/*
 * Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
 * Use of this file is governed by the BSD 3-clause license that
 * can be found in the LICENSE.txt file in the project root.
 */

package org.antlr.v4.parse;

import org.antlr.runtime.Token;
import org.antlr.v4.Tool;
import org.antlr.v4.codegen.CodeGenerator;
import org.antlr.v4.tool.ErrorType;
import org.antlr.v4.tool.Grammar;
import org.antlr.v4.tool.ast.GrammarAST;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/** */
public class TokenVocabParser {
	protected final Grammar g;

	public TokenVocabParser(Grammar g) {
		this.g = g;
	}

	
Load a vocab file <vocabName>.tokens and return mapping. /** Load a vocab file {@code <vocabName>.tokens} and return mapping. */
	public Map<String,Integer> load() {
		Map<String,Integer> tokens = new LinkedHashMap<String,Integer>();
		int maxTokenType = -1;
		File fullFile = getImportedVocabFile();
		FileInputStream fis = null;
		BufferedReader br = null;
		Tool tool = g.tool;
		String vocabName = g.getOptionString("tokenVocab");
		try {
			Pattern tokenDefPattern = Pattern.compile("([^\n]+?)[ \\t]*?=[ \\t]*?([0-9]+)");
			fis = new FileInputStream(fullFile);
			InputStreamReader isr;
			if (tool.grammarEncoding != null) {
				isr = new InputStreamReader(fis, tool.grammarEncoding);
			}
			else {
				isr = new InputStreamReader(fis);
			}

			br = new BufferedReader(isr);
			String tokenDef = br.readLine();
			int lineNum = 1;
			while ( tokenDef!=null ) {
				Matcher matcher = tokenDefPattern.matcher(tokenDef);
				if ( matcher.find() ) {
					String tokenID = matcher.group(1);
					String tokenTypeS = matcher.group(2);
					int tokenType;
					try {
						tokenType = Integer.valueOf(tokenTypeS);
					}
					catch (NumberFormatException nfe) {
						tool.errMgr.toolError(ErrorType.TOKENS_FILE_SYNTAX_ERROR,
											  vocabName + CodeGenerator.VOCAB_FILE_EXTENSION,
											  " bad token type: "+tokenTypeS,
											  lineNum);
						tokenType = Token.INVALID_TOKEN_TYPE;
					}
					tool.log("grammar", "import "+tokenID+"="+tokenType);
					tokens.put(tokenID, tokenType);
					maxTokenType = Math.max(maxTokenType,tokenType);
					lineNum++;
				}
				else {
					if ( tokenDef.length()>0 ) { // ignore blank lines
						tool.errMgr.toolError(ErrorType.TOKENS_FILE_SYNTAX_ERROR,
											  vocabName + CodeGenerator.VOCAB_FILE_EXTENSION,
											  " bad token def: " + tokenDef,
											  lineNum);
					}
				}
				tokenDef = br.readLine();
			}
		}
		catch (FileNotFoundException fnfe) {
			GrammarAST inTree = g.ast.getOptionAST("tokenVocab");
			String inTreeValue = inTree.getToken().getText();
			if ( vocabName.equals(inTreeValue) ) {
				tool.errMgr.grammarError(ErrorType.CANNOT_FIND_TOKENS_FILE_REFD_IN_GRAMMAR,
										 g.fileName,
										 inTree.getToken(),
										 fullFile);
			}
			else { // must be from -D option on cmd-line not token in tree
				tool.errMgr.toolError(ErrorType.CANNOT_FIND_TOKENS_FILE_GIVEN_ON_CMDLINE,
									  fullFile,
									  g.name);
			}
		}
		catch (Exception e) {
			tool.errMgr.toolError(ErrorType.ERROR_READING_TOKENS_FILE,
								  e,
								  fullFile,
								  e.getMessage());
		}
		finally {
			try {
				if ( br!=null ) br.close();
			}
			catch (IOException ioe) {
				tool.errMgr.toolError(ErrorType.ERROR_READING_TOKENS_FILE,
									  ioe,
									  fullFile,
									  ioe.getMessage());
			}
		}
		return tokens;
	}

	
Return a File descriptor for vocab file.  Look in library or
 in -o output path.  antlr -o foo T.g4 U.g4 where U needs T.tokens
 won't work unless we look in foo too. If we do not find the
 file in the lib directory then must assume that the .tokens file
 is going to be generated as part of this build and we have defined
 .tokens files so that they ALWAYS are generated in the base output
 directory, which means the current directory for the command line tool if there
 was no output directory specified.
/** Return a File descriptor for vocab file.  Look in library or
	 *  in -o output path.  antlr -o foo T.g4 U.g4 where U needs T.tokens
	 *  won't work unless we look in foo too. If we do not find the
	 *  file in the lib directory then must assume that the .tokens file
	 *  is going to be generated as part of this build and we have defined
	 *  .tokens files so that they ALWAYS are generated in the base output
	 *  directory, which means the current directory for the command line tool if there
	 *  was no output directory specified.
	 */
	public File getImportedVocabFile() {
		String vocabName = g.getOptionString("tokenVocab");
		File f = new File(g.tool.libDirectory,
						  File.separator +
						  vocabName +
						  CodeGenerator.VOCAB_FILE_EXTENSION);
		if (f.exists()) {
			return f;
		}

		// We did not find the vocab file in the lib directory, so we need
		// to look for it in the output directory which is where .tokens
		// files are generated (in the base, not relative to the input
		// location.)
		f = new File(g.tool.outputDirectory, vocabName + CodeGenerator.VOCAB_FILE_EXTENSION);
		if ( f.exists() ) {
			return f;
		}
		
		// Still not found? Use the grammar's subfolder then.
		String fileDirectory;

		if (g.fileName.lastIndexOf(File.separatorChar) == -1) {
			// No path is included in the file name, so make the file
			// directory the same as the parent grammar (which might still be just ""
			// but when it is not, we will write the file in the correct place.
			fileDirectory = ".";
		}
		else {
			fileDirectory = g.fileName.substring(0, g.fileName.lastIndexOf(File.separatorChar));
		}
		return new File(fileDirectory, vocabName + CodeGenerator.VOCAB_FILE_EXTENSION);
	}
}