"""
Pro-Widget-Konfiguration im Dashboard-Layout (v1).

Nur ausgewählte Widget-IDs dürfen nicht-leere config haben; bekannte Keys werden validiert.
"""
from __future__ import annotations

import json
import math
from typing import Any

MAX_WIDGET_CONFIG_JSON_BYTES = 1024

WIDGETS_ALLOWING_CONFIG: frozenset[str] = frozenset({"body_overview"})


def _config_json_size_bytes(config: dict[str, Any]) -> int:
    return len(json.dumps(config, sort_keys=True, ensure_ascii=False).encode("utf-8"))


def validate_widget_entry_config(widget_id: str, raw: Any) -> dict[str, Any]:
    if raw is None:
        return {}
    if not isinstance(raw, dict):
        raise ValueError(f"Widget {widget_id}: config muss ein Objekt sein")
    if _config_json_size_bytes(raw) > MAX_WIDGET_CONFIG_JSON_BYTES:
        raise ValueError(f"Widget {widget_id}: config zu groß (max. {MAX_WIDGET_CONFIG_JSON_BYTES} Byte JSON)")
    if not raw:
        return {}

    if widget_id not in WIDGETS_ALLOWING_CONFIG:
        raise ValueError(f"Widget {widget_id}: keine Konfiguration unterstützt")

    if widget_id == "body_overview":
        return _validate_body_overview_config(raw)

    raise ValueError(f"Widget {widget_id}: keine Konfiguration unterstützt")


def _validate_body_overview_config(raw: dict[str, Any]) -> dict[str, Any]:
    allowed = frozenset({"chart_days"})
    unknown = set(raw) - allowed
    if unknown:
        raise ValueError(f"body_overview: unbekannte config-Felder: {sorted(unknown)}")
    out: dict[str, Any] = {}
    if "chart_days" not in raw:
        return out
    v = raw["chart_days"]
    if isinstance(v, bool):
        raise ValueError("body_overview: chart_days muss ganze Zahl sein")
    if isinstance(v, float):
        if not math.isfinite(v):
            raise ValueError("body_overview: chart_days muss ganze Zahl sein")
        if abs(v - round(v)) > 1e-9:
            raise ValueError("body_overview: chart_days muss ganze Zahl sein")
        v = int(round(v))
    elif isinstance(v, int):
        pass
    else:
        raise ValueError("body_overview: chart_days muss ganze Zahl sein")
    if v < 7 or v > 90:
        raise ValueError("body_overview: chart_days muss zwischen 7 und 90 liegen")
    out["chart_days"] = v
    return out