/**
 * Copyright (C) 2012-2017 52°North Initiative for Geospatial Open Source
 * Software GmbH
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 * If the program is linked with libraries which are licensed under one of
 * the following licenses, the combination of the program with the linked
 * library is not considered a "derivative work" of the program:
 *
 *     - Apache License, version 2.0
 *     - Apache Software License, version 1.0
 *     - GNU Lesser General Public License, version 3
 *     - Mozilla Public License, versions 1.0, 1.1 and 2.0
 *     - Common Development and Distribution License (CDDL), version 1.0
 *
 * Therefore the distribution of the program linked with libraries licensed
 * under the aforementioned licenses, is permitted by the copyright holders
 * if the distribution is compliant with both the GNU General Public
 * License version 2 and the aforementioned licenses.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
 * Public License for more details.
 */
package org.n52.sos.encode.json;

import java.util.Arrays;
import java.util.Collections;
import java.util.Map;
import java.util.Set;

import org.n52.sos.coding.CodingRepository;
import org.n52.sos.coding.json.JSONConstants;
import org.n52.sos.util.JSONUtils;
import org.n52.sos.encode.Encoder;
import org.n52.sos.encode.EncoderKey;
import org.n52.sos.exception.ows.NoApplicableCodeException;
import org.n52.sos.exception.ows.concrete.NoEncoderForKeyException;
import org.n52.sos.ogc.gml.CodeType;
import org.n52.sos.ogc.gml.CodeWithAuthority;
import org.n52.sos.ogc.ows.OwsExceptionReport;
import org.n52.sos.ogc.sos.SosConstants.HelperValues;
import org.n52.sos.service.ServiceConstants.SupportedTypeKey;
import org.n52.sos.util.http.MediaType;
import org.n52.sos.util.http.MediaTypes;
import org.n52.sos.w3c.SchemaLocation;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.node.JsonNodeFactory;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.ImmutableSet.Builder;

/**
 * TODO JavaDoc
 *
 * @param <T>
 *
 * @author Christian Autermann <c.autermann@52north.org>
 *
 * @since 4.0.0
 */
public abstract class JSONEncoder<T> implements Encoder<JsonNode, T> {
    public static final String CONTENT_TYPE = "application/json";

    private final Set<EncoderKey> encoderKeys;

    public JSONEncoder(Class<? super T> type, EncoderKey... additionalKeys) {
        Builder<EncoderKey> set = ImmutableSet.builder();
        set.add(new JSONEncoderKey(type));
        set.addAll(Arrays.asList(additionalKeys));
        this.encoderKeys = set.build();
    }

    @Override
    public Set<EncoderKey> getEncoderKeyType() {
        return Collections.unmodifiableSet(encoderKeys);
    }

    @Override
    public Map<SupportedTypeKey, Set<String>> getSupportedTypes() {
        return Collections.emptyMap();
    }

    @Override
    public void addNamespacePrefixToMap(Map<String, String> nameSpacePrefixMap) {
        /* noop */
    }

    @Override
    public MediaType getContentType() {
        return MediaTypes.APPLICATION_JSON;
    }

    @Override
    public Set<SchemaLocation> getSchemaLocations() {
        return Collections.emptySet();
    }

    @Override
    public Set<String> getConformanceClasses() {
        return Collections.emptySet();
    }

    @Override
    public JsonNode encode(T objectToEncode, Map<HelperValues, String> v) throws OwsExceptionReport {
        return encode(objectToEncode);
    }

    @Override
    public JsonNode encode(T objectToEncode) throws OwsExceptionReport {
        try {
            if (objectToEncode == null) {
                return nodeFactory().nullNode();
            }
            return encodeJSON(objectToEncode);
        } catch (JSONEncodingException ex) {
            throw new NoApplicableCodeException().causedBy(ex);
        }
    }

    public abstract JsonNode encodeJSON(T t) throws OwsExceptionReport;

    protected JsonNode encodeObjectToJson(Object o) throws OwsExceptionReport {
        if (o == null) {
            return nodeFactory().nullNode();
        }
        JSONEncoderKey key = new JSONEncoderKey(o.getClass());
        Encoder<JsonNode, Object> encoder = CodingRepository.getInstance().getEncoder(key);
        if (encoder == null) {
            throw new NoEncoderForKeyException(key);
        }
        return encoder.encode(o);
    }

    protected JsonNodeFactory nodeFactory() {
        return JSONUtils.nodeFactory();
    }

    protected JsonNode encodeCodeType(CodeType codeType) {
        if (codeType.isSetCodeSpace()) {
            return nodeFactory().objectNode().put(JSONConstants.CODESPACE, codeType.getCodeSpace())
                    .put(JSONConstants.VALUE, codeType.getValue());
        } else {
            return nodeFactory().textNode(codeType.getValue());
        }
    }

    protected JsonNode encodeCodeWithAuthority(CodeWithAuthority cwa) {
        if (cwa.isSetCodeSpace()) {
            return nodeFactory().objectNode().put(JSONConstants.CODESPACE, cwa.getCodeSpace())
                    .put(JSONConstants.VALUE, cwa.getValue());
        } else {
            return nodeFactory().textNode(cwa.getValue());
        }
    }
}