/*
 * Copyright 2015-2023 Amazon Technologies, Inc.
 *
 * 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://aws.amazon.com/apache2.0
 *
 * This file 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 com.amazonaws.services.dynamodbv2.xspec;

import java.util.LinkedList;
import java.util.List;

import com.amazonaws.annotation.Immutable;

import com.amazonaws.annotation.Beta;

/**
 * A path operand that refers to a <a href=
 * "http://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_AttributeValue.html"
 * >string</a> attribute in DynamoDB; used for building expressions.
 * <p>
 * Use {@link ExpressionSpecBuilder#S(String)} to instantiate this class.
 */
@Beta
@Immutable
public final class S extends PathOperand {
    S(String path) { super(path); }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Functions"
     * >function condition</a> (that evaluates to true if the value of the
     * current attribute begins with the specified operand) for building
     * condition expression.
     */
    public FunctionCondition beginsWith(String value) {
        return new FunctionCondition("begins_with", this, new LiteralOperand(value));
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Functions"
     * >function condition</a> (that evaluates to true if the value of the
     * current attribute contains the specified substring) for building
     * condition expression.
     */
    public FunctionCondition contains(String substring) {
        return new FunctionCondition("contains", this, new LiteralOperand(substring));
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Comparators"
     * >comparator condition</a> (that evaluates to true if the value of the current
     * attribute is equal to that of the specified attribute) for building
     * condition expression.
     */
    public ComparatorCondition eq(S that) {
        return new ComparatorCondition("=", this, that);
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Comparators"
     * >comparator condition</a> (that evaluates to true if the value of the current
     * attribute is not equal to that of the specified attribute) for building
     * condition expression.
     */
    public ComparatorCondition ne(S that) {
        return new ComparatorCondition("<>", this, that);
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Comparators"
     * >comparator condition</a> (that evaluates to true if the value of the current
     * attribute is less than or equal to the specified value) for building
     * condition expression.
     */
    public ComparatorCondition le(String value) {
        return new ComparatorCondition("<=", this, new LiteralOperand(value));
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Comparators"
     * >comparator condition</a> (that evaluates to true if the value of the current
     * attribute is less than or equal to that of the specified attribute) for building
     * condition expression.
     */
    public ComparatorCondition le(S that) {
        return new ComparatorCondition("<=", this, that);
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Comparators"
     * >comparator condition</a> (that evaluates to true if the value of the current
     * attribute is less than the specified value) for building
     * condition expression.
     */
    public ComparatorCondition lt(String value) {
        return new ComparatorCondition("<", this, new LiteralOperand(value));
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Comparators"
     * >comparator condition</a> (that evaluates to true if the value of the current
     * attribute is less than that of the specified attribute) for building
     * condition expression.
     */
    public ComparatorCondition lt(S that) {
        return new ComparatorCondition("<", this, that);
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Comparators"
     * >comparator condition</a> (that evaluates to true if the value of the current
     * attribute is greater than or equal to the specified value) for building
     * condition expression.
     */
    public ComparatorCondition ge(String value) {
        return new ComparatorCondition(">=", this, new LiteralOperand(value));
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Comparators"
     * >comparator condition</a> (that evaluates to true if the value of the current
     * attribute is greater than or equal to that of the specified attribute) for building
     * condition expression.
     */
    public ComparatorCondition ge(S that) {
        return new ComparatorCondition(">=", this, that);
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Comparators"
     * >comparator condition</a> (that evaluates to true if the value of the current
     * attribute is greater than the specified value) for building
     * condition expression.
     */
    public ComparatorCondition gt(String value) {
        return new ComparatorCondition(">", this, new LiteralOperand(value));
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Comparators"
     * >comparator condition</a> (that evaluates to true if the value of the current
     * attribute is greater than that of the specified attribute) for building
     * condition expression.
     */
    public ComparatorCondition gt(S that) {
        return new ComparatorCondition(">", this, that);
    }

    /**
     * Returns a <code>BetweenCondition</code> that represents a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Comparators"
     * >BETWEEN comparison</a> (that evaluates to true if the value of the
     * current attribute is greater than or equal to the given low value, and
     * less than or equal to the given high value) for building condition
     * expression.
     */
    public BetweenCondition between(String low, String high) {
        return new BetweenCondition(this,
                new LiteralOperand(low),
                new LiteralOperand(high));
    }

    /**
     * Returns an <code>IfNotExists</code> object which represents an <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.Modifying.html"
     * >if_not_exists(path, operand)</a> function call where path refers to that
     * of the current attribute; used for building expressions.
     *
     * <pre>
     * "if_not_exists (path, operand) – If the item does not contain an attribute
     * at the specified path, then if_not_exists evaluates to operand; otherwise,
     * it evaluates to path. You can use this function to avoid overwriting an
     * attribute already present in the item."
     * </pre>
     *
     * @param defaultValue
     *            the default value that will be used as the operand to the
     *            if_not_exists function call.
     */
    public IfNotExistsFunction<S> ifNotExists(S defaultValue) {
        return ExpressionSpecBuilder.if_not_exists(this, defaultValue);
    }

    /**
     * Returns an <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Functions"
     * >InCondition</a> (that evaluates to true if the value of the current
     * attribute is equal to any of the specified values) for building condition
     * expression.
     *
     * @param values
     *            specified values. The number of values must be at least one
     *            and at most 100.
     */
    public final InCondition in(String... values) {
        List<LiteralOperand> list = new LinkedList<LiteralOperand>();
        for (String v: values)
            list.add(new LiteralOperand(v));
        return new InCondition(this, list);
    }

    /**
     * Returns an <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Functions"
     * >InCondition</a> (that evaluates to true if the value of the current
     * attribute is equal to any of the values in the specified list) for
     * building condition expression.
     *
     * @param values
     *            specified list of values. The number of values must be at
     *            least one and at most 100.
     */
    public final InCondition in(List<String> values) {
        List<LiteralOperand> list = new LinkedList<LiteralOperand>();
        for (String v: values)
            list.add(new LiteralOperand(v));
        return new InCondition(this, list);
    }

    /**
     * Returns a <code>SetAction</code> object used for building update
     * expression. If the attribute referred to by this path operand doesn't
     * exist, the returned object represents adding the attribute value of the
     * specified source path operand to an item. If the current attribute
     * already exists, the returned object represents the value replacement of
     * the current attribute by the attribute value of the specified source path
     * operand.
     */
    public SetAction set(S source) {
        return new SetAction(this, source);
    }

    /**
     * Returns a <code>SetAction</code> object used for building update
     * expression. If the attribute referred to by this path operand doesn't
     * exist, the returned object represents adding the specified value as an
     * attribute to an item. If the attribute referred to by this path operand
     * already exists, the returned object represents the value replacement of
     * the current attribute by the specified value.
     */
    public SetAction set(String value) {
        return new SetAction(this, new LiteralOperand(value));
    }

    /**
     * Returns a <code>SetAction</code> object used for building update
     * expression. If the attribute referred to by this path operand doesn't
     * exist, the returned object represents adding the value of evaluating the
     * specified <code>IfNotExists</code> function as an attribute to an item.
     * If the attribute referred to by this path operand already exists, the
     * returned object represents the value replacement of the current attribute
     * by the value of evaluating the specified <code>IfNotExists</code>
     * function.
     */
    public SetAction set(IfNotExistsFunction<S> ifNotExistsFunction) {
        return new SetAction(this, ifNotExistsFunction);
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Functions"
     * >comparator condition</a> (that evaluates to true if the attribute value
     * referred to by this path operand is equal to the specified value) for
     * building condition expression.
     */
    public ComparatorCondition eq(String value) {
        return new ComparatorCondition("=", this, new LiteralOperand(value));
    }

    /**
     * Returns a <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html#ConditionExpressionReference.Functions"
     * >comparator condition</a> (that evaluates to true if the attribute value
     * referred to by this path operand is not equal to that of the specified
     * path operand) for building condition expression.
     */
    public ComparatorCondition ne(String value) {
        return new ComparatorCondition("<>", this, new LiteralOperand(value));
    }

    /**
     * Returns an <code>IfNotExists</code> object which represents an <a href=
     * "http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.Modifying.html"
     * >if_not_exists(path, operand)</a> function call where path refers to that
     * of the current path operand; used for building expressions.
     *
     * <pre>
     * "if_not_exists (path, operand) – If the item does not contain an attribute
     * at the specified path, then if_not_exists evaluates to operand; otherwise,
     * it evaluates to path. You can use this function to avoid overwriting an
     * attribute already present in the item."
     * </pre>
     *
     * @param defaultValue
     *            the default value that will be used as the operand to the
     *            if_not_exists function call.
     */
    public IfNotExistsFunction<S> ifNotExists(String defaultValue) {
        return new IfNotExistsFunction<S>(this, new LiteralOperand(defaultValue));
    }
}