/*
 * 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;

import org.objectweb.asm.Type;

import static io.datakernel.codegen.Utils.newLocal;

final class ExpressionLet implements Variable {
	private final Expression field;
	private VarLocal var;

	ExpressionLet(Expression field) {
		this.field = field;
	}

	@Override
	public Type type(Context ctx) {
		return field.type(ctx);
	}

	@Override
	public Type load(Context ctx) {
		if (var == null) {
			var = newLocal(ctx, field.type(ctx));
			field.load(ctx);
			var.store(ctx);
		}
		var.load(ctx);
		return field.type(ctx);
	}

	@Override
	public Object beginStore(Context ctx) {
		return null;
	}

	@Override
	public void store(Context ctx, Object storeContext, Type type) {
		if (var == null) {
			var = newLocal(ctx, field.type(ctx));
			field.load(ctx);
			var.store(ctx);
		}

		var.store(ctx, storeContext, type);
	}

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

		ExpressionLet that = (ExpressionLet) o;

		return !(field != null ? !field.equals(that.field) : that.field != null);

	}

	@Override
	public int hashCode() {
		return field != null ? field.hashCode() : 0;
	}
}