package eu.openaire.urls_worker;

import eu.openaire.publications_retriever.PublicationsRetriever;
import eu.openaire.publications_retriever.util.file.FileUtils;
import eu.openaire.urls_worker.plugins.PublicationsRetrieverPlugin;
import eu.openaire.urls_worker.util.AssignmentsHandler;
import eu.openaire.urls_worker.util.UriBuilder;
import eu.openaire.urls_worker.util.WorkerConstants;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.core.env.Environment;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.CorsConfigurationSource;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;

import javax.annotation.PreDestroy;
import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Arrays;
import java.util.Collections;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;


@SpringBootApplication
@EnableConfigurationProperties
@EnableScheduling
public class UrlsWorkerApplication {

    private static final Logger logger = LoggerFactory.getLogger(UrlsWorkerApplication.class);

    private static final String inputDataFilePath = FileUtils.workingDir + "inputData.txt";
    public static String workerId = null;
    public static int maxAssignmentsLimitPerBatch = 0;
    public static int maxAssignmentsBatchesToHandleBeforeRestart = -1;  // Default value: -1 = argument-absent, 0 = infinite-batches
    public static String controllerBaseUrl = null;  // BaseUrl template: "http://IP:PORT/api/"

    private static ConfigurableApplicationContext context;


    public static void main(String[] args) {

        setInputData(); // This may cause the Server to terminate early, in case the workerId or the controllerBaseUrl cannot be found.
        new PublicationsRetrieverPlugin();
        new AssignmentsHandler();

        context = SpringApplication.run(UrlsWorkerApplication.class, args);

        Runtime javaRuntime = Runtime.getRuntime();
        logger.debug("HeapSize: " + javaRuntime.totalMemory());
        logger.debug("HeapMaxSize: " + javaRuntime.maxMemory());
        logger.debug("HeapFreeSize: " + javaRuntime.freeMemory());
    }


    public static void gentleShutdown()
    {
        int exitCode = SpringApplication.exit(context, () -> 0);    // The "PreDestroy" method will be called.
        System.exit(exitCode);
    }


    @PreDestroy
    public static void preDestroy()
    {
        if ( PublicationsRetriever.executor != null )
        {
            logger.info("Shutting down the threads used by \"PublicationsRetriever\"-plugin..");
            PublicationsRetriever.executor.shutdown();	// Define that no new tasks will be scheduled.
            try {
                if ( !PublicationsRetriever.executor.awaitTermination(1, TimeUnit.MINUTES) ) {
                    logger.warn("The working threads did not finish on time! Stopping them immediately..");
                    PublicationsRetriever.executor.shutdownNow();
                }
            } catch (SecurityException se) {
                logger.error("Could not shutdown the threads in any way..!", se);
            } catch (InterruptedException ie) {
                try {
                    PublicationsRetriever.executor.shutdownNow();
                } catch (SecurityException se) {
                    logger.error("Could not shutdown the threads in any way..!", se);
                }
            }
        }
    }

    @Bean
    public CorsConfigurationSource corsConfigurationSource() {
        CorsConfiguration configuration = new CorsConfiguration();
        configuration.setAllowedOrigins(Collections.singletonList("*"));
        configuration.setAllowedMethods(Arrays.asList("GET", "POST", "PUT", "PATCH", "DELETE", "OPTIONS"));
        configuration.setAllowedHeaders(Arrays.asList("authorization", "content-type", "x-auth-token"));
        configuration.setExposedHeaders(Collections.singletonList("x-auth-token"));
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", configuration);
        return source;
    }

    @Bean
    public CommandLineRunner setServerBaseUrl(Environment environment)
    {
        return args -> new UriBuilder(environment);
    }


    private static void setInputData()
    {
        // Take the workerId and the controllerBaseUrl from the file.
        Scanner myReader = null;
        try {
            File inputDataFile = new File(inputDataFilePath);
            if ( !inputDataFile.exists() ) {
                String errorMsg = "controllerBaseUrlFile \"" + inputDataFilePath + "\" does not exists!";
                logger.error(errorMsg);
                System.err.println(errorMsg);
                System.exit(60);
            }
            myReader = new Scanner(inputDataFile);
            if ( myReader.hasNextLine() ) {
                String[] data = myReader.nextLine().split(",");
                if ( data.length < 4 ) {
                    String errorMsg = "Not all data were retrieved from file \"" + inputDataFilePath + "\"!";
                    logger.error(errorMsg);
                    System.err.println(errorMsg);
                    System.exit(61);
                }
                workerId = data[0].trim();
                String maxAssignmentsLimitStr = data[1].trim();
                try {
                    maxAssignmentsLimitPerBatch = Integer.parseInt(maxAssignmentsLimitStr);
                } catch (NumberFormatException nfe) {
                    logger.warn("The given \"maxAssignmentsLimitPerBatch\" (" + maxAssignmentsLimitStr + ") was not a number! Will use the default one: " + WorkerConstants.ASSIGNMENTS_LIMIT);
                    maxAssignmentsLimitPerBatch = WorkerConstants.ASSIGNMENTS_LIMIT;
                }
                String maxAssignmentsBatchesStr = data[2].trim();
                try {
                    maxAssignmentsBatchesToHandleBeforeRestart = Integer.parseInt(maxAssignmentsBatchesStr);
                } catch (NumberFormatException nfe) {
                    logger.warn("The given \"maxAssignmentsBatchesToHandleBeforeRestart\" (" + maxAssignmentsBatchesStr + ") was not a number! Will handle an infinite number of batches!");
                    maxAssignmentsBatchesToHandleBeforeRestart = 0;
                }
                controllerBaseUrl = data[3].trim();
                try {
                    new URL(controllerBaseUrl);
                } catch (MalformedURLException mue) {
                    String errorMsg = "The given \"controllerBaseUrl\" (\"" + controllerBaseUrl + "\") was malformed! Please restart the program and give a valid URL.";
                    logger.error(errorMsg);
                    System.err.println(errorMsg);
                    System.exit(62);
                }
                if ( !controllerBaseUrl.endsWith("/") )
                    controllerBaseUrl += "/";   // Make sure the other urls will not break later.
            }

            if ( (workerId == null) || (maxAssignmentsLimitPerBatch == 0) || (maxAssignmentsBatchesToHandleBeforeRestart == -1) || (controllerBaseUrl == null) ) {
                String errorMsg = "No \"workerId\" or/and \"maxAssignmentsLimitPerBatch\" or/and \"maxAssignmentsBatchesToHandleBeforeRestart\" or/and \"controllerBaseUrl\" could be retrieved from the file: " + inputDataFilePath;
                logger.error(errorMsg);
                System.err.println(errorMsg);
                System.exit(63);
            }

            logger.info("workerId: " + workerId + ", maxAssignmentsLimitPerBatch: " + maxAssignmentsLimitPerBatch + ", maxAssignmentsBatchesToHandleBeforeRestart: " + maxAssignmentsBatchesToHandleBeforeRestart + ", controllerBaseUrl: " + controllerBaseUrl);    // It's safe and helpful to show them in the logs.

        } catch (Exception e) {
            String errorMsg = "An error prevented the retrieval of the workerId and the controllerBaseUrl from the file: " + inputDataFilePath + "\n" + e.getMessage();
            logger.error(errorMsg, e);
            System.err.println(errorMsg);
            System.exit(64);
        } finally {
            if ( myReader != null )
                myReader.close();
        }
    }

}