package net.minecraft.util.parsing.packrat.commands;

import com.mojang.brigadier.StringReader;
import com.mojang.brigadier.exceptions.CommandSyntaxException;
import net.minecraft.util.parsing.packrat.DelayedException;
import net.minecraft.util.parsing.packrat.ParseState;
import net.minecraft.util.parsing.packrat.Rule;
import org.jspecify.annotations.Nullable;

public abstract class NumberRunParseRule implements Rule<StringReader, String> {
	private final DelayedException<CommandSyntaxException> noValueError;
	private final DelayedException<CommandSyntaxException> underscoreNotAllowedError;

	public NumberRunParseRule(
		final DelayedException<CommandSyntaxException> noValueError, final DelayedException<CommandSyntaxException> underscoreNotAllowedError
	) {
		this.noValueError = noValueError;
		this.underscoreNotAllowedError = underscoreNotAllowedError;
	}

	@Nullable
	public String parse(final ParseState<StringReader> state) {
		StringReader input = state.input();
		input.skipWhitespace();
		String fullString = input.getString();
		int start = input.getCursor();
		int pos = start;

		while (pos < fullString.length() && this.isAccepted(fullString.charAt(pos))) {
			pos++;
		}

		int length = pos - start;
		if (length == 0) {
			state.errorCollector().store(state.mark(), this.noValueError);
			return null;
		} else if (fullString.charAt(start) != '_' && fullString.charAt(pos - 1) != '_') {
			input.setCursor(pos);
			return fullString.substring(start, pos);
		} else {
			state.errorCollector().store(state.mark(), this.underscoreNotAllowedError);
			return null;
		}
	}

	protected abstract boolean isAccepted(char c);
}