"""
Log Manager - 持久化日志管理器
支持日志加载、保存、追加、清空
"""
import json
import os
import threading
from datetime import datetime
from typing import List, Dict, Optional
from app import config


class LogManager:
    """日志管理器 - 线程安全"""

    def __init__(self, log_file: str = None, max_logs: int = None):
        self.log_file = log_file or config.LOG_FILE
        self.max_logs = max_logs or config.MAX_LOGS
        self._lock = threading.Lock()
        self.logs: List[Dict] = []
        self._load_logs()

    def _load_logs(self):
        """启动时加载历史日志"""
        with self._lock:
            if os.path.exists(self.log_file):
                try:
                    with open(self.log_file, 'r', encoding='utf-8') as f:
                        data = json.load(f)
                        self.logs = data.get('logs', [])
                except (json.JSONDecodeError, IOError) as e:
                    print(f"[LogManager] 加载日志文件失败: {e}")
                    self.logs = []
            else:
                self.logs = []

    def append(self, level: str, message: str, thread_id: Optional[str] = None) -> Dict:
        """
        追加新日志
        返回日志条目
        """
        with self._lock:
            log_entry = {
                "timestamp": datetime.now().isoformat(),
                "level": level,
                "message": message,
                "thread_id": thread_id
            }
            self.logs.append(log_entry)

            # 限制日志数量（保留最新的 max_logs 条）
            if len(self.logs) > self.max_logs:
                self.logs = self.logs[-self.max_logs:]

            # 异步保存到文件
            self._save()

            return log_entry

    def _save(self):
        """保存到文件（需在锁内调用）"""
        try:
            with open(self.log_file, 'w', encoding='utf-8') as f:
                json.dump({
                    "logs": self.logs,
                    "last_updated": datetime.now().isoformat()
                }, f, ensure_ascii=False, indent=2)
        except IOError as e:
            print(f"[LogManager] 保存日志文件失败: {e}")

    def get_logs(self, level: Optional[str] = None, limit: Optional[int] = None) -> List[Dict]:
        """
        获取日志
        :param level: 过滤级别 (None/INFO/SUCCESS/WARNING/ERROR/DEBUG)
        :param limit: 限制返回数量
        """
        with self._lock:
            if level:
                filtered = [log for log in self.logs if log['level'] == level]
            else:
                filtered = self.logs

            if limit:
                return filtered[-limit:]
            return filtered

    def search_logs(self, keyword: str, limit: Optional[int] = None) -> List[Dict]:
        """
        搜索日志
        :param keyword: 搜索关键词
        :param limit: 限制返回数量
        """
        with self._lock:
            filtered = [
                log for log in self.logs
                if keyword.lower() in log['message'].lower()
            ]

            if limit:
                return filtered[-limit:]
            return filtered

    def clear(self):
        """清空日志"""
        with self._lock:
            self.logs = []
            self._save()

    def get_stats(self) -> Dict:
        """获取日志统计信息"""
        with self._lock:
            stats = {
                "total": len(self.logs),
                "by_level": {}
            }

            for log in self.logs:
                level = log['level']
                stats["by_level"][level] = stats["by_level"].get(level, 0) + 1

            return stats

    def export_to_text(self) -> str:
        """导出为文本格式"""
        with self._lock:
            lines = []
            lines.append("=" * 80)
            lines.append("小红书采集器日志")
            lines.append(f"导出时间: {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}")
            lines.append(f"总日志数: {len(self.logs)}")
            lines.append("=" * 80)
            lines.append("")

            for log in self.logs:
                timestamp = log['timestamp'][:19]  # 去掉微秒
                level = log['level'].ljust(8)
                thread = f"[{log['thread_id']}]" if log.get('thread_id') else ""
                message = log['message']
                lines.append(f"{timestamp} | {level} | {thread} {message}")

            return "\n".join(lines)


# 全局日志管理器实例
_log_manager_instance = None


def get_log_manager() -> LogManager:
    """获取全局日志管理器实例"""
    global _log_manager_instance
    if _log_manager_instance is None:
        _log_manager_instance = LogManager()
    return _log_manager_instance