from dataclasses import dataclass
from typing import Literal

from PySide6.QtCore import Qt


ArrowStyle = Literal["open", "half", "filled"]


@dataclass(frozen=True)
class ConnectionStyle:
    color: str = "#285f9e"
    selected_color: str = "#f59e0b"
    width: float = 2.5
    selected_width: float = 4.0
    line_style: Qt.PenStyle = Qt.PenStyle.SolidLine
    arrow_at_source: bool = False
    arrow_at_target: bool = True
    arrow_size: float = 10.0
    arrow_style: ArrowStyle = "filled"

    def __post_init__(self) -> None:
        if self.arrow_style not in {"open", "half", "filled"}:
            raise ValueError(f"Unknown connection arrow style: {self.arrow_style}")


# This is the intentional code-level styling point for every port/connection type.
CONNECTION_STYLES: dict[str, ConnectionStyle] = {
    "signal": ConnectionStyle(),
    "power": ConnectionStyle(width=3.0, arrow_style="half", color="#000000", arrow_size=20.0),
}


def connection_style(port_type: str) -> ConnectionStyle:
    return CONNECTION_STYLES.get(port_type, ConnectionStyle())