package net.minecraft.util;

import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.HexFormat;

public record PngInfo(int width, int height) {
	private static final HexFormat FORMAT = HexFormat.of().withUpperCase().withPrefix("0x");
	private static final long PNG_HEADER = -8552249625308161526L;
	private static final int IHDR_TYPE = 1229472850;
	private static final int IHDR_SIZE = 13;

	public static PngInfo fromStream(InputStream stream) throws IOException {
		DataInputStream dataInputStream = new DataInputStream(stream);
		long l = dataInputStream.readLong();
		if (l != -8552249625308161526L) {
			throw new IOException("Bad PNG Signature: " + FORMAT.toHexDigits(l));
		} else {
			int i = dataInputStream.readInt();
			if (i != 13) {
				throw new IOException("Bad length for IHDR chunk: " + i);
			} else {
				int j = dataInputStream.readInt();
				if (j != 1229472850) {
					throw new IOException("Bad type for IHDR chunk: " + FORMAT.toHexDigits(j));
				} else {
					int k = dataInputStream.readInt();
					int m = dataInputStream.readInt();
					return new PngInfo(k, m);
				}
			}
		}
	}

	public static PngInfo fromBytes(byte[] bytes) throws IOException {
		return fromStream(new ByteArrayInputStream(bytes));
	}

	public static void validateHeader(ByteBuffer buffer) throws IOException {
		ByteOrder byteOrder = buffer.order();
		buffer.order(ByteOrder.BIG_ENDIAN);
		if (buffer.getLong(0) != -8552249625308161526L) {
			throw new IOException("Bad PNG Signature");
		} else if (buffer.getInt(8) != 13) {
			throw new IOException("Bad length for IHDR chunk!");
		} else if (buffer.getInt(12) != 1229472850) {
			throw new IOException("Bad type for IHDR chunk!");
		} else {
			buffer.order(byteOrder);
		}
	}
}