package eu.dnetlib.wfs.collector.filesystem;

import java.io.File;
import java.io.FileInputStream;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.time.LocalDateTime;
import java.util.Map;
import java.util.stream.Stream;

import org.apache.commons.io.IOUtils;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import eu.dnetlib.errors.DnetException;
import eu.dnetlib.utils.DnetStreamSupport;
import eu.dnetlib.utils.XmlCleaner;
import eu.dnetlib.wfs.annotations.CollectorPlugin;
import eu.dnetlib.wfs.collector.DnetCollectorPlugin;

@CollectorPlugin("filesystem")
public class FilesystemCollectorPlugin implements DnetCollectorPlugin {

	private static final Log log = LogFactory.getLog(FilesystemCollectorPlugin.class);

	@Override
	public Stream<String> collect(final String baseUrl, final Map<String, String> apiParams, final LocalDateTime from, final LocalDateTime until)
			throws Exception {

		final URL basePath = new URL(baseUrl);
		final File baseDir = new File(basePath.getPath());
		if (!baseDir.exists()) { throw new DnetException(String.format("The base URL %s, does not exist", basePath.getPath())); }

		final FileSystemIterator fsi = new FileSystemIterator(baseDir.getAbsolutePath(), apiParams.getOrDefault("extensions", "xml"));

		return DnetStreamSupport.stream(fsi).map(this::loadFile);
	}

	private String loadFile(final String inputFileName) {
		try (FileInputStream fileInputStream = new FileInputStream(inputFileName)) {
			final String s = IOUtils.toString(fileInputStream, StandardCharsets.UTF_8.toString());
			return XmlCleaner.cleanAllEntities(s.startsWith("\uFEFF") ? s.substring(1) : s);
		} catch (final Exception e) {
			log.error("Unable to read " + inputFileName);
			return "";
		}
	}

}