from fastapi import FastAPI, Request, HTTPException, Response
from fastapi.responses import StreamingResponse
import httpx
import logging
import os, json
import re  # 用于URL路径处理
from key_selector import KeySelector # 自动选择key

from app.routers import key_management # Import the new router

def get_target_url(url: str) -> str:
    """将url参数变了转换为合法的目标url；from http/ or https/ to http:// or https://"""
    url = re.sub(r"^http/", "http://", url)
    url = re.sub(r"^https/", "https://", url)
    return url

app = FastAPI()

# Include the new key management router
app.include_router(key_management.router, prefix="/api/keys", tags=["Key Management"])

# 配置日志
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger("uvicorn.error")

# 从环境变量获取配置
# X_Goog_Api_Key = os.getenv("X_Goog_Api_Key", "")

@app.get("/")
async def read_root():
    return {"message": "FastAPI Proxy is running"}

@app.post("/v25/{path:path}")
async def proxy(request: Request, path: str):
    # 添加流式请求判断逻辑
    is_streaming = ":streamGenerateContent" in path.lower()
    target_url = get_target_url(path)
    method = request.method
    headers = {k: v for k, v in request.headers.items()
        # if k.lower() not in ["host", "connection", "Postman-Token", "content-length"]}
        if k.lower() not in ["host", "content-length"]}
    
    key_selector = KeySelector()
    headers["X-Goog-Api-Key"] = key_selector.get_api_key_info()['key_value'] # 从数据库获取API密钥

    try:
        # 关键修复：禁用KeepAlive防止连接冲突
        transport = httpx.AsyncHTTPTransport(retries=3, http1=True)
        async with httpx.AsyncClient(
            transport=transport,
            timeout=httpx.Timeout(300.0, connect=30.0)
        ) as client:
            # 处理请求体
            req_content = await request.body()
            # 发送请求到上游服务
            response = await client.request(
                method=method,
                url=target_url,
                headers=headers,
                content=req_content,
                follow_redirects=True  # 自动处理重定向
            )
            if is_streaming:
                # 流式响应处理
                async def stream_generator():
                    try:
                        async for chunk in response.aiter_bytes():
                            yield chunk
                    except Exception as e:
                        logger.error(f"Stream interrupted: {str(e)}")
                        yield json.dumps({"error": "流中断"}).encode()
            
                # 移除冲突头部
                headers = dict(response.headers)
                headers.pop("Content-Length", None)
                return StreamingResponse(
                    content=stream_generator(),
                    status_code=response.status_code,
                    headers=headers,
                    media_type="application/x-ndjson"  # Gemini流式格式
                )
            else:
                # 非流式响应处理
                # 解析 JSON 字符串
                try:
                    data = json.loads(response.text)
                    # 格式化输出 JSON 数据
                    formatted_json = json.dumps(data, ensure_ascii=False, indent=4)
                    # return formatted_json
                    return Response(
                        content=formatted_json,
                        media_type="application/json"
                    )
                except json.JSONDecodeError as e:
                    print(f"Error decoding JSON: {e}")
    except httpx.ConnectError as e:
        logger.error(f"Connection failed to {target_url}: {e}")
        raise HTTPException(502, f"无法连接到上游服务: {target_url}") # Modified error message
    except httpx.ReadTimeout as e:
        logger.error(f"Timeout: {e}")
        raise HTTPException(504, "上游服务响应超时")
    except httpx.HTTPError as e:  # 捕获所有HTTP异常
        try:
            # 安全地获取异常信息
            error_type = type(e).__name__
            # 尝试获取状态码（如果存在）
            status_code = getattr(e, 'response', None) and e.response.status_code
            # 安全地获取错误详情
            error_detail = ""
            try:
                # 尝试获取文本响应（限制长度）
                if hasattr(e, 'response') and e.response:
                    error_detail = e.response.text[:500]  # 只取前500个字符
            except Exception as ex:
                error_detail = f"无法获取错误详情: {type(ex).__name__}"
            # 安全地记录日志
            logger.error(
                "HTTP代理错误 | "
                f"类型: {error_type} | "
                f"状态码: {status_code or 'N/A'} | "
                f"目标URL: {target_url} | "
                f"详情: {error_detail[:200]}"  # 日志中只记录前200字符
            )
            # 打印到控制台以便调试
            print(f"目标URL: {target_url}")
            print(f"状态码: {status_code or 'N/A'}")
            print(f"错误详情: {error_detail[:500]}")
        except Exception as ex:
            # 如果记录日志本身出错，使用最安全的方式记录
            logger.error(f"记录HTTP错误时发生异常: {type(ex).__name__}")
            print(f"严重错误: 记录HTTP错误时发生异常: {ex}")

        # 返回用户友好的错误响应
        raise HTTPException(
            status_code=502,
            detail=f"网关服务错误: {error_type} (上游状态: {status_code or '未知'})"
        )
    except Exception as e:
        logger.exception("Unexpected proxy error")
        raise HTTPException(500, f"内部服务器错误: {str(e)}")

if __name__ == "__main__":
    # In a real application, you would typically run uvicorn here:
    # import uvicorn
    # uvicorn.run(app, host="0.0.0.0", port=8000)
    pass # Placeholder to fix indentation error