

    public static void main(String[] args) {
        try {
            run(args);
        } catch (Exception e) {
            System.out.printf("ERROR: %s", e.getMessage());
        }
    }

    private static void run(String[] args) throws Exception {
        ScanOptions options = parseOptions(args);
        if (options == null) return;
        try (Scanner scanner = new Scanner(options)) {
            Scan scan = scanner.createScan(options);
            addShutdownHook(scan, scanner, options);
            scanner.runScan(scan);
            printScanResults(scan, options);
        } finally {
            removeShutdownHook();
        }
    }

    private static ScanOptions parseOptions(String[] args) {
        CliParser cliParser = new CliParser();
        try {
            return cliParser.parseArgs(args);
        } catch (IllegalArgumentException e) {
            System.out.printf("Error while parsing arguments: %s", e.getMessage());
            System.out.println();
        }

        cliParser.usageAndExit(1);
        return null;
    }

    /**
     * Allows us to handle signal int events
     * Prints intermediate result
     *
     * @param scan
     * @param scanner
     * @param scanOptions
     */
    private static void addShutdownHook(Scan scan, Scanner scanner, ScanOptions scanOptions) {
        shutdownHook = new Thread(() -> {
            System.err.println("\nCtrl-C received.");
            scanner.cancel();
            printScanResults(scan, scanOptions);
        });
        Runtime.getRuntime().addShutdownHook(shutdownHook);
    }

    private static void removeShutdownHook() {
        if (shutdownHook == null) {
            return;
        }

        try {
            Runtime.getRuntime().removeShutdownHook(shutdownHook);
        } catch (IllegalStateException ignored) {
            // JVM is already shutting down
        }
    }

    public static void printScanResults(Scan scan, ScanOptions scanOptions) {
        printScanResults(scan.getResults(), scan.getPeakConcurrentConnects(), scanOptions);
    }

    private static void printScanResults(List<ScanResult> result, int max, ScanOptions options) {
        printStats(max);
        result.forEach((ScanResult r) -> printPortsResults(r, options.showFilteredPorts()));
    }

    private static void printStats(int max) {
        System.out.println("--------------------");
        System.out.println("Stats:");
        System.out.println("Peak concurrent connects: " + max);
        System.out.println("--------------------");
    }

    private static void printPortsResults(ScanResult result, boolean showFilteredPorts) {
        if (result.openPorts().isEmpty() && (!showFilteredPorts || result.filteredPorts().isEmpty())) {
            return;
        }

        System.out.println(result.host());
        if (!result.openPorts().isEmpty()) {
            System.out.printf("\t (%d) open:\t%s%n", result.openPorts().cardinality(), map(result.openPorts(), result.bannerRecognition()));
        }
        if (showFilteredPorts && !result.filteredPorts().isEmpty()) {
            System.out.printf("\t (%d) filtered:\t%s%n", result.filteredPorts().cardinality(), map(result.filteredPorts()));
        }
        System.out.println();
    }

    private static String map(BitSet ports) {
        return ports.stream().mapToObj(String::valueOf).collect(Collectors.joining(","));
    }

    private static String map(BitSet ports, java.util.HashMap<Integer, ServiceType> bannerRecognition) {
        return ports.stream().mapToObj(port -> {
            ServiceType serviceType = bannerRecognition.getOrDefault(port, ServiceType.UNKNOWN);

            if (serviceType == ServiceType.UNKNOWN) {
                return String.valueOf(port);
            }

            return port + "/" + serviceType.name().toLowerCase();
        }).collect(Collectors.joining(","));
    }
}