/*
 * Copyright 2017-present Open Networking 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.
 */

package org.onosproject.ui.impl;

import com.fasterxml.jackson.databind.node.ObjectNode;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Sets;
import org.onosproject.codec.CodecContext;
import org.onosproject.net.Device;
import org.onosproject.net.DeviceId;
import org.onosproject.net.device.DeviceService;
import org.onosproject.net.pi.model.PiActionModel;
import org.onosproject.net.pi.model.PiHeaderFieldModel;
import org.onosproject.net.pi.model.PiHeaderModel;
import org.onosproject.net.pi.model.PiHeaderTypeModel;
import org.onosproject.net.pi.model.PiPipeconf;
import org.onosproject.net.pi.model.PiPipeconfId;
import org.onosproject.net.pi.model.PiPipelineInterpreter;
import org.onosproject.net.pi.model.PiPipelineModel;
import org.onosproject.net.pi.model.PiTableMatchFieldModel;
import org.onosproject.net.pi.model.PiTableModel;
import org.onosproject.net.pi.runtime.PiPipeconfService;
import org.onosproject.net.pi.runtime.PiTableId;
import org.onosproject.ui.RequestHandler;
import org.onosproject.ui.UiMessageHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Collection;
import java.util.Optional;
import java.util.Set;

public class PipeconfViewMessageHandler extends UiMessageHandler {
    private static final Logger log =
            LoggerFactory.getLogger(PipeconfViewMessageHandler.class);
    private static final String PIPECONF_REQUEST = "pipeconfRequest";
    private static final String PIPECONF_RESP = "pipeConfResponse";
    private static final String DEVICE_ID = "devId";
    private static final String PIPECONF = "pipeconf";
    private static final String PIPELINE_MODEL = "pipelineModel";
    private static final String NO_PIPECONF_RESP = "noPipeconfResp";

    @Override
    protected Collection<RequestHandler> createRequestHandlers() {
        return ImmutableSet.of(new PipeconfRequestHandler());
    }

    private class PipeconfRequestHandler extends RequestHandler {

        public PipeconfRequestHandler() {
            super(PIPECONF_REQUEST);
        }

        @Override
        public void process(ObjectNode payload) {
            PiPipeconfService piPipeconfService = get(PiPipeconfService.class);
            DeviceService deviceService = get(DeviceService.class);
            ObjectNode responseData = objectNode();
            String devId = string(payload, DEVICE_ID);
            if (devId == null || devId.isEmpty()) {
                log.warn("{}: Invalid device id", PIPECONF_REQUEST);
                sendMessage(NO_PIPECONF_RESP, null);
                return;
            }
            DeviceId deviceId = DeviceId.deviceId(devId);
            Optional<PiPipeconfId> pipeconfId = piPipeconfService.ofDevice(deviceId);
            if (!pipeconfId.isPresent()) {
                log.warn("{}: Can't find pipeconf id for device {}", PIPECONF_REQUEST, deviceId);
                sendMessage(NO_PIPECONF_RESP, null);
                return;
            }

            Optional<PiPipeconf> pipeconf = piPipeconfService.getPipeconf(pipeconfId.get());
            if (!pipeconf.isPresent()) {
                log.warn("{}: Can't find pipeconf {}", PIPECONF_REQUEST, pipeconfId);
                sendMessage(NO_PIPECONF_RESP, null);
                return;
            }
            CodecContext codecContext = getJsonCodecContext();

            ObjectNode pipeconfData = codecContext.encode(pipeconf.get(), PiPipeconf.class);
            responseData.set(PIPECONF, pipeconfData);

            // Filtered out models not exists in interpreter
            // usually they generated by compiler automatically
            Device device = deviceService.getDevice(deviceId);
            if (device == null || !deviceService.isAvailable(deviceId)) {
                log.warn("{}: Device {} is not available", PIPECONF_REQUEST, deviceId);
                sendMessage(NO_PIPECONF_RESP, null);
                return;
            }
            PiPipelineInterpreter interpreter = device.as(PiPipelineInterpreter.class);
            PiPipelineModel pipelineModel =
                    filteredOutAdditionalData(pipeconf.get().pipelineModel(), interpreter);

            ObjectNode pipelineModelData =
                    codecContext.encode(pipelineModel, PiPipelineModel.class);
            responseData.set(PIPELINE_MODEL, pipelineModelData);

            sendMessage(PIPECONF_RESP, responseData);
        }
    }

    private PiPipelineModel filteredOutAdditionalData(PiPipelineModel piPipelineModel,
                                                      PiPipelineInterpreter interpreter) {
        if (interpreter == null) {
            // Do nothing if there is no interpreter
            return piPipelineModel;
        }
        // filter out actions, headers and tables if not exists in interpreter
        Set<PiHeaderTypeModel> newHeaderTypesModels = Sets.newHashSet();
        Set<PiHeaderModel> newHeaderModels = Sets.newHashSet();
        Set<PiActionModel> newActionModels = Sets.newHashSet();
        Set<PiTableModel> newTableModels = Sets.newHashSet();

        piPipelineModel.tables().forEach(table -> {
            String tableName = table.name();
            PiTableId tableId = PiTableId.of(tableName);

            if (interpreter.mapPiTableId(tableId).isPresent()) {
                newTableModels.add(table);

                newActionModels.addAll(table.actions());
                table.matchFields().stream()
                        .map(PiTableMatchFieldModel::field)
                        .map(PiHeaderFieldModel::header)
                        .forEach(header -> {
                            newHeaderModels.add(header);
                            newHeaderTypesModels.add(header.type());
                        });

            }
        });

        return new FilteredPipelineModel(newHeaderTypesModels,
                                         newHeaderModels,
                                         newActionModels,
                                         newTableModels);
    }

    /**
     * Pipeline model for UI message.
     * FIXME: Is it necessary to create this class?
     */
    private class FilteredPipelineModel implements PiPipelineModel {

        private Set<PiHeaderTypeModel> headerTypesModels;
        private Set<PiHeaderModel> headerModels;
        private Set<PiActionModel> actionModels;
        private Set<PiTableModel> tableModels;

        public FilteredPipelineModel(Set<PiHeaderTypeModel> headerTypesModels,
                                     Set<PiHeaderModel> headerModels,
                                     Set<PiActionModel> actionModels,
                                     Set<PiTableModel> tableModels) {
            this.headerTypesModels = headerTypesModels;
            this.headerModels = headerModels;
            this.actionModels = actionModels;
            this.tableModels = tableModels;
        }

        @Override
        public Optional<PiHeaderTypeModel> headerType(String name) {
            return headerTypesModels.stream()
                    .filter(headerType -> headerType.name().equals(name))
                    .findFirst();
        }

        @Override
        public Collection<PiHeaderTypeModel> headerTypes() {
            return headerTypesModels;
        }

        @Override
        public Optional<PiHeaderModel> header(String name) {
            return headerModels.stream()
                    .filter(headerModel -> headerModel.name().equals(name))
                    .findFirst();
        }

        @Override
        public Collection<PiHeaderModel> headers() {
            return headerModels;
        }

        @Override
        public Optional<PiActionModel> action(String name) {
            return actionModels.stream()
                    .filter(actionModel -> actionModel.name().equals(name))
                    .findFirst();
        }

        @Override
        public Collection<PiActionModel> actions() {
            return actionModels;
        }

        @Override
        public Optional<PiTableModel> table(String name) {
            return tableModels.stream()
                    .filter(tableModel -> tableModel.name().equals(name))
                    .findFirst();
        }

        @Override
        public Collection<PiTableModel> tables() {
            return tableModels;
        }
    }
}