package com.amazonaws.iot.mitigationaction;

import software.amazon.awssdk.services.iot.IotClient;
import software.amazon.awssdk.services.iot.model.DeleteMitigationActionRequest;
import software.amazon.awssdk.services.iot.model.DescribeMitigationActionRequest;
import software.amazon.cloudformation.proxy.AmazonWebServicesClientProxy;
import software.amazon.cloudformation.proxy.HandlerErrorCode;
import software.amazon.cloudformation.proxy.Logger;
import software.amazon.cloudformation.proxy.OperationStatus;
import software.amazon.cloudformation.proxy.ProgressEvent;
import software.amazon.cloudformation.proxy.ResourceHandlerRequest;

import java.util.regex.Pattern;

public class DeleteHandler extends BaseHandler<CallbackContext> {

    private static final Pattern RESOURCE_NAME_PATTERN = Pattern.compile("[a-zA-Z0-9:_-]+");

    private final IotClient iotClient;

    public DeleteHandler() {
        iotClient = IotClient.builder().build();
    }

    @Override
    public ProgressEvent<ResourceModel, CallbackContext> handleRequest(
            AmazonWebServicesClientProxy proxy,
            ResourceHandlerRequest<ResourceModel> request,
            CallbackContext callbackContext,
            Logger logger) {

        ResourceModel model = request.getDesiredResourceState();

        // From https://docs.aws.amazon.com/cloudformation-cli/latest/userguide/resource-type-test-contract.html
        // "A delete handler MUST return FAILED with a NotFound error code if the
        // resource did not exist prior to the delete request."
        // DeleteMitigationAction API is idempotent, so we have to call Describe first.

        // Before we call Describe, we also need to deal with an InvalidRequest edge case.
        // If CFN is trying to delete a resource with an invalid name, returning InvalidRequest would
        // get CFN stuck in delete-failed state. If we return NotFound, it'll just succeed.
        // We wouldn't have to do this if aws-cloudformation-rpdk-java-plugin had functioning regex
        // pattern evaluation (known issue with an internal ticket).
        String actionName = model.getActionName();
        boolean matches = RESOURCE_NAME_PATTERN.matcher(actionName).matches();
        if (!matches) {
            logger.log("Returning NotFound from DeleteHandler due to invalid name " + actionName);
            return ProgressEvent.<ResourceModel, CallbackContext>builder()
                    .resourceModel(model)
                    .status(OperationStatus.FAILED)
                    .errorCode(HandlerErrorCode.NotFound)
                    .build();
        }

        DescribeMitigationActionRequest describeRequest = DescribeMitigationActionRequest.builder()
                .actionName(actionName)
                .build();
        try {
            proxy.injectCredentialsAndInvokeV2(describeRequest, iotClient::describeMitigationAction);
        } catch (RuntimeException e) {
            // If the resource doesn't exist, DescribeMitigationAction will throw ResourceNotFoundException,
            // and we'll return FAILED with HandlerErrorCode.NotFound.
            // CFN (the caller) will swallow the "failure" and the customer will see success.
            return Translator.translateExceptionToProgressEvent(model, e, logger);
        }
        logger.log(String.format("Called Describe for %s with name %s, accountId %s.",
                ResourceModel.TYPE_NAME, actionName, request.getAwsAccountId()));

        DeleteMitigationActionRequest deleteRequest = DeleteMitigationActionRequest.builder()
                .actionName(actionName)
                .build();
        try {
            proxy.injectCredentialsAndInvokeV2(deleteRequest, iotClient::deleteMitigationAction);
        } catch (RuntimeException e) {
            return Translator.translateExceptionToProgressEvent(model, e, logger);
        }

        logger.log(String.format("Deleted %s with name %s, accountId %s.",
                ResourceModel.TYPE_NAME, actionName, request.getAwsAccountId()));

        return ProgressEvent.defaultSuccessHandler(null);
    }
}