#
# Copyright (C) 2006, 2013 Red Hat, Inc.
# Copyright (C) 2006 Daniel P. Berrange <berrange@redhat.com>
#
# 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.
#

import os
import termios
import tty
import pty
import fcntl
import logging

from gi.repository import Gdk
from gi.repository import GLib
from gi.repository import Gtk
from gi.repository import Vte

import libvirt

from .baseclass import vmmGObject


class ConsoleConnection(vmmGObject):
    def __init__(self, vm):
        vmmGObject.__init__(self)

        self.vm = vm
        self.conn = vm.conn

    def _cleanup(self):
        self.close()

        self.vm = None
        self.conn = None

    def is_open(self):
        raise NotImplementedError()
    def open(self, dev, terminal):
        raise NotImplementedError()
    def close(self):
        raise NotImplementedError()

    def send_data(self, src, text, length, terminal):
        """
        Callback when data has been entered into VTE terminal
        """
        raise NotImplementedError()


class LocalConsoleConnection(ConsoleConnection):
    def __init__(self, vm):
        ConsoleConnection.__init__(self, vm)

        self.fd = None
        self.source = None
        self.origtermios = None

    def is_open(self):
        return self.fd is not None

    def open(self, dev, terminal):
        if self.fd is not None:
            self.close()

        ipty = dev and dev.source_path or None
        logging.debug("Opening serial tty path: %s", ipty)
        if ipty is None:
            return

        self.fd = pty.slave_open(ipty)
        fcntl.fcntl(self.fd, fcntl.F_SETFL, os.O_NONBLOCK)
        self.source = GLib.io_add_watch(self.fd,
                            GLib.IO_IN | GLib.IO_ERR | GLib.IO_HUP,
                            self.display_data, terminal)

        # Save term settings & set to raw mode
        self.origtermios = termios.tcgetattr(self.fd)
        tty.setraw(self.fd, termios.TCSANOW)

    def close(self):
        if self.fd is None:
            return

        # Restore term settings
        try:
            if self.origtermios:
                termios.tcsetattr(self.fd, termios.TCSANOW, self.origtermios)
        except:
            # domain may already have exited, destroying the pty, so ignore
            pass

        os.close(self.fd)
        self.fd = None

        GLib.source_remove(self.source)
        self.source = None
        self.origtermios = None

    def send_data(self, src, text, length, terminal):
        ignore = src
        ignore = length
        ignore = terminal

        if self.fd is None:
            return

        os.write(self.fd, text)

    def display_data(self, src, cond, terminal):
        ignore = src

        if cond != GLib.IO_IN:
            self.close()
            return False

        data = os.read(self.fd, 1024)
        terminal.feed(data)
        return True


class LibvirtConsoleConnection(ConsoleConnection):
    def __init__(self, vm):
        ConsoleConnection.__init__(self, vm)

        self.stream = None

        self.streamToTerminal = ""
        self.terminalToStream = ""

    def _event_on_stream(self, stream, events, opaque):
        ignore = stream
        terminal = opaque

        if (events & libvirt.VIR_EVENT_HANDLE_ERROR or
            events & libvirt.VIR_EVENT_HANDLE_HANGUP):
            logging.debug("Received stream ERROR/HANGUP, closing console")
            self.close()
            return

        if events & libvirt.VIR_EVENT_HANDLE_READABLE:
            try:
                got = self.stream.recv(1024 * 100)
            except:
                logging.exception("Error receiving stream data")
                self.close()
                return

            if got == -2:
                # This is basically EAGAIN
                return
            if len(got) == 0:
                logging.debug("Received EOF from stream, closing")
                self.close()
                return

            queued_text = bool(self.streamToTerminal)
            self.streamToTerminal += got
            if not queued_text:
                self.idle_add(self.display_data, terminal)

        if (events & libvirt.VIR_EVENT_HANDLE_WRITABLE and
            self.terminalToStream):

            try:
                done = self.stream.send(self.terminalToStream)
            except:
                logging.exception("Error sending stream data")
                self.close()
                return

            if done == -2:
                # This is basically EAGAIN
                return

            self.terminalToStream = self.terminalToStream[done:]

        if not self.terminalToStream:
            self.stream.eventUpdateCallback(libvirt.VIR_STREAM_EVENT_READABLE |
                                            libvirt.VIR_STREAM_EVENT_ERROR |
                                            libvirt.VIR_STREAM_EVENT_HANGUP)


    def is_open(self):
        return self.stream is not None

    def open(self, dev, terminal):
        if self.stream:
            self.close()

        name = dev and dev.alias.name or None
        logging.debug("Opening console stream for dev=%s alias=%s",
                      dev, name)
        if not name:
            raise RuntimeError(_("Cannot open a device with no alias name"))

        stream = self.conn.get_backend().newStream(libvirt.VIR_STREAM_NONBLOCK)
        self.vm.open_console(name, stream)
        self.stream = stream

        self.stream.eventAddCallback((libvirt.VIR_STREAM_EVENT_READABLE |
                                      libvirt.VIR_STREAM_EVENT_ERROR |
                                      libvirt.VIR_STREAM_EVENT_HANGUP),
                                     self._event_on_stream,
                                     terminal)

    def close(self):
        if self.stream:
            try:
                self.stream.eventRemoveCallback()
            except:
                logging.exception("Error removing stream callback")
            try:
                self.stream.finish()
            except:
                logging.exception("Error finishing stream")

        self.stream = None

    def send_data(self, src, text, length, terminal):
        ignore = src
        ignore = length
        ignore = terminal

        if self.stream is None:
            return

        self.terminalToStream += text
        if self.terminalToStream:
            self.stream.eventUpdateCallback(libvirt.VIR_STREAM_EVENT_READABLE |
                                            libvirt.VIR_STREAM_EVENT_WRITABLE |
                                            libvirt.VIR_STREAM_EVENT_ERROR |
                                            libvirt.VIR_STREAM_EVENT_HANGUP)

    def display_data(self, terminal):
        if not self.streamToTerminal:
            return

        terminal.feed(self.streamToTerminal)
        self.streamToTerminal = ""


class vmmSerialConsole(vmmGObject):
    @staticmethod
    def support_remote_console(vm):
        """
        Check if we can connect to a remote console
        """
        return bool(vm.remote_console_supported)

    @staticmethod
    def can_connect(vm, dev):
        """
        Check if we think we can actually open passed console/serial dev
        """
        usable_types = ["pty"]

        ctype = dev.type
        path = dev.source_path
        is_remote = vm.conn.is_remote()
        support_tunnel = vmmSerialConsole.support_remote_console(vm)

        err = ""

        if is_remote:
            if not support_tunnel:
                err = _("Serial console not yet supported over remote "
                        "connection")
        elif not vm.is_active():
            err = _("Serial console not available for inactive guest")
        elif ctype not in usable_types:
            err = (_("Console for device type '%s' not yet supported") %
                     ctype)
        elif (not is_remote and
              not support_tunnel and
              (path and not os.access(path, os.R_OK | os.W_OK))):
            err = _("Can not access console path '%s'") % str(path)

        return err

    def __init__(self, vm, target_port, name):
        vmmGObject.__init__(self)

        self.vm = vm
        self.target_port = target_port
        self.name = name
        self.lastpath = None

        # Always use libvirt console streaming if available, so
        # we exercise the same code path (it's what virsh console does)
        if vmmSerialConsole.support_remote_console(self.vm):
            self.console = LibvirtConsoleConnection(self.vm)
        else:
            self.console = LocalConsoleConnection(self.vm)

        self.serial_popup = None
        self.serial_copy = None
        self.serial_paste = None
        self.serial_close = None
        self.init_popup()

        self.terminal = None
        self.init_terminal()

        self.box = None
        self.error_label = None
        self.init_ui()

        self.vm.connect("status-changed", self.vm_status_changed)

    def init_terminal(self):
        self.terminal = Vte.Terminal()
        self.terminal.set_scrollback_lines(1000)
        self.terminal.set_audible_bell(False)

        self.terminal.connect("button-press-event", self.show_serial_rcpopup)
        self.terminal.connect("commit", self.console.send_data, self.terminal)
        self.terminal.show()

    def init_popup(self):
        self.serial_popup = Gtk.Menu()

        self.serial_copy = Gtk.ImageMenuItem.new_from_stock(Gtk.STOCK_COPY,
                                                            None)
        self.serial_copy.connect("activate", self.serial_copy_text)
        self.serial_popup.add(self.serial_copy)

        self.serial_paste = Gtk.ImageMenuItem.new_from_stock(Gtk.STOCK_PASTE,
                                                             None)
        self.serial_paste.connect("activate", self.serial_paste_text)
        self.serial_popup.add(self.serial_paste)

    def init_ui(self):
        self.box = Gtk.Notebook()
        self.box.set_show_tabs(False)
        self.box.set_show_border(False)

        align = Gtk.Alignment()
        align.set_padding(2, 2, 2, 2)
        evbox = Gtk.EventBox()
        evbox.modify_bg(Gtk.StateType.NORMAL, Gdk.Color(0, 0, 0))
        terminalbox = Gtk.HBox()
        scrollbar = Gtk.VScrollbar()
        self.error_label = Gtk.Label()
        self.error_label.set_width_chars(40)
        self.error_label.set_line_wrap(True)

        if self.terminal:
            scrollbar.set_adjustment(self.terminal.get_vadjustment())
            align.add(self.terminal)

        evbox.add(align)
        terminalbox.pack_start(evbox, True, True, 0)
        terminalbox.pack_start(scrollbar, False, False, 0)

        self.box.append_page(terminalbox, Gtk.Label(""))
        self.box.append_page(self.error_label, Gtk.Label(""))
        self.box.show_all()

        scrollbar.hide()
        scrollbar.get_adjustment().connect(
            "changed", self._scrollbar_adjustment_changed, scrollbar)

    def _scrollbar_adjustment_changed(self, adjustment, scrollbar):
        scrollbar.set_visible(
            adjustment.get_upper() > adjustment.get_page_size())

    def _cleanup(self):
        self.console.cleanup()
        self.console = None

        self.vm = None
        self.terminal = None
        self.box = None

    def close(self):
        if self.console:
            self.console.close()

    def show_error(self, msg):
        self.error_label.set_markup("<b>%s</b>" % msg)
        self.box.set_current_page(1)

    def open_console(self):
        try:
            if not self.console.is_open():
                self.console.open(self.lookup_dev(), self.terminal)
            self.box.set_current_page(0)
            return True
        except Exception, e:
            logging.exception("Error opening serial console")
            self.show_error(_("Error connecting to text console: %s") % e)
            try:
                self.console.close()
            except:
                pass

        return False

    def vm_status_changed(self, src_ignore, oldstatus_ignore, status):
        if status in [libvirt.VIR_DOMAIN_RUNNING]:
            self.open_console()
        else:
            self.console.close()

    def lookup_dev(self):
        devs = self.vm.get_serial_devs()
        for dev in devs:
            port = dev.vmmindex
            path = dev.source_path

            if port == self.target_port:
                if path != self.lastpath:
                    logging.debug("Serial console '%s' path changed to %s",
                                  self.target_port, path)
                self.lastpath = path
                return dev

        logging.debug("No devices found for serial target port '%s'",
                      self.target_port)
        self.lastpath = None
        return None

    #######################
    # Popup menu handling #
    #######################

    def show_serial_rcpopup(self, src, event):
        if event.button != 3:
            return

        self.serial_popup.show_all()

        if src.get_has_selection():
            self.serial_copy.set_sensitive(True)
        else:
            self.serial_copy.set_sensitive(False)
        self.serial_popup.popup(None, None, None, None, 0, event.time)

    def serial_copy_text(self, src_ignore):
        self.terminal.copy_clipboard()

    def serial_paste_text(self, src_ignore):
        self.terminal.paste_clipboard()
