import os
from random import randint
import unittest
from unittest.mock import MagicMock
import sys
import time
from asciimatics.event import KeyboardEvent, MouseEvent
from asciimatics.exceptions import StopApplication, NextScene
try:
    from asciimatics.screen import _SignalState
except ImportError:
    pass
from asciimatics.scene import Scene
from asciimatics.screen import Screen, Canvas, ManagedScreen, _DoubleBuffer
from tests.mock_objects import MockEffect
if sys.platform == "win32":
    import win32console
    import win32con
else:
    import signal
    import curses


def check_screen_and_canvas(screen, fn):
    """
    Helper function to check that a Screen and Canvas work identically.

    :param screen: The screen object to use for the test.
    :param fn: The function to call for the test.
    """
    for test_object in (screen, Canvas(screen, screen.height, screen.width)):
        fn(test_object)


class TestScreen(unittest.TestCase):
    def setUp(self):
        # Skip for non-Windows if the terminal definition is incomplete.
        # This typically means we're running inside a non-standard terminal.
        # For example, this happens when embedded in PyCharm.
        if sys.platform != "win32":
            if not (("FORCE_TTY" in os.environ and os.environ["FORCE_TTY"] == "Y") or sys.stdout.isatty()):
                self.skipTest("Not a valid TTY")
            curses.initscr()
            if curses.tigetstr("ri") is None:
                self.skipTest("No valid terminal definition")

    def assert_canvas_equals(self, canvas, expected, height=10, width=75):
        """
        Assert output to canvas/screen is as expected.
        """
        # TODO: Merge with widget test function of the same name.
        output = ""
        for y in range(height):
            for x in range(width):
                try:
                    char, _, _, _ = canvas.get_from(x, y)
                except Exception:
                    raise RuntimeError(f"{x} {y}")
                output += chr(char)
            output += "\n"
        self.assertEqual(output, expected)

    def test_wrapper(self):
        """
        Check that you can create a blank Screen.
        """
        def internal_checks(screen):
            # Check screen basically exists
            self.assertIsNotNone(screen)
            self.assertGreater(screen.width, 0)
            self.assertGreater(screen.height, 0)
            self.assertGreater(screen.colours, 0)

            # Check that the Screen is cleared ready for use.
            for x in range(screen.width):
                for y in range(screen.height):
                    char, fg, attr, bg = screen.get_from(x, y)
                    self.assertEqual(char, ord(" "))
                    self.assertEqual(fg, Screen.COLOUR_WHITE)
                    self.assertEqual(attr, 0)
                    self.assertEqual(bg, Screen.COLOUR_BLACK)

        Screen.wrapper(internal_checks)

    def test_wrapper_return(self):
        """
        Check that you get the result back from the wrapped function.
        """
        def internal_checks(_):
            return True

        self.assertTrue(Screen.wrapper(internal_checks))

    def test_print_and_get(self):
        """
        Check that basic print_at and get_from work as expected.
        """
        def internal_checks(screen):
            for x in range(screen.width):
                for y in range(15):
                    char = randint(0, 255)
                    fg = randint(Screen.COLOUR_DEFAULT, Screen.COLOUR_WHITE)
                    bg = randint(Screen.COLOUR_DEFAULT, Screen.COLOUR_WHITE)
                    attr = randint(0, Screen.A_UNDERLINE)
                    screen.print_at(chr(char), x, y, fg, attr, bg)
                    char2, fg2, attr2, bg2 = screen.get_from(x, y)
                    self.assertEqual(char, char2)
                    self.assertEqual(fg, fg2)
                    self.assertEqual(attr, attr2)
                    self.assertEqual(bg, bg2)

        Screen.wrapper(
            check_screen_and_canvas, height=15, arguments=[internal_checks])

    def test_highlight(self):
        """
        Check that highlight works as expected.
        """
        def internal_checks(screen):
            for x in range(screen.width):
                for y in range(15):
                    char = randint(0, 255)
                    fg = randint(Screen.COLOUR_RED, Screen.COLOUR_WHITE)
                    bg = randint(Screen.COLOUR_RED, Screen.COLOUR_WHITE)
                    attr = randint(0, Screen.A_UNDERLINE)
                    screen.print_at(chr(char), x, y, fg, attr, bg)

            # Check BG highlight first.
            screen.highlight(-1, -1, screen.width + 2, screen.height + 2, bg=0)
            for x in range(screen.width):
                for y in range(15):
                    _, fg2, _, bg2 = screen.get_from(x, y)
                    self.assertEqual(bg2, 0)
                    self.assertNotEqual(fg2, 0)

            # Now check FG highlighting.
            screen.highlight(-1, -1, screen.width + 2, screen.height + 2, fg=0)
            for x in range(screen.width):
                for y in range(15):
                    _, fg2, _, bg2 = screen.get_from(x, y)
                    self.assertEqual(bg2, 0)
                    self.assertEqual(fg2, 0)

            # Now check blending.
            screen.print_at("*" * screen.width,
                            0, 0,
                            Screen.COLOUR_CYAN,
                            Screen.A_NORMAL,
                            Screen.COLOUR_YELLOW)
            screen.highlight(0, 0, screen.width, 1, fg=0, bg=0, blend=50)
            for x in range(screen.width):
                _, fg2, _, bg2 = screen.get_from(x, 0)
                self.assertEqual(bg2, 0)
                self.assertEqual(fg2, 0)

        Screen.wrapper(
            check_screen_and_canvas, height=15, arguments=[internal_checks])

    def test_visible(self):
        """
        Check that is_visible works as expected.
        """
        def internal_checks(screen):
            # Check some points that must always be visible
            self.assertTrue(screen.is_visible(0, 0))
            self.assertTrue(screen.is_visible(
                screen.width - 1, screen.height - 1))

            # Check some points that cannot be visible
            self.assertFalse(screen.is_visible(-1, -1))
            self.assertFalse(screen.is_visible(
                screen.width, screen.height))

        Screen.wrapper(
            check_screen_and_canvas, height=15, arguments=[internal_checks])

    def test_paint(self):
        """
        Check that paint with colour map works.
        """
        def internal_checks(screen):
            # Put a simple colour map to screen.
            screen.paint(
                "Text", 0, 0,
                colour_map=((1, 0, 4), (2, 0, 3), (3, 0, 2), (4, 0, 1)))

            # Check it is rendered as expected.
            char, fg, _, bg = screen.get_from(0, 0)
            self.assertEqual(fg, 1)
            self.assertEqual(bg, 4)
            char, fg, _, bg = screen.get_from(3, 0)
            self.assertEqual(fg, 4)
            self.assertEqual(bg, 1)

        Screen.wrapper(
            check_screen_and_canvas, height=15, arguments=[internal_checks])

    def test_limits(self):
        """
        Check that get_from and print_at limit checking works.
        """
        def internal_checks(screen):
            # Check we have some canvas dimensions
            self.assertEqual(screen.dimensions[1], screen.width)
            self.assertEqual(screen.dimensions[0], screen.height)

            # Basic limit checking
            self.assertIsNone(screen.get_from(-1, -1))
            self.assertIsNone(screen.get_from(screen.width, screen.height))

            # Printing off-screen should not fail, but do nothing.
            screen.print_at("hello", 0, -1)
            screen.print_at("hello", 0, screen.height)

            # Printing across screen edge should crop.
            screen.print_at("12345", -1, 0)
            char, fg, _, bg = screen.get_from(0, 0)
            self.assertEqual(char, ord("2"))
            self.assertEqual(fg, Screen.COLOUR_WHITE)
            self.assertEqual(bg, Screen.COLOUR_BLACK)

        Screen.wrapper(
            check_screen_and_canvas, height=15, arguments=[internal_checks])

    def test_scroll(self):
        """
        Check that scrolling works as expected.
        """
        def internal_checks(screen):
            # New screen is not scrolled.
            self.assertEqual(screen.start_line, 0)

            # Scroll and check it has moved
            screen.scroll()
            self.assertEqual(screen.start_line, 1)

            # Scroll to specific location and check it has moved
            screen.scroll_to(0)
            self.assertEqual(screen.start_line, 0)

        Screen.wrapper(internal_checks, height=15)

    def test_centre(self):
        """
        Check that centre works as expected.
        """
        def internal_checks(screen):
            screen.centre("1234", 0)
            char, fg, _, bg = screen.get_from((screen.width - 4) // 2, 0)
            self.assertEqual(char, ord("1"))
            self.assertEqual(fg, Screen.COLOUR_WHITE)
            self.assertEqual(bg, Screen.COLOUR_BLACK)

        Screen.wrapper(internal_checks, height=15)

    def test_draw(self):
        """
        Check that line drawing works as expected.
        """
        def internal_checks(screen):
            # Draw thick and thin lines
            for line_type in (True, False):
                # Draw in opposite directions
                for start in range(0, 11, 10):
                    screen.print_at(str(start), 11, 2)
                    # Horizontal line
                    screen.move(start, 0)
                    screen.draw(10 - start, 0, thin=line_type)
                    res = screen.get_from(1, 0)
                    self.assertEqual(res[0], ord("^" if line_type else "#"))

                    # Check clearing works too
                    screen.draw(start, 0, char=" ", thin=line_type)
                    res = screen.get_from(1, 0)
                    self.assertEqual(res[0], ord(" "))

                    # Vertical line
                    screen.move(0, start)
                    screen.draw(0, 10 - start, thin=line_type)
                    res = screen.get_from(0, 1)
                    self.assertEqual(res[0], ord("|" if line_type else "#"))

                    # Check clearing works too
                    screen.draw(0, start, char=" ", thin=line_type)
                    res = screen.get_from(0, 1)
                    self.assertEqual(res[0], ord(" "))

                    # Diagonal line
                    screen.move(0, start)
                    screen.draw(10, 10 - start, thin=line_type)
                    res = screen.get_from(1, 9 if start else 1)
                    if line_type:
                        self.assertEqual(res[0], ord("'" if start else "\\"))
                    else:
                        self.assertEqual(res[0], ord("7" if start else "Y"))

                    # Check clearing works too
                    screen.move(0, start)
                    screen.draw(10, 10 - start, char=" ", thin=line_type)
                    res = screen.get_from(1, 9 if start else 1)
                    self.assertEqual(res[0], ord(" "))

        Screen.wrapper(
            check_screen_and_canvas,
            height=15,
            unicode_aware=False,
            arguments=[internal_checks])

    def test_polygons(self):
        """
        Check that filled polygons work as expected.
        """
        def internal_checks(screen):
            screen.fill_polygon([[(0, 0), (10, 0), (0, 10), (10, 10)]])
            screen.fill_polygon([[(20, 0), (30, 0), (30, 10), (25, 5), (20, 10)]])
            screen.fill_polygon([[(40, 0), (45, 5), (50, 0), (50, 10), (40, 10)]])
            screen.fill_polygon([[(60, 0), (70, 0), (70, 10), (60, 10)],
                                 [(63, 2), (67, 2), (67, 8), (63, 8)]])
            self.maxDiff = None
            self.assert_canvas_equals(
                screen,
                "Y########7          ##########          .        .          ##########     \n" +
                " Y######7           ##########          #.      .#          ##########     \n" +
                "  Y####7            ##########          ##.    .##          ###    ###     \n" +
                "   Y##7             ##########          ###.  .###          ###    ###     \n" +
                "    Y7              ##########          ####..####          ###    ###     \n" +
                "    ..              ####7Y####          ##########          ###    ###     \n" +
                "   .##.             ###7  Y###          ##########          ###    ###     \n" +
                "  .####.            ##7    Y##          ##########          ###    ###     \n" +
                " .######.           #7      Y#          ##########          ##########     \n" +
                ".########.          7        Y          ##########          ##########     \n")

        Screen.wrapper(
            check_screen_and_canvas,
            height=10,
            unicode_aware=False,
            arguments=[internal_checks])

    def test_last_pos(self):
        """
        Check that screen drawing is efficient and unaffected by draw.
        """
        def internal_checks(screen):
            # Should start with no known location.
            screen.reset()
            self.assertEqual(screen._cur_x, None)
            self.assertEqual(screen._cur_y, None)

            # Drawing should not affect latest update.  This was previously
            # bugged - hence this test case!
            screen.move(0, 0)
            screen.draw(10, 10)
            self.assertEqual(screen._cur_x, None)
            self.assertEqual(screen._cur_y, None)

            # Printing should not affect latest update.
            screen.print_at("Hi", 12, 12)
            self.assertEqual(screen._cur_x, None)
            self.assertEqual(screen._cur_y, None)

            # Refresh should update the last drawn character.
            screen.refresh()
            self.assertEqual(screen._cur_x, 14)
            self.assertEqual(screen._cur_y, 12)

        Screen.wrapper(
            internal_checks,
            height=15,
            unicode_aware=False)

    def test_palette(self):
        """
        Check that we have a valid colour palette.
        """
        def internal_checks(screen):
            # Check basic length
            self.assertGreater(screen.colours, 0)
            self.assertEqual(len(screen.palette), 256 * 3)

            # Should always have fundamental console colours
            for i, c in enumerate((0, 0, 0)):
                self.assertEqual(screen.palette[i], c)
            for i, c in enumerate((128, 0, 0)):
                self.assertEqual(screen.palette[i+3], c)
            for i, c in enumerate((0, 128, 0)):
                self.assertEqual(screen.palette[i+6], c)
            for i, c in enumerate((128, 128, 0)):
                self.assertEqual(screen.palette[i+9], c)
            for i, c in enumerate((0, 0, 128)):
                self.assertEqual(screen.palette[i+12], c)
            for i, c in enumerate((128, 0, 128)):
                self.assertEqual(screen.palette[i+15], c)
            for i, c in enumerate((0, 128, 128)):
                self.assertEqual(screen.palette[i+18], c)
            for i, c in enumerate((192, 192, 192)):
                self.assertEqual(screen.palette[i+21], c)

        Screen.wrapper(internal_checks, height=15)

    def test_putch_and_getch(self):
        """
        Check deprecated features still work.
        """
        def internal_checks(screen):
            for x in range(screen.width):
                for y in range(15):
                    char = randint(0, 255)
                    fg = randint(0, Screen.COLOUR_WHITE)
                    bg = randint(0, Screen.COLOUR_WHITE)
                    attr = randint(0, Screen.A_UNDERLINE)
                    screen.putch(chr(char), x, y, fg, attr, bg)
                    char2, fg2, attr2, bg2 = screen.getch(x, y)
                    self.assertEqual(char, char2)
                    self.assertEqual(fg, fg2)
                    self.assertEqual(attr, attr2)
                    self.assertEqual(bg, bg2)

        Screen.wrapper(internal_checks, height=15)

    def test_open_close(self):
        """
        Check Screen.open works.
        """
        def check_screen(local_screen):
            # If we get here there's not much new to test.  Check that we can
            # draw something without hitting an Exception.
            local_screen.print_at("Hello world!",
                                  0, 0,
                                  colour=Screen.COLOUR_CYAN,
                                  attr=Screen.A_BOLD,
                                  bg=Screen.COLOUR_BLUE)
            local_screen.refresh()

        screen = Screen.open()
        check_screen(screen)
        screen.close()

    def test_refresh(self):
        """
        Check that refresh works.
        """
        def internal_checks(screen):
            # Not much we can do here as refresh will draw to a screen we can't
            # query. Check that we don't hit an Exception on refresh().
            screen.print_at("Hello world!",
                            0, 0,
                            colour=Screen.COLOUR_CYAN,
                            attr=Screen.A_BOLD,
                            bg=Screen.COLOUR_BLUE)
            screen.refresh()

        Screen.wrapper(
            check_screen_and_canvas, height=15, arguments=[internal_checks])

    def test_origin(self):
        """
        Check that Canvas origin is correct.
        """
        def internal_checks(screen):
            canvas = Canvas(screen, 5, 5, 1, 2)
            self.assertEqual(canvas.origin, (1, 2))

        Screen.wrapper(internal_checks, height=15)

    def test_play(self):
        """
        Check that we can play a basic Effect in a Scene.
        """
        def internal_checks(screen):
            # Since the Screen draws things, there's not too much we can do
            # to genuinely verify this without verifying all Scene and Effect
            # function too.  Just play a dummy Effect for now.
            test_effect = MockEffect()
            screen.play([Scene([test_effect], 0)])
            self.assertTrue(test_effect.stop_called)
            self.assertTrue(test_effect.reset_called)

            # Now check that the desired duration is used.
            test_effect = MockEffect(count=6)
            screen.play([Scene([test_effect], 15)])
            self.assertFalse(test_effect.stop_called)
            self.assertTrue(test_effect.reset_called)

            # Now check that delete_count works.
            test_effect = MockEffect(count=6)
            test_effect2 = MockEffect(delete_count=3)
            scene = Scene([test_effect, test_effect2], 15)
            self.assertEqual(len(scene.effects), 2)
            screen.play([scene])
            self.assertEqual(len(scene.effects), 1)
            self.assertEqual(scene.effects[0], test_effect)

        Screen.wrapper(internal_checks, height=15)

    def test_next_scene(self):
        """
        Check that we can play multiple Scenes.
        """
        def internal_checks(screen):
            # First check that we can move between screens.
            test_effect1 = MockEffect(stop=False)
            test_effect2 = MockEffect(count=5)
            screen.play([
                Scene([test_effect1], 5),
                Scene([test_effect2], 0)])
            self.assertTrue(test_effect1.update_called)
            self.assertTrue(test_effect2.update_called)

            # Now check that we can start at the second scene.
            test_effect1 = MockEffect(stop=False)
            scene1 = Scene([test_effect1], 5, name="1")
            test_effect2 = MockEffect(count=3)
            scene2 = Scene([test_effect2], 0, name="2")
            screen.play([scene1, scene2], start_scene=scene2)
            self.assertFalse(test_effect1.update_called)
            self.assertTrue(test_effect2.update_called)

            # Now check that we can move to named scenes.
            test_effect1 = MockEffect(stop=False, next_scene="B")
            test_effect2 = MockEffect(count=5)
            screen.play([
                Scene([test_effect1], 15, name="A"),
                Scene([test_effect2], 0, name="B")])
            self.assertTrue(test_effect1.update_called)
            self.assertTrue(test_effect2.update_called)

            # Now check that bad names cause an exception.
            with self.assertRaises(RuntimeError):
                test_effect1 = MockEffect(stop=False, next_scene="C")
                test_effect2 = MockEffect(count=5)
                screen.play([
                    Scene([test_effect1], 15, name="A"),
                    Scene([test_effect2], 0, name="B")])
            self.assertTrue(test_effect1.update_called)
            self.assertFalse(test_effect2.update_called)

            # Now check that play stops at the end when repeat=False
            test_effect1 = MockEffect(stop=False)
            scene1 = Scene([test_effect1], 5, name="1")
            screen.play([scene1], repeat=False)
            self.assertTrue(test_effect1.update_called)

        Screen.wrapper(internal_checks, height=15)

    def test_forced_update(self):
        """
        Check that forcing an update works as expected.
        """
        def internal_checks(screen):
            # First check that Effects are always drawn at Scene start
            test_effect = MockEffect(count=101, stop_frame=101, frame_rate=100)
            screen.set_scenes([Scene([test_effect], 0)])
            screen.draw_next_frame()
            self.assertTrue(test_effect.update_called)

            # Now check that the Screen honours the long frame rate...
            test_effect.update_called = False
            for _ in range(90):
                screen.draw_next_frame()
            self.assertFalse(test_effect.update_called)

            # Now check that the forced update works as expected.
            screen.force_update()
            screen.draw_next_frame()
            self.assertTrue(test_effect.update_called)

            # Now check that a full refresh works.
            self.assertEqual(len(list(screen._buffer.deltas(0, 100))), 0)
            screen.force_update(full_refresh=True)
            self.assertGreater(len(list(screen._buffer.deltas(0, 100))), 0)

        Screen.wrapper(internal_checks, height=15)

    def test_catch_exceptions(self):
        """
        Check that we can catch exceptions (e.g. for ctrl-c).
        """
        def internal_checks(screen):
            # Not much we can do here as refresh will draw to a screen we can't
            # query. Check that we don't hit an Exception on refresh().
            if sys.platform == "win32":
                # Strictly speaking, this doesn't test catching ctrl-c as
                # it isn't possible to trigger the control handler (even if
                # we don't catch interrupts).  Still a good basic check for
                # input, though.
                event = win32console.PyINPUT_RECORDType(win32console.KEY_EVENT)
                event.Char = "\03"
                event.KeyDown = 1
                event.RepeatCount = 1
                event.ControlKeyState = win32con.LEFT_CTRL_PRESSED
                event.VirtualKeyCode = 67
                event.VirtualScanCode = 46
                screen._stdin.WriteConsoleInput([event])
                event.KeyDown = 0
                screen._stdin.WriteConsoleInput([event])
                ch = screen.get_event()
                self.assertEqual(ch.key_code, 3)
                self.assertIsNone(screen.get_event())
            else:
                # Check Ctrl-c (and no other input)
                os.kill(os.getpid(), signal.SIGINT)
                ch = screen.get_event()
                self.assertEqual(ch.key_code, 3)
                self.assertIsNone(screen.get_event())

                # Check Ctrl-z (and no other input)
                os.kill(os.getpid(), signal.SIGTSTP)
                ch = screen.get_event()
                self.assertEqual(ch.key_code, 26)
                self.assertIsNone(screen.get_event())

        Screen.wrapper(internal_checks, height=15, catch_interrupt=True)

    def test_scroll_redraw(self):
        """
        Check that scrolling works with screen locations.
        """
        def internal_checks(screen):
            # New screen is not scrolled.
            self.assertEqual(screen.start_line, 0)

            # Scroll and check it has not moved
            screen.print_at("Hello", 0, 1)
            for i, c in enumerate("Hello"):
                self.assertEqual(screen.get_from(i, 1)[0], ord(c))
            screen.scroll()
            for i, c in enumerate("Hello"):
                self.assertEqual(screen.get_from(i, 1)[0], ord(c))
            screen.refresh()
            for i, c in enumerate("Hello"):
                self.assertEqual(screen.get_from(i, 1)[0], ord(c))

        Screen.wrapper(internal_checks)

    @staticmethod
    def _inject_key(screen, char):
        """
        Inject a specified character into the input buffers.
        """
        if sys.platform == "win32":
            event = win32console.PyINPUT_RECORDType(win32console.KEY_EVENT)
            event.RepeatCount = 1
            event.ControlKeyState = 0
            event.VirtualScanCode = 0
            if char >= 0:
                event.Char = chr(char)
                event.VirtualKeyCode = ord(chr(char).upper())
            else:
                # Lookup in mapping dicts
                reverse = {v: k for k, v in
                               screen._EXTRA_KEY_MAP.items()}
                if char in reverse:
                    event.VirtualKeyCode = reverse[char]
                else:
                    # Fudge key state required for BACK_TAB if needed.
                    if char == Screen.KEY_BACK_TAB:
                        char = Screen.KEY_TAB
                        event.ControlKeyState = win32con.SHIFT_PRESSED
                    reverse = {v: k for k, v in
                                   screen._KEY_MAP.items()}
                    event.VirtualKeyCode = reverse[char]
            event.KeyDown = 1
            screen._stdin.WriteConsoleInput([event])
            event.KeyDown = 0
            screen._stdin.WriteConsoleInput([event])
        else:
            if char > 0:
                # Curses uses a LIFO stack for key injection, so reverse the
                # byte string to be injected.  Note that this still works for
                # ASCII as it is a single char subset of UTF-8.
                for c in reversed(bytes(chr(char).encode("utf-8"))):
                    curses.ungetch(c)
            else:
                reverse = {v: k for k, v in
                               screen._KEY_MAP.items()}
                curses.ungetch(reverse[char])

    @staticmethod
    def _inject_mouse(screen, x, y, button):
        """
        Inject a mouse event into the input buffers.
        """
        if sys.platform == "win32":
            event = win32console.PyINPUT_RECORDType(win32console.MOUSE_EVENT)
            event.MousePosition.X = x
            event.MousePosition.Y = y
            if button & MouseEvent.LEFT_CLICK != 0:
                event.ButtonState |= win32con.FROM_LEFT_1ST_BUTTON_PRESSED
            if button & MouseEvent.RIGHT_CLICK != 0:
                event.ButtonState |= win32con.RIGHTMOST_BUTTON_PRESSED
            if button & MouseEvent.DOUBLE_CLICK != 0:
                event.EventFlags |= win32con.DOUBLE_CLICK
            screen._stdin.WriteConsoleInput([event])
        else:
            # Curses doesn't like no value in some cases - use a dummy button
            # click which we don't use instead.
            bstate = curses.BUTTON4_CLICKED
            if button & MouseEvent.LEFT_CLICK != 0:
                bstate |= curses.BUTTON1_CLICKED
            if button & MouseEvent.RIGHT_CLICK != 0:
                bstate |= curses.BUTTON3_CLICKED
            if button & MouseEvent.DOUBLE_CLICK != 0:
                bstate |= curses.BUTTON1_DOUBLE_CLICKED
            curses.ungetmouse(0, x, y, 0, bstate)

    def test_key_input(self):
        """
        Check that keyboard input works.
        """
        def internal_checks(screen):
            # Inject a letter and check it is picked up
            self._inject_key(screen, ord("a"))
            ch = screen.get_event()
            self.assertEqual(ch.key_code, ord("a"))
            self.assertIsNone(screen.get_event())

            # Inject a letter and check it is picked up
            self._inject_key(screen, Screen.KEY_BACK_TAB)
            ch = screen.get_event()
            self.assertEqual(ch.key_code, Screen.KEY_BACK_TAB)
            self.assertIsNone(screen.get_event())

            # Check that get_key also works.
            self._inject_key(screen, ord("b"))
            ch = screen.get_key()
            self.assertEqual(ch, ord("b"))
            self.assertIsNone(screen.get_key())

            # Check that unicode input also works
            self._inject_key(screen, ord("├"))
            ch = screen.get_event()
            self.assertEqual(ch.key_code, ord("├"))
            self.assertIsNone(screen.get_event())

            # Check that unicode input colliding with curses KEY_MAP also works (code: 263)
            self._inject_key(screen, ord("ć"))
            ch = screen.get_event()
            self.assertEqual(ch.key_code, ord("ć"))
            self.assertIsNone(screen.get_event())

        Screen.wrapper(internal_checks, height=15, unicode_aware=True)

    def test_mouse_input(self):
        """
        Check that mouse input works.
        """
        def internal_checks(screen):
            # Inject a mouse move and check it is picked up
            self._inject_mouse(screen, 1, 2, 0)
            ev = screen.get_event()
            self.assertEqual(ev.x, 1)
            self.assertEqual(ev.y, 2)
            self.assertEqual(ev.buttons, 0)
            self.assertIsNone(screen.get_event())

            # Check left click
            self._inject_mouse(screen, 2, 3, MouseEvent.LEFT_CLICK)
            ev = screen.get_event()
            self.assertEqual(ev.x, 2)
            self.assertEqual(ev.y, 3)
            self.assertEqual(ev.buttons, MouseEvent.LEFT_CLICK)
            self.assertIsNone(screen.get_event())

            # Check right click
            self._inject_mouse(screen, 0, 0, MouseEvent.RIGHT_CLICK)
            ev = screen.get_event()
            self.assertEqual(ev.x, 0)
            self.assertEqual(ev.y, 0)
            self.assertEqual(ev.buttons, MouseEvent.RIGHT_CLICK)
            self.assertIsNone(screen.get_event())

            # Check double click
            self._inject_mouse(screen, 0, 0, MouseEvent.DOUBLE_CLICK)
            ev = screen.get_event()
            self.assertEqual(ev.x, 0)
            self.assertEqual(ev.y, 0)
            self.assertEqual(ev.buttons, MouseEvent.DOUBLE_CLICK)
            self.assertIsNone(screen.get_event())

        Screen.wrapper(internal_checks, height=15)

    def test_windows_input(self):
        """
        Check that extended keyboard input works on Windows.
        """
        def internal_checks(screen):
            if sys.platform != "win32":
                self.skipTest("Only valid for Windows platforms")

            # Test no mapping by default
            self._inject_key(screen, Screen.KEY_NUMPAD0)
            self.assertIsNone(screen.get_event())

            # Test switching on mapping picks up keys
            screen.map_all_keys(True)
            self._inject_key(screen, Screen.KEY_NUMPAD0)
            ch = screen.get_key()
            self.assertEqual(ch, Screen.KEY_NUMPAD0)
            self.assertIsNone(screen.get_key())

        Screen.wrapper(internal_checks, height=15)

    def test_unhandled_events(self):
        """
        Check that default handling of events works as documented.
        """
        def internal_checks(screen):
            # Check for exit
            for char in ("X", "x", "Q", "q"):
                with self.assertRaises(StopApplication):
                    event = KeyboardEvent(ord(char))
                    screen._unhandled_event_default(event)

            for char in (" ", "\n"):
                with self.assertRaises(NextScene):
                    event = KeyboardEvent(ord(char))
                    screen._unhandled_event_default(event)

        Screen.wrapper(internal_checks, height=15)

    def test_title(self):
        """
        Check that we can change the screen title.
        """
        def internal_checks(screen):
            # It's not possible to read values back, so just check code doesn't
            # crash.
            screen.set_title("Asciimatics test")

        Screen.wrapper(internal_checks, height=15)

    def test_wait(self):
        """
        Check that wait_for_input delays as requested when no input.
        """
        if sys.platform == "win32":
            self.skipTest("Broken on github runner.")
        if not sys.stdout.isatty():
            self.skipTest("Not a valid TTY")

        def internal_checks(screen):
            # Clear any outstanding events - sometimes windows has system events waiting.
            for _ in range (10):
                screen.get_event()
            start = time.time()
            screen.wait_for_input(0.1)
            self.assertGreaterEqual(time.time() - start, 0.1)

        Screen.wrapper(internal_checks, height=15)

    def test_ctrl(self):
        """
        Check that ctrl returns the right values.
        """
        # Check standard alphabetical range
        for i, char in enumerate(range(ord('@'), ord('Z'))):
            self.assertEqual(Screen.ctrl(char), i)
            self.assertEqual(Screen.ctrl(chr(char)), i)
            self.assertEqual(Screen.ctrl(chr(char).lower()), i)

        # Check last few options - which mostly aren't actually returned in
        # Linux and so probably only of limited value, but what the heck!
        for i, char in enumerate(["[", "\\", "]", "^", "_"]):
            self.assertEqual(Screen.ctrl(char), i + 27)

        # Check other things return None - pick boundaries for checks.
        for char in ["?", "`", "\x7f"]:
            self.assertIsNone(Screen.ctrl(char))

    def assert_line_equals(self, canvas, expected, y=0, length=None):
        """
        Assert first line of output to canvas is as expected.
        """
        output = ""
        for x in range(canvas.width):
            char, _, _, _ = canvas.get_from(x, y)
            output += chr(char)
        if length:
            self.assertEqual(output[:length], expected[:length])
        else:
            self.assertEqual(output, expected)

    def test_cjk_glyphs(self):
        """
        Check that CJK languages track double-width glyphs as expected.
        """
        screen = MagicMock(spec=Screen, colours=8, unicode_aware=True)
        canvas = Canvas(screen, 10, 40, 0, 0)

        # Check underflow and overflow work as expected for CJK languages.
        # These languages actually use two characters for some glyphs, so when you query the
        # contents, you will see the value for both characters.  Also, most terminals don't like
        # displaying half glyphs, so asciimatics doesn't even allow it.
        canvas.print_at("ab", -1, 0)
        canvas.print_at("cd", canvas.width - 1, 0)
        self.assert_line_equals(canvas, "b                                      c")

        canvas.reset()
        canvas.print_at("你確", -1, 0)
        canvas.print_at("你確", canvas.width - 1, 0)
        self.assert_line_equals(canvas, " 確確                                     ")

    def test_cjk_glyphs_overwrite(self):
        """
        Check that CJK languages delete half-glyphs correctly.
        """
        screen = Screen.open(unicode_aware=True)
        screen.print_at("aaaa", 0, 0)
        screen.print_at("你確", 0, 1)
        screen.print_at("bbbb", 0, 2)
        screen.refresh()
        screen.print_at("cccc", 0, 0)
        screen.print_at("你確", 1, 1)
        screen.print_at("dddd", 0, 2)
        screen.refresh()

        # Half-glyph appears as an "x" to show error and then double-width glyphs are returned
        # twice, reflecting their extra width.
        self.assert_line_equals(screen, "x你你確確 ", y=1, length=6)
        screen.close()

    def test_zero_width(self):
        """
        Check that zero width modifiers are ignored.
        """
        screen = Screen.open(unicode_aware=True)
        screen.print_at("Xx🛡️🍀🍀xX", 0, 0)
        self.assert_line_equals(screen, "Xx🛡🍀🍀🍀🍀xX", length=9)
        screen.close()

    def test_save_signal_state(self):
        """Tests that the signal state class works properly.

        The _SignalState class must set, save, and restore signals
        when needed.
        """
        if sys.platform == "win32":
            self.skipTest("Windows does not have signals.")

        def dummy_handler():
            """Assign dummy handler to an arbitrary signal."""
            pass
        self.assertNotEqual(signal.getsignal(signal.SIGWINCH), dummy_handler)
        signal_state = _SignalState()
        signal_state.set(signal.SIGWINCH, dummy_handler)
        self.assertEqual(signal.getsignal(signal.SIGWINCH), dummy_handler)
        signal_state.restore()
        self.assertNotEqual(signal.getsignal(signal.SIGWINCH), dummy_handler)

    def test_signal(self):
        """
        Check that signals are restored after using _CursesScreen
        """
        if sys.platform == "win32":
            self.skipTest("Windows does not have signals.")

        def dummy_signal_handler():
            """Dummy previous signal handler."""
            pass
        outer_state = _SignalState()
        self.assertNotEqual(signal.getsignal(signal.SIGWINCH), dummy_signal_handler)
        outer_state.set(signal.SIGWINCH, dummy_signal_handler)
        self.assertEqual(signal.getsignal(signal.SIGWINCH), dummy_signal_handler)
        Screen.wrapper(self.signal_check)
        self.assertEqual(signal.getsignal(signal.SIGWINCH), dummy_signal_handler)
        outer_state.restore()
        self.assertNotEqual(signal.getsignal(signal.SIGWINCH), dummy_signal_handler)

    def signal_check(self, screen):
        """Dummy callback for screen wrapper."""
        self.assertEqual(signal.getsignal(signal.SIGWINCH), screen._resize_handler)

    def test_function_decorator(self):
        """
        Check ManagedScreen function decorator works.
        """
        @ManagedScreen
        def demo(screen=None):
            canvas = Canvas(screen, 10, 40, 0, 0)

            # Check underflow and overflow work as expected
            canvas.print_at("ab", -1, 0)
            canvas.print_at("cd", canvas.width - 1, 0)
            self.assert_line_equals(canvas, "b                                      c")

        demo()

    @ManagedScreen
    def test_class_method_decorator(self, screen=None):
        """
        Check ManagedScreen method decorator works.
        """
        canvas = Canvas(screen, 10, 40, 0, 0)

        # Check underflow and overflow work as expected
        canvas.print_at("ab", -1, 0)
        canvas.print_at("cd", canvas.width - 1, 0)
        self.assert_line_equals(canvas, "b                                      c")

    def test_double_buffer(self):
        """
        Check _DoubleBuffer works.
        """
        buffer = _DoubleBuffer(20, 10)

        # Check clear works
        self.assertEqual(buffer._double_buffer[0][0], (' ', 7, 0, 0, 1))
        self.assertEqual(buffer._double_buffer[19][9], (' ', 7, 0, 0, 1))
        buffer.clear(1, 0, 2)
        self.assertEqual(buffer._double_buffer[0][0], (' ', 1, 0, 2, 1))
        self.assertEqual(buffer._double_buffer[19][9], (' ', 1, 0, 2, 1))

        # Check clear clips as needed.
        buffer.clear(3, 1, 4, x=1, y=1, w=100, h=100)
        self.assertEqual(buffer._double_buffer[0][0], (' ', 1, 0, 2, 1))
        self.assertEqual(buffer._double_buffer[19][9], (' ', 3, 1, 4, 1))

    def test_context_manager(self):
        """
        Check ManagedScreen context manager works.
        """
        with ManagedScreen() as screen:
            canvas = Canvas(screen, 10, 40, 0, 0)

            # Check underflow and overflow work as expected
            canvas.print_at("ab", -1, 0)
            canvas.print_at("cd", canvas.width - 1, 0)
            self.assert_line_equals(canvas, "b                                      c")


if __name__ == '__main__':
    unittest.main()