"""Popout viewport math: persistent intent + drift tolerance."""

from __future__ import annotations

from typing import NamedTuple


class Viewport(NamedTuple):
    """Where and how large the user wants popout content to appear.

    Three numbers, no aspect. Aspect is a property of the currently-
    displayed post and is recomputed from actual content on every
    navigation. The viewport stays put across navigations; the window
    rect is a derived projection (Viewport, content_aspect) → (x,y,w,h).

    `long_side` is the binding edge length: for landscape it becomes
    width, for portrait it becomes height. Symmetric across the two
    orientations, which is the property that breaks the
    width-anchor ratchet that the previous `_fit_to_content` had.
    """
    center_x: float
    center_y: float
    long_side: float


# Maximum drift between our last-dispatched window rect and the current
# Hyprland-reported rect that we still treat as "no user action happened."
# Anything within this tolerance is absorbed (Hyprland gap rounding,
# subpixel accumulation, decoration accounting). Anything beyond it is
# treated as "the user dragged or resized the window externally" and the
# persistent viewport gets updated from current state.
#
# 2px is small enough not to false-positive on real user drags (which
# are always tens of pixels minimum) and large enough to absorb the
# 1-2px per-nav drift that compounds across many navigations.
_DRIFT_TOLERANCE = 2