# -*- coding: utf-8 -*-

# Copyright (C) 2005 Osmo Salomaa
#
# 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 3 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/>.

"""Miscellaneous functions and decorators."""

import aeidon
import gaupol
import inspect
import sys
import traceback
import webbrowser

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


def char_to_px(nchar, font=None):
    """Convert characters to pixels."""
    if nchar < 0: return nchar
    label = Gtk.Label(label="etaoin shrdlu")
    gaupol.style.use_font(label, font)
    label.show()
    width = label.get_preferred_width()[1]
    return int(round(nchar * width/len(label.props.label)))

def delay_add(delay, function, *args, **kwargs):
    """Call `function` with `args` and `kwargs` once after `delay` (ms)."""
    def call_function(*args, **kwargs):
        function(*args, **kwargs)
        return False # to not be called again.
    return GLib.timeout_add(delay, call_function, *args, **kwargs)

def document_to_text_field(doc):
    """Return :attr:`gaupol.fields` item corresponding to `doc`."""
    if doc == aeidon.documents.MAIN:
        return gaupol.fields.MAIN_TEXT
    if doc == aeidon.documents.TRAN:
        return gaupol.fields.TRAN_TEXT
    raise ValueError("Invalid document: {}"
                     .format(repr(doc)))

def flash_dialog(dialog):
    """Run `dialog`, destroy it and return response."""
    response = dialog.run()
    dialog.destroy()
    return response

def get_content_size(widget, font=None):
    """Return the width and height desired by `widget`."""
    if isinstance(widget, Gtk.TextView):
        return get_text_view_size(widget, font)
    if isinstance(widget, Gtk.TreeView):
        return get_tree_view_size(widget, font)
    raise ValueError("Unsupported container type: {}"
                     .format(repr(type(widget))))

def get_font():
    """Return custom font or blank string."""
    return (gaupol.conf.editor.custom_font if
            gaupol.conf.editor.use_custom_font and
            gaupol.conf.editor.custom_font else "")

def get_gst_version():
    """Return :mod:`Gst` version number as string or ``None``."""
    try:
        from gi.repository import Gst
        return ".".join(map(str, Gst.version()))
    except Exception:
        return None

def get_icon_image(name, fallback, size):
    """Return icon image from `name` or `fallback` in theme."""
    theme = Gtk.IconTheme.get_default()
    if theme.has_icon(name):
        return Gtk.Image(icon_name=name, icon_size=size)
    return Gtk.Image(icon_name=fallback, icon_size=size)

def get_preview_command():
    """Return command to use for lauching video player."""
    if gaupol.conf.preview.use_custom_command:
        return gaupol.conf.preview.custom_command
    if gaupol.conf.preview.force_utf_8:
        return gaupol.conf.preview.player.command_utf_8
    return gaupol.conf.preview.player.command

def get_text_view_size(text_view, font=None):
    """Return the width and height desired by `text_view`."""
    text_buffer = text_view.get_buffer()
    start, end = text_buffer.get_bounds()
    text = text_buffer.get_text(start, end, False)
    label = Gtk.Label(label=text)
    gaupol.style.use_font(label, font)
    label.show()
    return (label.get_preferred_width()[1]
            + text_view.get_left_margin()
            + text_view.get_right_margin(),
            label.get_preferred_height()[1])

def get_tree_view_size(tree_view, font=None):
    """Return the width and height desired by `tree_view`."""
    scroller = tree_view.get_parent()
    policy = scroller.get_policy()
    scroller.set_policy(Gtk.PolicyType.NEVER, Gtk.PolicyType.NEVER)
    width = scroller.get_preferred_width()[1]
    height = scroller.get_preferred_height()[1]
    scroller.set_policy(*policy)
    return width, height

@aeidon.deco.once
def get_zebra_color(tree_view):
    """Return background color to use for tree view zebra-stripes."""
    # XXX: Zebra stripes would be faster and cleaner done with CSS
    # selectors :nth-child(odd) and :nth-child(even), but they don't
    # seem to work, might even be deliberately broken.
    # https://bugzilla.gnome.org/show_bug.cgi?id=709617#c1
    style = tree_view.get_style_context()
    fg = style.get_color(Gtk.StateFlags.NORMAL)
    bg = style.get_background_color(Gtk.StateFlags.NORMAL)
    color = Gdk.RGBA()
    color.red   = 0.92 * bg.red   + 0.08 * fg.red
    color.green = 0.92 * bg.green + 0.08 * fg.green
    color.blue  = 0.92 * bg.blue  + 0.08 * fg.blue
    return(color)

@aeidon.deco.once
def gst_available():
    """Return ``True`` if :mod:`Gst` and needed plugins are available."""
    try:
        from gi.repository import Gst
    except Exception:
        return False
    if not Gst.ElementFactory.find("playbin"):
        print("GStreamer found, but playbin missing.",
              "Try installing gst-plugins-base.",
              file=sys.stderr)
        return False
    if not Gst.ElementFactory.find("textoverlay"):
        print("GStreamer found, but textoverlay missing.",
              "Try installing gst-plugins-base.",
              file=sys.stderr)
        return False
    if not Gst.ElementFactory.find("timeoverlay"):
        print("GStreamer found, but timeoverlay missing.",
              "Try installing gst-plugins-base.",
              file=sys.stderr)
        return False
    if not Gst.ElementFactory.find("gtksink"):
        print("GStreamer found, but gtksink missing.",
              "Try installing gst-plugins-good.",
              file=sys.stderr)
        return False
    return True

@aeidon.deco.once
def gtkspell_available():
    """Return ``True`` if :mod:`GtkSpell` module is available."""
    try:
        from gi.repository import GtkSpell
        return True
    except Exception:
        return False

def hex_to_rgba(string):
    """Return a :class:`Gdk.RGBA` for hexadecimal `string`."""
    rgba = Gdk.RGBA()
    success = rgba.parse(string)
    if not success:
        raise ValueError("Parsing string {} failed".format(repr(string)))
    return rgba

def idle_add(function, *args, **kwargs):
    """Call `function` with `args` and `kwargs` when idle."""
    def call_function(*args, **kwargs):
        function(*args, **kwargs)
        return False # to not be called again.
    return GLib.idle_add(call_function, *args, **kwargs)

def install_module(name, obj):
    """
    Install `obj`'s module into the :mod:`gaupol` namespace.

    Typical call is of form::

        gaupol.util.install_module("foo", lambda: None)
    """
    gaupol.__dict__[name] = inspect.getmodule(obj)

def iterate_main():
    """Iterate the GTK+ main loop while events are pending."""
    while Gtk.events_pending():
        Gtk.main_iteration()

def lines_to_px(nlines, font=None):
    """Convert lines to pixels."""
    if nlines < 0: return nlines
    text = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
    label = Gtk.Label(label=text)
    gaupol.style.use_font(label, font)
    label.show()
    height = label.get_preferred_height()[1]
    return int(round(nlines * height))

def new_hbox(spacing):
    """Return a new horizontal :class:`Gtk.Box`."""
    return Gtk.Box(orientation=Gtk.Orientation.HORIZONTAL,
                   spacing=spacing)

def new_vbox(spacing):
    """Return a new vertical :class:`Gtk.Box`."""
    return Gtk.Box(orientation=Gtk.Orientation.VERTICAL,
                   spacing=spacing)

def pack_start(box, widget, padding=0):
    """Pack widget to box without fill or expand."""
    box.pack_start(widget,
                   expand=False,
                   fill=False,
                   padding=padding)

def pack_start_expand(box, widget, padding=0):
    """Pack widget to box with fill and expand."""
    box.pack_start(widget,
                   expand=True,
                   fill=True,
                   padding=padding)

def pack_start_fill(box, widget, padding=0):
    """Pack widget to box with fill, but no expand."""
    box.pack_start(widget,
                   expand=False,
                   fill=True,
                   padding=padding)

def prepare_text_view(text_view):
    """Set spell-check, line-length margin and font properties."""
    if (gaupol.util.gtkspell_available() and
        gaupol.conf.spell_check.inline):
        from gi.repository import GtkSpell
        language = gaupol.conf.spell_check.language
        with aeidon.util.silent(Exception):
            checker = GtkSpell.Checker()
            checker.set_language(language)
            def on_language_changed(checker, lang, *args):
                gaupol.conf.spell_check.language = lang
            checker.connect("language-changed", on_language_changed)
            checker.attach(text_view)
    connect = gaupol.conf.editor.connect
    def update_margin(section, value, text_view):
        if gaupol.conf.editor.show_lengths_edit:
            return gaupol.ruler.connect_text_view(text_view)
        return gaupol.ruler.disconnect_text_view(text_view)
    connect("notify::show_lengths_edit", update_margin, text_view)
    update_margin(None, None, text_view)
    def update_font(section, value, text_view):
        text_view.reset_style()
    gaupol.style.use_font(text_view, "custom")
    connect("notify::use_custom_font", update_font, text_view)
    connect("notify::custom_font", update_font, text_view)
    update_font(None, None, text_view)
    def update_spacing(section, value, text_view):
        if gaupol.conf.editor.show_lengths_cell:
            return text_view.set_pixels_above_lines(2)
        return text_view.set_pixels_above_lines(0)
    connect("notify::show_lengths_cell", update_spacing, text_view)
    update_spacing(None, None, text_view)

def raise_default(expression):
    """Raise :exc:`gaupol.Default` if `expression` evaluates to ``True``."""
    if expression:
        raise gaupol.Default

def rgba_to_hex(color):
    """Return hexadecimal string for :class:`Gdk.RGBA` `color`."""
    return "#{:02x}{:02x}{:02x}".format(int(color.red   * 255),
                                        int(color.green * 255),
                                        int(color.blue  * 255))

def run_dialog(dialog):
    """Run `dialog` and return response."""
    return dialog.run()

def scale_to_content(widget, min_nchar=0,  max_nchar=32768,
                     min_nlines=0, max_nlines=32768, font=None):
    """Set `widget's` size by content, but limited by `min` and `max`."""
    width, height = get_content_size(widget, font)
    width  = max(width, char_to_px(min_nchar, font))
    width  = min(width, char_to_px(max_nchar, font))
    height = max(height, lines_to_px(min_nlines, font))
    height = min(height, lines_to_px(max_nlines, font))
    parent = widget.get_parent()
    if isinstance(parent, Gtk.ScrolledWindow):
        # Vaguely account for possible scrollbars.
        return parent.set_size_request(width+24, height+24)
    widget.set_size_request(width, height)

def scale_to_size(widget, nchar, nlines, font=None):
    """Set `widget`'s size to `nchar` and `nlines`."""
    width  = char_to_px(nchar, font)
    height = lines_to_px(nlines, font)
    parent = widget.get_parent()
    if isinstance(parent, Gtk.ScrolledWindow):
        # Vaguely account for possible scrollbars.
        return parent.set_size_request(width+24, height+24)
    widget.set_size_request(width, height)

def separate_combo(store, itr, data=None):
    """Separator function for combo box models."""
    return store.get_value(itr, 0) == gaupol.COMBO_SEPARATOR

def set_cursor_busy(window):
    """Set mouse pointer busy when above window."""
    cursor = window.get_window().get_cursor()
    if (cursor is not None and cursor.get_cursor_type() ==
        Gdk.CursorType.WATCH): return
    cursor = Gdk.Cursor.new_for_display(
        Gdk.Display.get_default(), Gdk.CursorType.WATCH)
    window.get_window().set_cursor(cursor)
    iterate_main()

def set_cursor_normal(window):
    """Set mouse pointer normal when above window."""
    cursor = window.get_window().get_cursor()
    if (cursor is not None and cursor.get_cursor_type() ==
        Gdk.CursorType.LEFT_PTR): return
    cursor = Gdk.Cursor.new_for_display(
        Gdk.Display.get_default(), Gdk.CursorType.LEFT_PTR)
    window.get_window().set_cursor(cursor)
    iterate_main()

def show_exception(exctype, value, tb):
    """A :class:`gaupol.DebugDialog` :attr`sys.excepthook`."""
    traceback.print_exception(exctype, value, tb)
    if not isinstance(value, Exception): return
    try: # to avoid recursion.
        dialog = gaupol.DebugDialog()
        dialog.set_text(exctype, value, tb)
        response = dialog.run()
        dialog.destroy()
        if response == Gtk.ResponseType.NO:
            raise SystemExit(1)
    except Exception:
        traceback.print_exc()

def show_uri(uri):
    """Open `uri` in default application."""
    try:
        return Gtk.show_uri(None, uri, Gdk.CURRENT_TIME)
    except Exception:
        # Gtk.show_uri fails on Windows and some misconfigured installations.
        # GError: No application is registered as handling this file
        # Gtk.show_uri: Operation not supported
        if uri.startswith(("http://", "https://")):
            return webbrowser.open(uri)
        raise # Exception

def text_field_to_document(field):
    """Return :attr:`aeidon.documents` item corresponding to `field`."""
    if field == gaupol.fields.MAIN_TEXT:
        return aeidon.documents.MAIN
    if field == gaupol.fields.TRAN_TEXT:
        return aeidon.documents.TRAN
    raise ValueError("Invalid field: {}"
                     .format(repr(field)))

def tree_path_to_row(path):
    """
    Convert `path` to a list row integer.

    `path` can be either a :class:`Gtk.Treepath` instance or a string
    representation of it (as commonly used by various callbacks).
    """
    if path is None: return None
    if isinstance(path, Gtk.TreePath):
        return path.get_indices()[0]
    if isinstance(path, str):
        return int(path)
    raise TypeError("Bad type {} for path {}"
                    .format(repr(type(path)), repr(path)))

def tree_row_to_path(row):
    """Convert list row integer to a :class:`Gtk.TreePath`."""
    if row is None: return None
    return Gtk.TreePath.new_from_string(str(row))
