# core/utils/template_resolver.py

import re
from typing import Any, Dict

PLACEHOLDER_PATTERN = re.compile(r"\{\{\s*([a-zA-Z0-9_.]+)(\|[^}]+)?\s*\}\}")

def resolve_request_body_template(
    data: Any,
    variables: Dict[str, Any],
) -> Any:
    """
    仅解析请求参数中 {{var}} 模板

    Args:
        data: dict/list/str
        variables: {"next_cursor": "123", ...}

    Returns:
        替换后的结构
    """
    if isinstance(data, dict):
        return {k: resolve_request_body_template(v, variables) for k, v in data.items()}
    elif isinstance(data, list):
        return [resolve_request_body_template(item, variables) for item in data]
    elif isinstance(data, str):
        def replacer(match):
            var_name = match.group(1)
            default_value = match.group(2)[1:] if match.group(2) else None
            value = variables.get(var_name)
            if value is not None:
                return str(value)
            elif default_value is not None:
                return default_value
            else:
                return ""
        return PLACEHOLDER_PATTERN.sub(replacer, data)
    else:
        return data

if __name__ == '__main__':
    data = {
        "cursor": "{{next_cursor}}",
        "page_size": 20,
        "filters": {
            "start_date": "{{start_date}}",
            "end_date": "{{end_date|2025-01-01}}"
        },
        "tags": ["{{tag1}}", "{{tag2|default_tag}}"]
    }

    variables = {
        "next_cursor":"1",
        "start_date": "2025-06-30",
        "tag1": "news"
    }
    result = resolve_request_body_template(data, variables)
    print(result)