from gi.repository import Gtk

from gi.repository import Gdk

from gi.repository import Gio

from gi.repository import GObject

import sys

class MyWindow(Gtk.ApplicationWindow):

    def __init__(self, app):

        Gtk.Window.__init__(

            self, title="FileChooserDialog Example", application=app)

        self.set_default_size(400, 400)

        # the actions for the window menu, connected to the callback functions

        new_action = Gio.SimpleAction.new("new", None)

        new_action.connect("activate", self.new_callback)

        self.add_action(new_action)

        open_action = Gio.SimpleAction.new("open", None)

        open_action.connect("activate", self.open_callback)

        self.add_action(open_action)

        save_action = Gio.SimpleAction.new("save", None)

        save_action.connect("activate", self.save_callback)

        self.add_action(save_action)

        save_as_action = Gio.SimpleAction.new("save-as", None)

        save_as_action.connect("activate", self.save_as_callback)

        self.add_action(save_as_action)

        # the file

        self.file = None

        # the textview with the buffer

        self.buffer = Gtk.TextBuffer()

        textview = Gtk.TextView(buffer=self.buffer)

        textview.set_wrap_mode(Gtk.WrapMode.WORD)

        # a scrolled window for the textview

        self.scrolled_window = Gtk.ScrolledWindow()

        self.scrolled_window.set_policy(

            Gtk.PolicyType.AUTOMATIC, Gtk.PolicyType.AUTOMATIC)

        self.scrolled_window.add(textview)

        self.scrolled_window.set_border_width(5)

        # add the scrolled window to the window

        self.add(self.scrolled_window)

    # callback for new

    def new_callback(self, action, parameter):

        self.buffer.set_text("")

        print("New file created")

    # callback for open

    def open_callback(self, action, parameter):

        # create a filechooserdialog to open:

        # the arguments are: title of the window, parent_window, action,

        # (buttons, response)

        open_dialog = Gtk.FileChooserDialog("Pick a file", self,

                                            Gtk.FileChooserAction.OPEN,

                                           (Gtk.STOCK_CANCEL, Gtk.ResponseType.CANCEL,

                                            Gtk.STOCK_OPEN, Gtk.ResponseType.ACCEPT))

        # not only local files can be selected in the file selector

        open_dialog.set_local_only(False)

        # dialog always on top of the textview window

        open_dialog.set_modal(True)

        # connect the dialog with the callback function open_response_cb()

        open_dialog.connect("response", self.open_response_cb)

        # show the dialog

        open_dialog.show()

    # callback function for the dialog open_dialog

    def open_response_cb(self, dialog, response_id):

        open_dialog = dialog

        # if response is "ACCEPT" (the button "Open" has been clicked)

        if response_id == Gtk.ResponseType.ACCEPT:

            # self.file is the file that we get from the FileChooserDialog

            self.file = open_dialog.get_file()

            # an empty string (provisionally)

            content = ""

            try:

                # load the content of the file into memory:

                # success is a boolean depending on the success of the operation

                # content is self-explanatory

                # etags is an entity tag (can be used to quickly determine if the

                # file has been modified from the version on the file system)

                [success, content, etags] = self.file.load_contents(None)

            except GObject.GError as e:

                print("Error: " + e.message)

            # set the content as the text into the buffer

            self.buffer.set_text(content, len(content))

            print("opened: " + open_dialog.get_filename())

        # if response is "CANCEL" (the button "Cancel" has been clicked)

        elif response_id == Gtk.ResponseType.CANCEL:

            print("cancelled: FileChooserAction.OPEN")

        # destroy the FileChooserDialog

        dialog.destroy()

    # callback function for save_as

    def save_as_callback(self, action, parameter):

        # create a filechooserdialog to save:

        # the arguments are: title of the window, parent_window, action,

        # (buttons, response)

        save_dialog = Gtk.FileChooserDialog("Pick a file", self,

                                            Gtk.FileChooserAction.SAVE,

                                           (Gtk.STOCK_CANCEL, Gtk.ResponseType.CANCEL,

                                            Gtk.STOCK_SAVE, Gtk.ResponseType.ACCEPT))

        # the dialog will present a confirmation dialog if the user types a file name that

        # already exists

        save_dialog.set_do_overwrite_confirmation(True)

        # dialog always on top of the textview window

        save_dialog.set_modal(True)

        # if self.file has already been saved

        if self.file is not None:

            try:

                # set self.file as the current filename for the file chooser

                save_dialog.set_file(self.file)

            except GObject.GError as e:

                print("Error: " + e.message)

        # connect the dialog to the callback function save_response_cb()

        save_dialog.connect("response", self.save_response_cb)

        # show the dialog

        save_dialog.show()

    # callback function for the dialog save_dialog

    def save_response_cb(self, dialog, response_id):

        save_dialog = dialog

        # if response is "ACCEPT" (the button "Save" has been clicked)

        if response_id == Gtk.ResponseType.ACCEPT:

            # self.file is the currently selected file

            self.file = save_dialog.get_file()

            # save to file (see below)

            self.save_to_file()

        # if response is "CANCEL" (the button "Cancel" has been clicked)

        elif response_id == Gtk.ResponseType.CANCEL:

            print("cancelled: FileChooserAction.SAVE")

        # destroy the FileChooserDialog

        dialog.destroy()

    # callback function for save

    def save_callback(self, action, parameter):

        # if self.file is not already there

        if self.file is not None:

            self.save_to_file()

        # self.file is a new file

        else:

            # use save_as

            self.save_as_callback(action, parameter)

    # save_to_file

    def save_to_file(self):

        # get the content of the buffer, without hidden characters

        [start, end] = self.buffer.get_bounds()

        current_contents = self.buffer.get_text(start, end, False)

        # if there is some content

        if current_contents != "":

            # set the content as content of self.file.

            # arguments: contents, etags, make_backup, flags, GError

            try:

                self.file.replace_contents(current_contents,

                                           None,

                                           False,

                                           Gio.FileCreateFlags.NONE,

                                           None)

                print("saved: " + self.file.get_path())

            except GObject.GError as e:

                print("Error: " + e.message)

        # if the contents are empty

        else:

            # create (if the file does not exist) or overwrite the file in readwrite mode.

            # arguments: etags, make_backup, flags, GError

            try:

                self.file.replace_readwrite(None,

                                            False,

                                            Gio.FileCreateFlags.NONE,

                                            None)

                print("saved: " + self.file.get_path())

            except GObject.GError as e:

                print("Error: " + e.message)

class MyApplication(Gtk.Application):

    def __init__(self):

        Gtk.Application.__init__(self)

    def do_activate(self):

        win = MyWindow(self)

        win.show_all()

    def do_startup(self):

        Gtk.Application.do_startup(self)

        # app action quit, connected to the callback function

        quit_action = Gio.SimpleAction.new("quit", None)

        quit_action.connect("activate", self.quit_callback)

        self.add_action(quit_action)

        # get the menu from the ui file with a builder

        builder = Gtk.Builder()

        try:

            builder.add_from_file("filechooserdialog.ui")

        except:

            print("file not found")

            sys.exit()

        menu = builder.get_object("appmenu")

        self.set_app_menu(menu)

    # callback function for quit

    def quit_callback(self, action, parameter):

        self.quit()

app = MyApplication()

exit_status = app.run(sys.argv)

sys.exit(exit_status)