/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.javascript.tools.shell;

import java.awt.Font;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.io.IOException;
import java.io.InputStream;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.io.PrintStream;
import java.io.PrintWriter;
import java.nio.charset.StandardCharsets;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import javax.swing.text.Document;
import javax.swing.text.Segment;

class ConsoleWrite implements Runnable {
    private ConsoleTextArea textArea;
    private String str;

    public ConsoleWrite(ConsoleTextArea textArea, String str) {
        this.textArea = textArea;
        this.str = str;
    }

    @Override
    public void run() {
        textArea.write(str);
    }
}

class ConsoleWriter extends java.io.OutputStream {

    private ConsoleTextArea textArea;
    private StringBuilder buffer;

    public ConsoleWriter(ConsoleTextArea textArea) {
        this.textArea = textArea;
        buffer = new StringBuilder();
    }

    @Override
    public synchronized void write(int ch) {
        buffer.append((char) ch);
        if (ch == '\n') {
            flushBuffer();
        }
    }

    public synchronized void write(char[] data, int off, int len) {
        for (int i = off; i < len; i++) {
            buffer.append(data[i]);
            if (data[i] == '\n') {
                flushBuffer();
            }
        }
    }

    @Override
    public synchronized void flush() {
        if (buffer.length() > 0) {
            flushBuffer();
        }
    }

    @Override
    public void close() {
        flush();
    }

    private void flushBuffer() {
        String str = buffer.toString();
        buffer.setLength(0);
        SwingUtilities.invokeLater(new ConsoleWrite(textArea, str));
    }
}

public class ConsoleTextArea extends JTextArea implements KeyListener, DocumentListener {
    static final long serialVersionUID = 8557083244830872961L;

    private ConsoleWriter console1;
    private ConsoleWriter console2;
    private PrintStream out;
    private PrintStream err;
    private PrintWriter inPipe;
    private PipedInputStream in;
    private java.util.List<String> history;
    private int historyIndex = -1;
    private int outputMark = 0;

    @Override
    public void select(int start, int end) {
        requestFocus();
        super.select(start, end);
    }

    @SuppressWarnings("CatchAndPrintStackTrace")
    public ConsoleTextArea(String[] argv) {
        super();
        history = new java.util.ArrayList<String>();
        console1 = new ConsoleWriter(this);
        console2 = new ConsoleWriter(this);
        out = new PrintStream(console1, true);
        err = new PrintStream(console2, true);
        PipedOutputStream outPipe = new PipedOutputStream();
        inPipe = new PrintWriter(outPipe, false, StandardCharsets.UTF_8);
        in = new PipedInputStream();
        try {
            outPipe.connect(in);
        } catch (IOException exc) {
            exc.printStackTrace();
        }
        getDocument().addDocumentListener(this);
        addKeyListener(this);
        setLineWrap(true);
        setFont(new Font("Monospaced", 0, 12));
    }

    @SuppressWarnings("CatchAndPrintStackTrace")
    synchronized void returnPressed() {
        Document doc = getDocument();
        int len = doc.getLength();
        Segment segment = new Segment();
        try {
            doc.getText(outputMark, len - outputMark, segment);
        } catch (javax.swing.text.BadLocationException ignored) {
            ignored.printStackTrace();
        }
        if (segment.count > 0) {
            history.add(segment.toString());
        }
        historyIndex = history.size();
        inPipe.write(segment.array, segment.offset, segment.count);
        append("\n");
        outputMark = doc.getLength();
        inPipe.write("\n");
        inPipe.flush();
        console1.flush();
    }

    public void eval(String str) {
        inPipe.write(str);
        inPipe.write("\n");
        inPipe.flush();
        console1.flush();
    }

    @Override
    public void keyPressed(KeyEvent e) {
        int code = e.getKeyCode();
        if (code == KeyEvent.VK_BACK_SPACE || code == KeyEvent.VK_LEFT) {
            if (outputMark == getCaretPosition()) {
                e.consume();
            }
        } else if (code == KeyEvent.VK_HOME) {
            int caretPos = getCaretPosition();
            if (caretPos == outputMark) {
                e.consume();
            } else if (caretPos > outputMark) {
                if (!e.isControlDown()) {
                    if (e.isShiftDown()) {
                        moveCaretPosition(outputMark);
                    } else {
                        setCaretPosition(outputMark);
                    }
                    e.consume();
                }
            }
        } else if (code == KeyEvent.VK_ENTER) {
            returnPressed();
            e.consume();
        } else if (code == KeyEvent.VK_UP) {
            historyIndex--;
            if (historyIndex >= 0) {
                if (historyIndex >= history.size()) {
                    historyIndex = history.size() - 1;
                }
                if (historyIndex >= 0) {
                    String str = history.get(historyIndex);
                    int len = getDocument().getLength();
                    replaceRange(str, outputMark, len);
                    int caretPos = outputMark + str.length();
                    select(caretPos, caretPos);
                } else {
                    historyIndex++;
                }
            } else {
                historyIndex++;
            }
            e.consume();
        } else if (code == KeyEvent.VK_DOWN) {
            int caretPos = outputMark;
            if (history.size() > 0) {
                historyIndex++;
                if (historyIndex < 0) {
                    historyIndex = 0;
                }
                int len = getDocument().getLength();
                if (historyIndex < history.size()) {
                    String str = history.get(historyIndex);
                    replaceRange(str, outputMark, len);
                    caretPos = outputMark + str.length();
                } else {
                    historyIndex = history.size();
                    replaceRange("", outputMark, len);
                }
            }
            select(caretPos, caretPos);
            e.consume();
        }
    }

    @Override
    public void keyTyped(KeyEvent e) {
        int keyChar = e.getKeyChar();
        if (keyChar == 0x8 /* KeyEvent.VK_BACK_SPACE */) {
            if (outputMark == getCaretPosition()) {
                e.consume();
            }
        } else if (getCaretPosition() < outputMark) {
            setCaretPosition(outputMark);
        }
    }

    @Override
    public synchronized void keyReleased(KeyEvent e) {}

    public synchronized void write(String str) {
        insert(str, outputMark);
        int len = str.length();
        outputMark += len;
        select(outputMark, outputMark);
    }

    @Override
    public synchronized void insertUpdate(DocumentEvent e) {
        int len = e.getLength();
        int off = e.getOffset();
        if (outputMark > off) {
            outputMark += len;
        }
    }

    @Override
    public synchronized void removeUpdate(DocumentEvent e) {
        int len = e.getLength();
        int off = e.getOffset();
        if (outputMark > off) {
            if (outputMark >= off + len) {
                outputMark -= len;
            } else {
                outputMark = off;
            }
        }
    }

    public synchronized void postUpdateUI() {
        // this attempts to cleanup the damage done by updateComponentTreeUI
        requestFocus();
        setCaret(getCaret());
        select(outputMark, outputMark);
    }

    @Override
    public synchronized void changedUpdate(DocumentEvent e) {}

    public InputStream getIn() {
        return in;
    }

    public PrintStream getOut() {
        return out;
    }

    public PrintStream getErr() {
        return err;
    }
}
