"""Where the mini timer appears.

Two mechanisms, because one is not enough:

* **X11** — the application may place its own window, so the computed point is
  applied directly.
* **Wayland** — it may not: a client cannot position an xdg-toplevel, and
  setting `x`/`y` is quietly ignored. KWin *can* place it, through the same
  window rule that already forces "keep above", so the point is written there.

The geometry maths is a pure function so it can be checked without a screen.
"""

from __future__ import annotations

from dataclasses import dataclass

CORNERS = (
    "top-left",
    "top-centre",
    "top-right",
    "bottom-left",
    "bottom-centre",
    "bottom-right",
    "centre",
    "remember",
)

# What the settings page shows, in the order it shows them.
CORNER_LABELS = {
    "top-left": "Top left",
    "top-centre": "Top centre",
    "top-right": "Top right",
    "bottom-left": "Bottom left",
    "bottom-centre": "Bottom centre",
    "bottom-right": "Bottom right",
    "centre": "Centre of the screen",
    "remember": "Where I last dragged it",
}


@dataclass(frozen=True, slots=True)
class Rect:
    """A screen's usable area — panels and docks already taken off."""

    x: int
    y: int
    width: int
    height: int


def point_for(corner: str, screen: Rect, size: tuple[int, int], margin: int = 24) -> tuple[int, int]:
    """Top-left point that puts a `size` window in `corner` of `screen`."""
    width, height = size
    margin = max(0, margin)

    vertical, _, horizontal = corner.partition("-")
    if corner == "centre":
        vertical, horizontal = "centre", "centre"

    if horizontal == "left":
        x = screen.x + margin
    elif horizontal == "right":
        x = screen.x + screen.width - width - margin
    else:  # centre
        x = screen.x + (screen.width - width) // 2

    if vertical == "top":
        y = screen.y + margin
    elif vertical == "bottom":
        y = screen.y + screen.height - height - margin
    else:  # centre
        y = screen.y + (screen.height - height) // 2

    # Never place it off-screen, however small the screen or large the margin.
    x = max(screen.x, min(x, screen.x + max(screen.width - width, 0)))
    y = max(screen.y, min(y, screen.y + max(screen.height - height, 0)))
    return int(x), int(y)