# -*- coding: utf-8 -*-
# Copyright (c) Vispy Development Team. All Rights Reserved.
# Distributed under the (new) BSD License. See LICENSE.txt for more info.
"""vispy backend for sdl2."""

from __future__ import division

import atexit
import ctypes
from time import sleep
import warnings
import gc

from ..base import (BaseApplicationBackend, BaseCanvasBackend,
                    BaseTimerBackend)
from ...util import keys, logger
from ...util.ptime import time
from ... import config

USE_EGL = config['gl_backend'].lower().startswith('es')


# -------------------------------------------------------------------- init ---

try:
    with warnings.catch_warnings(record=True):  # can throw warnings
        import sdl2
        import sdl2.ext

    # Map native keys to vispy keys
    KEYMAP = {
        # http://www.ginkgobitter.org/sdl/?SDL_Keycode
        sdl2.SDLK_LSHIFT: keys.SHIFT,
        sdl2.SDLK_RSHIFT: keys.SHIFT,
        sdl2.SDLK_LCTRL: keys.CONTROL,
        sdl2.SDLK_RCTRL: keys.CONTROL,
        sdl2.SDLK_LALT: keys.ALT,
        sdl2.SDLK_RALT: keys.ALT,
        sdl2.SDLK_LGUI: keys.META,
        sdl2.SDLK_RGUI: keys.META,

        sdl2.SDLK_LEFT: keys.LEFT,
        sdl2.SDLK_UP: keys.UP,
        sdl2.SDLK_RIGHT: keys.RIGHT,
        sdl2.SDLK_DOWN: keys.DOWN,
        sdl2.SDLK_PAGEUP: keys.PAGEUP,
        sdl2.SDLK_PAGEDOWN: keys.PAGEDOWN,

        sdl2.SDLK_INSERT: keys.INSERT,
        sdl2.SDLK_DELETE: keys.DELETE,
        sdl2.SDLK_HOME: keys.HOME,
        sdl2.SDLK_END: keys.END,

        sdl2.SDLK_ESCAPE: keys.ESCAPE,
        sdl2.SDLK_BACKSPACE: keys.BACKSPACE,

        sdl2.SDLK_F1: keys.F1,
        sdl2.SDLK_F2: keys.F2,
        sdl2.SDLK_F3: keys.F3,
        sdl2.SDLK_F4: keys.F4,
        sdl2.SDLK_F5: keys.F5,
        sdl2.SDLK_F6: keys.F6,
        sdl2.SDLK_F7: keys.F7,
        sdl2.SDLK_F8: keys.F8,
        sdl2.SDLK_F9: keys.F9,
        sdl2.SDLK_F10: keys.F10,
        sdl2.SDLK_F11: keys.F11,
        sdl2.SDLK_F12: keys.F12,

        sdl2.SDLK_SPACE: keys.SPACE,
        sdl2.SDLK_RETURN: keys.ENTER,
        sdl2.SDLK_TAB: keys.TAB,
    }

    BUTTONMAP = {sdl2.SDL_BUTTON_LEFT: 1,
                 sdl2.SDL_BUTTON_MIDDLE: 2,
                 sdl2.SDL_BUTTON_RIGHT: 3
                 }
except Exception as exp:
    available, testable, why_not, which = False, False, str(exp), None
else:
    if USE_EGL:
        available, testable, why_not = False, False, 'EGL not supported'
    else:
        available, testable, why_not = True, True, None
    which = 'sdl2 %d.%d.%d' % sdl2.version_info[:3]

_SDL2_INITIALIZED = False
_VP_SDL2_ALL_WINDOWS = {}


def _get_sdl2_windows():
    return list(_VP_SDL2_ALL_WINDOWS.values())


# -------------------------------------------------------------- capability ---

capability = dict(  # things that can be set by the backend
    title=True,
    size=True,
    position=True,
    show=True,
    vsync=True,
    resizable=True,
    decorate=True,
    fullscreen=True,
    context=True,
    multi_window=True,
    scroll=True,
    parent=False,
    always_on_top=False,
)


# ------------------------------------------------------- set_configuration ---

def _set_config(c):
    """Set gl configuration for SDL2"""
    func = sdl2.SDL_GL_SetAttribute
    func(sdl2.SDL_GL_RED_SIZE, c['red_size'])
    func(sdl2.SDL_GL_GREEN_SIZE, c['green_size'])
    func(sdl2.SDL_GL_BLUE_SIZE, c['blue_size'])
    func(sdl2.SDL_GL_ALPHA_SIZE, c['alpha_size'])
    func(sdl2.SDL_GL_DEPTH_SIZE, c['depth_size'])
    func(sdl2.SDL_GL_STENCIL_SIZE, c['stencil_size'])
    func(sdl2.SDL_GL_DOUBLEBUFFER, 1 if c['double_buffer'] else 0)
    samps = c['samples']
    func(sdl2.SDL_GL_MULTISAMPLEBUFFERS, 1 if samps > 0 else 0)
    func(sdl2.SDL_GL_MULTISAMPLESAMPLES, samps if samps > 0 else 0)
    func(sdl2.SDL_GL_STEREO, c['stereo'])


# ------------------------------------------------------------- application ---

class ApplicationBackend(BaseApplicationBackend):

    def __init__(self):
        BaseApplicationBackend.__init__(self)
        self._timers = list()

    def _add_timer(self, timer):
        if timer not in self._timers:
            self._timers.append(timer)

    def _vispy_get_backend_name(self):
        return 'SDL2'

    def _vispy_process_events(self):
        events = sdl2.ext.get_events()
        while len(events) > 0:
            for event in events:
                _id = event.window.windowID
                if _id in _VP_SDL2_ALL_WINDOWS:
                    win = _VP_SDL2_ALL_WINDOWS[_id]
                    win._on_event(event)
            events = sdl2.ext.get_events()
        for timer in self._timers:
            timer._tick()
        wins = _get_sdl2_windows()
        for win in wins:
            if win._needs_draw:
                win._needs_draw = False
                win._on_draw()

    def _vispy_run(self):
        wins = _get_sdl2_windows()
        while any(w._id is not None for w in wins):
            self._vispy_process_events()
        self._vispy_quit()  # to clean up

    def _vispy_quit(self):
        # Close windows
        wins = _get_sdl2_windows()
        for win in wins:
            win._vispy_close()
        # tear down timers
        for timer in self._timers:
            timer._vispy_stop()
        self._timers = []

    def _vispy_get_native_app(self):
        global _SDL2_INITIALIZED
        if not _SDL2_INITIALIZED:
            sdl2.ext.init()
            atexit.register(sdl2.ext.quit)
            _SDL2_INITIALIZED = True
        return sdl2


# ------------------------------------------------------------------ canvas ---

class CanvasBackend(BaseCanvasBackend):
    """SDL2 backend for Canvas abstract class."""

    def __init__(self, vispy_canvas, **kwargs):
        BaseCanvasBackend.__init__(self, vispy_canvas)
        p = self._process_backend_kwargs(kwargs)
        self._initialized = False

        # Deal with config
        _set_config(p.context.config)
        # Deal with context
        p.context.shared.add_ref('sdl2', self)
        if p.context.shared.ref is self:
            share = None
        else:
            other = p.context.shared.ref
            share = other._id.window, other._native_context
            sdl2.SDL_GL_MakeCurrent(*share)
            sdl2.SDL_GL_SetAttribute(sdl2.SDL_GL_SHARE_WITH_CURRENT_CONTEXT, 1)

        sdl2.SDL_GL_SetSwapInterval(1 if p.vsync else 0)
        flags = sdl2.SDL_WINDOW_OPENGL
        flags |= sdl2.SDL_WINDOW_SHOWN  # start out shown
        flags |= sdl2.SDL_WINDOW_ALLOW_HIGHDPI
        flags |= sdl2.SDL_WINDOW_RESIZABLE if p.resizable else 0
        flags |= sdl2.SDL_WINDOW_BORDERLESS if not p.decorate else 0
        if p.fullscreen is not False:
            self._fullscreen = True
            if p.fullscreen is not True:
                logger.warning('Cannot specify monitor number for SDL2 '
                               'fullscreen, using default')
            flags |= sdl2.SDL_WINDOW_FULLSCREEN_DESKTOP
        else:
            self._fullscreen = False
        self._mods = list()
        self._buttons = []
        if p.position is None:
            position = [sdl2.SDL_WINDOWPOS_UNDEFINED] * 2
        else:
            position = None
        self._id = sdl2.ext.Window(p.title, p.size, position, flags)
        if not self._id.window:
            raise RuntimeError('Could not create window')
        if share is None:
            self._native_context = sdl2.SDL_GL_CreateContext(self._id.window)
        else:
            self._native_context = sdl2.SDL_GL_CreateContext(share[0])
        self._sdl_id = sdl2.SDL_GetWindowID(self._id.window)
        _VP_SDL2_ALL_WINDOWS[self._sdl_id] = self

        # Init
        self._initialized = True
        self._needs_draw = False
        self._vispy_canvas.set_current()
        self._vispy_canvas.events.initialize()
        if not p.show:
            self._vispy_set_visible(False)

    def _vispy_warmup(self):
        etime = time() + 0.1
        while time() < etime:
            sleep(0.01)
            self._vispy_canvas.set_current()
            self._vispy_canvas.app.process_events()

    def _vispy_set_current(self):
        if self._id is None:
            return
        # Make this the current context
        sdl2.SDL_GL_MakeCurrent(self._id.window, self._native_context)

    def _vispy_swap_buffers(self):
        if self._id is None:
            return
        # Swap front and back buffer
        sdl2.SDL_GL_SwapWindow(self._id.window)

    def _vispy_set_title(self, title):
        if self._id is None:
            return
        # Set the window title. Has no effect for widgets
        sdl2.SDL_SetWindowTitle(self._id.window, title.encode('UTF-8'))

    def _vispy_set_size(self, w, h):
        if self._id is None:
            return
        # Set size of the widget or window
        sdl2.SDL_SetWindowSize(self._id.window, w, h)

    def _vispy_set_position(self, x, y):
        if self._id is None:
            return
        # Set position of the widget or window. May have no effect for widgets
        sdl2.SDL_SetWindowPosition(self._id.window, x, y)

    def _vispy_set_visible(self, visible):
        # Show or hide the window or widget
        if self._id is None:
            return
        if visible:
            self._id.show()
            # this ensures that the show takes effect
            self._vispy_update()
        else:
            self._id.hide()

    def _vispy_update(self):
        # Invoke a redraw, passing it on to the canvas
        if self._vispy_canvas is None or self._id is None:
            return
        # Mark that this window wants to be drawn on the next loop iter
        self._needs_draw = True

    def _vispy_close(self):
        # Force the window or widget to shut down
        if self._id is not None:
            _id = self._id.window
            self._vispy_canvas = None
            self._id = None
            sdl2.SDL_DestroyWindow(_id)
            del _VP_SDL2_ALL_WINDOWS[self._sdl_id]
            self._sdl_id = None
            gc.collect()  # enforce gc to help context get destroyed

    def _vispy_get_size(self):
        if self._id is None:
            return
        w, h = ctypes.c_int(), ctypes.c_int()
        sdl2.SDL_GetWindowSize(self._id.window,
                               ctypes.byref(w), ctypes.byref(h))
        w, h = w.value, h.value
        return w, h

    def _vispy_get_fullscreen(self):
        return self._fullscreen

    def _vispy_set_fullscreen(self, fullscreen):
        self._fullscreen = bool(fullscreen)
        flags = sdl2.SDL_WINDOW_FULLSCREEN_DESKTOP if self._fullscreen else 0
        sdl2.SDL_SetWindowFullscreen(self._id.window, flags)

    def _vispy_get_position(self):
        if self._id is None:
            return
        x, y = ctypes.c_int(), ctypes.c_int()
        sdl2.SDL_GetWindowPosition(self._id.window,
                                   ctypes.byref(x), ctypes.byref(y))
        x, y = x.value, y.value
        return x, y

    ##########################################
    # Notify vispy of events triggered by SDL2
    def _get_mouse_position(self):
        if self._id is None:
            return (0, 0)
        x, y = ctypes.c_int(), ctypes.c_int()
        sdl2.SDL_GetMouseState(ctypes.byref(x), ctypes.byref(y))
        return x.value, y.value

    def _on_draw(self):
        if self._vispy_canvas is None or self._id is None:
            return
        self._vispy_canvas.set_current()
        self._vispy_canvas.events.draw(region=None)  # (0, 0, w, h))

    def _on_event(self, event):
        if self._vispy_canvas is None:
            return
        # triage event to proper handler
        if event.type == sdl2.SDL_QUIT:
            self._vispy_canvas.close()
        elif event.type == sdl2.SDL_WINDOWEVENT:
            if event.window.event == sdl2.SDL_WINDOWEVENT_RESIZED:
                w, h = event.window.data1, event.window.data2
                self._vispy_canvas.events.resize(size=(w, h))
            elif event.window.event == sdl2.SDL_WINDOWEVENT_CLOSE:
                self._vispy_canvas.close()
        elif event.type == sdl2.SDL_MOUSEMOTION:
            x, y = event.motion.x, event.motion.y
            self._vispy_mouse_move(pos=(x, y), buttons=self._buttons, modifiers=self._mods)
        elif event.type in (sdl2.SDL_MOUSEBUTTONDOWN,
                            sdl2.SDL_MOUSEBUTTONUP):
            x, y = event.button.x, event.button.y
            button = event.button.button
            if button in BUTTONMAP:
                button = BUTTONMAP.get(button, 0)
                if event.type == sdl2.SDL_MOUSEBUTTONDOWN:
                    func = self._vispy_mouse_press
                    if button not in self._buttons:
                        self._buttons.append(button)
                else:
                    func = self._vispy_mouse_release
                    if button in self._buttons:
                        self._buttons.remove(button)
                func(pos=(x, y), button=button, buttons=self._buttons, modifiers=self._mods)
        elif event.type == sdl2.SDL_MOUSEWHEEL:
            pos = self._get_mouse_position()
            delta = float(event.wheel.x), float(event.wheel.y)
            self._vispy_canvas.events.mouse_wheel(pos=pos, delta=delta,
                                                  buttons=self._buttons, modifiers=self._mods)
        elif event.type in (sdl2.SDL_KEYDOWN, sdl2.SDL_KEYUP):
            down = (event.type == sdl2.SDL_KEYDOWN)
            keysym = event.key.keysym
            mods = keysym.mod
            key = keysym.sym
            self._process_mod(mods, down)
            if key in KEYMAP:
                key, text = KEYMAP[key], ''
            elif key >= 32 and key <= 127:
                key, text = keys.Key(chr(key)), chr(key)
            else:
                key, text = None, ''
            if down:
                fun = self._vispy_canvas.events.key_press
            else:
                fun = self._vispy_canvas.events.key_release
            fun(key=key, text=text, modifiers=self._mods)

    def _process_mod(self, key, down):
        _modifiers = list()
        if key & (sdl2.SDLK_LSHIFT | sdl2.SDLK_RSHIFT):
            _modifiers.append(keys.SHIFT)
        if key & (sdl2.SDLK_LCTRL | sdl2.SDLK_RCTRL):
            _modifiers.append(keys.CONTROL)
        if key & (sdl2.SDLK_LALT | sdl2.SDLK_RALT):
            _modifiers.append(keys.ALT)
        if key & (sdl2.SDLK_LGUI | sdl2.SDLK_RGUI):
            _modifiers.append(keys.META)
        for mod in _modifiers:
            if mod not in self._mods:
                if down:
                    self._mods.append(mod)
            elif not down:
                self._mods.pop(self._mods.index(mod))

# ------------------------------------------------------------------- timer ---


# XXX should probably use SDL_Timer (and SDL_INIT_TIMER)

class TimerBackend(BaseTimerBackend):

    def __init__(self, vispy_timer):
        BaseTimerBackend.__init__(self, vispy_timer)
        vispy_timer._app._backend._add_timer(self)
        self._vispy_stop()

    def _vispy_start(self, interval):
        self._interval = interval
        self._next_time = time() + self._interval

    def _vispy_stop(self):
        self._next_time = float('inf')

    def _tick(self):
        if time() >= self._next_time:
            self._vispy_timer._timeout()
            self._next_time = time() + self._interval
