/*
 * Copyright (c) 2002-2019, the original author or authors.
 *
 * This software is distributable under the BSD license. See the terms of the
 * BSD license in the documentation provided with this software.
 *
 * https://opensource.org/licenses/BSD-3-Clause
 */
package jdk.internal.org.jline.terminal;

import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.nio.charset.Charset;
import java.nio.charset.UnsupportedCharsetException;
import java.util.Optional;
import java.util.ServiceLoader;
import java.util.function.Function;

import jdk.internal.org.jline.terminal.impl.AbstractPosixTerminal;
import jdk.internal.org.jline.terminal.impl.DumbTerminal;
import jdk.internal.org.jline.terminal.impl.ExecPty;
import jdk.internal.org.jline.terminal.impl.ExternalTerminal;
import jdk.internal.org.jline.terminal.impl.PosixPtyTerminal;
import jdk.internal.org.jline.terminal.impl.PosixSysTerminal;
import jdk.internal.org.jline.terminal.spi.JansiSupport;
import jdk.internal.org.jline.terminal.spi.JnaSupport;
import jdk.internal.org.jline.terminal.spi.Pty;
import jdk.internal.org.jline.utils.Log;
import jdk.internal.org.jline.utils.OSUtils;

Builder class to create terminals.
/**
 * Builder class to create terminals.
 */
public final class TerminalBuilder {

    //
    // System properties
    //

    public static final String PROP_ENCODING = "org.jline.terminal.encoding";
    public static final String PROP_CODEPAGE = "org.jline.terminal.codepage";
    public static final String PROP_TYPE = "org.jline.terminal.type";
    public static final String PROP_JNA = "org.jline.terminal.jna";
    public static final String PROP_JANSI = "org.jline.terminal.jansi";
    public static final String PROP_EXEC = "org.jline.terminal.exec";
    public static final String PROP_DUMB = "org.jline.terminal.dumb";
    public static final String PROP_DUMB_COLOR = "org.jline.terminal.dumb.color";

    //
    // Other system properties controlling various jline parts
    //

    public static final String PROP_NON_BLOCKING_READS = "org.jline.terminal.pty.nonBlockingReads";
    public static final String PROP_COLOR_DISTANCE = "org.jline.utils.colorDistance";
    public static final String PROP_DISABLE_ALTERNATE_CHARSET = "org.jline.utils.disableAlternateCharset";

    
Returns the default system terminal. Terminals should be closed properly using the Closeable.close() method in order to restore the original terminal state. 

This call is equivalent to:
builder().build()

Throws:
IOException – if an error occurs
Returns:
the default system terminal/**
     * Returns the default system terminal.
     * Terminals should be closed properly using the {@link Terminal#close()}
     * method in order to restore the original terminal state.
     *
     * <p>
     * This call is equivalent to:
     * <code>builder().build()</code>
     * </p>
     *
     * @return the default system terminal
     * @throws IOException if an error occurs
     */
    public static Terminal terminal() throws IOException {
        return builder().build();
    }

    
Creates a new terminal builder instance.
Returns:
a builder/**
     * Creates a new terminal builder instance.
     *
     * @return a builder
     */
    public static TerminalBuilder builder() {
        return new TerminalBuilder();
    }

    private String name;
    private InputStream in;
    private OutputStream out;
    private String type;
    private Charset encoding;
    private int codepage;
    private Boolean system;
    private Boolean jna;
    private Boolean jansi;
    private Boolean exec;
    private Boolean dumb;
    private Attributes attributes;
    private Size size;
    private boolean nativeSignals = false;
    private Terminal.SignalHandler signalHandler = Terminal.SignalHandler.SIG_DFL;
    private boolean paused = false;
    private Function<InputStream, InputStream> inputStreamWrapper = in -> in;

    private TerminalBuilder() {
    }

    public TerminalBuilder name(String name) {
        this.name = name;
        return this;
    }

    public TerminalBuilder streams(InputStream in, OutputStream out) {
        this.in = in;
        this.out = out;
        return this;
    }

    public TerminalBuilder system(boolean system) {
        this.system = system;
        return this;
    }

    public TerminalBuilder jna(boolean jna) {
        this.jna = jna;
        return this;
    }

    public TerminalBuilder jansi(boolean jansi) {
        this.jansi = jansi;
        return this;
    }

    public TerminalBuilder exec(boolean exec) {
        this.exec = exec;
        return this;
    }

    public TerminalBuilder dumb(boolean dumb) {
        this.dumb = dumb;
        return this;
    }

    public TerminalBuilder type(String type) {
        this.type = type;
        return this;
    }

    
Set the encoding to use for reading/writing from the console. If null (the default value), JLine will automatically select a Charset, usually the default system encoding. However, on some platforms (e.g. Windows) it may use a different one depending on the Terminal implementation. 
Use Terminal.encoding() to get the Charset that should be used for a Terminal.
Params:
encoding – The encoding to use or null to automatically select one
Throws:
UnsupportedCharsetException – If the given encoding is not supported
See Also:
Terminal.encoding()
Returns:
The builder/**
     * Set the encoding to use for reading/writing from the console.
     * If {@code null} (the default value), JLine will automatically select
     * a {@link Charset}, usually the default system encoding. However,
     * on some platforms (e.g. Windows) it may use a different one depending
     * on the {@link Terminal} implementation.
     *
     * <p>Use {@link Terminal#encoding()} to get the {@link Charset} that
     * should be used for a {@link Terminal}.</p>
     *
     * @param encoding The encoding to use or null to automatically select one
     * @return The builder
     * @throws UnsupportedCharsetException If the given encoding is not supported
     * @see Terminal#encoding()
     */
    public TerminalBuilder encoding(String encoding) throws UnsupportedCharsetException {
        return encoding(encoding != null ? Charset.forName(encoding) : null);
    }

    
Set the Charset to use for reading/writing from the console. If null (the default value), JLine will automatically select a Charset, usually the default system encoding. However, on some platforms (e.g. Windows) it may use a different one depending on the Terminal implementation. 
Use Terminal.encoding() to get the Charset that should be used to read/write from a Terminal.
Params:
encoding – The encoding to use or null to automatically select one
See Also:
Terminal.encoding()
Returns:
The builder/**
     * Set the {@link Charset} to use for reading/writing from the console.
     * If {@code null} (the default value), JLine will automatically select
     * a {@link Charset}, usually the default system encoding. However,
     * on some platforms (e.g. Windows) it may use a different one depending
     * on the {@link Terminal} implementation.
     *
     * <p>Use {@link Terminal#encoding()} to get the {@link Charset} that
     * should be used to read/write from a {@link Terminal}.</p>
     *
     * @param encoding The encoding to use or null to automatically select one
     * @return The builder
     * @see Terminal#encoding()
     */
    public TerminalBuilder encoding(Charset encoding) {
        this.encoding = encoding;
        return this;
    }

    
Params:
codepage – the codepage
Returns:
The builder
Deprecated:
JLine now writes Unicode output independently from the selected code page. Using this option will only make it emulate the selected code page for Terminal.input() and Terminal.output()./**
     * @param codepage the codepage
     * @return The builder
     * @deprecated JLine now writes Unicode output independently from the selected
     *   code page. Using this option will only make it emulate the selected code
     *   page for {@link Terminal#input()} and {@link Terminal#output()}.
     */
    @Deprecated
    public TerminalBuilder codepage(int codepage) {
        this.codepage = codepage;
        return this;
    }

    
Attributes to use when creating a non system terminal, i.e. when the builder has been given the input and outut streams using the streams(InputStream, OutputStream) method or when system(boolean) has been explicitely called with false.
Params:
attributes – the attributes to use
See Also:
size(Size)
system(boolean)
Returns:
The builder/**
     * Attributes to use when creating a non system terminal,
     * i.e. when the builder has been given the input and
     * outut streams using the {@link #streams(InputStream, OutputStream)} method
     * or when {@link #system(boolean)} has been explicitely called with
     * <code>false</code>.
     *
     * @param attributes the attributes to use
     * @return The builder
     * @see #size(Size)
     * @see #system(boolean)
     */
    public TerminalBuilder attributes(Attributes attributes) {
        this.attributes = attributes;
        return this;
    }

    
Initial size to use when creating a non system terminal, i.e. when the builder has been given the input and outut streams using the streams(InputStream, OutputStream) method or when system(boolean) has been explicitely called with false.
Params:
size – the initial size
See Also:
attributes(Attributes)
system(boolean)
Returns:
The builder/**
     * Initial size to use when creating a non system terminal,
     * i.e. when the builder has been given the input and
     * outut streams using the {@link #streams(InputStream, OutputStream)} method
     * or when {@link #system(boolean)} has been explicitely called with
     * <code>false</code>.
     *
     * @param size the initial size
     * @return The builder
     * @see #attributes(Attributes)
     * @see #system(boolean)
     */
    public TerminalBuilder size(Size size) {
        this.size = size;
        return this;
    }

    public TerminalBuilder nativeSignals(boolean nativeSignals) {
        this.nativeSignals = nativeSignals;
        return this;
    }

    public TerminalBuilder signalHandler(Terminal.SignalHandler signalHandler) {
        this.signalHandler = signalHandler;
        return this;
    }

    
Initial paused state of the terminal (defaults to false).
By default, the terminal is started, but in some cases,
one might want to make sure the input stream is not consumed
before needed, in which case the terminal needs to be created
in a paused state.
Params:
paused – the initial paused state
See Also:
Terminal.pause()
Returns:
The builder/**
     * Initial paused state of the terminal (defaults to false).
     * By default, the terminal is started, but in some cases,
     * one might want to make sure the input stream is not consumed
     * before needed, in which case the terminal needs to be created
     * in a paused state.
     * @param paused the initial paused state
     * @return The builder
     * @see Terminal#pause()
     */
    public TerminalBuilder paused(boolean paused) {
        this.paused = paused;
        return this;
    }

    public TerminalBuilder inputStreamWrapper(Function<InputStream, InputStream> wrapper) {
        this.inputStreamWrapper = wrapper;
        return this;
    }

    public Terminal build() throws IOException {
        Terminal terminal = doBuild();
        Log.debug(() -> "Using terminal " + terminal.getClass().getSimpleName());
        if (terminal instanceof AbstractPosixTerminal) {
            Log.debug(() -> "Using pty " + ((AbstractPosixTerminal) terminal).getPty().getClass().getSimpleName());
        }
        return terminal;
    }

    private Terminal doBuild() throws IOException {
        String name = this.name;
        if (name == null) {
            name = "JLine terminal";
        }
        Charset encoding = this.encoding;
        if (encoding == null) {
            String charsetName = System.getProperty(PROP_ENCODING);
            if (charsetName != null && Charset.isSupported(charsetName)) {
                encoding = Charset.forName(charsetName);
            }
        }
        int codepage = this.codepage;
        if (codepage <= 0) {
            String str = System.getProperty(PROP_CODEPAGE);
            if (str != null) {
                codepage = Integer.parseInt(str);
            }
        }
        String type = this.type;
        if (type == null) {
            type = System.getProperty(PROP_TYPE);
        }
        if (type == null) {
            type = System.getenv("TERM");
        }
        Boolean jna = this.jna;
        if (jna == null) {
            jna = getBoolean(PROP_JNA, true);
        }
        Boolean jansi = this.jansi;
        if (jansi == null) {
            jansi = getBoolean(PROP_JANSI, true);
        }
        Boolean exec = this.exec;
        if (exec == null) {
            exec = getBoolean(PROP_EXEC, true);
        }
        Boolean dumb = this.dumb;
        if (dumb == null) {
            dumb = getBoolean(PROP_DUMB, null);
        }
        if ((system != null && system) || (system == null && in == null && out == null)) {
            if (attributes != null || size != null) {
                Log.warn("Attributes and size fields are ignored when creating a system terminal");
            }
            IllegalStateException exception = new IllegalStateException("Unable to create a system terminal");
            if (OSUtils.IS_WINDOWS) {
                boolean cygwinTerm = "cygwin".equals(System.getenv("TERM"));
                boolean ansiPassThrough = OSUtils.IS_CONEMU;
                //
                // Cygwin support
                //
                if ((OSUtils.IS_CYGWIN || OSUtils.IS_MSYSTEM) && exec && !cygwinTerm) {
                    try {
                        Pty pty = ExecPty.current();
                        // Cygwin defaults to XTERM, but actually supports 256 colors,
                        // so if the value comes from the environment, change it to xterm-256color
                        if ("xterm".equals(type) && this.type == null && System.getProperty(PROP_TYPE) == null) {
                            type = "xterm-256color";
                        }
                        return new PosixSysTerminal(name, type, pty, inputStreamWrapper.apply(pty.getSlaveInput()), pty.getSlaveOutput(), encoding, nativeSignals, signalHandler);
                    } catch (IOException e) {
                        // Ignore if not a tty
                        Log.debug("Error creating EXEC based terminal: ", e.getMessage(), e);
                        exception.addSuppressed(e);
                    }
                }
                if (jna) {
                    try {
                        return load(JnaSupport.class).winSysTerminal(name, type, ansiPassThrough, encoding, codepage, nativeSignals, signalHandler, paused, inputStreamWrapper);
                    } catch (Throwable t) {
                        Log.debug("Error creating JNA based terminal: ", t.getMessage(), t);
                        exception.addSuppressed(t);
                    }
                }
                if (jansi) {
                    try {
                        return load(JansiSupport.class).winSysTerminal(name, type, ansiPassThrough, encoding, codepage, nativeSignals, signalHandler, paused);
                    } catch (Throwable t) {
                        Log.debug("Error creating JANSI based terminal: ", t.getMessage(), t);
                        exception.addSuppressed(t);
                    }
                }
            } else {
                if (jna) {
                    try {
                        Pty pty = load(JnaSupport.class).current();
                        return new PosixSysTerminal(name, type, pty, inputStreamWrapper.apply(pty.getSlaveInput()), pty.getSlaveOutput(), encoding, nativeSignals, signalHandler);
                    } catch (Throwable t) {
                        // ignore
                        Log.debug("Error creating JNA based terminal: ", t.getMessage(), t);
                        exception.addSuppressed(t);
                    }
                }
                if (jansi) {
                    try {
                        Pty pty = load(JansiSupport.class).current();
                        return new PosixSysTerminal(name, type, pty, inputStreamWrapper.apply(pty.getSlaveInput()), pty.getSlaveOutput(), encoding, nativeSignals, signalHandler);
                    } catch (Throwable t) {
                        Log.debug("Error creating JANSI based terminal: ", t.getMessage(), t);
                        exception.addSuppressed(t);
                    }
                }
                if (exec) {
                    try {
                        Pty pty = ExecPty.current();
                        return new PosixSysTerminal(name, type, pty, inputStreamWrapper.apply(pty.getSlaveInput()), pty.getSlaveOutput(), encoding, nativeSignals, signalHandler);
                    } catch (Throwable t) {
                        // Ignore if not a tty
                        Log.debug("Error creating EXEC based terminal: ", t.getMessage(), t);
                        exception.addSuppressed(t);
                    }
                }
            }
            if (dumb == null || dumb) {
                // forced colored dumb terminal
                boolean color = getBoolean(PROP_DUMB_COLOR, false);
                // detect emacs using the env variable
                if (!color) {
                    color = System.getenv("INSIDE_EMACS") != null;
                }
                // detect Intellij Idea
                if (!color) {
                    String command = getParentProcessCommand();
                    color = command != null && command.contains("idea");
                }
                if (!color && dumb == null) {
                    if (Log.isDebugEnabled()) {
                        Log.warn("Creating a dumb terminal", exception);
                    } else {
                        Log.warn("Unable to create a system terminal, creating a dumb terminal (enable debug logging for more information)");
                    }
                }
                return new DumbTerminal(name, color ? Terminal.TYPE_DUMB_COLOR : Terminal.TYPE_DUMB,
                        new FileInputStream(FileDescriptor.in),
                        new FileOutputStream(FileDescriptor.out),
                        encoding, signalHandler);
            } else {
                throw exception;
            }
        } else {
            if (jna) {
                try {
                    Pty pty = load(JnaSupport.class).open(attributes, size);
                    return new PosixPtyTerminal(name, type, pty, in, out, encoding, signalHandler, paused);
                } catch (Throwable t) {
                    Log.debug("Error creating JNA based terminal: ", t.getMessage(), t);
                }
            }
            if (jansi) {
                try {
                    Pty pty = load(JansiSupport.class).open(attributes, size);
                    return new PosixPtyTerminal(name, type, pty, in, out, encoding, signalHandler, paused);
                } catch (Throwable t) {
                    Log.debug("Error creating JANSI based terminal: ", t.getMessage(), t);
                }
            }
            Terminal terminal = new ExternalTerminal(name, type, in, out, encoding, signalHandler, paused);
            if (attributes != null) {
                terminal.setAttributes(attributes);
            }
            if (size != null) {
                terminal.setSize(size);
            }
            return terminal;
        }
    }

    private static String getParentProcessCommand() {
        try {
            Class<?> phClass = Class.forName("java.lang.ProcessHandle");
            Object current = phClass.getMethod("current").invoke(null);
            Object parent = ((Optional<?>) phClass.getMethod("parent").invoke(current)).orElse(null);
            Method infoMethod = phClass.getMethod("info");
            Object info = infoMethod.invoke(parent);
            Object command = ((Optional<?>) infoMethod.getReturnType().getMethod("command").invoke(info)).orElse(null);
            return (String) command;
        } catch (Throwable t) {
            return null;
        }
    }

    private static Boolean getBoolean(String name, Boolean def) {
        try {
            String str = System.getProperty(name);
            if (str != null) {
                return Boolean.parseBoolean(str);
            }
        } catch (IllegalArgumentException | NullPointerException e) {
        }
        return def;
    }

    private <S> S load(Class<S> clazz) {
        return ServiceLoader.load(clazz, clazz.getClassLoader()).iterator().next();
    }
}