package eu.openaire.urls_controller.controllers;


import eu.openaire.urls_controller.configuration.ImpalaConnector;
import eu.openaire.urls_controller.services.StatsService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

/**
 * This controller returns statistics for the database.
 */
@RestController
@RequestMapping("/stats")
public class StatsController {

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

    @Autowired
    private StatsService statsService;


    /**
     * This endpoint returns the total number of payloads existing in the database, independently of the way they were aggregated.
     * This includes the payloads created by other pieces of software, before the PDF-Aggregation-Service was created.
     * */
    @GetMapping("getNumberOfAllPayloads")
    public ResponseEntity<?> getNumberOfAllPayloads() {
        logger.info("Received a \"getNumberOfAllPayloads\" request.");
        final String getPayloadsNumberQuery = "select count(id) from " + ImpalaConnector.databaseName + ".payload";
        return statsService.getNumberOfPayloads(getPayloadsNumberQuery, "payloads");
    }


    /**
     * This endpoint returns the number of payloads aggregated by the PDF-Aggregated-Service itself.
     * It excludes the payloads aggregated by other methods, by applying a Date-filter for the records created in 2021 or later.
     * */
    @GetMapping("getNumberOfPayloadsAggregatedByService")
    public ResponseEntity<?> getNumberOfPayloadsAggregatedByService() {
        logger.info("Received a \"getNumberOfPayloadsAggregatedByService\" request.");
        String getPayloadsAggregatedQuery = "select count(id) from " + ImpalaConnector.databaseName + ".payload where `date` >= cast(cast('2021-01-01' as timestamp) as bigint)";
        return statsService.getNumberOfPayloads(getPayloadsAggregatedQuery, "payloads retrieved by the PDF Aggregation Service");
    }


    /**
     * This endpoint returns the number of payloads related to the given datasourceID.
     * */
    @GetMapping("getNumberOfPayloadsForDatasource")
    public ResponseEntity<?> getNumberOfPayloadsForDatasource(@RequestParam String datasourceId) {
        logger.info("Received a \"getNumberOfPayloadsForDatasource\" request.");
        final String getPayloadsNumberForDatasourceQuery =
                "select count(p.id) from " + ImpalaConnector.databaseName + ".payload p\n" +
                "       join " + ImpalaConnector.databaseName + ".publication pu on pu.id=p.id and pu.datasourceid=\"" + datasourceId + "\"";

        if ( logger.isTraceEnabled() )
            logger.trace("getPayloadsNumberForDatasourceQuery:\n" + getPayloadsNumberForDatasourceQuery);

        return statsService.getNumberOfPayloads(getPayloadsNumberForDatasourceQuery, "payloads related to datasourceId \"" + datasourceId + "\"");
    }



    // TODO - Add an endpoint to get the publication year as a param and return the number of payloads for the publications of that year.
    // select count(p.id) from payload p
    // join publication pu on pu.id=p.id and pu.year=<GIVEN_YEAR>



    // TODO - Add an endpoint to return the info of all datasources in the database with the count of their payloads (including 0).
    // Maybe have a param "numTopDatasources" which will work a a "limit" in the following query.
    // In case the "numTopDatasources" param is not given or is less or equal to 0, then no limit will be added to the query.
    /*
        select d.id, d.name, d.type, d.allow_harvest, count(p.id) as payload_count from datasource d
            join publication pu on pu.datasourceid=d.id
            left join payload p on p.id=pu.id   -- We want the datasources with 0 payloads too, so we use "left join".
        group by d.id, d.name, d.type, d.allow_harvest
        order by payload_count desc
     */



    /**
     * This endpoint returns the total number of distinct full-text files existing in the database.
     * */
    @GetMapping("getNumberOfAllDistinctFullTexts")
    public ResponseEntity<?> getNumberOfAllDistinctFullTexts() {
        logger.info("Received a \"getNumberOfAllDistinctFullTexts\" request.");
        final String getPayloadsNumberQuery = "select count(distinct `hash`) from " + ImpalaConnector.databaseName + ".payload";
        return statsService.getNumberOfPayloads(getPayloadsNumberQuery, "distinct full-text files");
    }


    /**
     * This endpoint returns the number of records inspected by the PDF-Aggregation-Service.
     * */
    @GetMapping("getNumberOfRecordsInspected")
    public ResponseEntity<?> getNumberOfRecordsInspected()
    {
        return statsService.getNumberOfRecordsInspected();
    }

}