""" A minimal application using the Qt console-style IPython frontend.
"""

#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------

# Systemm library imports
from PyQt4 import QtGui

# Local imports
from IPython.external.argparse import ArgumentParser
from IPython.frontend.qt.console.frontend_widget import FrontendWidget
from IPython.frontend.qt.console.ipython_widget import IPythonWidget
from IPython.frontend.qt.console.rich_ipython_widget import RichIPythonWidget
from IPython.frontend.qt.kernelmanager import QtKernelManager

#-----------------------------------------------------------------------------
# Constants
#-----------------------------------------------------------------------------

LOCALHOST = '127.0.0.1'

#-----------------------------------------------------------------------------
# Classes
#-----------------------------------------------------------------------------

class MainWindow(QtGui.QMainWindow):

    #---------------------------------------------------------------------------
    # 'object' interface
    #---------------------------------------------------------------------------
    
    def __init__(self, app, frontend, existing=False):
        """ Create a MainWindow for the specified FrontendWidget.
        
        The app is passed as an argument to allow for different
        closing behavior depending on whether we are the Kernel's parent.
        
        If existing is True, then this Window does not own the Kernel.
        """
        super(MainWindow, self).__init__()
        self._app = app
        self._frontend = frontend
        self._existing = existing
        self._frontend.exit_requested.connect(self.close)
        self.setCentralWidget(frontend)
    
    #---------------------------------------------------------------------------
    # QWidget interface
    #---------------------------------------------------------------------------
    
    def closeEvent(self, event):
        """ Reimplemented to prompt the user and close the kernel cleanly.
        """
        kernel_manager = self._frontend.kernel_manager
        if kernel_manager and kernel_manager.channels_running:
            title = self.window().windowTitle()
            reply = QtGui.QMessageBox.question(self, title,
                "Close just this console, or shutdown the kernel and close "+
                "all windows attached to it?", 
                'Cancel', 'Close Console', 'Close All')
            if reply == 2: # close All
                kernel_manager.shutdown_kernel()
                #kernel_manager.stop_channels()
                event.accept()
            elif reply == 1: # close Console
                if not self._existing:
                    # I have the kernel: don't quit, just close the window
                    self._app.setQuitOnLastWindowClosed(False)
                event.accept()
            else:
                event.ignore()

#-----------------------------------------------------------------------------
# Main entry point
#-----------------------------------------------------------------------------

def main():
    """ Entry point for application.
    """
    # Parse command line arguments.
    parser = ArgumentParser()
    kgroup = parser.add_argument_group('kernel options')
    kgroup.add_argument('-e', '--existing', action='store_true',
                        help='connect to an existing kernel')
    kgroup.add_argument('--ip', type=str, default=LOCALHOST,
                        help='set the kernel\'s IP address [default localhost]')
    kgroup.add_argument('--xreq', type=int, metavar='PORT', default=0,
                        help='set the XREQ channel port [default random]')
    kgroup.add_argument('--sub', type=int, metavar='PORT', default=0,
                        help='set the SUB channel port [default random]')
    kgroup.add_argument('--rep', type=int, metavar='PORT', default=0,
                        help='set the REP channel port [default random]')
    kgroup.add_argument('--hb', type=int, metavar='PORT', default=0,
                        help='set the heartbeat port [default: random]')

    egroup = kgroup.add_mutually_exclusive_group()
    egroup.add_argument('--pure', action='store_true', help = \
                        'use a pure Python kernel instead of an IPython kernel')
    egroup.add_argument('--pylab', type=str, metavar='GUI', nargs='?', 
                       const='auto', help = \
        "Pre-load matplotlib and numpy for interactive use. If GUI is not \
         given, the GUI backend is matplotlib's, otherwise use one of: \
         ['tk', 'gtk', 'qt', 'wx', 'inline'].")

    wgroup = parser.add_argument_group('widget options')
    wgroup.add_argument('--paging', type=str, default='inside',
                        choices = ['inside', 'hsplit', 'vsplit', 'none'],
                        help='set the paging style [default inside]')
    wgroup.add_argument('--rich', action='store_true',
                        help='enable rich text support')
    wgroup.add_argument('--gui-completion', action='store_true',
                        help='use a GUI widget for tab completion')

    args = parser.parse_args()

    # Don't let Qt or ZMQ swallow KeyboardInterupts.
    import signal
    signal.signal(signal.SIGINT, signal.SIG_DFL)

    # Create a KernelManager and start a kernel.
    kernel_manager = QtKernelManager(xreq_address=(args.ip, args.xreq),
                                     sub_address=(args.ip, args.sub),
                                     rep_address=(args.ip, args.rep),
                                     hb_address=(args.ip, args.hb))
    if args.ip == LOCALHOST and not args.existing:
        if args.pure:
            kernel_manager.start_kernel(ipython=False)
        elif args.pylab:
            kernel_manager.start_kernel(pylab=args.pylab)
        else:
            kernel_manager.start_kernel()
    kernel_manager.start_channels()

    # Create the widget.
    app = QtGui.QApplication([])
    if args.pure:
        kind = 'rich' if args.rich else 'plain'
        widget = FrontendWidget(kind=kind, paging=args.paging)
    elif args.rich or args.pylab:
        widget = RichIPythonWidget(paging=args.paging)
    else:
        widget = IPythonWidget(paging=args.paging)
    widget.gui_completion = args.gui_completion
    widget.kernel_manager = kernel_manager

    # Create the main window.
    window = MainWindow(app, widget, args.existing)
    window.setWindowTitle('Python' if args.pure else 'IPython')
    window.show()

    # Start the application main loop.
    app.exec_()


if __name__ == '__main__':
    main()