package ca.uhn.fhir.rest.param;

/*
 * #%L
 * HAPI FHIR - Core Library
 * %%
 * Copyright (C) 2014 - 2017 University Health Network
 * %%
 * 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.
 * #L%
 */

import static org.apache.commons.lang3.StringUtils.isNotBlank;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import ca.uhn.fhir.context.FhirContext;
import ca.uhn.fhir.context.FhirVersionEnum;

/**
 * Comparator/qualifier for values used in REST params, such as {@link DateParam}, {@link NumberParam}, and
 * {@link QuantityParam}
 * 
 * @since 1.5
 */
public enum ParamPrefixEnum {

	/**
	 * Code Value: <b>eq</b>
	 *
	 * The actual value is equal to the given value
	 */
	APPROXIMATE("~", "ap"),

	/**
	 * Code Value: <b>eb</b>
	 *
	 * The range of the search value does overlap not with the range of the target value, and the range above the search value contains the range of the target value
	 */
	ENDS_BEFORE("", "eb"),

	/**
	 * Code Value: <b>eq</b>
	 *
	 * The actual value is equal to the given value
	 */
	EQUAL("", "eq"),

	/**
	 * Code Value: <b>gt</b>
	 *
	 * The actual value is greater than the given value.
	 */
	GREATERTHAN(">", "gt"),

	/**
	 * Code Value: <b>ge</b>
	 *
	 * The actual value is greater than or equal to the given value.
	 */
	GREATERTHAN_OR_EQUALS(">=", "ge"),

	/**
	 * Code Value: <b>lt</b>
	 *
	 * The actual value is less than the given value.
	 */
	LESSTHAN("<", "lt"),

	/**
	 * Code Value: <b>le</b>
	 *
	 * The actual value is less than or equal to the given value.
	 */
	LESSTHAN_OR_EQUALS("<=", "le"), 
	
	/**
	 * Code Value: <b>ne</b>
	 *
	 * The actual value is not equal to the given value
	 */
	NOT_EQUAL("", "ne"),
	
	/**
	 * Code Value: <b>sa</b>
	 *
	 * The range of the search value does not overlap with the range of the target value, and the range below the search value contains the range of the target value
	 */
	STARTS_AFTER("", "sa");
	
	private static final Map<String, ParamPrefixEnum> DSTU1_TO_PREFIX;
	private static final Map<String, ParamPrefixEnum> VALUE_TO_PREFIX;

	static {
		HashMap<String, ParamPrefixEnum> valueToPrefix = new HashMap<String, ParamPrefixEnum>();
		HashMap<String, ParamPrefixEnum> dstu1ToPrefix = new HashMap<String, ParamPrefixEnum>();
		for (ParamPrefixEnum next : values()) {
			valueToPrefix.put(next.getValue(), next);
			if (isNotBlank(next.getDstu1Value())) {
				dstu1ToPrefix.put(next.getDstu1Value(), next);
			}
		}

		VALUE_TO_PREFIX = Collections.unmodifiableMap(valueToPrefix);
		DSTU1_TO_PREFIX = Collections.unmodifiableMap(dstu1ToPrefix);
	}

	private final String myDstu1Value;

	private final String myValue;

	private ParamPrefixEnum(String theDstu1Value, String theValue) {
		myDstu1Value = theDstu1Value;
		myValue = theValue;
	}

	/**
	 * Returns the DSTU1 value, e.g. <code><</code> or <code>~</code>
	 */
	public String getDstu1Value() {
		return myDstu1Value;
	}

	/**
	 * Returns the DSTU2+ value, e.g. <code>lt</code> or <code>eq</code>
	 */
	public String getValue() {
		return myValue;
	}

	/**
	 * Returns the appropriate value for the given context, based on the
	 * FHIR version supported by the context  
	 */
	public String getValueForContext(FhirContext theContext) {
		if (theContext.getVersion().getVersion() == FhirVersionEnum.DSTU1) {
			return getDstu1Value();
		}
		return getValue();
	}

	/**
	 * Returns the prefix associated with a given DSTU1 value (e.g. <code><</code> or <code>~</code>)
	 * 
	 * @param theValue
	 *           e.g. <code><</code> or <code>~</code>
	 * @return The prefix, or <code>null</code> if no prefix matches the value
	 */
	public static ParamPrefixEnum forDstu1Value(String theValue) {
		return DSTU1_TO_PREFIX.get(theValue);
	}

	/**
	 * Returns the prefix associated with a given DSTU2+ value (e.g. <code>lt</code> or <code>eq</code>)
	 * 
	 * @param theValue
	 *           e.g. <code><</code> or <code>~</code>
	 * @return The prefix, or <code>null</code> if no prefix matches the value
	 */
	public static ParamPrefixEnum forValue(String theValue) {
		return VALUE_TO_PREFIX.get(theValue);
	}
}