# Copyright (C) 2002-2006 Stephen Kennedy <stevek@gnome.org>
# Copyright (C) 2010-2013 Kai Willadsen <kai.willadsen@gmail.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, see <http://www.gnu.org/licenses/>.

import io
import logging
import optparse
import os

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

import meld.conf
import meld.preferences
import meld.ui.util
from meld.conf import _
from meld.filediff import FileDiff
from meld.meldwindow import MeldWindow

log = logging.getLogger(__name__)

# Monkeypatching optparse like this is obviously awful, but this is to
# handle Unicode translated strings within optparse itself that will
# otherwise crash badly. This just makes optparse use our ugettext
# import of _, rather than the non-unicode gettext.
optparse._ = _


class MeldApp(Gtk.Application):

    def __init__(self):
        super().__init__(
          application_id=meld.conf.APPLICATION_ID,
          flags=Gio.ApplicationFlags.HANDLES_COMMAND_LINE,
        )
        GLib.set_application_name("Meld")
        GLib.set_prgname(meld.conf.APPLICATION_ID)
        Gtk.Window.set_default_icon_name("meld")

    def do_startup(self):
        Gtk.Application.do_startup(self)

        actions = (
            ("preferences", self.preferences_callback),
            ("help", self.help_callback),
            ("about", self.about_callback),
            ("quit", self.quit_callback),
        )
        for (name, callback) in actions:
            action = Gio.SimpleAction.new(name, None)
            action.connect('activate', callback)
            self.add_action(action)

        # Keep clipboard contents after application exit
        clip = Gtk.Clipboard.get_default(Gdk.Display.get_default())
        clip.set_can_store(None)

        # TODO: Should not be necessary but Builder doesn't understand Menus
        builder = meld.ui.util.get_builder("application.ui")
        menu = builder.get_object("app-menu")
        self.set_app_menu(menu)
        # self.set_menubar()
        self.new_window()

    def do_activate(self):
        self.get_active_window().present()

    def do_command_line(self, command_line):
        tab = self.parse_args(command_line)

        if isinstance(tab, int):
            return tab
        elif tab:

            def done(tab, status):
                self.release()
                tab.command_line.set_exit_status(status)
                tab.command_line = None

            self.hold()
            tab.command_line = command_line
            tab.connect('close', done)

        window = self.get_active_window().meldwindow
        if not window.has_pages():
            window.append_new_comparison()
        self.activate()
        return 0

    def do_window_removed(self, widget):
        widget.meldwindow = None
        Gtk.Application.do_window_removed(self, widget)
        if not len(self.get_windows()):
            self.quit()

    # We can't override do_local_command_line because it has no introspection
    # annotations: https://bugzilla.gnome.org/show_bug.cgi?id=687912

    # def do_local_command_line(self, command_line):
    #     return False

    def preferences_callback(self, action, parameter):
        meld.preferences.PreferencesDialog(self.get_active_window())

    def help_callback(self, action, parameter):
        if meld.conf.DATADIR_IS_UNINSTALLED:
            uri = "http://meldmerge.org/help/"
        else:
            uri = "help:meld"
        Gtk.show_uri(
            Gdk.Screen.get_default(), uri, Gtk.get_current_event_time())

    def about_callback(self, action, parameter):
        about = meld.ui.util.get_widget("application.ui", "aboutdialog")
        about.set_version(meld.conf.__version__)
        about.set_transient_for(self.get_active_window())
        about.run()
        about.destroy()

    def quit_callback(self, action, parameter):
        for window in self.get_windows():
            cancelled = window.emit(
                "delete-event", Gdk.Event.new(Gdk.EventType.DELETE))
            if cancelled:
                return
            window.destroy()
        self.quit()

    def new_window(self):
        window = MeldWindow()
        self.add_window(window.widget)
        window.widget.meldwindow = window
        return window

    def get_meld_window(self):
        return self.get_active_window().meldwindow

    def open_files(
            self, gfiles, *, window=None, close_on_error=False, **kwargs):
        """Open a comparison between files in a Meld window

        :param gfiles: list of Gio.File to be compared
        :param window: window in which to open comparison tabs; if
            None, the current window is used
        :param close_on_error: if true, close window if an error occurs
        """
        window = window or self.get_meld_window()
        try:
            return window.open_paths(gfiles, **kwargs)
        except ValueError:
            if close_on_error:
                self.remove_window(window.widget)
            raise

    def diff_files_callback(self, option, opt_str, value, parser):
        """Gather --diff arguments and append to a list"""
        assert value is None
        diff_files_args = []
        while parser.rargs:
            # Stop if we find a short- or long-form arg, or a '--'
            # Note that this doesn't handle negative numbers.
            arg = parser.rargs[0]
            if arg[:2] == "--" or (arg[:1] == "-" and len(arg) > 1):
                break
            else:
                diff_files_args.append(arg)
                del parser.rargs[0]

        if len(diff_files_args) not in (1, 2, 3):
            raise optparse.OptionValueError(
                _("wrong number of arguments supplied to --diff"))
        parser.values.diff.append(diff_files_args)

    def parse_args(self, command_line):
        usages = [
            ("", _("Start with an empty window")),
            ("<%s|%s>" % (_("file"), _("folder")),
             _("Start a version control comparison")),
            ("<%s> <%s> [<%s>]" % ((_("file"),) * 3),
             _("Start a 2- or 3-way file comparison")),
            ("<%s> <%s> [<%s>]" % ((_("folder"),) * 3),
             _("Start a 2- or 3-way folder comparison")),
        ]
        pad_args_fmt = "%-" + str(max([len(s[0]) for s in usages])) + "s %s"
        usage_lines = ["  %prog " + pad_args_fmt % u for u in usages]
        usage = "\n" + "\n".join(usage_lines)

        class GLibFriendlyOptionParser(optparse.OptionParser):

            def __init__(self, command_line, *args, **kwargs):
                self.command_line = command_line
                self.should_exit = False
                self.output = io.StringIO()
                self.exit_status = 0
                super().__init__(*args, **kwargs)

            def exit(self, status=0, msg=None):
                self.should_exit = True
                # FIXME: This is... let's say... an unsupported method. Let's
                # be circumspect about the likelihood of this working.
                try:
                    self.command_line.do_print_literal(
                        self.command_line, self.output.getvalue())
                except Exception:
                    print(self.output.getvalue())
                self.exit_status = status

            def print_usage(self, file=None):
                if self.usage:
                    print(self.get_usage(), file=self.output)

            def print_version(self, file=None):
                if self.version:
                    print(self.get_version(), file=self.output)

            def print_help(self, file=None):
                print(self.format_help(), file=self.output)

            def error(self, msg):
                self.local_error(msg)
                raise ValueError()

            def local_error(self, msg):
                self.print_usage()
                error_string = _("Error: %s\n") % msg
                print(error_string, file=self.output)
                self.exit(2)

        parser = GLibFriendlyOptionParser(
            command_line=command_line,
            usage=usage,
            description=_("Meld is a file and directory comparison tool."),
            version="%prog " + meld.conf.__version__)
        parser.add_option(
            "-L", "--label", action="append", default=[],
            help=_("Set label to use instead of file name"))
        parser.add_option(
            "-n", "--newtab", action="store_true", default=False,
            help=_("Open a new tab in an already running instance"))
        parser.add_option(
            "-a", "--auto-compare", action="store_true", default=False,
            help=_("Automatically compare all differing files on startup"))
        parser.add_option(
            "-u", "--unified", action="store_true",
            help=_("Ignored for compatibility"))
        parser.add_option(
            "-o", "--output", action="store", type="string",
            dest="outfile", default=None,
            help=_("Set the target file for saving a merge result"))
        parser.add_option(
            "--auto-merge", None, action="store_true", default=False,
            help=_("Automatically merge files"))
        parser.add_option(
            "", "--comparison-file", action="store", type="string",
            dest="comparison_file", default=None,
            help=_("Load a saved comparison from a Meld comparison file"))
        parser.add_option(
            "", "--diff", action="callback", callback=self.diff_files_callback,
            dest="diff", default=[],
            help=_("Create a diff tab for the supplied files or folders"))

        def cleanup():
            if not command_line.get_is_remote():
                self.quit()
            parser.command_line = None

        rawargs = command_line.get_arguments()[1:]
        try:
            options, args = parser.parse_args(rawargs)
        except ValueError:
            # Thrown to avert further parsing when we've hit an error, because
            # of our weird when-to-exit issues.
            pass

        if parser.should_exit:
            cleanup()
            return parser.exit_status

        if len(args) > 3:
            parser.local_error(_("too many arguments (wanted 0-3, got %d)") %
                               len(args))
        elif options.auto_merge and len(args) < 3:
            parser.local_error(_("can’t auto-merge less than 3 files"))
        elif options.auto_merge and any([os.path.isdir(f) for f in args]):
            parser.local_error(_("can’t auto-merge directories"))

        if parser.should_exit:
            cleanup()
            return parser.exit_status

        if options.comparison_file or (len(args) == 1 and
                                       args[0].endswith(".meldcmp")):
            path = options.comparison_file or args[0]
            comparison_file_path = os.path.expanduser(path)
            gio_file = Gio.File.new_for_path(comparison_file_path)
            try:
                tab = self.get_meld_window().append_recent(gio_file.get_uri())
            except (IOError, ValueError):
                parser.local_error(_("Error reading saved comparison file"))
            if parser.should_exit:
                cleanup()
                return parser.exit_status
            return tab

        def make_file_from_command_line(arg):
            f = command_line.create_file_for_arg(arg)
            if not f.query_exists(cancellable=None):
                # May be a relative path with ':', misinterpreted as a URI
                cwd = Gio.File.new_for_path(command_line.get_cwd())
                relative = Gio.File.resolve_relative_path(cwd, arg)
                if relative.query_exists(cancellable=None):
                    return relative
                # Return the original arg for a better error message

            if f.get_uri() is None:
                raise ValueError(_("invalid path or URI “%s”") % arg)

            # TODO: support for directories specified by URIs
            file_type = f.query_file_type(Gio.FileQueryInfoFlags.NONE, None)
            if not f.is_native() and file_type == Gio.FileType.DIRECTORY:
                raise ValueError(
                    _("remote folder “{}” not supported").format(arg))

            return f

        tab = None
        error = None
        comparisons = [c for c in [args] + options.diff if c]

        # Every Meld invocation creates at most one window. If there is
        # no existing application, a window is created in do_startup().
        # If there is an existing application, then this is a remote
        # invocation, in which case we'll create a window if and only
        # if the new-tab flag is not provided.
        #
        # In all cases, all tabs newly created here are attached to the
        # same window, either implicitly by using the most-recently-
        # focused window, or explicitly as below.
        window = None
        close_on_error = False
        if command_line.get_is_remote() and not options.newtab:
            window = self.new_window()
            close_on_error = True

        for i, paths in enumerate(comparisons):
            auto_merge = options.auto_merge and i == 0
            try:
                files = [make_file_from_command_line(p) for p in paths]
                tab = self.open_files(
                    files,
                    window=window,
                    close_on_error=close_on_error,
                    auto_compare=options.auto_compare,
                    auto_merge=auto_merge,
                    focus=i == 0,
                )
            except ValueError as err:
                error = err
                log.debug("Couldn't open comparison: %s", error, exc_info=True)
            else:
                if i > 0:
                    continue

                if options.label:
                    tab.set_labels(options.label)

                if options.outfile and isinstance(tab, FileDiff):
                    outfile = make_file_from_command_line(options.outfile)
                    tab.set_merge_output_file(outfile)

        if error:
            if not tab:
                parser.local_error(error)
            else:
                print(error)
            # Delete the error here; otherwise we keep the local app
            # alive in a reference cycle, and the command line hangs.
            del error

        if parser.should_exit:
            cleanup()
            return parser.exit_status

        parser.command_line = None
        return tab if len(comparisons) == 1 else None


app = MeldApp()
