/**
 * ============LICENSE_START=======================================================
 * org.onap.aai
 * ================================================================================
 * Copyright © 2017-2018 AT&T Intellectual Property. All rights reserved.
 * Copyright © 2017-2018 Amdocs
 * ================================================================================
 * 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.
 * ============LICENSE_END=========================================================
 */
package org.onap.aai.sa.searchdbabstraction.searchapi;

import com.fasterxml.jackson.annotation.JsonProperty;

/**
 * This class represents a simple range query.
 *
 * <p>
 * A range query is composed of one or more operator/value pairs which define the upper and lower bounds of the range,
 * and a field to apply the query to.
 *
 * <p>
 * Operators may be one of the following:
 * <ul>
 * <li>gt - Greater than.</li>
 * <li>gte - Greater than or equal to.</li>
 * <li>lt - Less than.</li>
 * <li>lte - Less than or equal to.</li>
 * </ul>
 * Values may be either numeric values (Integer or Double) or Strings representing dates.
 *
 * <p>
 * The following examples illustrate a couple of variants of the range query:
 *
 * <p>
 * 
 * <pre>
 *     // A simple numeric range query:
 *     {
 *         "range": {
 *             "field": "fieldname",
 *             "gte": 5,
 *             "lte": 10
 *         }
 *     }
 *
 *     // A simple date range query:
 *     {
 *         "range": {
 *             "field": "fieldname",
 *             "gt": "2016-10-06T00:00:00.558+03:00",
 *             "lt": "2016-10-06T23:59:59.558+03:00"
 *         }
 *     }
 * </pre>
 */
public class RangeQuery {

    /**
     * The name of the field to apply the range query against.
     */
    private String field;

    /**
     * The value of the field must be greater than this value to be a match.<br>
     * NOTE: Only one of 'gt' or 'gte' should be set on any single {@link RangeQuery} instance.
     */
    private Object gt;

    /**
     * The value of the field must be greater than or equal to this value to be a match.<br>
     * NOTE: Only one of 'gt' or 'gte' should be set on any single {@link RangeQuery} instance.
     */
    private Object gte;

    /**
     * The value of the field must be less than this value to be a match.<br>
     * NOTE: Only one of 'lt' or 'lte' should be set on any single {@link RangeQuery} instance.
     */
    private Object lt;

    /**
     * The value of the field must be less than or equal to than this value to be a match.<br>
     * NOTE: Only one of 'lt' or 'lte' should be set on any single {@link RangeQuery} instance.
     */
    private Object lte;

    private String format;

    @JsonProperty("time-zone")
    private String timeZone;

    public String getField() {
        return field;
    }

    public void setField(String field) {
        this.field = field;
    }

    public Object getGt() {
        return gt;
    }

    public void setGt(Object gt) {

        // It does not make sense to assign a value to both the 'greater than'
        // and 'greater than or equal' operations, so make sure we are not
        // trying to do that.
        if (gte == null) {

            // Make sure that we are not trying to mix both numeric and date
            // type values in the same queries.
            if (((lt != null) && !typesMatch(gt, lt)) || ((lte != null) && !typesMatch(gt, lte))) {
                throw new IllegalArgumentException("Cannot mix date and numeric values in the same ranged query");
            }

            // If we made it here, then we're all good. Store the value.
            this.gt = gt;
        } else {
            throw new IllegalArgumentException("Cannot assign both 'gt' and 'gte' fields in the same ranged query");
        }
    }


    public Object getGte() {
        return gte;
    }

    public void setGte(Object gte) {

        // It does not make sense to assign a value to both the 'greater than'
        // and 'greater than or equal' operations, so make sure we are not
        // trying to do that.
        if (gt == null) {

            // Make sure that we are not trying to mix both numeric and date
            // type values in the same queries.
            if (((lt != null) && !typesMatch(gte, lt)) || ((lte != null) && !typesMatch(gte, lte))) {
                throw new IllegalArgumentException("Cannot mix date and numeric values in the same ranged query");
            }

            // If we made it here, then we're all good. Store the value.
            this.gte = gte;

        } else {
            throw new IllegalArgumentException("Cannot assign both 'gt' and 'gte' fields in the same ranged query");
        }
    }

    public Object getLt() {
        return lt;
    }

    public void setLt(Object lt) {

        // It does not make sense to assign a value to both the 'less than'
        // and 'less than or equal' operations, so make sure we are not
        // trying to do that.
        if (lte == null) {

            // Make sure that we are not trying to mix both numeric and date
            // type values in the same queries.
            if (((gt != null) && !typesMatch(lt, gt)) || ((gte != null) && !typesMatch(lt, gte))) {
                throw new IllegalArgumentException("Cannot mix date and numeric values in the same ranged query");
            }

            // If we made it here, then we're all good. Store the value.

            this.lt = lt;
        } else {
            throw new IllegalArgumentException("Cannot assign both 'lt' and 'lte' fields in the same ranged query");
        }
    }

    public Object getLte() {
        return lte;
    }

    public void setLte(Object lte) {

        // It does not make sense to assign a value to both the 'greater than'
        // and 'greater than or equal' operations, so make sure we are not
        // trying to do that.
        if (lt == null) {

            // Make sure that we are not trying to mix both numeric and date
            // type values in the same queries.
            if (((gt != null) && !typesMatch(lte, gt)) || ((gte != null) && !typesMatch(lte, gte))) {
                throw new IllegalArgumentException("Cannot mix date and numeric values in the same ranged query");
            }

            // If we made it here, then we're all good. Store the value.

            this.lte = lte;
        } else {
            throw new IllegalArgumentException("Cannot assign both 'lt' and 'lte' fields in the same ranged query");
        }
    }

    public String getFormat() {
        return format;
    }

    public void setFormat(String format) {
        this.format = format;
    }

    public String getTimeZone() {
        return timeZone;
    }

    public void setTimeZone(String timeZone) {
        this.timeZone = timeZone;
    }

    /**
     * This convenience method determines whether or not the supplied value needs to be enclosed in '"' characters when
     * generating ElasticSearch compatible syntax.
     *
     * @param val - The value to check.
     * @return - A string representation of the value for inclusion in an ElasticSearch syntax string.
     */
    private String formatStringOrNumericVal(Object val) {

        if (val instanceof String) {
            return "\"" + val.toString() + "\"";
        } else {
            return val.toString();
        }
    }


    /**
     * This convenience method verifies that the supplied objects are of classes considered to be compatible for a
     * ranged query.
     *
     * @param value1 - The first value to check.
     * @param value2 - The second value to check.
     * @return - True if the two objects are compatible for inclusion in the same ranged query, False, otherwise.
     */
    boolean typesMatch(Object value1, Object value2) {

        return ((value1 instanceof String) && (value2 instanceof String))
                || (!(value1 instanceof String) && !(value2 instanceof String));
    }


    /**
     * This method returns a string which represents this query in syntax that is understandable by ElasticSearch and is
     * suitable for inclusion in an ElasticSearch query string.
     *
     * @return - ElasticSearch syntax string.
     */
    public String toElasticSearch() {

        StringBuilder sb = new StringBuilder();

        sb.append("{");
        sb.append("\"range\": {");
        sb.append("\"").append(field).append("\": {");

        // We may have one or zero of 'greater than' or 'greater
        // than or equal'
        boolean needComma = false;
        if (gte != null) {
            sb.append("\"gte\": ").append(formatStringOrNumericVal(gte));
            needComma = true;
        } else if (gt != null) {
            sb.append("\"gt\": ").append(formatStringOrNumericVal(gt));
            needComma = true;
        }

        // We may have one or zero of 'less than' or 'less
        // than or equal'
        if (lte != null) {
            if (needComma) {
                sb.append(", ");
            }
            sb.append("\"lte\": ").append(formatStringOrNumericVal(lte));
        } else if (lt != null) {
            if (needComma) {
                sb.append(", ");
            }
            sb.append("\"lt\": ").append(formatStringOrNumericVal(lt));
        }

        // Append the format specifier if one was provided.
        if (format != null) {
            sb.append(", \"format\": \"").append(format).append("\"");
        }

        // Append the time zone specifier if one was provided.
        if (timeZone != null) {
            sb.append(", \"time_zone\": \"").append(timeZone).append("\"");
        }

        sb.append("}");
        sb.append("}");
        sb.append("}");

        return sb.toString();
    }

    @Override
    public String toString() {

        String str = "{ field: " + field + ", ";

        if (gt != null) {
            str += "gt: " + gt;
        } else if (gte != null) {
            str += "gte: " + gte;
        }

        if (lt != null) {
            str += (((gt != null) || (gte != null)) ? ", " : "") + "lt: " + lt;
        } else if (lte != null) {
            str += (((gt != null) || (gte != null)) ? ", " : "") + "lte: " + lte;
        }

        str += "}";

        return str;
    }
}