from sqlalchemy.orm import Session
from sqlalchemy import func, desc, and_, case
from datetime import datetime, timedelta, date
from typing import Dict, Any

from app.models.order import VasOrder
from app.models.ticket import VasTicket
from app.models.vas_task import VasTask
from app.models.user import VasUser
from app.models.product import VasProduct

# 静态汇率配置 (基准: CNY)
# 实际生产环境建议从数据库或缓存获取实时汇率
EXCHANGE_RATES = {
    "CNY": 1.0,
    "USD": 7.25,
    "EUR": 7.65,
    "GBP": 9.10,
    "HKD": 0.92,
    "JPY": 0.048
}

CURRENCY_SYMBOLS = {
    "CNY": "¥", "USD": "$", "EUR": "€", "GBP": "£", "HKD": "HK$", "JPY": "¥"
}

class StatisticsService:
    @staticmethod
    def _convert_to_cny(amount: any, currency: str) -> int:
        """
        辅助函数：将金额(分)转换为人民币(分)
        """
        if not amount:
            return 0
        rate = EXCHANGE_RATES.get(currency, 1.0) # 未知货币默认按 1:1 处理
        
        # 修复点：将 amount 转换为 float，解决 Decimal * float 报错的问题
        return int(float(amount) * rate)

    @staticmethod
    def overview(db: Session) -> Dict[str, Any]:
        """
        获取后台概览数据 (统一换算为 CNY 统计)
        """
        # --- 1. 核心指标卡片 ---
        
        # 1.1 总营收 (按币种分组求和，再换算)
        revenue_groups = db.query(
            VasOrder.base_currency,
            func.sum(VasOrder.base_amount)
        ).filter(
            VasOrder.status.in_(['paid', 'completed', 'succeeded'])
        ).group_by(VasOrder.base_currency).all()

        total_revenue_cny = 0
        for currency, amount in revenue_groups:
            total_revenue_cny += StatisticsService._convert_to_cny(amount, currency)

        # 1.2 活跃订单数
        total_orders = db.query(func.count(VasOrder.id))\
            .filter(VasOrder.status != 'closed')\
            .scalar() or 0

        # 1.3 活跃用户数
        active_users = db.query(func.count(VasUser.id)).scalar() or 0

        # 1.4 待处理工单
        pending_tickets = db.query(func.count(VasTicket.id))\
            .filter(VasTicket.status.in_(['pending', 'info_required']))\
            .scalar() or 0

        # 1.5 任务成功率
        task_counts = db.query(
            func.count(VasTask.id).label('total'),
            func.sum(case((VasTask.status == 'completed', 1), else_=0)).label('success')
        ).first()
        
        success_rate_str = "0%"
        if task_counts and task_counts.total > 0:
            rate = (task_counts.success / task_counts.total) * 100
            success_rate_str = f"{rate:.1f}%"

        # --- 2. 营收趋势图 (Last 7 Days) ---
        
        revenue_trend = []
        today = date.today()
        
        for i in range(6, -1, -1):
            target_date = today - timedelta(days=i)
            start_dt = datetime.combine(target_date, datetime.min.time())
            end_dt = datetime.combine(target_date, datetime.max.time())
            
            # 按币种分组查询当天的营收
            daily_groups = db.query(
                VasOrder.base_currency,
                func.sum(VasOrder.base_amount).label('amount'),
                func.count(VasOrder.id).label('orders')
            ).filter(
                VasOrder.created_at >= start_dt,
                VasOrder.created_at <= end_dt,
                VasOrder.status.in_(['paid', 'completed', 'succeeded'])
            ).group_by(VasOrder.base_currency).all()

            daily_amount_cny = 0
            daily_order_count = 0
            
            for curr, amt, cnt in daily_groups:
                daily_amount_cny += StatisticsService._convert_to_cny(amt, curr)
                daily_order_count += cnt

            revenue_trend.append({
                "date": target_date.strftime("%m-%d"),
                "amount": float(daily_amount_cny) / 100.0, # 转为元 (浮点数)
                "orders": daily_order_count
            })

        # --- 3. 商品销量分布 ---
        
        product_stats = db.query(
            VasProduct.title,
            func.count(VasOrder.id).label('count')
        ).join(VasOrder, VasOrder.product_id == VasProduct.id)\
         .filter(VasOrder.status.in_(['paid', 'completed', 'succeeded']))\
         .group_by(VasProduct.title)\
         .order_by(desc('count'))\
         .limit(5).all()

        product_dist = [{"name": p.title, "value": p.count} for p in product_stats]

        # --- 4. 最新动态 ---
        
        activities = []
        
        # 订单动态
        recent_orders = db.query(VasOrder).order_by(desc(VasOrder.created_at)).limit(5).all()
        for o in recent_orders:
            symbol = CURRENCY_SYMBOLS.get(o.base_currency, o.base_currency)
            amt_display = f"{symbol}{o.base_amount / 100}"
            
            activities.append({
                "id": f"order_{o.id}",
                "text": f"用户下单: {o.product_name or '未知商品'} ({amt_display})",
                "time": o.created_at,
                "type": "order" if o.status == 'pending' else "money"
            })

        # 工单动态
        recent_tickets = db.query(VasTicket).order_by(desc(VasTicket.created_at)).limit(5).all()
        for t in recent_tickets:
            reason_preview = t.reason[:20] + "..." if len(t.reason) > 20 else t.reason
            activities.append({
                "id": f"ticket_{t.id}",
                "text": f"新工单 #{t.id}: {reason_preview}",
                "time": t.created_at,
                "type": "ticket"
            })
        
        # 排序与时间格式化
        activities.sort(key=lambda x: x['time'], reverse=True)
        activities = activities[:10]

        now = datetime.now()
        for act in activities:
            dt = act['time']
            if not isinstance(dt, datetime):
                 continue
            diff = now - dt
            if diff.days > 0:
                time_str = f"{diff.days}天前"
            elif diff.seconds > 3600:
                time_str = f"{diff.seconds // 3600}小时前"
            elif diff.seconds > 60:
                time_str = f"{diff.seconds // 60}分钟前"
            else:
                time_str = "刚刚"
            act['time'] = time_str

        return {
            "stats": {
                "totalOrders": total_orders,
                "totalRevenue": total_revenue_cny, # 单位：分 (CNY)
                "activeUsers": active_users,
                "pendingTickets": pending_tickets,
                "successRate": success_rate_str
            },
            "revenue_trend": revenue_trend,
            "product_dist": product_dist,
            "recent_activities": activities
        }