/*
 * This file is part of lanterna (http://code.google.com/p/lanterna/).
 * 
 * lanterna is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * Copyright (C) 2010-2020 Martin Berglund
 */
package com.googlecode.lanterna.terminal.ansi;

import com.googlecode.lanterna.TerminalSize;

import java.io.*;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

This class extends UnixLikeTerminal and implements the Cygwin-specific implementations. This means, running a Java
application using Lanterna inside the Cygwin Terminal application. The standard Windows command prompt (cmd.exe) is
not supported by this class.

NOTE: This class is experimental and does not fully work! Some of the operations, like disabling echo and
changing cbreak seems to be impossible to do without resorting to native code. Running "stty raw" before starting the
JVM will improve compatibility.

NOTE: This class will try to find Cygwin by scanning the directories on java.library.path, but you can also
tell it where Cygwin is installed by setting the CYGWIN_HOME environment variable.
Author:
Martin, Andreas/**
 * This class extends UnixLikeTerminal and implements the Cygwin-specific implementations. This means, running a Java
 * application using Lanterna inside the Cygwin Terminal application. The standard Windows command prompt (cmd.exe) is
 * not supported by this class.
 * <p>
 * <b>NOTE:</b> This class is experimental and does not fully work! Some of the operations, like disabling echo and
 * changing cbreak seems to be impossible to do without resorting to native code. Running "stty raw" before starting the
 * JVM will improve compatibility.
 * <p>
 * <b>NOTE:</b> This class will try to find Cygwin by scanning the directories on java.library.path, but you can also
 * tell it where Cygwin is installed by setting the CYGWIN_HOME environment variable.
 *
 * @author Martin
 * @author Andreas
 */
public class CygwinTerminal extends UnixLikeTTYTerminal {
    private static final String STTY_LOCATION = findProgram("stty.exe");
    private static final Pattern STTY_SIZE_PATTERN = Pattern.compile(".*rows ([0-9]+);.*columns ([0-9]+);.*");
    private static final String JAVA_LIBRARY_PATH_PROPERTY = "java.library.path";
    private static final String CYGWIN_HOME_ENV = "CYGWIN_HOME";

    
Creates a new CygwinTerminal based off input and output streams and a character set to use
Params:
terminalInput – Input stream to read input from
terminalOutput – Output stream to write output to
terminalCharset – Character set to use when writing to the output stream
Throws:
IOException – If there was an I/O error when trying to initialize the class and setup the terminal/**
     * Creates a new CygwinTerminal based off input and output streams and a character set to use
     * @param terminalInput Input stream to read input from
     * @param terminalOutput Output stream to write output to
     * @param terminalCharset Character set to use when writing to the output stream
     * @throws IOException If there was an I/O error when trying to initialize the class and setup the terminal
     */
    public CygwinTerminal(
            InputStream terminalInput,
            OutputStream terminalOutput,
            Charset terminalCharset) throws IOException {
        super(null,
                terminalInput,
                terminalOutput,
                terminalCharset,
                CtrlCBehaviour.TRAP);
    }

    @Override
    protected TerminalSize findTerminalSize() throws IOException {
        try {
            String stty = runSTTYCommand("-a");
            Matcher matcher = STTY_SIZE_PATTERN.matcher(stty);
            if(matcher.matches()) {
                return new TerminalSize(Integer.parseInt(matcher.group(2)), Integer.parseInt(matcher.group(1)));
            }
            else {
                return new TerminalSize(80, 24);
            }
        }
        catch(Throwable e) {
            return new TerminalSize(80, 24);
        }
    }

    @Override
    protected String runSTTYCommand(String... parameters) throws IOException {
        List<String> commandLine = new ArrayList<String>(Arrays.asList(
                findSTTY(),
                "-F",
                getPseudoTerminalDevice()));
        commandLine.addAll(Arrays.asList(parameters));
        return exec(commandLine.toArray(new String[commandLine.size()]));
    }

    @Override
    protected void acquire() throws IOException {
        super.acquire();
        // Placeholder in case we want to add extra stty invocations for Cygwin
    }

    private String findSTTY() {
        return STTY_LOCATION;
    }

    private String getPseudoTerminalDevice() {
        //This will only work if you only have one terminal window open, otherwise we'll need to figure out somehow
        //which pty to use, which could be very tricky...
        return "/dev/pty0";
    }

    private static String findProgram(String programName) {
        if (System.getenv(CYGWIN_HOME_ENV) != null) {
            File cygwinHomeBinFile = new File(System.getenv(CYGWIN_HOME_ENV) + "/bin", programName);
            if (cygwinHomeBinFile.exists()) {
                return cygwinHomeBinFile.getAbsolutePath();
            }
        }
        String[] paths = System.getProperty(JAVA_LIBRARY_PATH_PROPERTY).split(";");
        for(String path : paths) {
            File shBin = new File(path, programName);
            if(shBin.exists()) {
                return shBin.getAbsolutePath();
            }
        }
        return programName;
    }
}