#!/usr/local/bin/python3.6

# Copyright (C) 2002-2006 Stephen Kennedy <stevek@gnome.org>
# Copyright (C) 2009-2014 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 locale
import logging
import os
import signal
import subprocess
import sys
from multiprocessing import freeze_support

# On Windows, pythonw.exe (which doesn't display a console window) supplies
# dummy stdout and stderr streams that silently throw away any output. However,
# these streams seem to have issues with flush() so we just redirect stdout and
# stderr to actual dummy files (the equivalent of /dev/null).
# Regarding pythonw.exe stdout, see also http://bugs.python.org/issue706263
# Also cx_Freeze built with Win32GUI base sets sys.stdout to None
# leading to exceptions in print() and freeze_support() that uses flush()
if sys.executable.endswith("pythonw.exe") or sys.stdout is None:
    devnull = open(os.devnull, "w")
    sys.stdout = sys.stderr = devnull

# Main module hasn't multiprocessing workers, so not imported in subprocesses.
# This allows skipping '__name__ == "main"' guard, but freezed case is special.
freeze_support()

def disable_stdout_buffering():

    class Unbuffered(object):

        def __init__(self, file):
            self.file = file

        def write(self, arg):
            self.file.write(arg)
            self.file.flush()

        def __getattr__(self, attr):
            return getattr(self.file, attr)

    sys.stdout = Unbuffered(sys.stdout)


def get_meld_dir():
    global frozen
    if frozen:
        return os.path.dirname(sys.executable)

    # Support running from an uninstalled version
    self_path = os.path.realpath(__file__)
    return os.path.abspath(os.path.join(os.path.dirname(self_path), ".."))

frozen = getattr(sys, 'frozen', False)
melddir = get_meld_dir()

uninstalled = False
if os.path.exists(os.path.join(melddir, "meld.doap")):
    sys.path[0:0] = [melddir]
    uninstalled = True
devel = os.path.exists(os.path.join(melddir, ".git"))

import meld.conf

# Silence warnings on non-devel releases (minor version is divisible by 2)
is_stable = not bool(int(meld.conf.__version__.split('.')[1]) % 2)
if is_stable:
    import warnings
    warnings.simplefilter("ignore")

if uninstalled:
    meld.conf.uninstalled()
elif frozen:
    meld.conf.frozen()

# TODO: Possibly move to elib.intl
import gettext
locale_domain = meld.conf.__package__
locale_dir = meld.conf.LOCALEDIR

gettext.bindtextdomain(locale_domain, locale_dir)
try:
    locale.setlocale(locale.LC_ALL, '')
except locale.Error as e:
    print("Couldn't set the locale: %s; falling back to 'C' locale" % e)
    locale.setlocale(locale.LC_ALL, 'C')
gettext.textdomain(locale_domain)
trans = gettext.translation(locale_domain, localedir=locale_dir, fallback=True)
try:
    _ = meld.conf._ = trans.ugettext
    meld.conf.ngettext = trans.ungettext
except AttributeError:
    # py3k
    _ = meld.conf._ = trans.gettext
    meld.conf.ngettext = trans.ngettext

try:
    if os.name == 'nt':
        from ctypes import cdll
        if frozen:
            libintl = cdll['libintl-8']
        else:
            libintl = cdll.intl
        libintl.bindtextdomain(locale_domain, locale_dir)
        libintl.bind_textdomain_codeset(locale_domain, 'UTF-8')
        del libintl
    else:
        locale.bindtextdomain(locale_domain, locale_dir)
        locale.bind_textdomain_codeset(locale_domain, 'UTF-8')
except AttributeError as e:
    # Python builds linked without libintl (i.e., OSX) don't have
    # bindtextdomain(), which causes Gtk.Builder translations to fail.
    print("Couldn't bind the translation domain. Some translations won't work.")
    print(e)
except locale.Error as e:
    print("Couldn't bind the translation domain. Some translations won't work.")
    print(e)
except WindowsError as e:
    # Accessing cdll.intl sometimes fails on Windows for unknown reasons.
    # Let's just continue, as translations are non-essential.
    print("Couldn't bind the translation domain. Some translations won't work.")
    print(e)


def show_error_and_exit(error_text):
    """
    Show error in a robust way: always print to stdout and try to
    display gui message via gtk or tkinter (first available).
    Empty toplevel window is used as message box parent since
    parentless message box cause toolkit and windowing system problems.
    This function is both python 2 and python 3 compatible since it is used
    to display wrong python version.
    """
    print(error_text)
    try:
        import gi
        gi.require_version("Gtk", "3.0")
        from gi.repository import Gtk
        toplevel = Gtk.Window(title="Meld")
        toplevel.show()
        Gtk.MessageDialog(
            toplevel, 0, Gtk.MessageType.ERROR,
            Gtk.ButtonsType.CLOSE, error_text).run()
    except Exception:
        # Although tkinter is imported here, it isn't meld's dependency:
        # if found it is used to show GUI error about lacking true dependecies.
        try:
            if sys.version_info < (3, 0):
                from Tkinter import Tk
                from tkMessageBox import showerror
            else:
                from tkinter import Tk
                from tkinter.messagebox import showerror
            toplevel = Tk(className="Meld")
            toplevel.wait_visibility()
            showerror("Meld", error_text, parent=toplevel)
        except Exception:
            # Displaying with tkinter failed too, just exit.
            pass
    sys.exit(1)


def check_requirements():

    gtk_requirement = (3, 14)
    glib_requirement = (2, 36, 0)
    gtksourceview_requirement = (3, 14, 0)
    pangocairo_requirement = (1, 34)

    def missing_reqs(mod, ver, exception=None):
        if isinstance(exception, ImportError):
            show_error_and_exit(_("Cannot import: ") + mod + "\n" + str(e))
        else:
            modver = mod + " " + ".".join(map(str, ver))
            show_error_and_exit(_("Meld requires %s or higher.") % modver)

    if sys.version_info[:2] < meld.conf.PYTHON_REQUIREMENT_TUPLE:
        missing_reqs("Python", meld.conf.PYTHON_REQUIREMENT_TUPLE)

    # gtk+ and related imports
    try:
        # FIXME: Extra clause for gi
        import gi
        gi.require_version("Gtk", "3.0")
        from gi.repository import Gtk
        version = (Gtk.get_major_version(), Gtk.get_minor_version())
        assert version >= gtk_requirement
    except (ImportError, AssertionError, ValueError) as e:
        missing_reqs("GTK+", gtk_requirement, e)

    try:
        from gi.repository import GObject
        assert GObject.glib_version >= glib_requirement
    except (ImportError, AssertionError, ValueError) as e:
        missing_reqs("GLib", glib_requirement, e)

    try:
        gi.require_version('GtkSource', '3.0')
        from gi.repository import GtkSource
        # TODO: There is no way to get at GtkSourceView's actual version
        assert hasattr(GtkSource, 'SearchSettings')
    except (ImportError, AssertionError, ValueError) as e:
        missing_reqs("GtkSourceView", gtksourceview_requirement, e)

    try:
        gi.require_version("PangoCairo", "1.0")
        from gi.repository import PangoCairo
        # Only check that imports ok; the version is fine since Gtk loaded fine
    except (ImportError, ValueError) as e:
        missing_reqs("PangoCairo", pangocairo_requirement, e)


def setup_resources():
    from gi.repository import GLib
    from gi.repository import Gtk
    from gi.repository import Gdk
    from gi.repository import GtkSource

    icon_dir = os.path.join(meld.conf.DATADIR, "icons")
    Gtk.IconTheme.get_default().append_search_path(icon_dir)

    css_file = os.path.join(meld.conf.DATADIR, "meld.css")
    provider = Gtk.CssProvider()
    try:
        provider.load_from_path(css_file)
    except GLib.GError as err:
        print(_("Couldn't load Meld-specific CSS (%s)\n%s") % (css_file, err))
    Gtk.StyleContext.add_provider_for_screen(
        Gdk.Screen.get_default(), provider,
        Gtk.STYLE_PROVIDER_PRIORITY_APPLICATION)

    style_path = os.path.join(meld.conf.DATADIR, "styles")
    GtkSource.StyleSchemeManager.get_default().append_search_path(style_path)


def setup_settings():
    import meld.conf

    schema_path = os.path.join(meld.conf.DATADIR, "org.gnome.meld.gschema.xml")
    compiled_schema_path = os.path.join(meld.conf.DATADIR, "gschemas.compiled")

    try:
        schema_mtime = os.path.getmtime(schema_path)
        compiled_mtime = os.path.getmtime(compiled_schema_path)
        have_schema = schema_mtime < compiled_mtime
    except OSError:
        have_schema = False

    if uninstalled and not have_schema:
        subprocess.call(["glib-compile-schemas", meld.conf.DATADIR],
                        cwd=melddir)

    import meld.settings
    meld.settings.create_settings()


def setup_logging():
    log = logging.getLogger()

    # If we're running uninstalled and from Git, turn up the logging level
    if uninstalled and devel:
        log.setLevel(logging.INFO)
    else:
        log.setLevel(logging.CRITICAL)

    handler = logging.StreamHandler()
    formatter = logging.Formatter("%(asctime)s %(levelname)s "
                                  "%(name)s: %(message)s")
    handler.setFormatter(formatter)
    log.addHandler(handler)


def setup_glib_logging():
    from gi.repository import GLib
    levels = {
        GLib.LogLevelFlags.LEVEL_DEBUG: logging.DEBUG,
        GLib.LogLevelFlags.LEVEL_INFO: logging.INFO,
        GLib.LogLevelFlags.LEVEL_MESSAGE: logging.INFO,
        GLib.LogLevelFlags.LEVEL_WARNING: logging.WARNING,
        GLib.LogLevelFlags.LEVEL_ERROR: logging.ERROR,
        GLib.LogLevelFlags.LEVEL_CRITICAL: logging.CRITICAL,
    }
    level_flag = (
        GLib.LogLevelFlags.LEVEL_WARNING |
        GLib.LogLevelFlags.LEVEL_ERROR |
        GLib.LogLevelFlags.LEVEL_CRITICAL
    )

    log_domain = "Gtk"
    log = logging.getLogger(log_domain)

    def silence(message):
        if "Drawing a gadget with negative dimensions" in message:
            return True
        return False

    # This logging handler is for "old" glib logging using a simple
    # syslog-style API.
    def log_adapter(domain, level, message, user_data):
        if not silence(message):
            log.log(levels.get(level, logging.WARNING), message)

    try:
        GLib.log_set_handler(log_domain, level_flag, log_adapter, None)
    except AttributeError:
        # Only present in glib 2.46+
        pass

    # This logging handler is for new glib logging using a structured
    # API. Unfortunately, it was added in such a way that the old
    # redirection API became a no-op, so we need to hack both of these
    # handlers to get it to work.
    def structured_log_adapter(level, fields, field_count, user_data):
        message = GLib.log_writer_format_fields(level, fields, True)
        if not silence(message):
            log.log(levels.get(level, logging.WARNING), message)
        return GLib.LogWriterOutput.HANDLED

    try:
        GLib.log_set_writer_func(structured_log_adapter, None)
    except AttributeError:
        # Only present in glib 2.50+
        pass


def environment_hacks():
    # We manage cwd ourselves for git operations, and GIT_DIR in particular
    # can mess with this when set.
    for var in ('GIT_DIR', 'GIT_WORK_TREE'):
        try:
            del os.environ[var]
        except KeyError:
            pass


if __name__ == '__main__':
    setup_logging()
    disable_stdout_buffering()
    check_requirements()
    setup_glib_logging()
    setup_resources()
    setup_settings()
    environment_hacks()

    import meld.meldapp
    if sys.platform != 'win32':
        from gi.repository import GLib
        GLib.unix_signal_add(GLib.PRIORITY_DEFAULT, signal.SIGINT,
                             lambda *args: meld.meldapp.app.quit(), None)
    if sys.platform == 'win32':
        # FontConfig on win32 at least with version <= 2.12.6 can cause several
        # minutes 'hang' during first startup. So use native fonts backend.
        from gi.repository import PangoCairo
        PangoCairo.FontMap.set_default(PangoCairo.Win32FontMap())
    status = meld.meldapp.app.run(sys.argv)
    sys.exit(status)
