/*
 *  ============LICENSE_START=======================================================
 *  Copyright (C) 2021-2022 Nordix Foundation
 *  Modifications Copyright (C) 2021 Bell Canada
 *  ================================================================================
 *  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.
 *
 *  SPDX-License-Identifier: Apache-2.0
 *  ============LICENSE_END=========================================================
 */

package org.onap.cps.ncmp.dmi.service.operation;

import com.jayway.jsonpath.Configuration;
import com.jayway.jsonpath.JsonPath;
import com.jayway.jsonpath.JsonPathException;
import com.jayway.jsonpath.TypeRef;
import com.jayway.jsonpath.spi.json.JacksonJsonProvider;
import com.jayway.jsonpath.spi.mapper.JacksonMappingProvider;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;
import org.onap.cps.ncmp.dmi.config.DmiConfiguration.SdncProperties;
import org.onap.cps.ncmp.dmi.exception.SdncException;
import org.onap.cps.ncmp.dmi.model.DataAccessRequest;
import org.onap.cps.ncmp.dmi.service.client.SdncRestconfClient;
import org.onap.cps.ncmp.dmi.service.model.ModuleSchema;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Component;
import org.springframework.util.LinkedMultiValueMap;
import org.springframework.util.MultiValueMap;
import org.springframework.web.util.UriComponentsBuilder;

@Component
public class SdncOperations {

    private static final String TOPOLOGY_URL_TEMPLATE_DATA =
        "/rests/data/network-topology:network-topology/";
    private static final String TOPOLOGY_URL_TEMPLATE_OPERATIONAL =
        "/rests/operations/network-topology:network-topology/";
    private static final String GET_SCHEMA_URL = "ietf-netconf-monitoring:netconf-state/schemas";
    private static final String GET_SCHEMA_SOURCES_URL = "/ietf-netconf-monitoring:get-schema";
    private static final String PATH_TO_MODULE_SCHEMAS = "$.ietf-netconf-monitoring:schemas.schema";
    private static final int QUERY_PARAM_SPLIT_LIMIT = 2;
    private static final int QUERY_PARAM_VALUE_INDEX = 1;
    private static final int QUERY_PARAM_NAME_INDEX = 0;

    private final SdncProperties sdncProperties;
    private final SdncRestconfClient sdncRestconfClient;
    private final String topologyUrlData;
    private final String topologyUrlOperational;

    private Configuration jsonPathConfiguration = Configuration.builder()
        .mappingProvider(new JacksonMappingProvider())
        .jsonProvider(new JacksonJsonProvider())
        .build();

    /**
     * Constructor for {@code SdncOperations}. This method also manipulates url properties.
     *
     * @param sdncProperties     {@code SdncProperties}
     * @param sdncRestconfClient {@code SdncRestconfClient}
     */
    public SdncOperations(final SdncProperties sdncProperties, final SdncRestconfClient sdncRestconfClient) {
        this.sdncProperties = sdncProperties;
        this.sdncRestconfClient = sdncRestconfClient;
        topologyUrlOperational = getTopologyUrlOperational();
        topologyUrlData = getTopologyUrlData();
    }

    /**
     * This method fetches list of modules usind sdnc client.
     *
     * @param nodeId node id for node
     * @return a collection of module schemas
     */
    public Collection<ModuleSchema> getModuleSchemasFromNode(final String nodeId) {
        final String urlWithNodeId = prepareGetSchemaUrl(nodeId);
        final ResponseEntity<String> modulesResponseEntity = sdncRestconfClient.getOperation(urlWithNodeId);
        if (modulesResponseEntity.getStatusCode() == HttpStatus.OK) {
            final String modulesResponseBody = modulesResponseEntity.getBody();
            if (modulesResponseBody == null || modulesResponseBody.isBlank()) {
                return Collections.emptyList();
            }
            return convertToModuleSchemas(modulesResponseBody);
        }
        throw new SdncException(
                String.format("SDNC failed to get Modules Schema for node %s", nodeId),
                modulesResponseEntity.getStatusCode(), modulesResponseEntity.getBody());
    }

    /**
     * Get module schema.
     *
     * @param nodeId           node ID
     * @param moduleProperties module properties
     * @return response entity
     */
    public ResponseEntity<String> getModuleResource(final String nodeId, final String moduleProperties) {
        final var getYangResourceUrl = prepareGetOperationSchemaUrl(nodeId);
        final var httpHeaders = new HttpHeaders();
        httpHeaders.setContentType(MediaType.APPLICATION_JSON);
        return sdncRestconfClient.httpOperationWithJsonData(
            HttpMethod.POST, getYangResourceUrl, moduleProperties, httpHeaders);
    }

    /**
     * This method fetches the resource data for given node identifier on given resource using sdnc client.
     *
     * @param nodeId                    network resource identifier
     * @param resourceId                resource identifier
     * @param optionsParamInQuery       fields query
     * @param acceptParamInHeader       accept parameter
     * @param restConfContentQueryParam restConf content query param
     * @return {@code ResponseEntity} response entity
     */
    public ResponseEntity<String> getResouceDataForOperationalAndRunning(final String nodeId,
        final String resourceId,
        final String optionsParamInQuery,
        final String acceptParamInHeader,
        final String restConfContentQueryParam) {
        final String getResourceDataUrl = prepareResourceDataUrl(nodeId,
            resourceId,
                buildQueryParamMap(optionsParamInQuery, restConfContentQueryParam));
        final HttpHeaders httpHeaders = new HttpHeaders();
        if (acceptParamInHeader != null && !acceptParamInHeader.isBlank()) {
            httpHeaders.set(HttpHeaders.ACCEPT, acceptParamInHeader);
        }
        return sdncRestconfClient.getOperation(getResourceDataUrl, httpHeaders);
    }

    /**
     * Write resource data.
     *
     * @param nodeId      network resource identifier
     * @param resourceId  resource identifier
     * @param contentType http content type
     * @param requestData request data
     * @return {@code ResponseEntity} response entity
     */
    public ResponseEntity<String> writeData(final DataAccessRequest.OperationEnum operation,
                                            final String nodeId,
                                            final String resourceId,
                                            final String contentType,
                                            final String requestData) {
        final var getResourceDataUrl = prepareWriteUrl(nodeId, resourceId);
        final var httpHeaders = new HttpHeaders();
        httpHeaders.setContentType(MediaType.parseMediaType(contentType));
        final HttpMethod httpMethod = getHttpMethod(operation);
        return sdncRestconfClient.httpOperationWithJsonData(httpMethod, getResourceDataUrl, requestData, httpHeaders);
    }

    private MultiValueMap<String, String> buildQueryParamMap(final String optionsParamInQuery,
                                                             final String restConfContentQueryParam) {
        return getQueryParamsAsMap(optionsParamInQuery, restConfContentQueryParam);
    }

    private MultiValueMap<String, String> getQueryParamsAsMap(final String optionsParamInQuery,
                                                              final String restConfContentQueryParam) {
        final MultiValueMap<String, String> queryParams = new LinkedMultiValueMap<>();
        if (optionsParamInQuery != null && !optionsParamInQuery.isBlank()) {
            queryParams.setAll(extractQueryParams(optionsParamInQuery, restConfContentQueryParam));
        }
        return queryParams;
    }

    private String stripParenthesisFromOptionsQuery(final String optionsParamInQuery) {
        return optionsParamInQuery.substring(1, optionsParamInQuery.length() - 1);
    }

    private String prepareGetSchemaUrl(final String nodeId) {
        return addResource(addTopologyDataUrlwithNode(nodeId), GET_SCHEMA_URL);
    }

    private String prepareWriteUrl(final String nodeId, final String resourceId) {
        return addResource(addTopologyDataUrlwithNode(nodeId), resourceId);
    }

    private String prepareGetOperationSchemaUrl(final String nodeId) {
        return UriComponentsBuilder.fromUriString(topologyUrlOperational)
                .pathSegment("node={nodeId}")
                .pathSegment("yang-ext:mount")
                .path(GET_SCHEMA_SOURCES_URL)
                .buildAndExpand(nodeId).toUriString();
    }

    private String prepareResourceDataUrl(final String nodeId,
                                          final String resourceId,
                                          final MultiValueMap<String, String> queryMap) {
        return addQuery(addResource(addTopologyDataUrlwithNode(nodeId), resourceId), queryMap);
    }

    private String addResource(final String url, final String resourceId) {
        return UriComponentsBuilder.fromUriString(url)
                .pathSegment(resourceId)
                .buildAndExpand().toUriString();
    }

    private String addQuery(final String url, final MultiValueMap<String, String> queryMap) {
        return UriComponentsBuilder.fromUriString(url)
                .queryParams(queryMap)
                .buildAndExpand().toUriString();
    }

    private String addTopologyDataUrlwithNode(final String nodeId) {
        return UriComponentsBuilder.fromUriString(topologyUrlData)
                .pathSegment("node={nodeId}")
                .pathSegment("yang-ext:mount")
                .buildAndExpand(nodeId).toUriString();
    }

    private List<ModuleSchema> convertToModuleSchemas(final String modulesListAsJson) {
        try {
            return JsonPath.using(jsonPathConfiguration).parse(modulesListAsJson).read(
                PATH_TO_MODULE_SCHEMAS, new TypeRef<>() {
                });
        } catch (final JsonPathException jsonPathException) {
            throw new SdncException("SDNC Response processing failed",
                "SDNC response is not in the expected format.", jsonPathException);
        }
    }

    private HttpMethod getHttpMethod(final DataAccessRequest.OperationEnum operation) {
        HttpMethod httpMethod = null;
        switch (operation) {
            case READ:
                httpMethod = HttpMethod.GET;
                break;
            case CREATE:
                httpMethod = HttpMethod.POST;
                break;
            case PATCH:
                httpMethod = HttpMethod.PATCH;
                break;
            case UPDATE:
                httpMethod = HttpMethod.PUT;
                break;
            case DELETE:
                httpMethod = HttpMethod.DELETE;
                break;
            default:
                //unreachable code but checkstyle made me do this!
        }
        return httpMethod;
    }

    private String getTopologyUrlData() {
        return UriComponentsBuilder.fromUriString(TOPOLOGY_URL_TEMPLATE_DATA)
                .path("topology={topologyId}")
                .buildAndExpand(this.sdncProperties.getTopologyId()).toUriString();
    }

    private String getTopologyUrlOperational() {
        return UriComponentsBuilder.fromUriString(
                        TOPOLOGY_URL_TEMPLATE_OPERATIONAL)
                .path("topology={topologyId}")
                .buildAndExpand(this.sdncProperties.getTopologyId()).toUriString();
    }

    private Map<String, String> extractQueryParams(final String optionsParamInQuery,
                                                   final String restConfContentQueryParam) {
        final String QueryParamsAsString = stripParenthesisFromOptionsQuery(optionsParamInQuery)
                + "," + restConfContentQueryParam;
        final String[] splitTempQueryByComma = QueryParamsAsString.split(",");
        return Arrays.stream(splitTempQueryByComma)
                .map(queryParamPair -> queryParamPair.split("=", QUERY_PARAM_SPLIT_LIMIT))
                .filter(queryParam -> queryParam.length > 1)
                .collect(Collectors.toMap(
                        queryParam -> queryParam[QUERY_PARAM_NAME_INDEX],
                        queryParam -> queryParam[QUERY_PARAM_VALUE_INDEX]));
    }
}