package org.autoplot.util;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.net.URI;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.logging.Logger;
import org.das2.datum.DatumRange;
import org.das2.datum.LoggerManager;
import org.das2.fsm.FileStorageModel;
import org.das2.util.filesystem.FileSystem;
import org.autoplot.datasource.AutoplotSettings;
import org.autoplot.datasource.URISplit;



/**
 * This was intended to provide a mechanism to remove old files from
 * an enduser's cache, where version number updates result in files which
 * will never be seen.
 * @author mmclouth
 */
public class CacheCleanup {
    
    private static final Logger logger= LoggerManager.getLogger("autoplot");
    
    /**
     * this should not be instantiated
     */
    private CacheCleanup() {

    }
    
    private static int numberOfLines( File filePath ) throws IOException {
        int numOfLines= 0;
        try ( BufferedReader bf= new BufferedReader( new FileReader(filePath)) ) {
            while ( bf.readLine() != null)  { // this is a nice bit of code that avoids two calls to readLine!
                numOfLines++;
            }
        }
        return numOfLines;
    }
    
    /**
     * find aggregations within the user's history.  This currently looks for $Y, but aggregations
     * can also be $y, etc.
     * 
     * @return list of aggregations.
     * @throws IOException 
     */
    public static String[] findAggs() throws IOException {
        File filePath= new File( AutoplotSettings.settings().resolveProperty( AutoplotSettings.PROP_AUTOPLOTDATA ) + "/bookmarks/history.txt" );
        
        ArrayList<String> result= new ArrayList(100);
        boolean hasAgg;
        int numOfLines = numberOfLines( filePath );
                
        int i;
        String[] data = new String[numOfLines];
        String[] parts;
        
        try ( BufferedReader bf= new BufferedReader( new FileReader(filePath)) ) {
            for (i=0 ; i<numOfLines ; i++) {
                data[i] = bf.readLine();
                hasAgg = data[i].contains("$Y");
                if (hasAgg == true) {

                    int iq= data[i].indexOf('?'); 
                    int iy= data[i].indexOf("$Y"); 
                    if ( iq==-1 || iq>iy ) {
                        parts = data[i].split("\\s+"); 
                        if (parts.length > 1)  {
                            result.add(parts[1]);
                        }
                    }
                }
            }
        }

        return result.toArray( new String[result.size()] );
    }
    
    /**
     * Return an array of files where newer versions prevent the older from being used.  This will
     * not look for version constraints (e.g. $(v,lt=2)), so use with some care.
     * @return an array of files where newer versions prevent the older from being used.
     * @throws IOException 
     */
    public static String[] findOldVersions() throws IOException {
        String[] aggs = findAggs();
        ArrayList<String> oldversions= new ArrayList(1000);
        String[] result;
        FileSystem.settings().setOffline(true); // turn off web access        
        for (String agg : aggs) {
            URI fileagguri = URISplit.parse(agg).resourceUri;
            String fileagg= fileagguri.toString();
            int i = FileStorageModel.splitIndex( fileagg );
            String constantPart= fileagg.substring(0,i);
            String templatePart= fileagg.substring(i);
            //System.out.println(constantPart);
            //System.out.println(templatePart);
            FileSystem fs= FileSystem.create( constantPart );
            FileStorageModel fsm = FileStorageModel.create( fs, templatePart );
            String localRoot= fsm.getFileSystem().getLocalRoot().toString();
            File[] ff= fsm.getFilesFor(null); // null means load everything.
            //File[] ff= fsm.getFilesFor(DatumRangeUtil.parseTimeRangeValid("2010-mar")); // ffor testing, just do one month.  None means everything but it's much slower.
            for (File ff1 : ff) {
                DatumRange tr = fsm.getRangeFor(ff1.toString().substring(localRoot.length() + 1));
                File[] fbest= fsm.getBestFilesFor(tr);
                if (!ff1.toString().equals(fbest[0].toString())) {
                    oldversions.add(ff1.toString());
                }
            }
        }
        if (oldversions.size() > 0) {
            result = oldversions.toArray( new String[oldversions.size()] );
        } else {
            result = new String[] {"No Old Versions"};
        }
        FileSystem.settings().setOffline(false); // turn off web access
        
        return result;
    }
    
    public static void deleteOldVersions() throws ParseException, IOException  {
        String[] oldversions = findOldVersions();
        logger.warning( "deleteOldVersions not implemented ");
        System.err.println("oldversions:");
        for ( String s : oldversions ) {
            System.err.println("  "+s);
        }
    }
}