/*
 * Copyright (c) 2006, 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.parser;

import java.util.Collection;
import java.util.List;
import org.eclipse.persistence.jpa.jpql.ExpressionTools;
import org.eclipse.persistence.jpa.jpql.WordParser;

/**
 * Used in conditional expression to determine whether the result of an expression falls within an
 * inclusive range of values. Numeric, string and date expression can be evaluated in this way.
 *
 * <div><b>BNF:</b> <code>between_expression ::= arithmetic_expression [NOT] BETWEEN arithmetic_expression AND arithmetic_expression |<br>
 *                                                      string_expression [NOT] BETWEEN string_expression AND string_expression |<br>
 *                                                      datetime_expression [NOT] BETWEEN datetime_expression AND datetime_expression</code></div>
 *
 * @version 2.5
 * @since 2.3
 * @author Pascal Filion
 */
public final class BetweenExpression extends AbstractExpression {

    /**
     * The actual <b>AND</b> identifier found in the string representation of the JPQL query.
     */
    private String andIdentifier;

    /**
     * The actual identifier found in the string representation of the JPQL query.
     */
    private String betweenIdentifier;

    /**
     * The {@link Expression} to be tested for an inclusive range of values.
     */
    private AbstractExpression expression;

    /**
     * Determines whether a whitespace was found after <b>AND</b>.
     */
    private boolean hasSpaceAfterAnd;

    /**
     * Determines whether a whitespace was found after <b>BETWEEN</b>.
     */
    private boolean hasSpaceAfterBetween;

    /**
     * Determines whether a whitespace was found after the lower bound expression.
     */
    private boolean hasSpaceAfterLowerBound;

    /**
     * The {@link Expression} representing the lower bound expression.
     */
    private AbstractExpression lowerBoundExpression;

    /**
     * The actual <b>NOT</b> identifier found in the string representation of the JPQL query.
     */
    private String notIdentifier;

    /**
     * The {@link Expression} representing the upper bound expression.
     */
    private AbstractExpression upperBoundExpression;

    /**
     * Creates a new <code>BetweenExpression</code>.
     *
     * @param parent The parent of this expression
     * @param expression The {@link Expression} that is tested to be inclusive in a range of values
     */
    public BetweenExpression(AbstractExpression parent, AbstractExpression expression) {
        super(parent, BETWEEN);

        if (expression != null) {
            this.expression = expression;
            this.expression.setParent(this);
        }
    }

    @Override
    public void accept(ExpressionVisitor visitor) {
        visitor.visit(this);
    }

    @Override
    public void acceptChildren(ExpressionVisitor visitor) {
        getExpression().accept(visitor);
        getLowerBoundExpression().accept(visitor);
        getUpperBoundExpression().accept(visitor);
    }

    @Override
    protected void addChildrenTo(Collection<Expression> children) {
        children.add(getExpression());
        children.add(getLowerBoundExpression());
        children.add(getUpperBoundExpression());
    }

    @Override
    protected void addOrderedChildrenTo(List<Expression> children) {

        // Expression
        if (hasExpression()) {
            children.add(expression);
            children.add(buildStringExpression(SPACE));
        }

        // 'NOT'
        if (notIdentifier != null) {
            children.add(buildStringExpression(NOT));
            children.add(buildStringExpression(SPACE));
        }

        // BETWEEN x AND y
        // Identifier
        children.add(buildStringExpression(getText()));

        if (hasSpaceAfterBetween) {
            children.add(buildStringExpression(SPACE));
        }

        // Lower bound expression
        if (lowerBoundExpression != null) {
            children.add(lowerBoundExpression);
        }

        if (hasSpaceAfterLowerBound) {
            children.add(buildStringExpression(SPACE));
        }

        // 'AND'
        if (andIdentifier != null) {
            children.add(buildStringExpression(AND));
        }

        if (hasSpaceAfterAnd) {
            children.add(buildStringExpression(SPACE));
        }

        // Upper bound expression
        if (upperBoundExpression != null) {
            children.add(upperBoundExpression);
        }
    }

    @Override
    public JPQLQueryBNF findQueryBNF(Expression expression) {

        if ((upperBoundExpression != null) && upperBoundExpression.isAncestor(expression) ||
            (lowerBoundExpression != null) && lowerBoundExpression.isAncestor(expression)) {

            return getQueryBNF(InternalBetweenExpressionBNF.ID);
        }

        // There is no generic BNF so we'll generalize with scalar expression
        if ((this.expression != null) && expression.isAncestor(expression)) {
            return getQueryBNF(ScalarExpressionBNF.ID);
        }

        return super.findQueryBNF(expression);
    }

    /**
     * Returns the actual <b>AND</b> identifier found in the string representation of the JPQL query,
     * which has the actual case that was used.
     *
     * @return The <b>AND</b> identifier that was actually parsed, or an empty string if it was not parsed
     */
    public String getActualAndIdentifier() {
        return (andIdentifier != null) ? andIdentifier : ExpressionTools.EMPTY_STRING;
    }

    /**
     * Returns the actual identifier found in the string representation of the JPQL query, which has the actual
     * case that was used.
     *
     * @return The identifier that was actually parsed
     */
    public String getActualBetweenIdentifier() {
        return betweenIdentifier;
    }

    /**
     * Returns the actual <b>NOT</b> identifier found in the string representation of the JPQL query,
     * which has the actual case that was used.
     *
     * @return The <b>NOT</b> identifier that was actually parsed, or an empty string if it was not
     * parsed
     */
    public String getActualNotIdentifier() {
        return (notIdentifier != null) ? notIdentifier : ExpressionTools.EMPTY_STRING;
    }

    /**
     * Returns the unique identifier of the BNF for the lower and upper bound expressions.
     *
     * @return The unique identifier of the JPQL query BNF for the lower and upper bound expressions
     */
    public String getBoundExpressionQueryBNFId() {
        return InternalBetweenExpressionBNF.ID;
    }

    /**
     * Returns the {@link Expression} representing the expression to be tested for a range of values.
     *
     * @return The expression that was parsed representing the expression to be tested
     */
    public Expression getExpression() {
        if (expression == null) {
            expression = buildNullExpression();
        }
        return expression;
    }

    /**
     * Returns the identifier for this expression that may include <b>NOT</b> if it was parsed.
     *
     * @return Either <b>BETWEEN</b> or <b>NOT BETWEEN</b>
     */
    public String getIdentifier() {
        return (notIdentifier != null) ? NOT_BETWEEN : BETWEEN;
    }

    /**
     * Returns the {@link Expression} representing the lower bound expression.
     *
     * @return The expression that was parsed representing the lower bound expression
     */
    public Expression getLowerBoundExpression() {
        if (lowerBoundExpression == null) {
            lowerBoundExpression = buildNullExpression();
        }
        return lowerBoundExpression;
    }

    @Override
    public JPQLQueryBNF getQueryBNF() {
        return getQueryBNF(BetweenExpressionBNF.ID);
    }

    /**
     * Returns the {@link Expression} representing the upper bound expression.
     *
     * @return The expression that was parsed representing the upper bound expression
     */
    public Expression getUpperBoundExpression() {
        if (upperBoundExpression == null) {
            upperBoundExpression = buildNullExpression();
        }
        return upperBoundExpression;
    }

    /**
     * Determines whether the identifier <b>AND</b> was part of the query.
     *
     * @return <code>true</code> if the identifier <b>AND</b> was parsed; <code>false</code> otherwise
     */
    public boolean hasAnd() {
        return andIdentifier != null;
    }

    /**
     * Determines whether the identifier <b>BETWEEN</b> was part of the query.
     *
     * @return <code>true</code> if the identifier <b>BETWEEN</b> was parsed; <code>false</code> otherwise
     */
    protected boolean hasBetween() {
        return betweenIdentifier != null;
    }

    /**
     * Determines whether the expression before the identifier was parsed.
     *
     * @return <code>true</code> if the query has the expression before <b>BETWEEN</b>;
     * <code>false</code> otherwise
     */
    public boolean hasExpression() {
        return expression != null &&
              !expression.isNull();
    }

    /**
     * Determines whether the lower bound expression was parsed.
     *
     * @return <code>true</code> if the query has the lower bound expression; <code>false</code>
     * otherwise
     */
    public boolean hasLowerBoundExpression() {
        return lowerBoundExpression != null &&
              !lowerBoundExpression.isNull();
    }

    /**
     * Determines whether the identifier <b>NOT</b> was part of the query.
     *
     * @return <code>true</code> if the identifier <b>NOT</b> was parsed; <code>false</code> otherwise
     */
    public boolean hasNot() {
        return notIdentifier != null;
    }

    /**
     * Determines whether a whitespace was found after <b>AND</b>.
     *
     * @return <code>true</code> if there was a whitespace after <b>AND</b>; <code>false</code> otherwise
     */
    public boolean hasSpaceAfterAnd() {
        return hasSpaceAfterAnd;
    }

    /**
     * Determines whether a whitespace was found after <b>BETWEEN</b>.
     *
     * @return <code>true</code> if there was a whitespace after the <b>BETWEEN</b>;
     * <code>false</code> otherwise
     */
    public boolean hasSpaceAfterBetween() {
        return hasSpaceAfterBetween;
    }

    /**
     * Determines whether a whitespace was found after the lower bound expression.
     *
     * @return <code>true</code> if there was a whitespace after the lower bound expression;
     * <code>false</code> otherwise
     */
    public boolean hasSpaceAfterLowerBound() {
        return hasSpaceAfterLowerBound;
    }

    /**
     * Determines whether the upper bound expression was parsed.
     *
     * @return <code>true</code> if the query has the upper bound expression; <code>false</code> otherwise
     */
    public boolean hasUpperBoundExpression() {
        return upperBoundExpression != null &&
              !upperBoundExpression.isNull();
    }

    @Override
    protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression) {
        return wordParser.character() == RIGHT_PARENTHESIS ||
               word.equalsIgnoreCase(AND)                  ||
               word.equalsIgnoreCase(THEN)                 ||
               word.equalsIgnoreCase(ELSE)                 ||
               super.isParsingComplete(wordParser, word, expression);
    }

    @Override
    protected void parse(WordParser wordParser, boolean tolerant) {

        // Parse 'NOT'
        if (wordParser.startsWithIgnoreCase('N')) {
            notIdentifier = wordParser.moveForward(NOT);
            wordParser.skipLeadingWhitespace();
        }

        // Parse 'BETWEEN'
        betweenIdentifier = wordParser.moveForward(BETWEEN);
        hasSpaceAfterBetween = (wordParser.skipLeadingWhitespace() > 0);

        // Parse lower bound expression
        lowerBoundExpression = parse(wordParser, InternalBetweenExpressionBNF.ID, tolerant);

        if (lowerBoundExpression != null) {
            hasSpaceAfterLowerBound = (wordParser.skipLeadingWhitespace() > 0);
        }

        // Parse 'AND'
        if (!tolerant || wordParser.startsWithIdentifier(AND)) {
            andIdentifier = wordParser.moveForward(AND);
            hasSpaceAfterAnd = (wordParser.skipLeadingWhitespace() > 0);
        }

        // Parse upper bound expression
        upperBoundExpression = parse(wordParser, InternalBetweenExpressionBNF.ID, tolerant);
    }

    @Override
    protected void toParsedText(StringBuilder writer, boolean actual) {

        // Expression
        if (hasExpression()) {
            expression.toParsedText(writer, actual);
            writer.append(SPACE);
        }

        // 'NOT'
        if (notIdentifier != null) {
            writer.append(actual ? notIdentifier : NOT);
            writer.append(SPACE);
        }

        // Identifier
        if (betweenIdentifier != null) {
            writer.append(actual ? betweenIdentifier : BETWEEN);
        }

        if (hasSpaceAfterBetween) {
            writer.append(SPACE);
        }

        // Lower bound expression
        if (lowerBoundExpression != null) {
            lowerBoundExpression.toParsedText(writer, actual);
        }

        if (hasSpaceAfterLowerBound) {
            writer.append(SPACE);
        }

        // 'AND'
        if (andIdentifier != null) {
            writer.append(actual ? andIdentifier : AND);
        }

        if (hasSpaceAfterAnd) {
            writer.append(SPACE);
        }

        // Upper bound expression
        if (upperBoundExpression != null) {
            upperBoundExpression.toParsedText(writer, actual);
        }
    }
}