/* Copyright (c) 2013-2014 Boundless and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Distribution License v1.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/org/documents/edl-v10.html
 *
 * Contributors:
 * Victor Olaya (Boundless) - initial implementation
 */
package org.locationtech.geogig.osm.internal.log;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.List;

import org.locationtech.geogig.api.AbstractGeoGigOp;

import com.google.common.base.Charsets;
import com.google.common.base.Throwables;
import com.google.common.collect.Lists;
import com.google.common.io.Files;
import com.google.common.io.LineProcessor;

/**
 * Returns the set of entries of the OSM log in the current repository.
 */
public class ReadOSMLogEntries extends AbstractGeoGigOp<List<OSMLogEntry>> {

    @Override
    protected List<OSMLogEntry> _call() {
        URL url = command(ResolveOSMLogfile.class).call();
        File file = new File(url.getFile());
        List<OSMLogEntry> entries;
        try {
            synchronized (file.getCanonicalPath().intern()) {
                entries = Files.readLines(file, Charsets.UTF_8,
                        new LineProcessor<List<OSMLogEntry>>() {
                            List<OSMLogEntry> entries = Lists.newArrayList();

                            @Override
                            public List<OSMLogEntry> getResult() {
                                return entries;
                            }

                            @Override
                            public boolean processLine(String s) throws IOException {
                                OSMLogEntry entry = OSMLogEntry.valueOf(s);
                                entries.add(entry);
                                return true;
                            }
                        });
            }
        } catch (IOException e) {
            throw Throwables.propagate(e);
        }
        return entries;
    }

}