/*
 * Copyright (c) 2011, 2021 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0 which is available at
 * http://www.eclipse.org/legal/epl-2.0,
 * or the Eclipse Distribution License v. 1.0 which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
 */

// Contributors:
//     Oracle - initial API and implementation
//
package org.eclipse.persistence.jpa.jpql.tools.model.query;

import java.io.IOException;
import java.util.List;
import org.eclipse.persistence.jpa.jpql.tools.spi.IEntity;
import static org.eclipse.persistence.jpa.jpql.parser.AbstractExpression.*;

/**
 * The abstract definition of a modify statement. TODO
 *
 * @see DeleteStatementStateObject
 * @see UpdateStatementStateObject
 *
 * @version 2.4
 * @since 2.4
 * @author Pascal Filion
 */
@SuppressWarnings("nls")
public abstract class AbstractModifyStatementStateObject extends AbstractStateObject {

    /**
     * The state object representing the modify clause.
     */
    private AbstractModifyClauseStateObject modifyClause;

    /**
     * The state object representing the <code><b>WHERE</b></code> clause.
     */
    private WhereClauseStateObject whereClause;

    /**
     * Notify the state object representing the <code><b>WHERE</b></code> clause has changed.
     */
    public static final String WHERE_CLAUSE_PROPERTY = "whereClause";

    /**
     * Creates a new <code>AbstractModifyStatementStateObject</code>.
     *
     * @param parent The parent of this state object, which cannot be <code>null</code>
     * @exception NullPointerException The given parent cannot be <code>null</code>
     */
    protected AbstractModifyStatementStateObject(JPQLQueryStateObject parent) {
        super(parent);
    }

    @Override
    protected void addChildren(List<StateObject> children) {
        super.addChildren(children);
        children.add(modifyClause);
        if (whereClause != null) {
            children.add(whereClause);
        }
    }

    /**
     * Adds the <code><b>WHERE</b></code> clause. The clause is not added if it's already present.
     *
     * @return The {@link GroupByClauseStateObject}
     */
    public WhereClauseStateObject addWhereClause() {
        WhereClauseStateObject whereClause = new WhereClauseStateObject(this);
        setWhereClause(whereClause);
        return whereClause;
    }

    /**
     * Creates the actual {@link AbstractModifyClauseStateObject} that represents the modify clause.
     *
     * @return The modify clause part of this modify statement
     */
    protected abstract AbstractModifyClauseStateObject buildModifyClause();

    /**
     * Returns the abstract schema name.
     *
     * @return The name of the abstract schema type for which the identification variable is ranging
     * over
     */
    public String getAbstractSchemaName() {
        return getAbstractSchemaNameStateObject().getText();
    }

    /**
     * Returns the {@link AbstractSchemaNameStateObject} holding onto the abstract schema name.
     *
     * @return The {@link AbstractSchemaNameStateObject}, which is never <code>null</code>
     */
    public AbstractSchemaNameStateObject getAbstractSchemaNameStateObject() {
        return getModifyClause().getAbstractSchemaNameStateObject();
    }

    @Override
    public DeclarationStateObject getDeclaration() {
        return modifyClause.getDeclaration();
    }

    /**
     * Returns the actual {@link IEntity} that has the abstract schema name.
     *
     * @return The actual {@link IEntity} or <code>null</code> if no entity exists
     */
    public IEntity getEntity() {
        return getModifyClause().getEntity();
    }

    /**
     * Returns the identification variable name that is ranging over the abstract schema type.
     *
     * @return The identification variable name
     */
    public String getIdentificationVariable() {
        return getModifyClause().getIdentificationVariable();
    }

    /**
     * Returns the {@link IdentificationVariableStateObject} holding onto the identification variable.
     *
     * @return The {@link IdentificationVariableStateObject}, which is never <code>null</code>
     */
    public IdentificationVariableStateObject getIdentificationVariableStateObject() {
        return getModifyClause().getIdentificationVariableStateObject();
    }

    /**
     * Returns the state object representing the modify clause part of the modify statement.
     *
     * @return The state object representing the modify clause part of the modify statement, which is
     * never <code>null</code>
     */
    public AbstractModifyClauseStateObject getModifyClause() {
        return modifyClause;
    }

    @Override
    public JPQLQueryStateObject getParent() {
        return (JPQLQueryStateObject) super.getParent();
    }

    /**
     * Returns the {@link StateObject} that defines the range variable declaration.
     *
     * @return The {@link StateObject} that defines the range variable declaration, which is never
     * <code>null</code>
     */
    public RangeVariableDeclarationStateObject getRangeVariableDeclaration() {
        return getModifyClause().getRangeVariableDeclaration();
    }

    /**
     * Returns the state object representing the <code><b>WHERE</b></code> clause.
     *
     * @return Either the actual state object representing the <code><b>WHERE</b></code> clause or
     * the <code>null</code> state object since <code>null</code> is never returned
     */
    public WhereClauseStateObject getWhereClause() {
        return whereClause;
    }

    /**
     * Returns the state object representing the <code><b>WHERE</b></code> clause.
     *
     * @return Either the actual state object representing the <code><b>WHERE</b></code> clause or
     * <code>null</code> if it's not present
     */
    public boolean hasWhereClause() {
        return whereClause != null;
    }

    @Override
    protected void initialize() {
        super.initialize();
        modifyClause = buildModifyClause();
    }

    @Override
    public boolean isEquivalent(StateObject stateObject) {

        if (super.isEquivalent(stateObject)) {
            AbstractModifyStatementStateObject clause = (AbstractModifyStatementStateObject) stateObject;
            return modifyClause.isEquivalent(clause.modifyClause) &&
                   areEquivalent(whereClause, clause.whereClause);
        }

        return false;
    }

    /**
     * Removes the <code><b>WHERE</b></code> clause.
     */
    public void removeWhereClause() {
        setWhereClause(null);
    }

    /**
     * Sets the given {@link StateObject} to be the conditional expression of the <code><b>WHERE</b></code>
     * clause.
     *
     * @param conditionalStateObject The new conditional expression
     */
    public void setConditionalStateObject(StateObject conditionalStateObject) {
        if (!hasWhereClause()) {
            addWhereClause();
        }
        getWhereClause().setConditional(conditionalStateObject);
    }

    /**
     * Sets the abstract schema name to the given value.
     *
     * @param entity The {@link IEntity} that this clause will range over
     */
    public void setDeclaration(IEntity entity) {
        getModifyClause().setDeclaration(entity);
    }

    /**
     * Sets the abstract schema name to the given value and the identification variable that will
     * range over it.
     *
     * @param entity The {@link IEntity} that this clause will range over
     * @param identificationVariable The new identification variable
     */
    public void setDeclaration(IEntity entity, String identificationVariable) {
        getModifyClause().setDeclaration(entity, identificationVariable);
    }

    /**
     * Sets the abstract schema name to the given value and removes the identification variable.
     *
     * @param abstractSchemaName The name of the abstract schema, which is the name of the entity
     */
    public void setDeclaration(String abstractSchemaName) {
        getModifyClause().setDeclaration(abstractSchemaName);
    }

    /**
     * Sets the abstract schema name to the given value and the identification variable that will
     * range over it.
     *
     * @param abstractSchemaName The name of the abstract schema, which is the name of the entity
     * @param identificationVariable The new identification variable
     */
    public void setDeclaration(String abstractSchemaName, String identificationVariable) {
        getModifyClause().setDeclaration(abstractSchemaName, identificationVariable);
    }

    /**
     * Sets the actual {@link IEntity} and updates the abstract schema name.
     *
     * @param entity The {@link IEntity} that this clause will range over
     */
    public void setEntity(IEntity entity) {
        getModifyClause().setEntity(entity);
    }

    /**
     * Sets the name of the abstract schema, which is the name of the entity.
     *
     * @param entityName The name of the entity
     */
    public void setEntityName(String entityName) {
        getModifyClause().setEntityName(entityName);
    }

    /**
     * Sets the new identification variable that will range over the abstract schema name.
     *
     * @param identificationVariable The new identification variable
     */
    public void setIdentificationVariable(String identificationVariable) {
        getModifyClause().setIdentificationVariable(identificationVariable);
    }

    private void setWhereClause(WhereClauseStateObject whereClause) {
        WhereClauseStateObject oldWhereClause = this.whereClause;
        this.whereClause = whereClause;
        firePropertyChanged(WHERE_CLAUSE_PROPERTY, oldWhereClause, whereClause);
    }

    /**
     * Either adds or removes the state object representing the <code><b>WHERE</b></code> clause.
     */
    public void toggleWhereClause() {
        if (hasWhereClause()) {
            removeWhereClause();
        }
        else {
            addWhereClause();
        }
    }

    @Override
    protected void toTextInternal(Appendable writer) throws IOException {
        modifyClause.toString(writer);
        if (whereClause != null) {
            writer.append(SPACE);
            whereClause.toString(writer);
        }
    }
}