"""Mock 宿主的效果类型注册表与渲染语义（参数带 min/max/choices）。

``get_effect_params`` 从这张表读出参数元数据，供工具适配层回填 tool schema
（计划文档 §3.2：参数 min/max/choices 由 get_params 类信息回填）。
"""
from __future__ import annotations

from dataclasses import dataclass
from typing import Any


@dataclass(frozen=True)
class ParamSpec:
    """单个效果参数的定义。"""

    name: str
    type: str  # number | string | boolean
    min: float | None = None
    max: float | None = None
    choices: tuple[str, ...] | None = None
    default: Any = None
    description: str = ""

    def to_json(self) -> dict:
        out: dict = {"name": self.name, "type": self.type, "default": self.default}
        if self.min is not None:
            out["min"] = self.min
        if self.max is not None:
            out["max"] = self.max
        if self.choices is not None:
            out["choices"] = list(self.choices)
        if self.description:
            out["description"] = self.description
        return out


MOCK_EFFECT_TYPES: dict[str, dict] = {
    "brightness": {
        "description": "亮度调整（level 为 -1..1 的亮度增量）",
        "params": [
            ParamSpec("level", "number", min=-1.0, max=1.0, default=0.0, description="亮度增量"),
            ParamSpec("enabled", "boolean", default=True, description="是否启用"),
        ],
    },
    "color_shift": {
        "description": "色相偏移（0..360 度）",
        "params": [
            ParamSpec("hue", "number", min=0.0, max=360.0, default=0.0, description="色相偏移角度"),
            ParamSpec("enabled", "boolean", default=True),
        ],
    },
    "crop": {
        "description": "裁切（各边 0..0.95 比例）",
        "params": [
            ParamSpec("left", "number", min=0.0, max=0.95, default=0.0),
            ParamSpec("top", "number", min=0.0, max=0.95, default=0.0),
            ParamSpec("right", "number", min=0.0, max=0.95, default=0.0),
            ParamSpec("bottom", "number", min=0.0, max=0.95, default=0.0),
        ],
    },
    "blur": {
        "description": "模糊（像素半径，近似盒式平均）",
        "params": [
            ParamSpec("radius", "number", min=0.0, max=50.0, default=0.0),
            ParamSpec("enabled", "boolean", default=True),
        ],
    },
    "overlay": {
        "description": "叠加混合（blend_mode 带 choices，供参数回填测试）",
        "params": [
            ParamSpec(
                "blend_mode",
                "string",
                choices=("normal", "screen", "multiply"),
                default="normal",
            ),
            ParamSpec("opacity", "number", min=0.0, max=1.0, default=0.5),
        ],
    },
}


def effect_spec(effect_type: str) -> dict:
    spec = MOCK_EFFECT_TYPES.get(effect_type)
    if spec is None:
        raise KeyError(effect_type)
    return spec


def validate_param(effect_type: str, name: str, value: Any) -> None:
    """校验参数值是否满足注册表的类型/范围/choices，非法抛 ValueError。"""
    spec = effect_spec(effect_type)
    pspec = next((p for p in spec["params"] if p.name == name), None)
    if pspec is None:
        raise ValueError(
            f"效果 {effect_type} 无参数 {name!r}（可选: {[p.name for p in spec['params']]}）"
        )
    ok = _valid_value(pspec, value)
    if not ok:
        raise ValueError(
            f"参数 {name}={value!r} 非法：类型 {pspec.type}"
            + (f"，范围 {pspec.min}..{pspec.max}" if pspec.min is not None or pspec.max is not None else "")
            + (f"，可选 {list(pspec.choices)}" if pspec.choices is not None else "")
        )


def _valid_value(pspec: ParamSpec, value: Any) -> bool:
    if pspec.type == "boolean":
        return isinstance(value, bool)
    if pspec.type == "string":
        if not isinstance(value, str):
            return False
        if pspec.choices is not None and value not in pspec.choices:
            return False
        return True
    if pspec.type == "number":
        if not isinstance(value, (int, float)) or isinstance(value, bool):
            return False
        if pspec.min is not None and value < pspec.min:
            return False
        if pspec.max is not None and value > pspec.max:
            return False
        return True
    return False