import uuid
from datetime import datetime, timezone

from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.orm import Session

from app.core.database import get_db
from app.core.deps import get_superuser
from app.core.security import get_password_hash, verify_password
from app.models.user import SystemSettings, User
from app.schemas import (
    AdminProfileUpdate,
    AdminUserCreate,
    AdminUserOut,
    AdminUserPasswordUpdate,
    AIProviderEnum,
    PublicSettingsOut,
    SystemSettingsOut,
    SystemSettingsUpdate,
)

router = APIRouter(prefix="/admin", tags=["admin"])


def settings_to_out(row: SystemSettings) -> SystemSettingsOut:
    return SystemSettingsOut(
        registration_enabled=row.registration_enabled,
        ai_provider=AIProviderEnum(row.ai_provider or "ollama"),
        ollama_base_url=row.ollama_base_url,
        ollama_model=row.ollama_model,
        openai_base_url=row.openai_base_url,
        openai_model=row.openai_model,
        openai_api_key_set=bool(row.openai_api_key),
        updated_at=row.updated_at,
    )


def get_or_create_settings(db: Session) -> SystemSettings:
    row = db.get(SystemSettings, 1)
    if row is None:
        row = SystemSettings(id=1, registration_enabled=True)
        db.add(row)
        db.commit()
        db.refresh(row)
    return row


@router.get("/settings", response_model=SystemSettingsOut)
def get_settings(
    db: Session = Depends(get_db),
    _: User = Depends(get_superuser),
):
    return settings_to_out(get_or_create_settings(db))


@router.patch("/settings", response_model=SystemSettingsOut)
def update_settings(
    data: SystemSettingsUpdate,
    db: Session = Depends(get_db),
    _: User = Depends(get_superuser),
):
    row = get_or_create_settings(db)
    if data.registration_enabled is not None:
        row.registration_enabled = data.registration_enabled
    if data.ai_provider is not None:
        row.ai_provider = data.ai_provider.value
    if data.ollama_base_url is not None:
        row.ollama_base_url = data.ollama_base_url or None
    if data.ollama_model is not None:
        row.ollama_model = data.ollama_model or None
    if data.openai_base_url is not None:
        row.openai_base_url = data.openai_base_url or None
    if data.openai_model is not None:
        row.openai_model = data.openai_model or None
    if data.openai_api_key is not None and data.openai_api_key.strip():
        row.openai_api_key = data.openai_api_key.strip()
    row.updated_at = datetime.now(timezone.utc)
    db.commit()
    db.refresh(row)
    return settings_to_out(row)


@router.patch("/profile", response_model=AdminUserOut)
def update_profile(
    data: AdminProfileUpdate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_superuser),
):
    if not data.username and not data.password:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="请填写要修改的内容")

    if data.password:
        if not data.current_password:
            raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="修改密码需提供当前密码")
        if not verify_password(data.current_password, current_user.password_hash):
            raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="当前密码错误")

    if data.username and data.username != current_user.username:
        if db.query(User).filter(User.username == data.username).first():
            raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="用户名已存在")
        current_user.username = data.username

    if data.password:
        current_user.password_hash = get_password_hash(data.password)

    db.commit()
    db.refresh(current_user)
    return current_user


@router.get("/users", response_model=list[AdminUserOut])
def list_users(
    db: Session = Depends(get_db),
    _: User = Depends(get_superuser),
):
    return db.query(User).order_by(User.created_at).all()


@router.post("/users", response_model=AdminUserOut, status_code=status.HTTP_201_CREATED)
def create_user(
    data: AdminUserCreate,
    db: Session = Depends(get_db),
    _: User = Depends(get_superuser),
):
    if db.query(User).filter(User.username == data.username).first():
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="用户名已存在")
    user = User(username=data.username, password_hash=get_password_hash(data.password))
    db.add(user)
    db.commit()
    db.refresh(user)
    return user


@router.patch("/users/{user_id}", response_model=AdminUserOut)
def reset_user_password(
    user_id: uuid.UUID,
    data: AdminUserPasswordUpdate,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_superuser),
):
    user = db.get(User, user_id)
    if user is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="用户不存在")
    if user.is_superuser and user.id != current_user.id:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="不能修改其他超级管理员")
    user.password_hash = get_password_hash(data.password)
    db.commit()
    db.refresh(user)
    return user


@router.delete("/users/{user_id}", status_code=status.HTTP_204_NO_CONTENT)
def delete_user(
    user_id: uuid.UUID,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_superuser),
):
    if user_id == current_user.id:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="不能删除当前登录账号")
    user = db.get(User, user_id)
    if user is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="用户不存在")
    if user.is_superuser:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="不能删除超级管理员")
    db.delete(user)
    db.commit()