import os
from typing import Optional

from tavily import AsyncTavilyClient


async def _resolve_api_key(explicit: Optional[str]) -> Optional[str]:
    """按优先级解析 Tavily API key：显式参数 > GSM 配置 > 环境变量。"""
    if explicit:
        return explicit
    try:
        from kilostar.core.global_state_machine.gsm_snapshot import fetch_snapshot

        snapshot = await fetch_snapshot()
        cfg = snapshot.tool_configs.get("tavily_search") or {}
        if isinstance(cfg, dict) and cfg.get("api_key"):
            return cfg["api_key"]
    except Exception:
        pass
    return os.environ.get("TAVILY_API_KEY")


async def tavily_search(
    query: str,
    max_results: int = 5,
    search_depth: str = "basic",
    include_answer: bool = True,
    api_key: Optional[str] = None,
) -> str:
    """使用 Tavily 进行网络搜索，获取高质量的网络搜索结果。

    Args:
        query: 搜索查询内容
        max_results: 返回的最大结果数量（1-10）
        search_depth: 搜索深度，"basic" 或 "advanced"
        include_answer: 是否包含 AI 生成的答案摘要
        api_key: 可选；不传则按 GSM 配置 → 环境变量顺序解析

    Returns:
        格式化的搜索结果文本，包含标题、URL、摘要和可选的 AI 答案
    """
    resolved_key = await _resolve_api_key(api_key)
    if not resolved_key:
        return (
            "[Error] Tavily API key 未配置。"
            "请在 ``/api/v1/resource/tool/config`` 写入或设置环境变量 ``TAVILY_API_KEY``。"
        )

    try:
        client = AsyncTavilyClient(api_key=resolved_key)
        result = await client.search(
            query=query,
            max_results=min(max_results, 10),
            search_depth=search_depth,
            include_answer=include_answer,
        )

        lines = []
        if include_answer and result.get("answer"):
            lines.append(f"【AI 摘要】{result['answer']}\n")

        results = result.get("results", [])
        if not results:
            return "No results found for the query."

        lines.append("【搜索结果】")
        for i, item in enumerate(results, 1):
            title = item.get("title", "Untitled")
            url = item.get("url", "")
            content = item.get("content", "").strip()
            lines.append(f"\n{i}. {title}")
            lines.append(f"   URL: {url}")
            if content:
                lines.append(f"   {content[:300]}{'...' if len(content) > 300 else ''}")

        return "\n".join(lines)
    except Exception as e:
        return f"[Error] Tavily search failed: {str(e)}"