/*
 * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: MIT-0
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this
 * software and associated documentation files (the "Software"), to deal in the Software
 * without restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package software.amazon.qldb.tutorial;

import com.amazonaws.client.builder.AwsClientBuilder;
import com.amazonaws.services.qldb.AmazonQLDB;
import com.amazonaws.services.qldb.AmazonQLDBClientBuilder;
import com.amazonaws.services.qldb.model.CreateLedgerRequest;
import com.amazonaws.services.qldb.model.CreateLedgerResult;
import com.amazonaws.services.qldb.model.DescribeLedgerResult;
import com.amazonaws.services.qldb.model.LedgerState;
import com.amazonaws.services.qldb.model.PermissionsMode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Create a ledger and wait for it to be active.
 * <p>
 * This code expects that you have AWS credentials setup per:
 * http://docs.aws.amazon.com/java-sdk/latest/developer-guide/setup-credentials.html
 */
public final class CreateLedger {
    public static final Logger log = LoggerFactory.getLogger(CreateLedger.class);
    public static final Long LEDGER_CREATION_POLL_PERIOD_MS = 10_000L;
    public static String endpoint = null;
    public static String region = null;
    public static AmazonQLDB client = getClient();

    private CreateLedger() {
    }

    /**
     * Build a low-level QLDB client.
     *
     * @return {@link AmazonQLDB} control plane client.
     */
    public static AmazonQLDB getClient() {
        AmazonQLDBClientBuilder builder = AmazonQLDBClientBuilder.standard();
        if (null != endpoint && null != region) {
            builder.setEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration(endpoint, region));
        }
        return builder.build();
    }

    public static void main(final String... args) throws Exception {
        try {
            client = getClient();

            create(Constants.LEDGER_NAME);

            waitForActive(Constants.LEDGER_NAME);

        } catch (Exception e) {
            log.error("Unable to create the ledger!", e);
            throw e;
        }
    }

    /**
     * Create a new ledger with the specified ledger name.
     *
     * @param ledgerName Name of the ledger to be created.
     * @return {@link CreateLedgerResult} from QLDB.
     */
    public static CreateLedgerResult create(final String ledgerName) {
        log.info("Let's create the ledger with name: {}...", ledgerName);
        CreateLedgerRequest request = new CreateLedgerRequest()
                .withName(ledgerName)
                .withPermissionsMode(PermissionsMode.ALLOW_ALL);
        CreateLedgerResult result = client.createLedger(request);
        log.info("Success. Ledger state: {}.", result.getState());
        return result;
    }

    /**
     * Wait for a newly created ledger to become active.
     *
     * @param ledgerName Name of the ledger to wait on.
     * @return {@link DescribeLedgerResult} from QLDB.
     * @throws InterruptedException if thread is being interrupted.
     */
    public static DescribeLedgerResult waitForActive(final String ledgerName) throws InterruptedException {
        log.info("Waiting for ledger to become active...");
        while (true) {
            DescribeLedgerResult result = DescribeLedger.describe(ledgerName);
            if (result.getState().equals(LedgerState.ACTIVE.name())) {
                log.info("Success. Ledger is active and ready to use.");
                return result;
            }
            log.info("The ledger is still creating. Please wait...");
            Thread.sleep(LEDGER_CREATION_POLL_PERIOD_MS);
        }
    }
}