/*********************************************************************************************************************************
 * Autorskie Prawa Majątkowe - Moose Spółka z ograniczoną odpowiedzialnością
 * Copyright 2019 Moose Spółka z ograniczoną odpowiedzialnością
 ********************************************************************************************************************************/

package eu.mooseinc.documents.explorer.bean;

import eu.mooseinc.documents.explorer.ApplicationBean;
import org.apache.log4j.Logger;

import javax.annotation.PostConstruct;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ManagedProperty;
import javax.faces.bean.RequestScoped;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;
import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * Bean for operations related to files.
 */
@RequestScoped
@ManagedBean(name = "FilesBean")
public class FilesBean {
	private static final Logger logger = Logger.getLogger( FilesBean.class );
	
	private final List<String> documents = new ArrayList<>();
	
	@ManagedProperty(value="#{applicationBean}")
	private ApplicationBean application;
	
	@PostConstruct
	public void init() {
		try (Stream<Path> stream = Files.walk(Paths.get(application.getDocumentsDirectory()))) {
			this.documents.addAll( stream
									   .filter(Files::isRegularFile)
									   .map(file -> file.getFileName().toString())
									   .collect(Collectors.toList())
								 );
		}
		catch (final IOException e) {
			logger.error( "Read documents error", e );
		}
	}
	
	/**
	 * Finds uploaded files on the disk.
	 *
	 * @return List of files available for download.
	 */
	public List<String> getDocuments() {
		return documents;
	}

	/**
	 * Returns requested file.
	 *
	 * @param documentName The name of the requested file.
	 */
	public void downloadDocument(final String documentName) {
		final FacesContext facesContext = FacesContext.getCurrentInstance();
		final ExternalContext externalContext = facesContext.getExternalContext();

		final Path pathFile = Paths.get(application.getDocumentsDirectory() + File.separator + documentName);
		final File file = pathFile.toFile();

		if (!file.exists()) {
			externalContext.responseReset();
			externalContext.setResponseStatus(404);
			return;
		}

		externalContext.responseReset();

		try {
			externalContext.setResponseContentType(Files.probeContentType(pathFile)); // mimetype
			externalContext.setResponseContentLength((int) file.length()); // length

			final String attachmentName = MessageFormat.format("attachment; filename=\"{0}\"", documentName);
			externalContext.setResponseHeader("Content-Disposition", attachmentName);

			final OutputStream outputStream = externalContext.getResponseOutputStream();
			Files.copy(pathFile, outputStream);

			facesContext.responseComplete();
		} catch (final IOException e) {
			logger.error( "Error ", e );
		}
	}

	/**
	 * Deletes the file from the disk.
	 *
	 * @param documentName The name of the file to be deleted.
	 *
	 * @throws IOException Exception thrown during redirection.
	 */
	public void deleteDocument(final String documentName, final HttpServletRequest request) throws IOException {
		if (!request.isUserInRole("admin")) {
			final ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();
			externalContext.responseReset();
			externalContext.setResponseStatus(403);
			return;
		}

		final File fileToDelete = Paths.get(application.getDocumentsDirectory() + File.separator + documentName).toFile();
		if (fileToDelete.exists() && fileToDelete.isFile())
			Files.delete( fileToDelete.toPath() );

		FacesContext.getCurrentInstance().getExternalContext().redirect("index.jsp");
	}
	
	public void setApplication( ApplicationBean application ) {
		this.application = application;
	}
}