import os
import logging
import pandas as pd
from datetime import datetime
from django.db.models import Q, F
from django.utils import timezone
from apps.gmail.models import GmailConversation, GmailAttachment, ConversationSummary
from apps.chat.models import ChatHistory

logger = logging.getLogger(__name__)

class GmailExportService:
    """
    Gmail导出服务，提供将达人回复导出为Excel的功能
    """
    
    @staticmethod
    def export_replied_influencers(user, format='xlsx'):
        """
        导出已回复的达人Gmail列表
        
        Args:
            user: 用户对象
            format: 导出格式, 默认为xlsx
            
        Returns:
            tuple: (文件路径, 错误信息)
        """
        try:
            # 获取用户所有的Gmail对话
            conversations = GmailConversation.objects.filter(
                user=user,
                is_active=True
            )
            
            if not conversations.exists():
                return None, "未找到任何Gmail对话"
            
            # 准备导出数据
            export_data = []
            
            for conversation in conversations:
                # 查询达人是否有回复
                chat_history = ChatHistory.objects.filter(
                    user=user,
                    conversation_id=conversation.conversation_id,
                    metadata__contains={"from": conversation.influencer_email}
                ).order_by('created_at')
                
                # 如果达人有回复，则添加到导出列表
                if chat_history.exists():
                    # 获取第一条回复的时间
                    first_reply = chat_history.first()
                    first_reply_time = first_reply.created_at.replace(tzinfo=None) if first_reply else None
                    
                    # 获取最后一条回复的时间
                    last_reply = chat_history.last()
                    last_reply_time = last_reply.created_at.replace(tzinfo=None) if last_reply else None
                    
                    # 获取回复次数
                    reply_count = chat_history.count()
                    
                    # 直接从数据库中获取对话摘要，不调用外部API
                    summary = ""
                    try:
                        # 先从ConversationSummary模型中查找
                        conversation_summary = ConversationSummary.objects.filter(
                            conversation=conversation
                        ).first()
                        
                        if conversation_summary:
                            summary = conversation_summary.content
                        else:
                            # 如果没有摘要，尝试获取最新的几条消息内容
                            recent_messages = ChatHistory.objects.filter(
                                user=user,
                                conversation_id=conversation.conversation_id
                            ).order_by('-created_at')[:5]
                            
                            if recent_messages:
                                summary = "最近消息: " + " | ".join([msg.content[:100] + ("..." if len(msg.content) > 100 else "") for msg in recent_messages])
                    except Exception as e:
                        logger.error(f"获取对话摘要失败: {str(e)}")
                        summary = '无法获取摘要'
                    
                    # 构建导出记录 - 注意移除时区信息
                    export_record = {
                        '用户邮箱': conversation.user_email,
                        '达人邮箱': conversation.influencer_email,
                        '对话标题': conversation.title,
                        '对话开始时间': conversation.created_at.replace(tzinfo=None),
                        '首次回复时间': first_reply_time,
                        '最近回复时间': last_reply_time,
                        '回复次数': reply_count,
                        '对话摘要': summary,
                        '对话ID': conversation.conversation_id
                    }
                    
                    export_data.append(export_record)
            
            if not export_data:
                return None, "没有找到已回复的达人"
            
            # 创建DataFrame
            df = pd.DataFrame(export_data)
            
            # 生成文件名和路径
            timestamp = datetime.now().strftime('%Y%m%d_%H%M%S')
            file_name = f"influencer_replies_{timestamp}.{format}"
            export_dir = os.path.join('media', 'exports')
            os.makedirs(export_dir, exist_ok=True)
            file_path = os.path.join(export_dir, file_name)
            
            # 根据格式导出
            if format == 'xlsx':
                df.to_excel(file_path, index=False, engine='openpyxl')
            elif format == 'csv':
                df.to_csv(file_path, index=False, encoding='utf-8-sig')
            else:
                return None, f"不支持的导出格式: {format}"
            
            return file_path, None
        
        except Exception as e:
            logger.error(f"导出已回复达人失败: {str(e)}")
            import traceback
            logger.error(traceback.format_exc())
            return None, f"导出失败: {str(e)}"