package eu.openaire.urls_controller.controllers;

import eu.openaire.urls_controller.models.WorkerInfo;
import eu.openaire.urls_controller.services.ShutdownService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletRequest;


@RestController
@RequestMapping("")
public class ShutdownController {

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

    @Autowired
    ShutdownService shutdownService;

    public static boolean shouldShutdownService = false;


    @PostMapping("shutdownService")
    public ResponseEntity<?> shutdownServiceGracefully(HttpServletRequest request)
    {
        String initMsg = "Received a \"shutdownService\" request. ";
        ResponseEntity<?> responseEntity = shutdownService.passSecurityChecks(request, initMsg);
        if ( responseEntity != null )
            return responseEntity;

        String finalMsg = "";
        if ( shouldShutdownService )
            finalMsg = "The controller has already received a \"shutdownService\" (which was not canceled afterwards).";
        else {
            shouldShutdownService = true;
            // Send "shutdownWorker" requests to all Workers.
            for ( String workerId : UrlsController.workersInfoMap.keySet() )
                shutdownService.postShutdownOrCancelRequestToWorker(workerId, UrlsController.workersInfoMap.get(workerId).getWorkerIP(), false);

            // That's it for now. The workers may take some hours to finish their work (including delivering the full-text files).
            // TODO - Add a scheduler to monitor the "HasShutdown" values for all workers.
            // TODO - Once all have the value "true", gently shutdown the Controller, just like we do for the worker.
            // TODO - Each worker, upon "shutdown" should send a "workerShutdownReport" to the Controller.
        }

        finalMsg += "The service will shutdown, after finishing current work.";
        logger.info(initMsg + finalMsg);
        return ResponseEntity.ok().body(finalMsg + "\n");
    }


    @PostMapping("cancelShutdownService")
    public ResponseEntity<?> cancelShutdownServiceGracefully(HttpServletRequest request)
    {
        String initMsg = "Received a \"cancelShutdownService\" request. ";
        ResponseEntity<?> responseEntity = shutdownService.passSecurityChecks(request, initMsg);
        if ( responseEntity != null )
            return responseEntity;

        shouldShutdownService = false;
        // Send "cancelShutdownWorker" requests to all Workers.
        for ( String workerId : UrlsController.workersInfoMap.keySet() )
            shutdownService.postShutdownOrCancelRequestToWorker(workerId, UrlsController.workersInfoMap.get(workerId).getWorkerIP(), true);

        String finalMsg = "Any previous \"shutdownService\"-request is canceled.";
        logger.info(initMsg + finalMsg);
        return ResponseEntity.ok().body(finalMsg + "\n");
    }


    @PostMapping("workerShutdownReport")
    public ResponseEntity<?> workerShutdownReport(@RequestParam String workerId, HttpServletRequest request)
    {
        String initMsg = "Received a \"workerShutdownReport\" from worker: \"" + workerId + "\".";
        WorkerInfo workerInfo = UrlsController.workersInfoMap.get(workerId);
        if ( workerInfo == null ) {
            String errorMsg = "The worker with id \"" + workerId + "\" has not participated in the PDF-Aggregation-Service";
            logger.warn(initMsg + "\n" + errorMsg);
            return ResponseEntity.badRequest().body(errorMsg);
        }

        String remoteAddr = request.getHeader("X-FORWARDED-FOR");
        if ( remoteAddr == null || remoteAddr.isEmpty() )
            remoteAddr = request.getRemoteAddr();

        if ( ! remoteAddr.equals(workerInfo.getWorkerIP()) ) {
            logger.error(initMsg + " The request came from another IP: " + remoteAddr + " | while this worker was registered with the IP: " + workerInfo.getWorkerIP());
            return ResponseEntity.status(HttpStatus.FORBIDDEN).build();
        }

        logger.info(initMsg);

        workerInfo.setHasShutdown(true);    // This will update the map.

        // Return "HTTP-OK" to this worker and wait for the scheduler to check and shutdown the service.
        return ResponseEntity.ok().build();
    }

}