"""
Admin 用户管理 API（仅平台管理员可访问）
"""
from __future__ import annotations

import logging
import uuid
from datetime import datetime
from typing import List, Optional

from fastapi import APIRouter, Depends, HTTPException, Query
from pydantic import BaseModel, Field, EmailStr
from sqlalchemy.orm import Session
from sqlalchemy import func

from app.api.auth import get_current_user
from app.core.database import get_db
from app.core.security import get_password_hash
from app.models.user import User
from app.models.workspace import WorkspaceMembership

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/api/v1/admin/users", tags=["admin-users"])


def _require_admin(current_user: User = Depends(get_current_user)) -> User:
    if current_user.role != "admin":
        raise HTTPException(status_code=403, detail="仅平台管理员可访问")
    return current_user


# ── Request / Response schemas ──

class UserCreateRequest(BaseModel):
    username: str = Field(..., min_length=2, max_length=50)
    email: EmailStr
    password: str = Field(..., min_length=6, max_length=128)
    role: str = Field(default="user")
    phone: Optional[str] = None
    status: str = Field(default="active")


class UserUpdateRequest(BaseModel):
    username: Optional[str] = Field(None, min_length=2, max_length=50)
    email: Optional[EmailStr] = None
    role: Optional[str] = None
    phone: Optional[str] = None
    status: Optional[str] = None
    subscription_tier: Optional[str] = None


class ResetPasswordRequest(BaseModel):
    new_password: str = Field(..., min_length=6, max_length=128)


class UserItem(BaseModel):
    id: str
    username: str
    email: str
    role: str
    phone: Optional[str] = None
    phone_verified: bool = False
    status: str
    is_email_verified: bool = False
    subscription_tier: str = "free"
    daily_usage_count: int = 0
    workspace_count: int = 0
    created_at: Optional[datetime] = None
    updated_at: Optional[datetime] = None

    class Config:
        from_attributes = True


class UserListResponse(BaseModel):
    items: List[UserItem]
    total: int
    page: int
    page_size: int


# ── Endpoints ──

@router.get("", response_model=UserListResponse)
def list_users(
    page: int = Query(1, ge=1),
    page_size: int = Query(20, ge=1, le=100),
    search: Optional[str] = Query(None, description="搜索用户名或邮箱"),
    status: Optional[str] = Query(None, description="过滤状态: active/disabled/deleted"),
    role: Optional[str] = Query(None, description="过滤角色"),
    db: Session = Depends(get_db),
    _admin: User = Depends(_require_admin),
):
    """获取用户列表（分页、搜索、过滤）"""
    q = db.query(User)

    if search:
        like = f"%{search}%"
        q = q.filter((User.username.ilike(like)) | (User.email.ilike(like)))
    if status:
        q = q.filter(User.status == status)
    if role:
        q = q.filter(User.role == role)

    total = q.count()
    items = q.order_by(User.created_at.desc()).offset((page - 1) * page_size).limit(page_size).all()

    # 获取每个用户的 workspace 数量
    user_ids = [u.id for u in items]
    ws_counts = {}
    if user_ids:
        rows = (
            db.query(
                WorkspaceMembership.user_id,
                func.count(WorkspaceMembership.workspace_id).label("cnt"),
            )
            .filter(WorkspaceMembership.user_id.in_(user_ids))
            .group_by(WorkspaceMembership.user_id)
            .all()
        )
        ws_counts = {r.user_id: r.cnt for r in rows}

    return {
        "items": [
            {**{c.name: getattr(u, c.name) for c in User.__table__.columns},
             "workspace_count": ws_counts.get(u.id, 0)}
            for u in items
        ],
        "total": total,
        "page": page,
        "page_size": page_size,
    }


@router.post("", response_model=UserItem)
def create_user(
    data: UserCreateRequest,
    db: Session = Depends(get_db),
    _admin: User = Depends(_require_admin),
):
    """管理员创建新用户"""
    if db.query(User).filter(User.username == data.username).first():
        raise HTTPException(status_code=409, detail="用户名已存在")
    if db.query(User).filter(User.email == data.email).first():
        raise HTTPException(status_code=409, detail="邮箱已存在")

    user = User(
        id=str(uuid.uuid4()),
        username=data.username,
        email=data.email,
        password_hash=get_password_hash(data.password),
        role=data.role,
        phone=data.phone,
        status=data.status,
    )
    db.add(user)
    db.commit()
    db.refresh(user)

    logger.info("管理员创建了用户: %s (%s)", user.username, user.id)
    return {**{c.name: getattr(user, c.name) for c in User.__table__.columns}, "workspace_count": 0}


@router.get("/{user_id}", response_model=UserItem)
def get_user(
    user_id: str,
    db: Session = Depends(get_db),
    _admin: User = Depends(_require_admin),
):
    """获取用户详情"""
    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="用户不存在")

    ws_count = (
        db.query(func.count(WorkspaceMembership.workspace_id))
        .filter(WorkspaceMembership.user_id == user_id)
        .scalar()
    ) or 0

    return {**{c.name: getattr(user, c.name) for c in User.__table__.columns}, "workspace_count": ws_count}


@router.put("/{user_id}", response_model=UserItem)
def update_user(
    user_id: str,
    data: UserUpdateRequest,
    db: Session = Depends(get_db),
    _admin: User = Depends(_require_admin),
):
    """编辑用户"""
    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="用户不存在")

    if data.username is not None and data.username != user.username:
        if db.query(User).filter(User.username == data.username, User.id != user_id).first():
            raise HTTPException(status_code=409, detail="用户名已存在")
        user.username = data.username
    if data.email is not None and data.email != user.email:
        if db.query(User).filter(User.email == data.email, User.id != user_id).first():
            raise HTTPException(status_code=409, detail="邮箱已存在")
        user.email = data.email
    if data.role is not None:
        user.role = data.role
    if data.phone is not None:
        user.phone = data.phone
    if data.status is not None:
        if data.status not in ("active", "disabled", "deleted"):
            raise HTTPException(status_code=400, detail="无效的状态值")
        user.status = data.status
    if data.subscription_tier is not None:
        user.subscription_tier = data.subscription_tier

    db.commit()
    db.refresh(user)

    logger.info("管理员更新了用户: %s (%s)", user.username, user.id)
    ws_count = (
        db.query(func.count(WorkspaceMembership.workspace_id))
        .filter(WorkspaceMembership.user_id == user_id)
        .scalar()
    ) or 0
    return {**{c.name: getattr(user, c.name) for c in User.__table__.columns}, "workspace_count": ws_count}


@router.delete("/{user_id}")
def delete_user(
    user_id: str,
    db: Session = Depends(get_db),
    _admin: User = Depends(_require_admin),
):
    """软删除用户（标记为 deleted）"""
    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="用户不存在")
    if user.role == "admin":
        raise HTTPException(status_code=400, detail="不能删除平台管理员")

    user.status = "deleted"
    db.commit()

    logger.info("管理员软删除了用户: %s (%s)", user.username, user.id)
    return {"message": "用户已删除"}


@router.post("/{user_id}/reset-password")
def reset_password(
    user_id: str,
    data: ResetPasswordRequest,
    db: Session = Depends(get_db),
    _admin: User = Depends(_require_admin),
):
    """重置用户密码"""
    user = db.query(User).filter(User.id == user_id).first()
    if not user:
        raise HTTPException(status_code=404, detail="用户不存在")

    user.password_hash = get_password_hash(data.new_password)
    db.commit()

    logger.info("管理员重置了用户 %s 的密码", user.username)
    return {"message": "密码已重置"}