import contextlib
import functools
import io
import shlex
import sys
from typing import List

import pytest
from hecate import Runner

import babi


def test_position_repr():
    ret = repr(babi.Position())
    assert ret == 'Position(file_line=0, cursor_line=0, x=0, x_hint=0)'


@pytest.mark.parametrize(
    ('s', 'lines', 'nl', 'mixed'),
    (
        pytest.param('', [''], '\n', False, id='trivial'),
        pytest.param('1\n2\n', ['1', '2', ''], '\n', False, id='lf'),
        pytest.param('1\r\n2\r\n', ['1', '2', ''], '\r\n', False, id='crlf'),
        pytest.param('1\r\n2\n', ['1', '2', ''], '\n', True, id='mixed'),
        pytest.param('1\n2', ['1', '2', ''], '\n', False, id='noeol'),
    ),
)
def test_get_lines(s, lines, nl, mixed):
    ret = babi._get_lines(io.StringIO(s))
    assert ret == (lines, nl, mixed)


@functools.lru_cache(maxsize=1)
def _tmux_height_off_by_one():
    with Runner(sys.executable, '-c', 'input(">")', height=24) as h:
        h.await_text('>')
        cmd = ('display', '-t0', '-p', '#{pane_height}')
        height = int(h.tmux.execute_command(*cmd))
        h.press('Enter')
        h.await_exit()
    assert height in (23, 24)
    return height == 23


class PrintsErrorRunner(Runner):
    def __init__(self, *args, height=24, **kwargs):
        self._screenshots: List[str] = []
        if _tmux_height_off_by_one():  # pragma: no cover (tmux 2.1)
            height += 1
        super().__init__(*args, height=height, **kwargs)

    def screenshot(self, *args, **kwargs):
        ret = super().screenshot(*args, **kwargs)
        if not self._screenshots or self._screenshots[-1] != ret:
            self._screenshots.append(ret)
        return ret

    @contextlib.contextmanager
    def _onerror(self):
        try:
            yield
        except Exception:  # pragma: no cover
            # take a screenshot of the final state
            self.screenshot()
            print('=' * 79, flush=True)
            for screenshot in self._screenshots:
                print(screenshot, end='', flush=True)
                print('=' * 79, flush=True)
            raise

    def await_exit(self, *args, **kwargs):
        with self._onerror():
            return super().await_exit(*args, **kwargs)

    def await_text(self, text, timeout=None):
        """copied from the base implementation but doesn't munge newlines"""
        with self._onerror():
            for _ in self.poll_until_timeout(timeout):
                screen = self.screenshot()
                if text in screen:  # pragma: no branch
                    return
            raise AssertionError(
                f'Timeout while waiting for text {text!r} to appear',
            )

    def await_text_missing(self, s):
        """largely based on await_text"""
        with self._onerror():
            for _ in self.poll_until_timeout():
                screen = self.screenshot()
                munged = screen.replace('\n', '')
                if s not in munged:  # pragma: no branch
                    return
            raise AssertionError(
                f'Timeout while waiting for text {s!r} to disappear',
            )

    def get_pane_size(self):
        cmd = ('display', '-t0', '-p', '#{pane_width}\t#{pane_height}')
        w, h = self.tmux.execute_command(*cmd).split()
        return int(w), int(h)

    def _get_cursor_position(self):
        cmd = ('display', '-t0', '-p', '#{cursor_x}\t#{cursor_y}')
        x, y = self.tmux.execute_command(*cmd).split()
        return int(x), int(y)

    def await_cursor_position(self, *, x, y):
        with self._onerror():
            for _ in self.poll_until_timeout():
                pos = self._get_cursor_position()
                if pos == (x, y):  # pragma: no branch
                    return

            raise AssertionError(
                f'Timeout while waiting for cursor to reach {(x, y)}\n'
                f'Last cursor position: {pos}',
            )

    @contextlib.contextmanager
    def resize(self, width, height):
        current_w, current_h = self.get_pane_size()
        sleep_cmd = (
            'bash', '-c',
            f'echo {"*" * (current_w * current_h)} && '
            f'exec sleep infinity',
        )

        panes = 0

        hsplit_w = current_w - width - 1
        if hsplit_w > 0:
            cmd = ('split-window', '-ht0', '-l', hsplit_w, *sleep_cmd)
            self.tmux.execute_command(*cmd)
            panes += 1

        vsplit_h = current_h - height - 1
        if vsplit_h > 0:  # pragma: no branch  # TODO
            cmd = ('split-window', '-vt0', '-l', vsplit_h, *sleep_cmd)
            self.tmux.execute_command(*cmd)
            panes += 1

        assert self.get_pane_size() == (width, height)
        try:
            yield
        finally:
            for _ in range(panes):
                self.tmux.execute_command('kill-pane', '-t1')


@contextlib.contextmanager
def run(*args, color=True, **kwargs):
    cmd = (sys.executable, '-mcoverage', 'run', '-m', 'babi', *args)
    quoted = ' '.join(shlex.quote(p) for p in cmd)
    term = 'screen-256color' if color else 'screen'
    cmd = ('bash', '-c', f'export TERM={term}; exec {quoted}')
    with PrintsErrorRunner(*cmd, **kwargs) as h:
        h.await_text(babi.VERSION_STR)
        yield h


@contextlib.contextmanager
def and_exit(h):
    yield
    # only try and exit in non-exceptional cases
    h.press('C-x')
    h.await_exit()


@pytest.mark.parametrize('color', (True, False))
def test_color_test(color):
    with run('--color-test', color=color) as h, and_exit(h):
        h.await_text('*  1*  2')


def test_can_start_without_color():
    with run(color=False) as h, and_exit(h):
        pass


def test_window_height_2(tmpdir):
    # 2 tall:
    # - header is hidden, otherwise behaviour is normal
    f = tmpdir.join('f.txt')
    f.write('hello world')

    with run(str(f)) as h, and_exit(h):
        h.await_text('hello world')

        with h.resize(80, 2):
            h.await_text_missing(babi.VERSION_STR)
            assert h.screenshot() == 'hello world\n\n'
            h.press('C-j')
            h.await_text('unknown key')

        h.await_text(babi.VERSION_STR)


def test_window_height_1(tmpdir):
    # 1 tall:
    # - only file contents as body
    # - status takes precedence over body, but cleared after single action
    f = tmpdir.join('f.txt')
    f.write('hello world')

    with run(str(f)) as h, and_exit(h):
        h.await_text('hello world')

        with h.resize(80, 1):
            h.await_text_missing(babi.VERSION_STR)
            assert h.screenshot() == 'hello world\n'
            h.press('C-j')
            h.await_text('unknown key')
            h.press('Right')
            h.await_text_missing('unknown key')
            h.press('Down')


def test_status_clearing_behaviour():
    with run() as h, and_exit(h):
        h.press('C-j')
        h.await_text('unknown key')
        for i in range(24):
            h.press('LEFT')
        h.await_text('unknown key')
        h.press('LEFT')
        h.await_text_missing('unknown key')


def test_reacts_to_resize():
    with run() as h, and_exit(h):
        first_line = h.screenshot().splitlines()[0]
        with h.resize(40, 20):
            # the first line should be different after resize
            h.await_text_missing(first_line)


def test_mixed_newlines(tmpdir):
    f = tmpdir.join('f')
    f.write_binary(b'foo\nbar\r\n')
    with run(str(f)) as h, and_exit(h):
        # should start as modified
        h.await_text('f *')
        h.await_text(r"mixed newlines will be converted to '\n'")


def test_arrow_key_movement(tmpdir):
    f = tmpdir.join('f')
    f.write(
        'short\n'
        '\n'
        'long long long long\n',
    )
    with run(str(f)) as h, and_exit(h):
        h.await_text('short')
        h.await_cursor_position(x=0, y=1)
        # should not go off the beginning of the file
        h.press('Left')
        h.await_cursor_position(x=0, y=1)
        h.press('Up')
        h.await_cursor_position(x=0, y=1)
        # left and right should work
        h.press('Right')
        h.press('Right')
        h.await_cursor_position(x=2, y=1)
        h.press('Left')
        h.await_cursor_position(x=1, y=1)
        # up should still be a noop on line 1
        h.press('Up')
        h.await_cursor_position(x=1, y=1)
        # down once should put it on the beginning of the second line
        h.press('Down')
        h.await_cursor_position(x=0, y=2)
        # down again should restore the x positon on the next line
        h.press('Down')
        h.await_cursor_position(x=1, y=3)
        # down once more should put it on the special end-of-file line
        h.press('Down')
        h.await_cursor_position(x=0, y=4)
        # should not go off the end of the file
        h.press('Down')
        h.await_cursor_position(x=0, y=4)
        h.press('Right')
        h.await_cursor_position(x=0, y=4)
        # left should put it at the end of the line
        h.press('Left')
        h.await_cursor_position(x=19, y=3)
        # right should put it to the next line
        h.press('Right')
        h.await_cursor_position(x=0, y=4)
        # if the hint-x is too high it should not go past the end of line
        h.press('Left')
        h.press('Up')
        h.press('Up')
        h.await_cursor_position(x=5, y=1)
        # and moving back down should still retain the hint-x
        h.press('Down')
        h.press('Down')
        h.await_cursor_position(x=19, y=3)


def test_scrolling_arrow_key_movement(tmpdir):
    f = tmpdir.join('f')
    f.write('\n'.join(f'line_{i}' for i in range(10)))

    with run(str(f), height=10) as h, and_exit(h):
        h.await_text('line_7')
        # we should not have scrolled after 7 presses
        for _ in range(7):
            h.press('Down')
        h.await_text('line_0')
        h.await_cursor_position(x=0, y=8)
        # but this should scroll down
        h.press('Down')
        h.await_text('line_8')
        h.await_cursor_position(x=0, y=4)
        assert h.screenshot().splitlines()[4] == 'line_8'
        # we should not have scrolled after 3 up presses
        for _ in range(3):
            h.press('Up')
        h.await_text('line_9')
        # but this should scroll up
        h.press('Up')
        h.await_text('line_0')


@pytest.mark.parametrize('k', ('End', 'C-e'))
def test_end_key(tmpdir, k):
    f = tmpdir.join('f')
    f.write('hello world\nhello world\n')

    with run(str(f)) as h, and_exit(h):
        h.await_text('hello world')
        h.await_cursor_position(x=0, y=1)
        h.press(k)
        h.await_cursor_position(x=11, y=1)
        h.press('Down')
        h.await_cursor_position(x=11, y=2)


@pytest.mark.parametrize('k', ('Home', 'C-a'))
def test_home_key(tmpdir, k):
    f = tmpdir.join('f')
    f.write('hello world\nhello world\n')

    with run(str(f)) as h, and_exit(h):
        h.await_text('hello world')
        h.press('Down')
        h.press('Left')
        h.await_cursor_position(x=11, y=1)
        h.press(k)
        h.await_cursor_position(x=0, y=1)
        h.press('Down')
        h.await_cursor_position(x=0, y=2)


def test_resize_scrolls_up(tmpdir):
    f = tmpdir.join('f')
    f.write('\n'.join(f'line_{i}' for i in range(10)))

    with run(str(f)) as h, and_exit(h):
        h.await_text('line_9')

        for _ in range(7):
            h.press('Down')
        h.await_cursor_position(x=0, y=8)

        # a resize to a height of 10 should not scroll
        with h.resize(80, 10):
            h.await_text_missing('line_8')
            h.await_cursor_position(x=0, y=8)

        h.await_text('line_8')

        # but a resize to smaller should
        with h.resize(80, 9):
            h.await_text_missing('line_0')
            h.await_cursor_position(x=0, y=3)
            # make sure we're still on the same line
            assert h.screenshot().splitlines()[3] == 'line_7'


def test_very_narrow_window_status():
    with run(height=50) as h, and_exit(h):
        with h.resize(5, 50):
            h.press('C-j')
            h.await_text('unkno')


def test_horizontal_scrolling(tmpdir):
    f = tmpdir.join('f')
    lots_of_text = ''.join(
        ''.join(str(i) * 10 for i in range(10))
        for _ in range(10)
    )
    f.write(f'line1\n{lots_of_text}\n')

    with run(str(f)) as h, and_exit(h):
        h.await_text('6777777777»')
        h.press('Down')
        for _ in range(78):
            h.press('Right')
        h.await_text('6777777777»')
        h.press('Right')
        h.await_text('«77777778')
        h.await_text('344444444445»')
        h.await_cursor_position(x=7, y=2)
        for _ in range(71):
            h.press('Right')
        h.await_text('«77777778')
        h.await_text('344444444445»')
        h.press('Right')
        h.await_text('«444445')
        h.await_text('1222»')


def test_horizontal_scrolling_exact_width(tmpdir):
    f = tmpdir.join('f')
    f.write('0' * 80)

    with run(str(f)) as h, and_exit(h):
        h.await_text('000')
        for _ in range(78):
            h.press('Right')
        h.await_text_missing('»')
        h.await_cursor_position(x=78, y=1)
        h.press('Right')
        h.await_text('«0000000')
        h.await_cursor_position(x=7, y=1)


def test_horizontal_scrolling_narrow_window(tmpdir):
    f = tmpdir.join('f')
    f.write(''.join(str(i) * 10 for i in range(10)))

    with run(str(f)) as h, and_exit(h):
        with h.resize(5, 24):
            h.await_text('0000»')
            for _ in range(3):
                h.press('Right')
            h.await_text('0000»')
            h.press('Right')
            h.await_cursor_position(x=3, y=1)
            h.await_text('«000»')
            for _ in range(6):
                h.press('Right')
            h.await_text('«001»')


def test_window_width_1(tmpdir):
    f = tmpdir.join('f')
    f.write('hello')

    with run(str(f)) as h, and_exit(h):
        with h.resize(1, 24):
            h.await_text('»')
            for _ in range(3):
                h.press('Right')
        h.await_text('hello')
        h.await_cursor_position(x=3, y=1)


def test_basic_text_editing(tmpdir):
    with run() as h, and_exit(h):
        h.press('hello world')
        h.await_text('hello world')
        h.press('Down')
        h.press('bye!')
        h.await_text('bye!')
        assert h.screenshot().strip().endswith('world\nbye!')


def test_backspace_at_beginning_of_file():
    with run() as h, and_exit(h):
        h.press('Bspace')
        h.await_text_missing('unknown key')
        assert h.screenshot().strip().splitlines()[1:] == []
        assert '*' not in h.screenshot()


def test_backspace_joins_lines(tmpdir):
    f = tmpdir.join('f')
    f.write('foo\nbar\nbaz\n')

    with run(str(f)) as h, and_exit(h):
        h.await_text('foo')
        h.press('Down')
        h.press('Bspace')
        h.await_text('foobar')
        h.await_text('f *')
        h.await_cursor_position(x=3, y=1)
        # pressing down should retain the X position
        h.press('Down')
        h.await_cursor_position(x=3, y=2)


def test_backspace_at_end_of_file_still_allows_scrolling_down(tmpdir):
    f = tmpdir.join('f')
    f.write('hello world')

    with run(str(f)) as h, and_exit(h):
        h.await_text('hello world')
        h.press('Down')
        h.press('Bspace')
        h.press('Down')
        h.await_cursor_position(x=0, y=2)
        assert '*' not in h.screenshot()


def test_backspace_deletes_text(tmpdir):
    f = tmpdir.join('f')
    f.write('ohai there')

    with run(str(f)) as h, and_exit(h):
        h.await_text('ohai there')
        for _ in range(3):
            h.press('Right')
        h.press('Bspace')
        h.await_text('ohi')
        h.await_text('f *')
        h.await_cursor_position(x=2, y=1)


def test_delete_at_end_of_file(tmpdir):
    with run() as h, and_exit(h):
        h.press('DC')
        h.await_text_missing('unknown key')
        h.await_text_missing('*')


def test_delete_removes_character_afterwards(tmpdir):
    f = tmpdir.join('f')
    f.write('hello world')

    with run(str(f)) as h, and_exit(h):
        h.await_text('hello world')
        h.press('Right')
        h.press('DC')
        h.await_text('hllo world')
        h.await_text('f *')


def test_delete_at_end_of_line(tmpdir):
    f = tmpdir.join('f')
    f.write('hello\nworld\n')

    with run(str(f)) as h, and_exit(h):
        h.await_text('hello')
        h.press('Down')
        h.press('Left')
        h.press('DC')
        h.await_text('helloworld')
        h.await_text('f *')


def test_press_enter_beginning_of_file(tmpdir):
    f = tmpdir.join('f')
    f.write('hello world')

    with run(str(f)) as h, and_exit(h):
        h.await_text('hello world')
        h.press('Enter')
        h.await_text('\n\nhello world')
        h.await_cursor_position(x=0, y=2)
        h.await_text('f *')


def test_press_enter_mid_line(tmpdir):
    f = tmpdir.join('f')
    f.write('hello world')

    with run(str(f)) as h, and_exit(h):
        h.await_text('hello world')
        for _ in range(5):
            h.press('Right')
        h.press('Enter')
        h.await_text('hello\n world')
        h.await_cursor_position(x=0, y=2)
        h.press('Up')
        h.await_cursor_position(x=0, y=1)