"""图层分析模块 —— 统计每层实体数量与类型，并基于图层名称进行角色推断。"""

# 角色推断规则（启发式，基于常见中文/英文命名）
_ROLE_RULES = [
    (["WALL", "墙", "W", "A-WALL", "A-WALL-"], "墙体"),
    (["DOOR", "门", "窗", "WINDOW", "D", "M"], "门窗"),
    (["DIM", "标注", "DEFPOINTS", "PUB_DIM", "PUB_DIM"], "标注"),
    (["TEXT", "文字", "NOTE"], "文字"),
    (["COLUMN", "柱", "Z"], "柱"),
    (["E", "EQUIP", "设备"], "设备"),
    (["HATCH", "填充", "BH"], "填充"),
    (["AXIS", "轴", "AXIS"], "轴网"),
    (["GRID", "网格"], "网格"),
    (["FURN", "家具", "FURNITURE"], "家具"),
    (["BEAM", "梁", "B"], "梁"),
    (["SLAB", "板"], "板"),
    (["STAIR", "楼梯", "S"], "楼梯"),
    (["ROOF", "屋顶", "R"], "屋顶"),
    (["PIPE", "管", "P"], "管道"),
    (["DUCT", "风管"], "风管"),
    (["ELEC", "电气", "E-"], "电气"),
    (["PLUMB", "给排水", "P-"], "给排水"),
    (["FOUND", "基础", "F"], "基础"),
    (["SITE", "场地", "总图"], "场地"),
    (["CEIL", "天花", "吊顶", "C"], "天花"),
    (["FLOOR", "地面", "FL"], "地面"),
    (["SECTION", "剖面", "SECT"], "剖面"),
    (["ELEV", "立面", "ELEVATION"], "立面"),
    (["0", "A-"], "主体结构"),
]


def _infer_role(layer_name: str) -> str:
    """根据图层名称推断图层角色（仅作建议）。"""
    upper_name = layer_name.upper()
    for keywords, role in _ROLE_RULES:
        for kw in keywords:
            if kw in upper_name or kw in layer_name:
                return role
    return "其他"


def analyze_layers(doc) -> list:
    """分析所有图层，返回每层的实体统计和角色推断。

    Args:
        doc: ezdxf Drawing 对象

    Returns:
        list[dict]: 每层信息，格式为 {
            "name": str,
            "entity_count": int,
            "entity_types": list[str],
            "suggested_role": str
        }
    """
    msp = doc.modelspace()

    # 按图层聚合实体
    layer_entities = {}  # layer_name -> list of dxftype
    for entity in msp:
        layer_name = entity.dxf.layer
        if layer_name not in layer_entities:
            layer_entities[layer_name] = []
        layer_entities[layer_name].append(entity.dxftype())

    # 也包含没有实体的图层（在 doc.layers 中定义但模型空间无实体）
    result = []
    seen_layers = set()

    for layer_name, types in layer_entities.items():
        seen_layers.add(layer_name)
        unique_types = sorted(set(types))
        result.append({
            "name": layer_name,
            "entity_count": len(types),
            "entity_types": unique_types,
            "suggested_role": _infer_role(layer_name),
        })

    # 补充空图层（在图层定义中存在但无实体）
    for layer in doc.layers:
        name = layer.dxf.name
        if name not in seen_layers:
            result.append({
                "name": name,
                "entity_count": 0,
                "entity_types": [],
                "suggested_role": _infer_role(name),
            })

    # 按实体数降序排列
    result.sort(key=lambda x: -x["entity_count"])
    return result