from typing import List, Optional, Dict, Any
from datetime import datetime
from sqlalchemy.ext.asyncio import AsyncSession
import apprise
from backend import crud
from backend.models import Channel

class NotifyService:
    def __init__(self):
        self.apobj = apprise.Apprise()
    
    def _build_apprise_url(self, channel: Channel) -> Optional[str]:
        """根据通道类型构建 apprise URL"""
        config = channel.config or {}
        
        if channel.type == "discord":
            webhook_url = config.get("webhook_url", "")
            if webhook_url:
                return f"{webhook_url}"
        
        elif channel.type == "telegram":
            bot_token = config.get("bot_token", "")
            chat_id = config.get("chat_id", "")
            if bot_token and chat_id:
                return f"tgram://{bot_token}/{chat_id}"
        
        elif channel.type == "email":
            smtp_host = config.get("smtp_host", "")
            smtp_port = config.get("smtp_port", 587)
            username = config.get("username", "")
            password = config.get("password", "")
            to_email = config.get("to_email", "")
            
            if username and password and to_email:
                return f"mailtos://{username}:{password}@{smtp_host}:{smtp_port}?to={to_email}"
        
        elif channel.type == "slack":
            webhook_url = config.get("webhook_url", "")
            if webhook_url:
                return f"{webhook_url}"
        
        elif channel.type == "webhook":
            url = config.get("url", "")
            if url:
                return f"json://{url.replace('https://', '').replace('http://', '')}"
        
        # 支持 apprise 原生 URL 格式
        elif channel.type == "apprise":
            return config.get("url", "")
        
        return None
    
    async def send_notification(
        self,
        db: AsyncSession,
        channel_id: int,
        title: Optional[str],
        body: str,
        priority: str = "normal"
    ) -> Dict[str, Any]:
        """发送单条通知到指定通道"""
        channel = await crud.get_channel(db, channel_id)
        if not channel:
            return {
                "channel_id": channel_id,
                "status": "failed",
                "error_msg": "Channel not found"
            }
        
        if not channel.is_active:
            return {
                "channel": channel.name,
                "channel_id": channel_id,
                "status": "skipped",
                "error_msg": "Channel is inactive"
            }
        
        # 创建通知记录
        notification = await crud.create_notification(
            db, channel_id, {
                "title": title,
                "body": body,
                "priority": priority,
                "status": "pending"
            }
        )
        
        # 构建 apprise URL
        apprise_url = self._build_apprise_url(channel)
        if not apprise_url:
            error_msg = f"Invalid configuration for channel type: {channel.type}"
            await crud.update_notification_status(
                db, notification.id, "failed", error_msg
            )
            return {
                "channel": channel.name,
                "channel_id": channel_id,
                "status": "failed",
                "notification_id": notification.id,
                "error_msg": error_msg
            }
        
        try:
            # 发送通知
            apobj = apprise.Apprise()
            apobj.add(apprise_url)
            
            # 构建消息
            message = body
            if title:
                message = f"**{title}**\n\n{body}"
            
            # 发送
            result = apobj.notify(body=message)
            
            if result:
                await crud.update_notification_status(
                    db, notification.id, "sent", sent_at=datetime.utcnow()
                )
                return {
                    "channel": channel.name,
                    "channel_id": channel_id,
                    "status": "sent",
                    "notification_id": notification.id
                }
            else:
                error_msg = "Failed to send notification"
                await crud.update_notification_status(
                    db, notification.id, "failed", error_msg
                )
                return {
                    "channel": channel.name,
                    "channel_id": channel_id,
                    "status": "failed",
                    "notification_id": notification.id,
                    "error_msg": error_msg
                }
        
        except Exception as e:
            error_msg = str(e)
            await crud.update_notification_status(
                db, notification.id, "failed", error_msg
            )
            return {
                "channel": channel.name,
                "channel_id": channel_id,
                "status": "failed",
                "notification_id": notification.id,
                "error_msg": error_msg
            }
    
    async def send_to_channels(
        self,
        db: AsyncSession,
        channels: Optional[List[str]],
        tags: Optional[List[str]],
        title: Optional[str],
        body: str,
        priority: str = "normal"
    ) -> List[Dict[str, Any]]:
        """批量发送通知到多个通道或按标签发送"""
        results = []
        target_channels = []
        
        # 按名称获取通道
        if channels:
            for channel_name in channels:
                channel = await crud.get_channel_by_name(db, channel_name)
                if channel:
                    target_channels.append(channel)
        
        # 按标签获取通道
        if tags:
            tagged_channels = await crud.get_channels_by_tags(db, tags)
            # 合并去重
            existing_ids = {c.id for c in target_channels}
            for channel in tagged_channels:
                if channel.id not in existing_ids:
                    target_channels.append(channel)
                    existing_ids.add(channel.id)
        
        # 发送通知
        for channel in target_channels:
            result = await self.send_notification(
                db, channel.id, title, body, priority
            )
            results.append(result)
        
        return results