package software.amazon.devopsguru.resourcecollection;

import com.google.common.collect.Lists;
import com.google.common.collect.Sets;
import software.amazon.awssdk.services.devopsguru.DevOpsGuruClient;
import software.amazon.awssdk.services.devopsguru.model.AccessDeniedException;
import software.amazon.awssdk.services.devopsguru.model.GetResourceCollectionRequest;
import software.amazon.awssdk.services.devopsguru.model.GetResourceCollectionResponse;
import software.amazon.awssdk.services.devopsguru.model.InternalServerException;
import software.amazon.awssdk.services.devopsguru.model.ResourceNotFoundException;
import software.amazon.awssdk.services.devopsguru.model.ThrottlingException;
import software.amazon.awssdk.services.devopsguru.model.UpdateCloudFormationCollectionFilter;
import software.amazon.awssdk.services.devopsguru.model.UpdateResourceCollectionFilter;
import software.amazon.awssdk.services.devopsguru.model.UpdateResourceCollectionRequest;
import software.amazon.awssdk.services.devopsguru.model.UpdateResourceCollectionResponse;
import software.amazon.awssdk.services.devopsguru.model.ResourceCollectionType;
import software.amazon.awssdk.services.devopsguru.model.UpdateTagCollectionFilter;
import software.amazon.awssdk.services.devopsguru.model.ValidationException;
import software.amazon.cloudformation.exceptions.CfnAccessDeniedException;
import software.amazon.cloudformation.exceptions.CfnInvalidRequestException;
import software.amazon.cloudformation.exceptions.CfnNotFoundException;
import software.amazon.cloudformation.exceptions.CfnServiceInternalErrorException;
import software.amazon.cloudformation.exceptions.CfnThrottlingException;
import software.amazon.cloudformation.proxy.AmazonWebServicesClientProxy;
import software.amazon.cloudformation.proxy.Logger;
import software.amazon.cloudformation.proxy.ProgressEvent;
import software.amazon.cloudformation.proxy.ProxyClient;
import software.amazon.cloudformation.proxy.ResourceHandlerRequest;
import software.amazon.cloudformation.proxy.delay.Constant;

import java.time.Duration;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.Arrays;

// Placeholder for the functionality that could be shared across Create/Read/Update/Delete/List Handlers

public abstract class BaseHandlerStd extends BaseHandler<CallbackContext> {

    protected static final Constant BACKOFF_STRATEGY =
            Constant.of().timeout(Duration.ofMinutes(5L)).delay(Duration.ofSeconds(10L)).build();
    protected static final int MAX_STACK_NAME_NUMBER_PER_API_CALL = 100;

    @Override
    public final ProgressEvent<ResourceModel, CallbackContext> handleRequest(
            final AmazonWebServicesClientProxy proxy,
            final ResourceHandlerRequest<ResourceModel> request,
            final CallbackContext callbackContext,
            final Logger logger) {
        return handleRequest(
                proxy,
                request,
                callbackContext != null ? callbackContext : new CallbackContext(),
                proxy.newProxy(DevOpsGuruClientBuilder::getClient),
                logger
        );
    }

    protected abstract ProgressEvent<ResourceModel, CallbackContext> handleRequest(
            final AmazonWebServicesClientProxy proxy,
            final ResourceHandlerRequest<ResourceModel> request,
            final CallbackContext callbackContext,
            final ProxyClient<DevOpsGuruClient> proxyClient,
            final Logger logger);

    protected  GetResourceCollectionRequest getResourceCollectionRequestWithResourceCollectionType(
            String resourceCollectionType
    ) {
        return GetResourceCollectionRequest.builder()
                .resourceCollectionType(resourceCollectionType)
                .build();
    }

    protected GetResourceCollectionRequest getResourceCollectionRequestWithResourceCollectionType(
            ResourceCollectionType resourceCollectionType
    ) {
        return getResourceCollectionRequestWithResourceCollectionType(resourceCollectionType.toString());
    }

    protected GetResourceCollectionResponse getSingleResourceCollection(
            final GetResourceCollectionRequest getResourceCollectionRequest,
            final ProxyClient<DevOpsGuruClient> proxyClient,
            final ResourceModel model) {
        GetResourceCollectionRequest awsRequest = getResourceCollectionRequest;

        try {
            GetResourceCollectionResponse awsResponse = proxyClient.injectCredentialsAndInvokeV2(awsRequest,
                    proxyClient.client()::getResourceCollection);
            if (ResourceCollectionType.AWS_CLOUD_FORMATION.name().equals(model.getResourceCollectionType())
                    && (awsResponse.resourceCollection().cloudFormation() == null
                        || awsResponse.resourceCollection().cloudFormation().stackNames().isEmpty())) {
                throw new CfnNotFoundException(ResourceModel.TYPE_NAME, model.getResourceCollectionType());
            }
            if (ResourceCollectionType.AWS_TAGS.name().equals(model.getResourceCollectionType())
                    && (awsResponse.resourceCollection().tags() == null
                            || awsResponse.resourceCollection().tags().get(0).tagValues().isEmpty())) {
                throw new CfnNotFoundException(ResourceModel.TYPE_NAME, model.getResourceCollectionType());
            }
            return awsResponse;
        } catch (final AccessDeniedException e) {
            throw new CfnAccessDeniedException(ResourceModel.TYPE_NAME, e);
        } catch (final ThrottlingException e) {
            throw new CfnThrottlingException(ResourceModel.TYPE_NAME, e);
        } catch (final InternalServerException e) {
            throw new CfnServiceInternalErrorException(ResourceModel.TYPE_NAME, e);
        } catch (final ResourceNotFoundException e) {
            throw new CfnNotFoundException(ResourceModel.TYPE_NAME, model.getResourceCollectionType(), e);
        }
    }

    protected List<String> getAllCloudFormationResourceCollection(
            final GetResourceCollectionRequest getResourceCollectionRequest,
            final ProxyClient<DevOpsGuruClient> proxyClient,
            final ResourceModel model,
            final Logger logger) {
        GetResourceCollectionResponse awsResponse = null;
        GetResourceCollectionRequest awsRequest = getResourceCollectionRequest;
        List<String> stackNamesList = new ArrayList<>();

        try {
            do {
                awsResponse = getSingleResourceCollection(awsRequest, proxyClient, model);
                stackNamesList.addAll(awsResponse.resourceCollection().cloudFormation().stackNames());
                awsRequest = GetResourceCollectionRequest.builder()
                        .resourceCollectionType(ResourceCollectionType.AWS_CLOUD_FORMATION)
                        .nextToken(awsResponse.nextToken())
                        .build();
            } while (awsResponse.nextToken() != null);
        } catch (CfnNotFoundException ex) {
            // Interpret empty stacks as RNF
            if (stackNamesList.isEmpty()) {
                logger.log("Empty resource collection. Throwing NotFoundException");
                throw ex;
            }
        }

        return stackNamesList;
    }

    protected TagCollection getAllTagsResourceCollection(
            final GetResourceCollectionRequest getResourceCollectionRequest,
            final ProxyClient<DevOpsGuruClient> proxyClient,
            final ResourceModel model,
            final Logger logger) {
        GetResourceCollectionResponse awsResponse = null;
        GetResourceCollectionRequest awsRequest = getResourceCollectionRequest;
        List<String> tagValues = new ArrayList<>();
        String appBoundaryKey = null;

        try {
            do {
                awsResponse = getSingleResourceCollection(awsRequest, proxyClient, model);
                tagValues.addAll(awsResponse.resourceCollection().tags().get(0).tagValues());
                appBoundaryKey  = awsResponse.resourceCollection().tags().get(0).appBoundaryKey();
                awsRequest = GetResourceCollectionRequest.builder()
                        .resourceCollectionType(ResourceCollectionType.AWS_TAGS)
                        .nextToken(awsResponse.nextToken())
                        .build();
            } while (awsResponse.nextToken() != null);
        } catch (CfnNotFoundException ex) {
            // Interpret empty stacks as RNF
            if (tagValues.isEmpty()) {
                logger.log("Empty resource collection. Throwing NotFoundException");
                throw ex;
            }
        }

        return TagCollection.builder().appBoundaryKey(appBoundaryKey).tagValues(tagValues).build();
    }

    protected void checkIsEmptyResourceCollection(
            final GetResourceCollectionRequest getResourceCollectionRequest,
            final ProxyClient<DevOpsGuruClient> proxyClient,
            final ResourceModel model,
            final Logger logger) {
        GetResourceCollectionResponse getResourceCollectionResponse = getSingleResourceCollection(getResourceCollectionRequest, proxyClient, model);
        if (ResourceCollectionType.AWS_CLOUD_FORMATION.name().equals(model.getResourceCollectionType()) &&
            getResourceCollectionResponse.resourceCollection().cloudFormation().stackNames().isEmpty()) {
            logger.log("Empty CloudFormation resource collection. Throwing NotFoundException");
            throw new CfnNotFoundException(ResourceModel.TYPE_NAME, model.getResourceCollectionType());
        };
        if (ResourceCollectionType.AWS_TAGS.name().equals(model.getResourceCollectionType()) &&
                getResourceCollectionResponse.resourceCollection().tags().get(0).tagValues().isEmpty()) {
            logger.log("Empty Tags resource collection. Throwing NotFoundException");
            throw new CfnNotFoundException(ResourceModel.TYPE_NAME, model.getResourceCollectionType());
        };
    }

    protected UpdateResourceCollectionResponse updateResourceCollection(
            final UpdateResourceCollectionRequest updateResourceCollectionRequest,
            final ProxyClient<DevOpsGuruClient> proxyClient,
            final ResourceModel model,
            final Logger logger,
            final boolean overrideEmpty) {


        if(model.getResourceCollectionFilter().getCloudFormation() != null
                && model.getResourceCollectionFilter().getTags() != null) {
            throw new CfnInvalidRequestException("Input request is invalid, missing ResourceCollectionType " +
                    "or too many ResourceCollectionFilter");
        } else if (model.getResourceCollectionFilter().getCloudFormation() != null
                && model.getResourceCollectionFilter().getTags() == null) {
            model.setResourceCollectionType(ResourceCollectionType.AWS_CLOUD_FORMATION.name());
            return updateCloudFormationResourceCollection(updateResourceCollectionRequest, proxyClient, model, logger, overrideEmpty);
        } else if (model.getResourceCollectionFilter().getCloudFormation() == null
                && model.getResourceCollectionFilter().getTags() != null){
            model.setResourceCollectionType(ResourceCollectionType.AWS_TAGS.name());
            return updateTagsResourceCollection(updateResourceCollectionRequest, proxyClient, model, logger, overrideEmpty);
        }

        throw new CfnInvalidRequestException("Input request is invalid, missing ResourceCollectionType " +
                "or too many ResourceCollectionFilter");
    }

    protected UpdateResourceCollectionResponse updateTagsResourceCollection(
            final UpdateResourceCollectionRequest updateResourceCollectionRequest,
            final ProxyClient<DevOpsGuruClient> proxyClient,
            final ResourceModel model,
            final Logger logger,
            final boolean overrideEmpty) {
        UpdateResourceCollectionResponse updateResourceCollectionResponse = null;
        List<String> tagValues = null;
        String appBoundaryKey = null;

        try {
            GetResourceCollectionRequest getResourceCollectionRequest =
                    GetResourceCollectionRequest.builder().resourceCollectionType(ResourceCollectionType.AWS_TAGS).build();
            TagCollection allTagsResourceCollection = getAllTagsResourceCollection(getResourceCollectionRequest,
                    proxyClient, model, logger);
            tagValues = allTagsResourceCollection.getTagValues();
            appBoundaryKey = allTagsResourceCollection.getAppBoundaryKey();
            logger.log(String.format("getSingleResourceCollection return %s", allTagsResourceCollection));
        } catch (CfnNotFoundException e) {
            if (overrideEmpty) {
                appBoundaryKey = model.getResourceCollectionFilter().getTags().get(0).getAppBoundaryKey();
                tagValues = new ArrayList<>();
                logger.log("This is user first time onboarding. Setting existing list as empty.");
            } else {
                logger.log("Attempting to update non-existent resource");
                throw e;
            }
        }

        List<String> updateTagValues =
                updateResourceCollectionRequest.resourceCollection().tags().get(0).tagValues();
        String updateAppBoundaryKey = updateResourceCollectionRequest.resourceCollection().tags().get(0).appBoundaryKey();

        if(!updateAppBoundaryKey.equals(appBoundaryKey)) {
            throw new CfnInvalidRequestException("The updated tag value belong to a different appBoundaryKey" +
                    "please remove all tags from current appBoundaryKey first");
        }

        Set<String> updateTagValuesSet = new HashSet<>(updateTagValues);
        Set<String> existingTagValuesSet = new HashSet<>(tagValues);
        List<String> addTagValuesNames = new ArrayList<>(Sets.difference(updateTagValuesSet, existingTagValuesSet));
        List<String> removeTagValuesName = new ArrayList<>(Sets.difference(existingTagValuesSet, updateTagValuesSet));

        if (addTagValuesNames.size() > 0) {
            updateResourceCollectionResponse = updateTagResourceCollectionByBatch(addTagValuesNames, appBoundaryKey, Translator.AddAction,
                    proxyClient, logger);
        }

        if (removeTagValuesName.size() > 0 && !existingTagValuesSet.contains("*") && !updateTagValuesSet.contains("*")) {
            updateResourceCollectionResponse = updateTagResourceCollectionByBatch(removeTagValuesName, appBoundaryKey,
                    Translator.RemoveAction, proxyClient, logger);
        }
        if (updateResourceCollectionResponse == null)
            return UpdateResourceCollectionResponse.builder().build();
        else
            return updateResourceCollectionResponse;
    }

    protected UpdateResourceCollectionResponse updateCloudFormationResourceCollection(
            final UpdateResourceCollectionRequest updateResourceCollectionRequest,
            final ProxyClient<DevOpsGuruClient> proxyClient,
            final ResourceModel model,
            final Logger logger,
            final boolean overrideEmpty) {
        UpdateResourceCollectionResponse updateResourceCollectionResponse = null;
        List<String> getResourceCollectionResponseStackNames = null;

        try {
            GetResourceCollectionRequest getResourceCollectionRequest =
                    GetResourceCollectionRequest.builder().resourceCollectionType(ResourceCollectionType.AWS_CLOUD_FORMATION.name()).build();
            getResourceCollectionResponseStackNames = getAllCloudFormationResourceCollection(getResourceCollectionRequest,
                    proxyClient, model, logger);
            logger.log(String.format("getAllResourceCollection return %s", getResourceCollectionResponseStackNames));
        } catch (CfnNotFoundException e) {
            if (overrideEmpty) {
                getResourceCollectionResponseStackNames = new ArrayList<>();
                logger.log("This is user first time onboarding. Setting existing list as empty.");
            } else {
                logger.log("Attempting to update non-existent resource");
                throw e;
            }
        }
        List<String> updateStackNames =
                updateResourceCollectionRequest.resourceCollection().cloudFormation().stackNames();

        Set<String> updateStackNamesSet = new HashSet<>(updateStackNames);
        Set<String> existingStackNamesSet = new HashSet<>(getResourceCollectionResponseStackNames);
        List<String> addStackNames = new ArrayList<>(Sets.difference(updateStackNamesSet, existingStackNamesSet));
        List<String> removeStackNames = new ArrayList<>(Sets.difference(existingStackNamesSet, updateStackNamesSet));

        if (addStackNames.size() > 0) {
            updateResourceCollectionResponse = updateCloudFormationResourceCollectionByBatch(addStackNames, Translator.AddAction,
                    proxyClient, logger);
        }

        if (removeStackNames.size() > 0 && !existingStackNamesSet.contains("*") && !updateStackNamesSet.contains("*")) {
            updateResourceCollectionResponse = updateCloudFormationResourceCollectionByBatch(removeStackNames,
                    Translator.RemoveAction, proxyClient, logger);
        }
        if (updateResourceCollectionResponse == null)
            return UpdateResourceCollectionResponse.builder().build();
        else
            return updateResourceCollectionResponse;
    }

    protected UpdateResourceCollectionResponse updateCloudFormationResourceCollectionByBatch(
            final List<String> updateResourceCollectionStackNamesList,
            final String action,
            final ProxyClient<DevOpsGuruClient> proxyClient,
            final Logger logger) {
        UpdateResourceCollectionResponse awsResponse = null;
        logger.log(String.format("UpdateCloudFormationResourceCollectionByBatch of action [%s] and stacks [%s]", action, updateResourceCollectionStackNamesList));
        try {
            List<String> stackNames = updateResourceCollectionStackNamesList;
            for (List<String> stackNamesPartition : Lists.partition(stackNames, MAX_STACK_NAME_NUMBER_PER_API_CALL)) {
                UpdateResourceCollectionFilter updateResourceCollectionFilter =
                        UpdateResourceCollectionFilter.builder().cloudFormation(UpdateCloudFormationCollectionFilter.builder().stackNames(stackNamesPartition).build()).build();
                UpdateResourceCollectionRequest tempRequest = UpdateResourceCollectionRequest.builder()
                        .action(action)
                        .resourceCollection(updateResourceCollectionFilter)
                        .build();
                awsResponse = proxyClient.injectCredentialsAndInvokeV2(tempRequest,
                        proxyClient.client()::updateResourceCollection);
                logger.log(String.format("UpdateCloudFormationResourceCollectionByBatch response: %s", awsResponse.toString()));
            }
        } catch (final AccessDeniedException e) {
            throw new CfnAccessDeniedException(ResourceModel.TYPE_NAME, e);
        } catch (final ThrottlingException e) {
            throw new CfnThrottlingException(ResourceModel.TYPE_NAME, e);
        } catch (final InternalServerException e) {
            throw new CfnServiceInternalErrorException(ResourceModel.TYPE_NAME, e);
        } catch (final ValidationException e) {
            throw new CfnInvalidRequestException(ResourceModel.TYPE_NAME, e);
        }

        return awsResponse;
    }

    protected UpdateResourceCollectionResponse updateTagResourceCollectionByBatch(
            final List<String> updateTagValuesNamesList,
            final String appBoundaryKey,
            final String action,
            final ProxyClient<DevOpsGuruClient> proxyClient,
            final Logger logger) {
        UpdateResourceCollectionResponse awsResponse = null;
        logger.log(String.format("UpdateTagsResourceCollectionByBatch of action [%s] and tagValues [%s]", action, updateTagValuesNamesList));
        try {
            List<String> tagValues = updateTagValuesNamesList;
            for (List<String> tagValuePartition : Lists.partition(tagValues, MAX_STACK_NAME_NUMBER_PER_API_CALL)) {
                UpdateResourceCollectionFilter updateResourceCollectionFilter =
                        UpdateResourceCollectionFilter.builder().tags(
                                Arrays.asList(UpdateTagCollectionFilter.builder()
                                        .appBoundaryKey(appBoundaryKey)
                                        .tagValues(tagValuePartition)
                                        .build()))
                                .build();
                UpdateResourceCollectionRequest tempRequest = UpdateResourceCollectionRequest.builder()
                        .action(action)
                        .resourceCollection(updateResourceCollectionFilter)
                        .build();
                awsResponse = proxyClient.injectCredentialsAndInvokeV2(tempRequest,
                        proxyClient.client()::updateResourceCollection);
                logger.log(String.format("UpdateTagsResourceCollectionByBatch response: %s", awsResponse.toString()));
            }
        } catch (final AccessDeniedException e) {
            throw new CfnAccessDeniedException(ResourceModel.TYPE_NAME, e);
        } catch (final ThrottlingException e) {
            throw new CfnThrottlingException(ResourceModel.TYPE_NAME, e);
        } catch (final InternalServerException e) {
            throw new CfnServiceInternalErrorException(ResourceModel.TYPE_NAME, e);
        } catch (final ValidationException e) {
            throw new CfnInvalidRequestException(ResourceModel.TYPE_NAME, e);
        }
        return awsResponse;
    }
}