"""Tools for enabling and registering chart themes."""

from __future__ import annotations

from typing import TYPE_CHECKING, Final, Literal, get_args

from altair.utils.theme import ThemeRegistry
from altair.vegalite.v5.schema._typing import VegaThemes

if TYPE_CHECKING:
    import sys

    if sys.version_info >= (3, 10):
        from typing import TypeAlias
    else:
        from typing_extensions import TypeAlias

AltairThemes: TypeAlias = Literal["default", "opaque"]
VEGA_THEMES: list[str] = list(get_args(VegaThemes))


class VegaTheme:
    """Implementation of a builtin vega theme."""

    def __init__(self, theme: str) -> None:
        self.theme = theme

    def __call__(self) -> dict[str, dict[str, dict[str, str | int]]]:
        return {
            "usermeta": {"embedOptions": {"theme": self.theme}},
            "config": {"view": {"continuousWidth": 300, "continuousHeight": 300}},
        }

    def __repr__(self) -> str:
        return f"VegaTheme({self.theme!r})"


# The entry point group that can be used by other packages to declare other
# themes that will be auto-detected. Explicit registration is also
# allowed by the PluginRegistry API.
ENTRY_POINT_GROUP: Final = "altair.vegalite.v5.theme"
themes = ThemeRegistry(entry_point_group=ENTRY_POINT_GROUP)

themes.register(
    "default",
    lambda: {"config": {"view": {"continuousWidth": 300, "continuousHeight": 300}}},
)
themes.register(
    "opaque",
    lambda: {
        "config": {
            "background": "white",
            "view": {"continuousWidth": 300, "continuousHeight": 300},
        }
    },
)
themes.register("none", dict)

for theme in VEGA_THEMES:
    themes.register(theme, VegaTheme(theme))

themes.enable("default")