import os
from typing import Any, Callable
from textual.css.query import NoMatches, TooManyMatches
from textual.dom import DOMNode
from textual.errors import NoWidget
from textual.events import Event, Key, MouseDown, MouseMove, MouseUp
from textual.geometry import Offset
from textual.pilot import Pilot
from textual.screen import Screen
from textual_paint.paint import PaintApp

def unique_file(path: str) -> str:
    filename, extension = os.path.splitext(path)
    counter = 1

    while os.path.exists(path):
        path = f"{filename}_{counter}{extension}"
        counter += 1

    return path

def indent(text: str, spaces: int) -> str:
    return "\n".join(" " * spaces + line for line in text.splitlines())

OUTPUT_FILE = unique_file("tests/test_paint_something.py")

steps: list[tuple[Event, Offset, str, int|None]] = []

def get_selector(target: DOMNode) -> tuple[str, int|None]:
    """Return a selector that can be used to find the widget."""
    assert app is not None, "app should be set by now"
    widget = target
    if widget.id:
        return f"#{widget.id}", None
    selector = widget.css_identifier
    while widget.parent and not isinstance(widget.parent, Screen):
        widget = widget.parent
        if widget.id:
            selector = f"#{widget.id} {selector}"
            break
        else:
            selector = f"{widget.css_identifier} {selector}"
    try:
        query_result = app.query_one(selector)
    except TooManyMatches:
        return selector, app.query(selector).nodes.index(target)
        # smarter differentiators would be nice, like tooltip or text content,
        # but at least with indices, you'll know when you changed the tab order
    except NoMatches:
        raise Exception(f"Selector {selector!r} didn't match the target widget ({target!r})")
    if query_result is not target:
        raise Exception(f"Selector {selector!r} matched a different widget than the target ({query_result!r} rather than {target!r})")

    return selector, None

original_on_event = PaintApp.on_event
async def on_event(self: PaintApp, event: Event) -> None:
    await original_on_event(self, event)
    if isinstance(event, (MouseDown, MouseMove, MouseUp)):
        try:
            widget, _ = self.get_widget_at(*event.screen_offset)
        except NoWidget:
            return
        offset = event.screen_offset - widget.region.offset
        steps.append((event, offset, *get_selector(widget)))
    elif isinstance(event, Key):
        if event.key == "ctrl+z":
            steps.pop()
            run() # restart the app to replay up to this point
        elif event.key == "ctrl+c":
            save_replay()

app: PaintApp | None = None
next_after_exit: Callable[[], None] | None = None

async def async_exec(code: str, **kwargs: object) -> object:
    # This dict will be used for passing variables to the `exec`ed code
    # as well as retrieving the function defined by the code.
    scope = kwargs

    # Make an async function with the code and `exec` it
    exec(f"async def async_exec_code():\n{indent(code, 4)}", scope)

    # Get `async_exec_code` from the scope, call it and return the result
    return await scope['async_exec_code']()

async def replay_steps(pilot: Pilot[Any]) -> None:
    global app
    assert app is not None, "app should be set by now"
    # for event, offset, selector, index in steps:
    #     ...
    if not steps:
        return
    # pilot = Pilot(app)
    # await pilot._wait_for_screen()
    await async_exec(get_replay_code(), pilot=pilot, Offset=Offset)

def run() -> None:
    global app, next_after_exit
    def startup_and_replay() -> None:
        global app, next_after_exit
        next_after_exit = None # important to allowing you to exit; don't keep launching the app
        app = PaintApp()
        app.on_event = on_event.__get__(app)
        # app.call_later(replay_steps)
        # app.run()
        app.run(auto_pilot=replay_steps)
        # run is blocking, so this will happen after the app exits
        if next_after_exit:
            next_after_exit()
    if app is not None:
        # exit can't be awaited, because it stops the whole event loop (eventually)
        # but we need to wait for the event loop to stop before we can start a new app
        next_after_exit = startup_and_replay
        app.exit()
    else:
        startup_and_replay()


def get_replay_code() -> str:
    steps_code = ""
    for event, offset, selector, index in steps:
        if isinstance(event, MouseDown):
            if index is None:
                steps_code += f"await pilot.click({selector!r}, offset=Offset({offset.x}, {offset.y}))\n"
            else:
                steps_code += f"widget = pilot.app.query({selector!r})[{index!r}]\n"
                # can't pass a widget to pilot.click, only a selector, or None
                steps_code += f"await pilot.click(offset=Offset({offset.x}, {offset.y}) + widget.region.offset)\n"
        elif isinstance(event, MouseMove):
            # TODO: generate code for drags (but not extraneous mouse movement)
            pass
        elif isinstance(event, MouseUp):
            pass
        elif isinstance(event, Key):
            steps_code += f"await pilot.press({event.key!r})\n"
        else:
            raise Exception(f"Unexpected event type {type(event)}")
    return steps_code


def save_replay() -> None:
    assert app is not None, "app should be set by now"

    script = f"""\
from pathlib import Path, PurePath
from typing import Awaitable, Callable, Iterable, Protocol

import pytest
from textual.geometry import Offset
from textual.pilot import Pilot
from textual.widgets import Input

class SnapCompareType(Protocol):
    \"\"\"Type of the function returned by the snap_compare fixture.\"\"\"
    def __call__(
        self,
        app_path: str | PurePath,
        press: Iterable[str] = (),
        terminal_size: tuple[int, int] = (80, 24),
        run_before: Callable[[Pilot], Awaitable[None] | None] | None = None,  # type: ignore
    ) -> bool:
        ...

# Relative paths are treated as relative to this file, when using snap_compare.
PAINT = Path("../src/textual_paint/paint.py")

# Prevent flaky tests due to timing issues.
Input.cursor_blink = False  # type: ignore

def test_paint_something(snap_compare: SnapCompareType):
    async def test_paint_something_steps(pilot: Pilot[None]):
{indent(get_replay_code(), 8)}

    assert snap_compare(PAINT, run_before=test_paint_something_steps, terminal_size=({app.size.width}, {app.size.height}))
"""
    with open(OUTPUT_FILE, "w") as f:
        f.write(script)
    # app.exit(None, Text(f"Saved replay to {OUTPUT_FILE}"))

if __name__ == "__main__":
    run()