from pydantic import BaseModel, create_model
from typing import Any, Dict, List, Optional, get_args, get_origin
import json
from datetime import datetime, date

def generate_example_json(model: type[BaseModel]) -> str:
    """
    根据 Pydantic V2 模型生成示例 JSON 数据结构。
    """

    def _generate_example(field_type: Any) -> Any:
        origin = get_origin(field_type)
        args = get_args(field_type)

        if origin is list or origin is List:
            if args:
                return [_generate_example(args[0])]
            else:
                return []
        elif origin is dict or origin is Dict:
            if len(args) == 2 and args[0] is str:
                return {"key": _generate_example(args[1])}
            else:
                return {}
        elif origin is Optional or origin is type(None):
            if args:
                return _generate_example(args[0])
            else:
                return None
        elif field_type is str:
            return "string"
        elif field_type is int:
            return 0
        elif field_type is float:
            return 0.0
        elif field_type is bool:
            return True
        elif field_type is datetime:
            return datetime.now().isoformat()
        elif field_type is date:
            return date.today().isoformat()
        elif issubclass(field_type, BaseModel):
            return generate_example_json(field_type)
        else:
            return "unknown"  # 对于未知类型返回 "unknown"

    example_data = {}
    for field_name, field in model.model_fields.items():
        example_data[field_name] = _generate_example(field.annotation)

    return json.dumps(example_data, indent=2, default=str)

if __name__ == "__main__":
    import sys
    from pathlib import Path
    # 添加项目根目录到sys.path
    sys.path.append(str(Path(__file__).resolve().parent.parent))
    from schema import Q_A
    class Q_A_list(BaseModel):
        Q_As: List[Q_A]

    print("示例 JSON:")
    print(generate_example_json(Q_A_list))