/*
    * dpkg - Debian Package library and the Debian Package Maven plugin
    * (c) Copyright 2016 Gerrit Hohl
    *
    * This program is free software; you can redistribute it and/or
    * modify it under the terms of the GNU General Public License
    * as published by the Free Software Foundation; either version 2
    * of the License, or (at your option) any later version.
    *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
   */
  package net.sourceforge.javadpkg.impl;
  
  import java.io.BufferedReader;
  import java.io.ByteArrayInputStream;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.util.List;
  
  import net.sourceforge.javadpkg.Context;
  import net.sourceforge.javadpkg.GlobalConstants;
  import net.sourceforge.javadpkg.ParseException;
  import net.sourceforge.javadpkg.Symbols;
  import net.sourceforge.javadpkg.SymbolsParser;
  import net.sourceforge.javadpkg.control.PackageDependency;
  import net.sourceforge.javadpkg.control.PackageDependencyParser;
  import net.sourceforge.javadpkg.control.PackageVersion;
  import net.sourceforge.javadpkg.control.PackageVersionParser;
  import net.sourceforge.javadpkg.control.impl.PackageDependencyParserImpl;
  import net.sourceforge.javadpkg.control.impl.PackageNameParserImpl;
  import net.sourceforge.javadpkg.control.impl.PackageVersionParserImpl;
  import net.sourceforge.javadpkg.control.impl.PackageVersionRelationOperatorParserImpl;
  import net.sourceforge.javadpkg.field.Field;
  import net.sourceforge.javadpkg.field.FieldParser;
  import net.sourceforge.javadpkg.field.impl.FieldParserImpl;
  import net.sourceforge.javadpkg.io.DataSource;
  import net.sourceforge.javadpkg.io.impl.DataStreamSource;
  
  
  /**
   * <p>
   * A {@link SymbolsParser} implementation.
   * </p>
   *
   * @author Gerrit Hohl (gerrit-hohl@users.sourceforge.net)
   * @version <b>1.0</b>, 10.01.2016 by Gerrit Hohl
   */
  public class SymbolsParserImpl implements SymbolsParser, GlobalConstants {
  	
  	
  	/** The parser for the package version. */
  	private PackageVersionParser	packageVersionParser;
  	/** The parser for the package dependencies. */
  	private PackageDependencyParser	packageDependencyParser;
  	/** The parser for the fields. */
  	private FieldParser				fieldParser;
  
  
  	/**
  	 * <p>
  	 * Creates a parser.
  	 * </p>
  	 */
  	public SymbolsParserImpl() {
  		super();
  
  		this.packageVersionParser = new PackageVersionParserImpl();
  		this.packageDependencyParser = new PackageDependencyParserImpl(new PackageNameParserImpl(),
  				new PackageVersionRelationOperatorParserImpl(), this.packageVersionParser);
  		this.fieldParser = new FieldParserImpl(false, false, false);
  	}
  	
  	
  	@Override
  	public Symbols parseSymbols(DataSource source, Context context) throws IOException, ParseException {
  		SymbolsImpl symbols = null;
  		String line;
  		boolean contentParsed = false;
  		SymbolsEntryImpl entry = null;
  		
  		
  		if (source == null)
  			throw new IllegalArgumentException("Argument source is null.");
  		if (context == null)
  			throw new IllegalArgumentException("Argument context is null.");
  		
  		symbols = new SymbolsImpl();
  		try {
  			try (BufferedReader reader = new BufferedReader(new InputStreamReader(source.getInputStream(), UTF_8_CHARSET))) {
  				while ((line = reader.readLine()) != null) {
  					// --- Alternative dependency ---
  					if (line.startsWith("| ")) {
 						if (entry == null)
 							throw new ParseException("Symbol line |" + line + "| of symbols from source |" + source.getName()
 									+ "| contains an alternative dependency template also no initial line of an entry has been read.");
 						if (contentParsed)
 							throw new ParseException("Symbol line |" + line + "| of symbols from source |" + source.getName()
 									+ "| contains an alternative dependency template also symbols have been already read.");
 						this.parseAlternativeDependencyTemplate(source, entry, line);
 					}
 					// --- Symbol ---
 					else if (line.startsWith(" ")) {
 						if (entry == null)
 							throw new ParseException("Symbol line |" + line + "| of symbols from source |" + source.getName()
 									+ "| contains a symbol also no initial line of an entry has been read.");
 						this.parseSymbol(source, context, entry, line);
 						contentParsed = true;
 					}
 					// --- Meta data fields --
 					else if (line.startsWith("* ")) {
 						if (entry == null)
 							throw new ParseException("Symbol line |" + line + "| of symbols from source |" + source.getName()
 									+ "| contains a meta data field also no initial line of an entry has been read.");
 						this.parseMetaData(source, context, entry, line);
 						contentParsed = true;
 					}
 					// --- Initial line of an entry ---
 					else {
 						entry = this.parseInitialLine(source, context, line);
 						symbols.addEntry(entry);
 						contentParsed = false;
 					}
 				}
 			}
 		} catch (IOException e) {
 			throw new IOException(
 					"Couldn't read the shared libraries from source |" + source.getName() + "|: " + e.getMessage());
 		}
 		if (entry == null)
 			throw new ParseException("The shared libraries from source |" + source.getName() + "| were empty.");
 		return symbols;
 	}
 	
 	
 	/**
 	 * <p>
 	 * Parses the initial line.
 	 * </p>
 	 *
 	 * @param source
 	 *            The source.
 	 * @param context
 	 *            The context.
 	 * @param line
 	 *            The initial line.
 	 * @return The symbols.
 	 * @throws ParseException
 	 *             If an error occurs during parsing.
 	 */
 	private SymbolsEntryImpl parseInitialLine(DataSource source, Context context, String line) throws ParseException {
 		SymbolsEntryImpl entry;
 		String[] parts;
 		String libraryName, dependencyTemplate;
 		PackageDependency dependency = null;
 		
 		
 		parts = line.split(" ", 2);
 		if (parts.length != 2)
 			throw new ParseException("Couldn't split line |" + line + "| of symbols from source |" + source.getName()
 					+ "| into 3 parts. Got " + parts.length);
 		libraryName = parts[0];
 		dependencyTemplate = parts[1];
 		if (!dependencyTemplate.endsWith("#MINVER#")) {
 			try {
 				dependency = this.packageDependencyParser.parsePackageDependency(dependencyTemplate, context);
 			} catch (ParseException e) {
 				throw new ParseException("Couldn't parse dependency |" + dependencyTemplate + "| from |" + line
 						+ "| of symbols from source |" + source.getName() + "| into 3 parts. Got " + parts.length);
 			}
 		}
 		
 		if (dependency == null) {
 			entry = new SymbolsEntryImpl(libraryName, dependencyTemplate);
 		} else {
 			entry = new SymbolsEntryImpl(libraryName, dependency);
 		}
 		return entry;
 	}
 
 
 	/**
 	 * <p>
 	 * Parses the alternative dependency template.
 	 * </p>
 	 *
 	 * @param source
 	 *            The source.
 	 * @param entry
 	 *            The entry.
 	 * @param line
 	 *            The line.
 	 * @throws ParseException
 	 *             If an error occurs during parsing.
 	 */
 	private void parseAlternativeDependencyTemplate(DataSource source, SymbolsEntryImpl entry, String line)
 			throws ParseException {
 		
 		String alternativeDependencyTemplate;
 
 		// TODO Implement the parsing of the dependencies.
 		alternativeDependencyTemplate = line.substring(2);
 		entry.setAlternativeDependencyValue(alternativeDependencyTemplate);
 	}
 	
 	
 	/**
 	 * <p>
 	 * Parses a symbol.
 	 * </p>
 	 *
 	 * @param source
 	 *            The source.
 	 * @param context
 	 *            The context.
 	 * @param entry
 	 *            The entry.
 	 * @param line
 	 *            The line.
 	 * @throws ParseException
 	 *             If an error occurs during parsing.
 	 */
 	private void parseSymbol(DataSource source, Context context, SymbolsEntryImpl entry, String line) throws ParseException {
 		String[] parts;
 		PackageVersion version;
 		String symbolName, symbolVersion;
 
 
 		parts = line.trim().split(" ", 3);
 		if ((parts.length < 2) || (parts.length > 3))
 			throw new ParseException("Couldn't split line |" + line + "| of symbols from source |" + source.getName()
 					+ "| into 2 or 3 parts. Got " + parts.length);
 		
 		try {
 			version = this.packageVersionParser.parsePackageVersion(parts[1], context);
 		} catch (ParseException e) {
 			throw new ParseException("Couldn't parse version |" + parts[1] + "| from |" + line + "| of symbols from source |"
 					+ source.getName() + "|: " + e.getMessage(), e);
 		}
 		parts = parts[0].split("@", 2);
 		if (parts.length != 2)
 			throw new ParseException("Couldn't split |" + line + "| of symbols from source |" + source.getName()
 					+ "| into 2 parts. Got " + parts.length);
 		symbolName = parts[0];
 		symbolVersion = parts[1];
 		
 		entry.addSymbol(symbolName, symbolVersion, version);
 	}
 	
 	
 	/**
 	 * <p>
 	 * Parses a meta data field.
 	 * </p>
 	 *
 	 * @param source
 	 *            The source.
 	 * @param context
 	 *            The context.
 	 * @param entry
 	 *            The entry.
 	 * @param line
 	 *            The line.
 	 * @throws ParseException
 	 *             If an error occurs during parsing.
 	 */
 	private void parseMetaData(DataSource source, Context context, SymbolsEntryImpl entry, String line) throws ParseException {
 		String trimmedLine;
 		List<Field> fields;
 		Field field;
 		PackageDependency dependency;
 		
 		
 		trimmedLine = line.substring(2);
 		try {
 			try (DataSource fieldSource = new DataStreamSource(new ByteArrayInputStream(trimmedLine.getBytes()), "field",
 					false)) {
 				fields = this.fieldParser.parseFieldsAsList(fieldSource, context);
 			}
 		} catch (IOException | ParseException e) {
 			throw new ParseException("Couldn't parse meta data field in line |" + line + "| of symbols from source |"
 					+ source.getName() + "|: " + e.getMessage(), e);
 		}
 		if (fields.isEmpty())
 			throw new ParseException("Couldn't parse meta data field in line |" + line + "| of symbols from source |"
 					+ source.getName() + "|: Didn't find any field.");
 		field = fields.get(0);
 		switch (field.getName().toLowerCase()) {
 			case "build-depends-package":
 				// TODO Check if the field is already set in the entry.
 				try {
 					dependency = this.packageDependencyParser.parsePackageDependency(field.getValue(), context);
 				} catch (ParseException e) {
 					throw new ParseException("Couldn't parse meta data field |" + field.getName() + "| in line |" + line
 							+ "| of symbols from source |" + source.getName() + "|: " + e.getMessage(), e);
 				}
 				entry.setBuildDependsPackage(dependency);
 				break;
 			
 			default:
 				throw new ParseException("Found unsupported meta data field |" + field.getName() + "| in line |" + line
 						+ "| of symbols from source |" + source.getName() + "|.");
 		}
 	}
 	
 	
 }