package eu.openaire.urls_worker.util;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.collect.HashMultimap;
import com.google.common.collect.Multimap;
import eu.openaire.urls_worker.models.Assignment;
import eu.openaire.urls_worker.models.Task;
import eu.openaire.urls_worker.payloads.requests.AssignmentRequest;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.web.client.RestTemplate;

import java.util.*;


public class AssignmentHandler {

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

    public static boolean isAvailableForWork = true;

    public static Assignment requestAssignment()
    {
        RestTemplate restTemplate = new RestTemplateBuilder().build();
        String url = "http://localhost:8080/api/urls/test?workerId=" + WorkerConstants.WORKER_ID + "&tasksLimit=" + WorkerConstants.TASKS_LIMIT;
        String json = null;
        try {
            json = restTemplate.getForObject(url, String.class);
        } catch (Exception e) {
            logger.error("Could not retrieve the assignment: " + e.getMessage());
            return null;
        }

        AssignmentRequest assignmentRequest = null;
        ObjectMapper objectMapper = new ObjectMapper();
        try {
            assignmentRequest = objectMapper.readValue(json, AssignmentRequest.class);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }

        if ( assignmentRequest == null ) {
            String errorMessage = "Could not map the json to an \"assignmentRequest\"!";
            System.err.println(errorMessage);
            logger.error(errorMessage);
            System.exit(1);
        }

        //logger.debug(assignmentRequest.toString());   // DEBUG!

        Assignment assignment = assignmentRequest.getAssignment();
        logger.info("Assignment with id < " + assignment.getAssignmentId() + " > was received and it's ready to be processed. It contains " + assignment.getTasks().size() + " tasks.");
        // TODO - Maybe create a HashSet with these IDs. It may be useful for the Worker to know and report which assignments (and how many) it has processed.

        return assignment;
    }


    public static void handleAssignment()
    {
        Assignment assignment = requestAssignment();
        if ( assignment == null ) {
            logger.warn("The assignment was found to be null!");
            return;
        }

        // Start handling the assignment, the worker is busy.
        isAvailableForWork = false;

        List<Task> tasks = assignment.getTasks();

        // Iterate over the tasks and add each task in it's own list depending on the DATASOURCE in order to decide which plugin to use later.

        Multimap<String, Task> tasksForPlugins = HashMultimap.create();

        for ( Task task : tasks ) {
            // Add each task in its own HashSet.
            tasksForPlugins.put(task.getDatasource().getId(), task);
        }

        // First run -in parallel- the tasks which require some specific plugin.

        // Then run the remaining tasks in the generic plugin (which handles parallelism itself).




        // Check availability-endpoint using Thread-sleep here. DEBUG!
        try {
            Thread.sleep(30_000);   // 30 seconds
        } catch (InterruptedException ie) {
            logger.warn("Sleeping interrupted!");
        }

        isAvailableForWork = true;
    }

}