/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.internal.kernel.api.exceptions.schema;

import org.neo4j.common.TokenNameLookup;
import org.neo4j.exceptions.KernelException;
import org.neo4j.internal.schema.ConstraintDescriptor;
import org.neo4j.kernel.api.exceptions.Status;

/**
 * Constraint verification happens when a new constraint is created, and the database verifies that existing
 * data adheres to the new constraint.
 */
public abstract class ConstraintValidationException extends KernelException {
    /**
     * Constraint validation failures can happen during one of two phases of the constraint lifecycle.
     *
     * VERIFICATION is the process to control that a constraint holds with respect to all the data in the graph. This
     * happens before creating a constraint for example, and if the verification fails the constraint is not created.
     * Verification can also occur during batch import for example.
     *
     * VALIDATION is what happens when the graph is modified, and the resulting state is controlled against a
     * constraint to see that the modified state does not violate the constraint. If validation fails the modifying
     * transaction is rolled back.
     */
    public enum Phase {
        VERIFICATION(Status.Statement.ConstraintVerificationFailed),
        VALIDATION(Status.Schema.ConstraintValidationFailed);

        private final Status status;

        Phase(Status status) {
            this.status = status;
        }

        public Status getStatus() {
            return status;
        }
    }

    protected final ConstraintDescriptor constraint;

    protected ConstraintValidationException(
            ConstraintDescriptor constraint, Phase phase, String subject, TokenNameLookup tokenNameLookup) {
        super(phase.getStatus(), "%s does not satisfy %s.", subject, constraint.userDescription(tokenNameLookup));
        this.constraint = constraint;
    }

    protected ConstraintValidationException(
            ConstraintDescriptor constraint,
            Phase phase,
            String subject,
            Throwable failure,
            TokenNameLookup tokenNameLookup) {
        super(
                phase.getStatus(),
                failure,
                "%s does not satisfy %s: %s",
                subject,
                constraint.userDescription(tokenNameLookup),
                failure.getMessage());
        this.constraint = constraint;
    }

    @Override
    public abstract String getUserMessage(TokenNameLookup tokenNameLookup);

    public ConstraintDescriptor constraint() {
        return constraint;
    }
}
