package launcher.serialize;

import java.io.ByteArrayInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.util.UUID;

import launcher.LauncherAPI;
import launcher.helper.IOHelper;

public final class HInput implements AutoCloseable {
	@LauncherAPI public final InputStream stream;

	@LauncherAPI
	public HInput(InputStream stream) {
		this.stream = stream;
	}

	@LauncherAPI
	public HInput(byte[] bytes) {
		stream = new ByteArrayInputStream(bytes);
	}

	@Override
	public void close() throws IOException {
		stream.close();
	}

	@LauncherAPI
	public String readASCII(int maxBytes) throws IOException {
		return IOHelper.decodeASCII(readByteArray(maxBytes));
	}

	@LauncherAPI
	public BigInteger readBigInteger(int maxBytes) throws IOException {
		return new BigInteger(readByteArray(maxBytes));
	}

	@LauncherAPI
	public boolean readBoolean() throws IOException {
		int b = readUnsignedByte();
		switch (b) {
			case 0b0:
				return false;
			case 0b1:
				return true;
			default:
				throw new IOException("Invalid boolean state: " + b);
		}
	}

	@LauncherAPI
	public byte[] readByteArray(int max) throws IOException {
		byte[] bytes = new byte[readLength(max)];
		IOHelper.read(stream, bytes);
		return bytes;
	}

	@LauncherAPI
	public int readInt() throws IOException {
		return (readUnsignedByte() << 24) + (readUnsignedByte() << 16) + (readUnsignedByte() << 8) + readUnsignedByte();
	}

	@LauncherAPI
	public int readLength(int max) throws IOException {
		if (max < 0) {
			return -max;
		}
		return IOHelper.verifyLength(readVarInt(), max);
	}

	@LauncherAPI
	public long readLong() throws IOException {
		return (long) readInt() << 32 | readInt() & 0xFFFFFFFFL;
	}

	@LauncherAPI
	public short readShort() throws IOException {
		return (short) ((readUnsignedByte() << 8) + readUnsignedByte());
	}

	@LauncherAPI
	public String readString(int maxBytes) throws IOException {
		return IOHelper.decode(readByteArray(maxBytes));
	}

	@LauncherAPI
	public UUID readUUID() throws IOException {
		return new UUID(readLong(), readLong());
	}

	@LauncherAPI
	public int readUnsignedByte() throws IOException {
		int b = stream.read();
		if (b < 0) {
			throw new EOFException("readUnsignedByte");
		}
		return b;
	}

	@LauncherAPI
	public int readUnsignedShort() throws IOException {
		return Short.toUnsignedInt(readShort());
	}

	@LauncherAPI
	public int readVarInt() throws IOException {
		int shift = 0;
		int result = 0;
		while (shift < Integer.SIZE) {
			int b = readUnsignedByte();
			result |= (b & 0x7F) << shift;
			if ((b & 0x80) == 0) {
				return result;
			}
			shift += 7;
		}
		throw new IOException("VarInt too big");
	}

	@LauncherAPI
	public long readVarLong() throws IOException {
		int shift = 0;
		long result = 0;
		while (shift < Long.SIZE) {
			int b = readUnsignedByte();
			result |= (long) (b & 0x7F) << shift;
			if ((b & 0x80) == 0) {
				return result;
			}
			shift += 7;
		}
		throw new IOException("VarLong too big");
	}
}