/*******************************************************************************
 * Copyright (c) 2012 IT Just working.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IT Just working - initial API and implementation
 *******************************************************************************/
package com.minres.scviewer.database.text;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.zip.GZIPInputStream;

import org.eclipse.collections.impl.map.mutable.UnifiedMap;
import org.mapdb.DB;
import org.mapdb.DB.TreeMapSink;
import org.mapdb.DBMaker;
import org.mapdb.Serializer;

import com.google.common.collect.HashMultimap;
import com.minres.scviewer.database.AssociationType;
import com.minres.scviewer.database.DataType;
import com.minres.scviewer.database.EventKind;
import com.minres.scviewer.database.IWaveform;
import com.minres.scviewer.database.IWaveformDb;
import com.minres.scviewer.database.IWaveformDbLoader;
import com.minres.scviewer.database.InputFormatException;
import com.minres.scviewer.database.RelationType;
import com.minres.scviewer.database.RelationTypeFactory;
import com.minres.scviewer.database.tx.ITx;

public class TextDbLoader implements IWaveformDbLoader{

	private Long maxTime=0L;

	DB mapDb=null;
	
    final List<String> attrValues = new ArrayList<>();

	final Map<String, RelationType> relationTypes = UnifiedMap.newMap();
    
    final Map<Long, TxStream> txStreams = UnifiedMap.newMap();
    
    final Map<Long, TxGenerator> txGenerators = UnifiedMap.newMap();
    
    Map<Long, ScvTx> transactions = null;

    final Map<String, TxAttributeType> attributeTypes = UnifiedMap.newMap();

	final HashMultimap<Long, ScvRelation> relationsIn = HashMultimap.create();

	final HashMultimap<Long, ScvRelation> relationsOut = HashMultimap.create();

    HashMap<Long, Tx> txCache = new HashMap<>();

    List<Thread> threads = new ArrayList<>();
    
    @Override
	public Long getMaxTime() {
		return maxTime;
	}

	@Override
	public Collection<IWaveform> getAllWaves() {
		return new ArrayList<>(txStreams.values());
	}

	static final byte[] x = "scv_tr_stream".getBytes();

	@SuppressWarnings("unchecked")
	@Override
	public	boolean load(IWaveformDb db, File file) throws InputFormatException {
		dispose();
		if(file.isDirectory() || !file.exists()) return false;
		TextDbParser parser = new TextDbParser(this);
		boolean gzipped = isGzipped(file);
		try {
		if(!isTxfile(gzipped?new GZIPInputStream(new FileInputStream(file)):new FileInputStream(file)))
			return false;
		} catch(Exception e) {
			throw new InputFormatException();
		}
		
		if(file.length() < 75000000*(gzipped?1:10) || "memory".equals(System.getProperty("ScvBackingDB", "file")))
			mapDb = DBMaker
			.memoryDirectDB()
			.allocateStartSize(512l*1024l*1024l)
			.allocateIncrement(128l*1024l*1024l)
			.cleanerHackEnable()
			.make();
		else {
			File mapDbFile;
			try {
				mapDbFile = File.createTempFile("."+file.getName(), ".mapdb", null /*file.parentFile*/);
				Files.delete(Paths.get(mapDbFile.getPath()));
			} catch (IOException e1) {
				return false;
			}
			mapDb = DBMaker
			.fileDB(mapDbFile)
			.fileMmapEnable()            // Always enable mmap
			.fileMmapEnableIfSupported()
			.fileMmapPreclearDisable()
			.allocateStartSize(512l*1024l*1024l)
			.allocateIncrement(128l*1024l*1024l)
			.cleanerHackEnable()
			.make();
			mapDbFile.deleteOnExit();
		}
		try {
			parser.txSink = mapDb.treeMap("transactions", Serializer.LONG,Serializer.JAVA).createFromSink();
			parser.parseInput(gzipped?new GZIPInputStream(new FileInputStream(file)):new FileInputStream(file));
			transactions = parser.txSink.create();
		} catch(IllegalArgumentException|ArrayIndexOutOfBoundsException e) {
		} catch(Exception e) {
			System.out.println("---->>> Exception "+e.toString()+" caught while loading database");
			e.printStackTrace();
			return false;
		}
		for(TxStream stream:txStreams.values()) {
			Thread t = new Thread() {
				@Override
				public void run() {
					try {
					stream.calculateConcurrency();
					} catch (Exception e) {/* don't let exceptions bubble up */ }
				}
			};
			threads.add(t);
			t.start();
		}
		return true;
	}
	
	@Override
	public void dispose() {
		attrValues.clear();
		relationTypes.clear();
	    txStreams.clear();
	    txGenerators.clear();
	    transactions = null;
	    attributeTypes.clear(); 
		relationsIn.clear();
		relationsOut.clear();
		if(mapDb!=null) {
			mapDb.close();
			mapDb=null;
		}
	}
	
	private static boolean isTxfile(InputStream istream) {
		byte[] buffer = new byte[x.length];
		try {
			int readCnt = istream.read(buffer, 0, x.length);
			istream.close();
			if(readCnt==x.length){
				for(int i=0; i<x.length; i++)
					if(buffer[i]!=x[i]) return false;
			}
			return true;
		} catch (IOException e) {
			return false;
		}
	}

	private static boolean isGzipped(File f) {
		try(InputStream is = new FileInputStream(f)) {
			byte [] signature = new byte[2];
			int nread = is.read( signature ); //read the gzip signature
			return nread == 2 && signature[ 0 ] == (byte) 0x1f && signature[ 1 ] == (byte) 0x8b;
		} catch (IOException e) {
			return false;
		}
	}

	public Collection<RelationType> getAllRelationTypes(){
		return relationTypes.values();
	}

	static class TextDbParser {
		static final Pattern scv_tr_stream = Pattern.compile("^scv_tr_stream\\s+\\(ID (\\d+),\\s+name\\s+\"([^\"]+)\",\\s+kind\\s+\"([^\"]+)\"\\)$");
		static final Pattern scv_tr_generator = Pattern.compile("^scv_tr_generator\\s+\\(ID\\s+(\\d+),\\s+name\\s+\"([^\"]+)\",\\s+scv_tr_stream\\s+(\\d+),$");
		static final Pattern begin_attribute = Pattern.compile("^begin_attribute \\(ID (\\d+), name \"([^\"]+)\", type \"([^\"]+)\"\\)$");
		static final Pattern end_attribute = Pattern.compile("^end_attribute \\(ID (\\d+), name \"([^\"]+)\", type \"([^\"]+)\"\\)$");
				
		final TextDbLoader loader;
		
		HashMap<Long, ScvTx> transactionById = new HashMap<>();
		
		TreeMapSink<Long, ScvTx> txSink;
		
		BufferedReader reader = null;
		
		TxGenerator generator=null;
		
		Map<String, Integer> attrValueLut = new HashMap<>();
		
		public TextDbParser(TextDbLoader loader) {
			super();
			this.loader = loader;
		}

		void parseInput(InputStream inputStream) throws IOException{
			reader = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8));
			String curLine = reader.readLine();
			String nextLine = null;
			while((nextLine=reader.readLine())!=null && curLine!=null) {
				curLine=parseLine(curLine, nextLine);
			}
			if(curLine!=null)
				parseLine(curLine, nextLine);
		}

		private TxAttributeType getAttrType(String name, DataType dataType, AssociationType type){
			String key =name+"-"+dataType.toString();
			TxAttributeType res;
			if(loader.attributeTypes.containsKey(key)){
				res=loader.attributeTypes.get(key);
			} else {
				res=new TxAttributeType(name, dataType, type);
				loader.attributeTypes.put(key, res);
			}
			return res;
		}

		private String parseLine(String curLine, String nextLine) throws IOException{
			String[] tokens = curLine.split("\\s+");
			if("tx_record_attribute".equals(tokens[0])){
				Long id = Long.parseLong(tokens[1]);
				String name = tokens[2].substring(1, tokens[2].length());
				DataType type = DataType.valueOf(tokens[3]);
				String remaining = tokens.length>5?String.join(" ", Arrays.copyOfRange(tokens, 5, tokens.length)):"";
				TxAttributeType attrType = getAttrType(name, type, AssociationType.RECORD);
				transactionById.get(id).attributes.add(new TxAttribute(attrType, getAttrString(attrType, remaining)));
			} else if("tx_begin".equals(tokens[0])){
				Long id = Long.parseLong(tokens[1]);
				Long genId = Long.parseLong(tokens[2]);
				TxGenerator gen=loader.txGenerators.get(genId);
				ScvTx scvTx = new ScvTx(id, gen.stream.getId(), genId, Long.parseLong(tokens[3])*stringToScale(tokens[4]));
				loader.maxTime = loader.maxTime>scvTx.beginTime?loader.maxTime:scvTx.beginTime;
				TxStream stream = loader.txStreams.get(gen.stream.getId());
				stream.setConcurrency(stream.getConcurrency()+1);
				if(nextLine!=null && nextLine.charAt(0)=='a') {
					int idx=0;
					while(nextLine!=null && nextLine.charAt(0)=='a') {
						String[] attrTokens=nextLine.split("\\s+");
						TxAttributeType attrType = gen.beginAttrs.get(idx);
						TxAttribute attr = new TxAttribute(attrType, getAttrString(attrType, attrTokens[1]));
						scvTx.attributes.add(attr);
						idx++;
						nextLine=reader.readLine();
					}
				}
				txSink.put(id, scvTx);
				transactionById.put(id, scvTx);
			} else if("tx_end".equals(tokens[0])){
				Long id = Long.parseLong(tokens[1]);
				ScvTx scvTx = transactionById.get(id);
				assert Long.parseLong(tokens[2])==scvTx.generatorId;
				scvTx.endTime=Long.parseLong(tokens[3])*stringToScale(tokens[4]);
				loader.maxTime = loader.maxTime>scvTx.endTime?loader.maxTime:scvTx.endTime;
				TxGenerator gen = loader.txGenerators.get(scvTx.generatorId);
				TxStream stream = loader.txStreams.get(gen.stream.getId());
				if(scvTx.beginTime==scvTx.endTime)
					stream.addEvent(new TxEvent(loader, EventKind.SINGLE, id, scvTx.beginTime));
				else {
					stream.addEvent(new TxEvent(loader, EventKind.BEGIN, id, scvTx.beginTime));
					stream.addEvent(new TxEvent(loader, EventKind.END, id, scvTx.endTime));
				}
				stream.setConcurrency(stream.getConcurrency()-1);
				if(nextLine!=null && nextLine.charAt(0)=='a') {
					int idx=0;
					while(nextLine!=null && nextLine.charAt(0)=='a') {
						String[] attrTokens=nextLine.split("\\s+");
						TxAttributeType attrType = gen.endAttrs.get(idx);
						TxAttribute attr = new TxAttribute(attrType, getAttrString(attrType, attrTokens[1]));
						scvTx.attributes.add(attr);
						idx++;
						nextLine=reader.readLine();
					}
				}
			} else if("tx_relation".equals(tokens[0])){
				Long tr2= Long.parseLong(tokens[2]);
				Long tr1= Long.parseLong(tokens[3]);
				String relType=tokens[1].substring(1, tokens[1].length()-1);
				if(!loader.relationTypes.containsKey(relType))
					loader.relationTypes.put(relType, RelationTypeFactory.create(relType));
				ScvRelation rel = new ScvRelation(loader.relationTypes.get(relType), tr1, tr2);
				loader.relationsOut.put(tr1, rel);
				loader.relationsIn.put(tr2, rel);
			} else if("scv_tr_stream".equals(tokens[0])){
				Matcher matcher = scv_tr_stream.matcher(curLine);
				if (matcher.matches()) {
					Long id = Long.parseLong(matcher.group(1));
					TxStream stream = new TxStream(loader, id, matcher.group(2), matcher.group(3));
					loader.txStreams.put(id, stream);
				}
			} else if("scv_tr_generator".equals(tokens[0])){
				Matcher matcher = scv_tr_generator.matcher(curLine);
				if ((matcher.matches())) {
					Long id = Long.parseLong(matcher.group(1));
					TxStream stream=loader.txStreams.get(Long.parseLong(matcher.group(3)));
					generator=new TxGenerator(id, stream, matcher.group(2));
					loader.txGenerators.put(id,  generator);
				}
			} else if("begin_attribute".equals(tokens[0])){
				Matcher matcher = begin_attribute.matcher(curLine);
				if ((matcher.matches())) {
					TxAttributeType attrType = getAttrType(matcher.group(2), DataType.valueOf(matcher.group(3)), AssociationType.BEGIN);
					generator.beginAttrs.add(attrType);
				}
			} else if("end_attribute".equals(tokens[0])){
				Matcher matcher = end_attribute.matcher(curLine);
				if ((matcher.matches())) {
					TxAttributeType attrType = getAttrType(matcher.group(2), DataType.valueOf(matcher.group(3)), AssociationType.END);
					generator.endAttrs.add(attrType);
				}
			} else if(")".equals(tokens[0])){
				generator=null;
			} else if("a".equals(tokens[0])){//matcher = line =~ /^a\s+(.+)$/
				System.out.println("Don't know what to do with: '"+curLine+"'");
			} else
				System.out.println("Don't know what to do with: '"+curLine+"'");
			return nextLine;
		}
		
		private String getAttrString(TxAttributeType attrType, String string) {
			String value;
			switch(attrType.getDataType()){
			case STRING:
			case ENUMERATION:
				value=string.substring(1, string.length()-1);
				break;
			default:
				value=string;
			}
			if(attrValueLut.containsKey(value)){
				return loader.attrValues.get(attrValueLut.get(value));
			} else {
				attrValueLut.put(value, loader.attrValues.size());
				loader.attrValues.add(value);
				return value;
			}
		}

		private long stringToScale(String scale){
			String cmp = scale.trim();
			if("fs".equals(cmp)) return 1L;
			if("ps".equals(cmp)) return 1000L;
			if("ns".equals(cmp)) return 1000000L;
			if("us".equals(cmp)) return 1000000000L;
			if("ms".equals(cmp)) return 1000000000000L;
			if("s".equals(cmp) ) return 1000000000000000L;
			return 1L;
		}
	}

	public ITx getTransaction(long txId) {
		if(txCache.containsKey(txId))
			return txCache.get(txId);
		Tx tx = new Tx(this, txId);
		txCache.put(txId, tx);
		return tx;
	}

}