package net.shadowfacts.phycon.api.util;

import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;

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

/**
 * @author shadowfacts
 */
public final class IPAddress {

	@NotNull
	public static IPAddress random(@NotNull Random random) {
		int value = 0;
		// don't accidentally generate reserved, broadcast, or loopback addresses
		while (value == 0 || value == 0xff_ff_ff_ff || (value >> 24) == 127) {
			value = random.nextInt();
		}
		return new IPAddress(value);
	}

	private static final Random ipAddressRandom = new Random();
	@NotNull
	public static IPAddress random() {
		return random(ipAddressRandom);
	}

	private static final Pattern IP_PATTERN = Pattern.compile("^(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})$");
	@Nullable
	public static IPAddress parse(String s) {
		Matcher matcher = IP_PATTERN.matcher(s);
		if (!matcher.matches()) {
			return null;
		}
		int a = Integer.parseInt(matcher.group(1));
		int b = Integer.parseInt(matcher.group(2));
		int c = Integer.parseInt(matcher.group(3));
		int d = Integer.parseInt(matcher.group(4));
		if (a > 255 || b > 255 || c > 255 || d > 255) {
			return null;
		}
		return new IPAddress(a, b, c, d);
	}

	public static final IPAddress BROADCAST = new IPAddress(0xff_ff_ff_ff);

	public final int address;

	public IPAddress(int address) {
		if (address == 0) {
			throw new RuntimeException("IP address 0.0.0.0 is reserved");
		}
		this.address = address;
	}

	public IPAddress(int a, int b, int c, int d) {
		this(((a & 0xff) << 24) | ((b & 0xff) << 16) | ((c & 0xff) << 8) | (d & 0xff));
	}

	/**
	 * @return If this IP address is a broadcast address (255.255.255.255).
	 */
	public boolean isBroadcast() {
		return address == 0xff_ff_ff_ff;
	}

	@Override
	public boolean equals(Object o) {
		if (this == o) return true;
		if (o == null || getClass() != o.getClass()) return false;
		IPAddress ipAddress = (IPAddress) o;
		return address == ipAddress.address;
	}

	@Override
	public int hashCode() {
		return address;
	}

	@Override
	public String toString() {
		StringBuilder builder = new StringBuilder();
		for (int i = 3; i >= 0; i--) {
			if (i < 3) {
				builder.append('.');
			}
			int octet = (address >> (i * 8)) & 0xff;
			builder.append(octet);
		}
		return builder.toString();
	}
}