/*
 *  ============LICENSE_START=======================================================
 *  Copyright (C) 2021 Nordix Foundation
 *  ================================================================================
 *  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.rest.controller;

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.List;
import javax.validation.Valid;
import lombok.extern.slf4j.Slf4j;
import org.onap.cps.ncmp.dmi.model.CmHandles;
import org.onap.cps.ncmp.dmi.model.DataAccessRequest;
import org.onap.cps.ncmp.dmi.model.ModuleReferencesRequest;
import org.onap.cps.ncmp.dmi.model.ModuleResourcesReadRequest;
import org.onap.cps.ncmp.dmi.model.ModuleSet;
import org.onap.cps.ncmp.dmi.model.YangResources;
import org.onap.cps.ncmp.dmi.rest.api.DmiPluginApi;
import org.onap.cps.ncmp.dmi.rest.api.DmiPluginInternalApi;
import org.onap.cps.ncmp.dmi.service.DmiService;
import org.onap.cps.ncmp.dmi.service.model.ModuleReference;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RequestMapping("${rest.api.dmi-base-path}")
@RestController
@Slf4j
public class DmiRestController implements DmiPluginApi, DmiPluginInternalApi {

    private DmiService dmiService;

    private ObjectMapper objectMapper;

    public DmiRestController(final DmiService dmiService, final ObjectMapper objectMapper) {
        this.dmiService = dmiService;
        this.objectMapper = objectMapper;
    }

    @Override
    public ResponseEntity<ModuleSet> getModuleReferences(final String cmHandle,
                                                           final @Valid ModuleReferencesRequest body) {
        // For onap-dmi-plugin we don't need cmHandleProperties, so DataAccessReadRequest is not used.
        final var moduleSet = dmiService.getModulesForCmHandle(cmHandle);
        return ResponseEntity.ok(moduleSet);
    }

    @Override
    public ResponseEntity<YangResources> retrieveModuleResources(
        final @Valid ModuleResourcesReadRequest moduleResourcesReadRequest,
        final String cmHandle) {
        final List<ModuleReference> moduleReferences = convertRestObjectToJavaApiObject(moduleResourcesReadRequest);
        final YangResources yangResources = dmiService.getModuleResources(cmHandle, moduleReferences);
        return new ResponseEntity<>(yangResources, HttpStatus.OK);
    }

    /**
     * This method register given list of cm-handles to ncmp.
     *
     * @param cmHandles list of cm-handles
     * @return (@ code ResponseEntity) response entity
     */
    public ResponseEntity<String> registerCmHandles(final @Valid CmHandles cmHandles) {
        final List<String> cmHandlesList = cmHandles.getCmHandles();
        if (cmHandlesList.isEmpty()) {
            return new ResponseEntity<>("Need at least one cmHandle to process.", HttpStatus.BAD_REQUEST);
        }
        dmiService.registerCmHandles(cmHandlesList);
        return new ResponseEntity<>("cm-handle registered successfully.", HttpStatus.CREATED);
    }

    /**
     * This method fetches the resource for given cm handle using pass through operational. It filters the response on
     * the basis of options query parameters and returns response. Does not support write operations.
     *
     * @param resourceIdentifier    resource identifier to fetch data
     * @param cmHandle              cm handle identifier
     * @param dataAccessRequest     data Access Request
     * @param acceptParamInHeader   accept header parameter
     * @param optionsParamInQuery   options query parameter
     * @return {@code ResponseEntity} response entity
     */
    @Override
    public ResponseEntity<Object> dataAccessPassthroughOperational(final String resourceIdentifier,
                                                                   final String cmHandle,
                                                                   final @Valid DataAccessRequest
                                                                                dataAccessRequest,
                                                                   final String acceptParamInHeader,
                                                                   final @Valid String optionsParamInQuery) {
        if (isReadOperation(dataAccessRequest)) {
            final String resourceDataAsJson = dmiService.getResourceData(cmHandle,
                resourceIdentifier,
                acceptParamInHeader,
                optionsParamInQuery,
                DmiService.RESTCONF_CONTENT_PASSTHROUGH_OPERATIONAL_QUERY_PARAM);
            return ResponseEntity.ok(resourceDataAsJson);
        }
        return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
    }

    @Override
    public ResponseEntity<String> dataAccessPassthroughRunning(final String resourceIdentifier,
                                                               final String cmHandle,
                                                               final @Valid DataAccessRequest
                                                                       dataAccessRequest,
                                                               final String acceptParamInHeader,
                                                               final @Valid String optionsParamInQuery) {
        final String sdncResponse;
        if (isReadOperation(dataAccessRequest)) {
            sdncResponse = dmiService.getResourceData(cmHandle,
                resourceIdentifier,
                acceptParamInHeader,
                optionsParamInQuery,
                DmiService.RESTCONF_CONTENT_PASSTHROUGH_RUNNING_QUERY_PARAM);
        } else {
            sdncResponse = dmiService.writeData(
                dataAccessRequest.getOperation(),
                cmHandle,
                resourceIdentifier,
                MediaType.APPLICATION_JSON_VALUE,
                dataAccessRequest.getData());
        }
        return new ResponseEntity<>(sdncResponse, getHttpStatus(dataAccessRequest));
    }

    private boolean isReadOperation(final @Valid DataAccessRequest dataAccessRequest) {
        return dataAccessRequest.getOperation() == null
            || dataAccessRequest.getOperation().equals(DataAccessRequest.OperationEnum.READ);
    }

    private HttpStatus getHttpStatus(final DataAccessRequest dataAccessRequest) {
        final HttpStatus httpStatus;
        if (dataAccessRequest.getOperation() == null) {
            httpStatus = HttpStatus.OK;
        } else {
            switch (dataAccessRequest.getOperation()) {
                case CREATE:
                    httpStatus = HttpStatus.CREATED;
                    break;
                case READ:
                case UPDATE:
                    httpStatus = HttpStatus.OK;
                    break;
                case DELETE:
                    httpStatus = HttpStatus.NO_CONTENT;
                    break;
                default:
                    httpStatus = HttpStatus.BAD_REQUEST;
            }
        }
        return httpStatus;
    }

    private List<ModuleReference> convertRestObjectToJavaApiObject(
            final ModuleResourcesReadRequest moduleResourcesReadRequest) {
        return objectMapper
            .convertValue(moduleResourcesReadRequest.getData().getModules(),
                          new TypeReference<List<ModuleReference>>() {});
    }
}