# app/services/task_handlers.py

import logging
from datetime import datetime
from typing import Callable, Awaitable, Dict, Any
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from app.models.user import VasUser
from app.models.vas_task import VasTask
from app.models.order import VasOrder

# 导入具体的业务服务 (用于发邮件等)
from app.services.email_authorizations_service import EmailAuthorizationService

logger = logging.getLogger(__name__)

# 定义处理器函数的类型签名
HandlerFunc = Callable[[AsyncSession, VasTask, VasOrder], Awaitable[None]]

class TaskHandlerRegistry:
    """
    任务后处理注册表
    用于管理 routing_key 与处理函数的对应关系
    """
    def __init__(self):
        self._handlers: Dict[str, HandlerFunc] = {}

    def register(self, *routing_keys: str):
        """
        装饰器：将一个或多个 routing_key 注册到同一个处理函数
        
        用法:
        @task_processor.register("key1", "key2")
        async def my_handler(...):
            pass
        """
        def decorator(func: HandlerFunc):
            for key in routing_keys:
                if key in self._handlers:
                    logger.warning(f"⚠️ [TaskHandler] Overwriting handler for key: {key}")
                self._handlers[key] = func
            return func
        return decorator

    async def execute(self, routing_key: str, db: AsyncSession, task: VasTask, order: VasOrder):
        """
        根据 routing_key 查找并执行对应的处理函数
        """
        handler = self._handlers.get(routing_key)
        
        if not handler:
            # 如果没有注册处理器，通常直接跳过即可
            logger.debug(f"ℹ️ [TaskHandler] No handler found for routing_key: {routing_key}, skipping.")
            return

        try:
            logger.info(f"▶️ [TaskHandler] Executing handler '{handler.__name__}' for task {task.id} (key: {routing_key})")
            
            # 执行具体的业务逻辑
            await handler(db, task, order)
            
            logger.info(f"✅ [TaskHandler] Handler '{handler.__name__}' completed successfully.")
            
        except Exception as e:
            # 捕获异常，防止阻断主流程 (manual_confirm) 的事务提交
            # 也可以选择在这里将错误写入 task.meta
            logger.error(f"❌ [TaskHandler] Error executing handler for task {task.id}: {str(e)}", exc_info=True)
            
            # 可选：记录错误到 Task Meta
            # await self._record_error(db, task, str(e))

    async def _record_error(self, db: AsyncSession, task: VasTask, error_msg: str):
        """辅助方法：将错误信息回写到 Task (可选)"""
        try:
            meta = dict(task.meta) if task.meta else {}
            meta["post_process_error"] = error_msg
            task.meta = meta
            # 注意：这里不需要 commit，因为外层 manual_confirm 会统一 commit
        except Exception:
            pass


# =================================================================
# 实例化注册表 (在其他地方 import 这个实例)
# =================================================================
task_processor = TaskHandlerRegistry()


# =================================================================
# 具体的处理函数 (Handlers)
# =================================================================

@task_processor.register("auto.slot.dub.fr.tourist")
async def forward_troov_appointment_letter(db: AsyncSession, task: VasTask, order: VasOrder):
    """
    处理邮件转发相关的任务
    支持 routing_key: email.forward, email.auto_reply
    """
    # 1. 解析参数
    # 假设参数存储在 task.user_inputs 或 task.config 中
    inputs: Dict[str, Any] = task.user_inputs or {}
    grabbed_history = task.grabbed_history or {}
    
    task_config = task.config or {}

    
    email_account = "visafly666@gmail.com"
    forward_to = inputs.get("email", "")
    if not forward_to:
        uid = order.user_id
        stmt = select(VasUser).where(VasUser.id == uid)
        result = await db.execute(stmt)
        user = result.scalar_one_or_none()
        forward_to = user.email
        
    recipient = task_config.get('alias_email', "")
    
    first_name = inputs.get('first_name', '')
    last_name = inputs.get('last_name', '')
    
    first_name = first_name.capitalize()
    last_name = last_name.capitalize()
    
    book_date_str = grabbed_history.get("book_date", "")
    dt = datetime.strptime(book_date_str, "%Y-%m-%dT%H:%M:%S")
    formatted_date_time = dt.strftime("%B %-d, %Y to %Hh%M")
    
    # 过滤条件
    sender = "ne-pas-repondre at consulat.gouv.fr"
    
    subject_keywords = inputs.get("subjectKeywords", "Confirmed,appointment,Section,Ambassade,France,Irlande")
    body_keywords = inputs.get("bodyKeywords", f"Concerned,person,{first_name},{last_name},{formatted_date_time}")

    if not email_account or not forward_to:
        logger.warning(f"Task {task.id} missing required inputs for email forwarding.")
        return

    logger.info(f"Task {task.id}: Forwarding emails from {email_account} to {forward_to}")

    # 2. 获取授权配置
    auth = await EmailAuthorizationService.get_by_email(db, email_account)
    if not auth:
        raise ValueError(f"Email authorization not found for account: {email_account}")

    # 3. 调用邮件服务执行转发
    # 这里复用你之前写的 Service 方法
    result = await EmailAuthorizationService.forward_first_matching_email2(
        db=db,
        auth=auth,
        forward_to=forward_to,
        sender=sender,
        recipient=recipient,
        subject_keywords=subject_keywords,
        body_keywords=body_keywords
    )

    # 4. (可选) 将结果回写到 Task Meta
    meta = dict(task.meta) if task.meta else {}
    meta["forward_result"] = result
    task.meta = meta
    
    
@task_processor.register("auto.slot.dub.nl.tourist")
async def forward_vfs_appointment_letter(db: AsyncSession, task: VasTask, order: VasOrder):
    """
    处理邮件转发相关的任务
    支持 routing_key: email.forward, email.auto_reply
    """
    # 1. 解析参数
    # 假设参数存储在 task.user_inputs 或 task.config 中
    inputs: Dict[str, Any] = task.user_inputs or {}
    grabbed_history = task.grabbed_history or {}
    
    task_config = task.config or {}

    
    email_account = "visafly666@gmail.com"
    forward_to = inputs.get("email", "")
    if not forward_to:
        uid = order.user_id
        stmt = select(VasUser).where(VasUser.id == uid)
        result = await db.execute(stmt)
        user = result.scalar_one_or_none()
        forward_to = user.email
    

    
    urn = grabbed_history.get("urn", "")
    
    # 过滤条件
    sender = "donotreply at vfsglobal.com"
    recipient = task_config.get('alias_email', "")
    subject_keywords = inputs.get("subjectKeywords", "Appointment,Confirm")
    body_keywords = inputs.get("bodyKeywords", f"urn")

    if not email_account or not forward_to:
        logger.warning(f"Task {task.id} missing required inputs for email forwarding.")
        return

    logger.info(f"Task {task.id}: Forwarding emails from {email_account} to {forward_to}")

    # 2. 获取授权配置
    auth = await EmailAuthorizationService.get_by_email(db, email_account)
    if not auth:
        raise ValueError(f"Email authorization not found for account: {email_account}")

    # 3. 调用邮件服务执行转发
    # 这里复用你之前写的 Service 方法
    result = await EmailAuthorizationService.forward_first_matching_email2(
        db=db,
        auth=auth,
        forward_to=forward_to,
        sender=sender,
        recipient=recipient,
        subject_keywords=subject_keywords,
        body_keywords=body_keywords
    )

    # 4. (可选) 将结果回写到 Task Meta
    meta = dict(task.meta) if task.meta else {}
    meta["forward_result"] = result
    task.meta = meta
    
@task_processor.register("auto.slot.dub.de.tourist")
async def forward_visametric_appointment_letter(db: AsyncSession, task: VasTask, order: VasOrder):
    """
    处理邮件转发相关的任务
    支持 routing_key: email.forward, email.auto_reply
    """
    # 1. 解析参数
    # 假设参数存储在 task.user_inputs 或 task.config 中
    inputs: Dict[str, Any] = task.user_inputs or {}
    grabbed_history = task.grabbed_history or {}
    
    task_config = task.config or {}

    
    email_account = "visafly666@gmail.com"
    forward_to = inputs.get("email", "")
    if not forward_to:
        uid = order.user_id
        stmt = select(VasUser).where(VasUser.id == uid)
        result = await db.execute(stmt)
        user = result.scalar_one_or_none()
        forward_to = user.email
    
    first_name = inputs.get('first_name', '')
    last_name = inputs.get('last_name', '')
    
    pnr_number = grabbed_history.get('pnr_number', '')
    slot_date = grabbed_history.get('slot_date', '')
    slot_time = grabbed_history.get('slot_time', '')
    
    # 过滤条件
    sender = "noreply at visametric.com"
    recipient = task_config.get("alias_email", "")
    subject_keywords = inputs.get("subjectKeywords", f"{pnr_number},Visametric,Appointment,Request")
    body_keywords = inputs.get("bodyKeywords", f"{pnr_number},{slot_date},{slot_time},{first_name},{last_name}")

    if not email_account or not forward_to:
        logger.warning(f"Task {task.id} missing required inputs for email forwarding.")
        return

    logger.info(f"Task {task.id}: Forwarding emails from {email_account} to {forward_to}")

    # 2. 获取授权配置
    auth = await EmailAuthorizationService.get_by_email(db, email_account)
    if not auth:
        raise ValueError(f"Email authorization not found for account: {email_account}")

    # 3. 调用邮件服务执行转发
    # 这里复用你之前写的 Service 方法
    result = await EmailAuthorizationService.forward_first_matching_email2(
        db=db,
        auth=auth,
        forward_to=forward_to,
        sender=sender,
        recipient=recipient,
        subject_keywords=subject_keywords,
        body_keywords=body_keywords
    )

    # 4. (可选) 将结果回写到 Task Meta
    meta = dict(task.meta) if task.meta else {}
    meta["forward_result"] = result
    task.meta = meta