package org.simantics.logging.ui.handlers;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import javax.inject.Named;

import org.eclipse.core.runtime.Platform;
import org.eclipse.e4.core.di.annotations.Execute;
import org.eclipse.e4.ui.services.IServiceConstants;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.FileDialog;
import org.eclipse.swt.widgets.Shell;
import org.simantics.logging.LogCollector;
import org.simantics.utils.FileUtils;
import org.simantics.utils.ui.ExceptionUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class SaveLogFilesHandler {

    private static final Logger LOGGER = LoggerFactory.getLogger(SaveLogFilesHandler.class);

    private static final String[] FILTER_NAMES = { "ZIP-archive", "AllFiles (*:*)" };
    private static final String[] FILTER_EXTENSIONS = { "*.zip", "*.*" };
    private static final String USER_HOME = System.getProperty("user.home");
    
    @Execute
    public void execute(@Named(IServiceConstants.ACTIVE_SHELL) Shell shell) {
        
        FileDialog dialog = new FileDialog(shell, SWT.SAVE);
        dialog.setFilterNames(FILTER_NAMES);
        dialog.setFilterExtensions(FILTER_EXTENSIONS);
        if (USER_HOME != null) {
            if (Files.exists(Paths.get(USER_HOME))) {
                dialog.setFilterPath(USER_HOME);
            }
        }
        StringBuilder fileName = new StringBuilder();
        String productName = Platform.getProduct().getName();
        if (productName != null)
            fileName.append(productName.replaceAll(" ", "_")).append("-");
        
        fileName.append("logs-").append(currentLocalDateTimeStamp());
        String actualFileName = fileName.toString();
        if (LOGGER.isDebugEnabled())
            LOGGER.debug("Resolved log files name {}", actualFileName);
        dialog.setFileName(actualFileName);
        
        String destination = dialog.open();
        if (destination != null) {
            if (LOGGER.isDebugEnabled())
                LOGGER.debug("Destination for saving log files is {}", destination);
            
            try {
                Path tempDir = Files.createTempDirectory(actualFileName);
                Map<String, List<Path>> allLogs = LogCollector.allLogs();
                for (Entry<String, List<Path>> logEntry : allLogs.entrySet()) {
                    Path subFolder = tempDir.resolve(logEntry.getKey());
                    Files.createDirectory(subFolder);
                    for (Path p : logEntry.getValue()) {
                        try {
                            Files.copy(p, subFolder.resolve(p.getFileName()));
                        } catch (IOException e) {
                            LOGGER.error("Could not copy {}", p.toAbsolutePath(), e);
                        }
                    }
                }
                FileUtils.compressZip(tempDir.toAbsolutePath().toString(), destination);
                FileUtils.delete(tempDir);
            } catch (Throwable t) {
                LOGGER.error("Could not save log files to ZIP", t);
                ExceptionUtils.logAndShowError("Could not save log files to ZIP", t);
            }
        } else {
            if (LOGGER.isDebugEnabled()) {
                LOGGER.debug("No destination selected for saving logs");
            }
        }
    }
    
    private static String currentLocalDateTimeStamp() {
        return LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd_HHmm"));
    }

}