import logging
import os
import contextvars
from logging.handlers import RotatingFileHandler

# 日志配置常量
BASE_LOG_DIR = 'logs'
MAX_BYTES = 10 * 1024 * 1024  # 10MB
BACKUP_COUNT = 5

# ContextVar for task_id
task_id_var = contextvars.ContextVar("task_id", default=None)


class TaskIdFormatter(logging.Formatter):
    """
    Custom Formatter that injects task_id if available, or 'N/A' if not.
    Does NOT rely on Filter injection, making it robust for third-party loggers.
    """
    def format(self, record):
        # 1. Try to get task_id from ContextVar
        task_id = task_id_var.get()
        
        # 2. If not in ContextVar, check if it's already in record (e.g. passed via extra)
        if not hasattr(record, 'task_id'):
            record.task_id = task_id if task_id else 'N/A'
        elif record.task_id is None:
             # Ensure it's not None if attribute exists
             record.task_id = 'N/A'

        return super().format(record)


def setup_logging(service_name: str, level=logging.INFO):
    """
    集中配置日志系统，每个服务使用单独的日志文件。

    Args:
        service_name (str): 服务的名称（例如 'app' 或 'worker'），用于命名 logger 和日志文件。
        level (int): 日志级别。
    """
    # 确保日志目录存在
    os.makedirs(BASE_LOG_DIR, exist_ok=True)

    # 1. 确定日志文件路径
    log_file_name = f'{service_name}.log'
    log_file_path = os.path.join(BASE_LOG_DIR, log_file_name)

    # 2. 获取 logger 实例
    logger = logging.getLogger(service_name)
    logger.setLevel(level)

    # 3. 使用自定义格式化器
    # 注意：这里我们移除了 Filter，改用 Formatter 处理
    formatter = TaskIdFormatter(
        '%(asctime)s - [%(task_id)s] - %(name)s - %(levelname)s - %(message)s'
    )

    # 4. 控制台处理器 (StreamHandler)
    console_handler = logging.StreamHandler()
    console_handler.setFormatter(formatter)

    # 5. 文件处理器 (RotatingFileHandler)
    file_handler = RotatingFileHandler(
        log_file_path,
        maxBytes=MAX_BYTES,
        backupCount=BACKUP_COUNT,
        encoding='utf-8'
    )
    file_handler.setFormatter(formatter)
    
    # 6. 配置 root logger 或 propagation
    # 获取 log_file_path 的绝对路径进行比较
    abs_log_file_path = os.path.abspath(log_file_path)

    # Helper function to add handlers if not present
    def attach_handlers_to(target_logger_name):
        target = logging.getLogger(target_logger_name)
        target.setLevel(level)
        
        # 检查是否已经添加了对应的 FileHandler
        has_file_handler = any(
            isinstance(h, RotatingFileHandler) and 
            os.path.abspath(h.baseFilename) == abs_log_file_path 
            for h in target.handlers
        )
        
        if not has_file_handler:
            target.addHandler(file_handler)
            # 避免控制台重复
            if not any(isinstance(h, logging.StreamHandler) for h in target.handlers):
                target.addHandler(console_handler)

    # 针对 worker 进程，配置 services 和 ls_ocr logger
    attach_handlers_to('services')
    # 虽然已经移除 OCR，但保留机制以防其他 module 使用 services logger
    
    # 避免重复添加 handlers 到主 logger
    attach_handlers_to(service_name)
    
    return logger


# 辅助函数，用于简化调用
def get_app_logger():
    return setup_logging(service_name='app')


def get_process_worker_logger():
    return setup_logging(service_name='process_worker')


def get_upload_worker_logger():
    return setup_logging(service_name='upload_worker')


class RequestLogger:
    """请求日志记录器（用于Flask）"""

    @staticmethod
    def log_request(request, response, duration: float = None):
        """
        记录HTTP请求日志

        Args:
            request: Flask request对象
            response: Flask response对象
            duration: 请求处理时间（秒）
        """
        logger = get_app_logger()

        # 构建日志消息
        msg_parts = [
            f"{request.method} {request.path}",
            f"status={response.status_code}",
        ]

        if duration is not None:
            msg_parts.append(f"duration={duration:.3f}s")

        # 添加查询参数
        if request.query_string:
            msg_parts.append(f"query={request.query_string.decode('utf-8')}")

        # 添加客户端IP
        client_ip = request.headers.get('X-Forwarded-For', request.remote_addr)
        msg_parts.append(f"ip={client_ip}")

        msg = " | ".join(msg_parts)

        # 根据状态码选择日志级别
        if response.status_code >= 500:
            logger.error(msg)
        elif response.status_code >= 400:
            logger.warning(msg)
        else:
            logger.info(msg)

    @staticmethod
    def log_error(request, error: Exception):
        """
        记录错误日志

        Args:
            request: Flask request对象
            error: 异常对象
        """
        logger = get_app_logger()
        logger.exception(
            f"请求错误 | {request.method} {request.path} | "
            f"error={type(error).__name__}: {str(error)}"
        )