package eu.dnetlib.ariadneplus.workflows.nodes;

import gr.forth.ics.isl.x3ml.X3MLEngineFactory;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.function.Function;

public class ApplyX3MMappingFunction implements Function<String, String> {

    private static final Log log = LogFactory.getLog(ApplyX3MMappingFunction.class);
    private String generatorPolicy;
    private boolean verboseLogging;
    private URL mappingUrl;
    private byte[] mappingBytes;

    public ApplyX3MMappingFunction(final URL mappingUrl, final String generatorPolicy, final boolean verboseLogging) {
        this.mappingUrl = mappingUrl;
        this.generatorPolicy = generatorPolicy;
        this.verboseLogging = verboseLogging;

        try {
            this.mappingBytes = IOUtils.toByteArray(mappingUrl.openStream());
            log.info("Loaded mapping file from: "+mappingUrl.toString());
        } catch (IOException e) {
            log.error("Saving mappings in bytes array: "+e.getMessage()+"\n");
            throw new RuntimeException(e);
        }
    }

    @Override
    public String apply(final String metadata) {
        try (
                InputStream policyStream = getStream(generatorPolicy);
                InputStream metadataStream = getStream(metadata);
                final ByteArrayOutputStream os = new ByteArrayOutputStream()){

            X3MLEngineFactory x3mEngineFactory = getConfiguredX3MEngineFactory(/*mappingUrl,*/ policyStream);

            x3mEngineFactory.withInput(metadataStream).withOutput(os, X3MLEngineFactory.OutputFormat.RDF_XML_PLAIN);
            x3mEngineFactory.execute();
            return new String(os.toByteArray());
        } catch (Exception e) {
            log.error("Error transforming record: "+e.getMessage()+"\n"+metadata);
            throw new RuntimeException(e);
        }
    }

    private InputStream getStream(String s) throws IOException {
        if (StringUtils.isNotBlank(s)) {
            return IOUtils.toInputStream(s, "UTF-8");
        }
        return null;
    }

    private X3MLEngineFactory getConfiguredX3MEngineFactory(/*URL mappingUrl,*/ InputStream policy) {
        log.debug("Loading mapping from url: " + mappingUrl);

//		X3MLEngineFactory x3mEngineFactory = X3MLEngineFactory.create().withMappings(mappingUrl);
        X3MLEngineFactory x3mEngineFactory = X3MLEngineFactory.create().withMappings(new ByteArrayInputStream(this.mappingBytes));
        if (policy != null) {
            x3mEngineFactory.withGeneratorPolicy(policy);
        }
        if (verboseLogging)
            x3mEngineFactory.withVerboseLogging();
        //to enable real UUID
        x3mEngineFactory.withUuidSize(0);
        return x3mEngineFactory;
    }

    public URL getMappingUrl() {
        return mappingUrl;
    }

    public void setMappingUrl(URL mappingUrl) {
        this.mappingUrl = mappingUrl;
    }


}