/*
 * Copyright (C) 2015 SoftIndex LLC.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.datakernel.codegen.utils;

public final class Preconditions {
	private Preconditions() {}

	public static void check(boolean expression) {
		if (!expression) {
			throw new RuntimeException();
		}
	}

	public static void check(boolean expression, Object message) {
		if (!expression) {
			throw new RuntimeException(String.valueOf(message));
		}
	}

	public static void check(boolean expression, String template, Object... args) {
		if (!expression) {
			throw new RuntimeException(format(template, args));
		}
	}

	public static <T> T checkNotNull(T reference) {
		if (reference == null) {
			throw new NullPointerException();
		}
		return reference;
	}

	public static <T> T checkNotNull(T reference, Object message) {
		if (reference == null) {
			throw new NullPointerException(String.valueOf(message));
		}
		return reference;
	}

	public static <T> T checkNotNull(T reference, String template, Object... args) {
		if (reference == null) {
			throw new NullPointerException(format(template, args));
		}
		return reference;
	}

	static String format(String template, Object... args) {
		template = String.valueOf(template);

		StringBuilder sb = new StringBuilder(template.length() + 16 * args.length);
		int templateStart = 0;
		int i = 0;
		while (i < args.length) {
			int holderStart = template.indexOf("%s", templateStart);
			if (holderStart == -1) {
				break;
			}
			sb.append(template.substring(templateStart, holderStart));
			sb.append(args[(i++)]);
			templateStart = holderStart + 2;
		}
		sb.append(template.substring(templateStart));
		if (i < args.length) {
			sb.append(" {");
			sb.append(args[(i++)]);
			while (i < args.length) {
				sb.append(", ");
				sb.append(args[(i++)]);
			}
			sb.append('}');
		}
		return sb.toString();
	}
}