"""Ground truth for the duel: where the target element really is on screen.

Every GTK app on the virtual desktop exposes its widgets through the AT-SPI
accessibility bus. a11y_dump.py lists the visible ones with their screen
boxes, so a predicted click is scored as a hit when it lands inside the box,
whatever the current theme, font size, or window layout.
"""

import json
import re
import subprocess
import time
from dataclasses import dataclass
from pathlib import Path

DUMP = Path(__file__).with_name("a11y_dump.py")


@dataclass
class Element:
    app: str
    role: str
    name: str
    x: int
    y: int
    w: int
    h: int

    @property
    def box(self):
        return self.x, self.y, self.x + self.w, self.y + self.h

    @property
    def center(self):
        return self.x + self.w // 2, self.y + self.h // 2

    def contains(self, point):
        px, py = point
        return self.x <= px < self.x + self.w and self.y <= py < self.y + self.h


@dataclass
class Target:
    """What a challenge step must hit: an element name, optionally narrowed by role/app."""
    name: str
    role: str | None = None
    app: str | None = None


ROLE_ALIASES = {"push button": "button"}  # AT-SPI renamed the role in 2.5x


def _role(role: str) -> str:
    return ROLE_ALIASES.get(role, role)


def _norm(s: str) -> str:
    return re.sub(r"[_.…\s]+", " ", s).strip().lower()


def elements(env, apps=()) -> list[Element]:
    out = subprocess.run(["/usr/bin/python3", str(DUMP), *apps], env=env,
                         capture_output=True, text=True, timeout=30).stdout
    return [Element(**json.loads(line)) for line in out.splitlines() if line.startswith("{")]


def find(env, target: Target, width: int, height: int, wait: float = 3.0) -> Element | None:
    """The smallest visible on-screen element matching the target, if any.

    Retries for up to `wait` seconds, since dialogs and menus can appear late.
    """
    apps = (target.app,) if target.app else ()
    deadline = time.time() + wait
    while True:
        matches = [
            e for e in elements(env, apps)
            if _norm(e.name) == _norm(target.name)
            and (target.role is None or _role(e.role) == _role(target.role))
            and e.x < width and e.y < height and e.x + e.w > 0 and e.y + e.h > 0
        ]
        if matches or time.time() > deadline:
            return min(matches, key=lambda e: e.w * e.h, default=None)
        time.sleep(0.5)