"""Application configuration (grid, snapping, routing, animation, theming)."""
from __future__ import annotations

from PyQt6.QtCore import QObject, pyqtSignal


class AppConfig(QObject):
    """Live, observable editor configuration.

    Emitting :attr:`changed` lets the canvas and items refresh when the user
    tweaks a setting in the configuration dialog.
    """

    changed = pyqtSignal()

    def __init__(self, parent: QObject | None = None) -> None:
        super().__init__(parent)
        self.grid_size = 20
        self.show_grid = True
        self.snap_to_grid = True
        # Draw a small arc "hop" where an edge crosses another edge.
        self.arc_on_crossing = True
        self.arc_radius = 5.0
        # Routing stub length from a port before turning.
        self.route_stub = 20
        # Flow animation.
        self.animation_speed = 1.0  # multiplier
        self.color_scheme = "default"
        # Canvas theme.
        self.background = "#fafafa"
        self.grid_color = "#e0e0e0"

    def snap(self, value: float) -> float:
        if not self.snap_to_grid or self.grid_size <= 0:
            return value
        g = self.grid_size
        return round(value / g) * g

    def snap_point(self, x: float, y: float) -> tuple[float, float]:
        return self.snap(x), self.snap(y)

    def emit_changed(self) -> None:
        self.changed.emit()

    def to_dict(self) -> dict:
        return {
            "grid_size": self.grid_size,
            "show_grid": self.show_grid,
            "snap_to_grid": self.snap_to_grid,
            "arc_on_crossing": self.arc_on_crossing,
            "arc_radius": self.arc_radius,
            "route_stub": self.route_stub,
            "animation_speed": self.animation_speed,
            "color_scheme": self.color_scheme,
            "background": self.background,
            "grid_color": self.grid_color,
        }

    def update_from(self, data: dict) -> None:
        for k, v in data.items():
            if hasattr(self, k):
                setattr(self, k, v)
        self.changed.emit()