package org.maltparser.core.symbol.trie;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.UnsupportedEncodingException;

import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.HashMap;
import java.util.Set;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

import org.apache.log4j.Logger;

import org.maltparser.core.exception.MaltChainedException;
import org.maltparser.core.symbol.SymbolException;
import org.maltparser.core.symbol.SymbolTable;
import org.maltparser.core.symbol.SymbolTableHandler;


/**

@author Johan Hall
@since 1.0
*/
public class TrieSymbolTableHandler implements SymbolTableHandler {
	private Trie trie;
	private HashMap<String, TrieSymbolTable> symbolTables;
	
	public TrieSymbolTableHandler() {
		trie = new Trie();
		symbolTables = new HashMap<String, TrieSymbolTable>();
	}

	public TrieSymbolTable addSymbolTable(String tableName) throws MaltChainedException {
		TrieSymbolTable symbolTable = symbolTables.get(tableName);
		if (symbolTable == null) {
			symbolTable = new TrieSymbolTable(tableName, trie);
			symbolTables.put(tableName, symbolTable);
		}
		return symbolTable;
	}
	
	public TrieSymbolTable addSymbolTable(String tableName, SymbolTable parentTable) throws MaltChainedException {
		TrieSymbolTable symbolTable = symbolTables.get(tableName);
		if (symbolTable == null) {
			TrieSymbolTable trieParentTable = (TrieSymbolTable)parentTable;
			symbolTable = new TrieSymbolTable(tableName, trie, trieParentTable.getColumnCategory(), trieParentTable.getNullValueStrategy());
			symbolTables.put(tableName, symbolTable);
		}
		return symbolTable;
	}
	
	public TrieSymbolTable addSymbolTable(String tableName, int columnCategory, String nullValueStrategy) throws MaltChainedException {
		TrieSymbolTable symbolTable = symbolTables.get(tableName);
		if (symbolTable == null) {
			symbolTable = new TrieSymbolTable(tableName, trie, columnCategory, nullValueStrategy);
			symbolTables.put(tableName, symbolTable);
		}
		return symbolTable;
	}
	
	public TrieSymbolTable addSymbolTable(String tableName, int columnCategory, String nullValueStrategy, String rootLabel) throws MaltChainedException {
		TrieSymbolTable symbolTable = symbolTables.get(tableName);
		if (symbolTable == null) {
			symbolTable = new TrieSymbolTable(tableName, trie, columnCategory, nullValueStrategy, rootLabel);
			symbolTables.put(tableName, symbolTable);
		}
		return symbolTable;
	}
	
	public TrieSymbolTable getSymbolTable(String tableName) {
		return symbolTables.get(tableName);
	}
	
	public Set<String> getSymbolTableNames() {
		return symbolTables.keySet();
	}
	
	public void save(OutputStreamWriter osw) throws MaltChainedException  {
		try {
			BufferedWriter bout = new BufferedWriter(osw);
			for (TrieSymbolTable table : symbolTables.values()) {
				table.saveHeader(bout);
			}
			bout.write('\n');
			for (TrieSymbolTable table : symbolTables.values()) {
				table.save(bout);
			}
			bout.close();
		} catch (IOException e) {
			throw new SymbolException("Could not save the symbol tables. ", e);
		}		
	}
	
	public void save(String fileName, String charSet) throws MaltChainedException  {
		try {
			save(new OutputStreamWriter(new FileOutputStream(fileName), charSet));
		} catch (FileNotFoundException e) {
			throw new SymbolException("The symbol table file '"+fileName+"' cannot be created. ", e);
		} catch (UnsupportedEncodingException e) {
			throw new SymbolException("The char set '"+charSet+"' is not supported. ", e);
		}
	}
	
	public void loadHeader(BufferedReader bin) throws MaltChainedException {
		String fileLine = "";
		Pattern tabPattern = Pattern.compile("\t");
		try {
			while ((fileLine = bin.readLine()) != null) {
				if (fileLine.length() == 0 || fileLine.charAt(0) != '\t') {
					break;
				}
				String items[];
				try {
					items = tabPattern.split(fileLine.substring(1));
				} catch (PatternSyntaxException e) {
					throw new SymbolException("The header line of the symbol table  '"+fileLine.substring(1)+"' could not split into atomic parts. ", e);
				}
				if (items.length != 4) {
					throw new SymbolException("The header line of the symbol table  '"+fileLine.substring(1)+"' must contain four columns. ");
				}
				if (items[3].equals("#DUMMY#")) {
					addSymbolTable(items[0], Integer.parseInt(items[1]), items[2]);
				} else {
					addSymbolTable(items[0], Integer.parseInt(items[1]), items[2], items[3]);
				}
			}
		} catch (NumberFormatException e) {
			throw new SymbolException("The symbol table file (.sym) contains a non-integer value in the header. ", e);
		} catch (IOException e) {
			throw new SymbolException("Could not load the symbol table. ", e);
		}
	}
	
	
	public void load(InputStreamReader isr) throws MaltChainedException  {
		try {
			BufferedReader bin = new BufferedReader(isr);
			String fileLine;
			SymbolTable table = null;
			bin.mark(2);
			if (bin.read() == '\t') {
				bin.reset();
				loadHeader(bin);
			} else {
				bin.reset();
			}
			while ((fileLine = bin.readLine()) != null) {
				if (fileLine.length() > 0) {
					table = addSymbolTable(fileLine);
					table.load(bin);
				}
			}
			bin.close();
		} catch (IOException e) {
			throw new SymbolException("Could not load the symbol tables. ", e);
		}			
	}
	
	public void load(String fileName, String charSet) throws MaltChainedException  {
		try {
			load(new InputStreamReader(new FileInputStream(fileName), charSet));

		} catch (FileNotFoundException e) {
			throw new SymbolException("The symbol table file '"+fileName+"' cannot be found. ", e);
		} catch (UnsupportedEncodingException e) {
			throw new SymbolException("The char set '"+charSet+"' is not supported. ", e);
		}		
	}
	
	
	public SymbolTable loadTagset(String fileName, String tableName, String charSet, int columnCategory, String nullValueStrategy) throws MaltChainedException {
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(fileName), charSet));
			String fileLine;
			TrieSymbolTable table = addSymbolTable(tableName, columnCategory, nullValueStrategy);

			while ((fileLine = br.readLine()) != null) {
				table.addSymbol(fileLine.trim());
			}
			return table;
		} catch (FileNotFoundException e) {
			throw new SymbolException("The tagset file '"+fileName+"' cannot be found. ", e);
		} catch (UnsupportedEncodingException e) {
			throw new SymbolException("The char set '"+charSet+"' is not supported. ", e);
		} catch (IOException e) {
			throw new SymbolException("The tagset file '"+fileName+"' cannot be loaded. ", e);
		}
	}
	
	public SymbolTable loadTagset(String fileName, String tableName, String charSet, int columnCategory, String nullValueStrategy, String rootLabel) throws MaltChainedException {
		try {
			BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(fileName), charSet));
			String fileLine;
			TrieSymbolTable table = addSymbolTable(tableName, columnCategory, nullValueStrategy, rootLabel);

			while ((fileLine = br.readLine()) != null) {
				table.addSymbol(fileLine.trim());
			}
			return table;
		} catch (FileNotFoundException e) {
			throw new SymbolException("The tagset file '"+fileName+"' cannot be found. ", e);
		} catch (UnsupportedEncodingException e) {
			throw new SymbolException("The char set '"+charSet+"' is not supported. ", e);
		} catch (IOException e) {
			throw new SymbolException("The tagset file '"+fileName+"' cannot be loaded. ", e);
		}
	}
	
	public void printSymbolTables(Logger logger) throws MaltChainedException  {
		for (TrieSymbolTable table : symbolTables.values()) {
			table.printSymbolTable(logger);
		}	
	}
}