from typing import Optional, List

from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.database import get_db
from app.core.security import get_current_user, require_role
from app.models.user import User
from app.models.instance import Instance
from app.schemas.instance import InstanceCreate, InstanceUpdate, InstanceResponse, ConnectionTestResult
from app.services.instance_service import InstanceService
from app.core.crypto import encrypt_password, decrypt_password
from app.services.audit_log_service import AuditLogService

router = APIRouter(prefix="/instances", tags=["数据源管理"])


@router.get("", response_model=List[InstanceResponse])
async def list_instances(
    db_type: Optional[str] = None,
    env: Optional[str] = None,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    stmt = select(Instance).order_by(Instance.id)
    if db_type:
        stmt = stmt.where(Instance.db_type == db_type)
    if env:
        stmt = stmt.where(Instance.env == env)
    result = await db.execute(stmt)
    return result.scalars().all()


@router.post("", response_model=InstanceResponse, status_code=201)
async def create_instance(
    data: InstanceCreate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(require_role("admin", "dba")),
):
    instance = Instance(
        name=data.name,
        db_type=data.db_type,
        host=data.host,
        port=data.port,
        username=data.username,
        password=encrypt_password(data.password),
        database=data.database,
        env=data.env,
        description=data.description,
    )
    db.add(instance)
    await db.flush()
    await AuditLogService.log(
        db, user_id=current_user.id, action="CREATE_INSTANCE",
        target_type="instance", target_id=instance.id,
        detail=f"创建数据源: {data.name} ({data.db_type}@{data.host}:{data.port})",
    )
    await db.commit()
    await db.refresh(instance)
    return instance


@router.get("/{instance_id}", response_model=InstanceResponse)
async def get_instance(
    instance_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    result = await db.execute(select(Instance).where(Instance.id == instance_id))
    instance = result.scalar_one_or_none()
    if not instance:
        raise HTTPException(status_code=404, detail="数据源不存在")
    return instance


@router.put("/{instance_id}", response_model=InstanceResponse)
async def update_instance(
    instance_id: int,
    data: InstanceUpdate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(require_role("admin", "dba")),
):
    result = await db.execute(select(Instance).where(Instance.id == instance_id))
    instance = result.scalar_one_or_none()
    if not instance:
        raise HTTPException(status_code=404, detail="数据源不存在")

    update_data = data.model_dump(exclude_unset=True)
    if "password" in update_data:
        update_data["password"] = encrypt_password(update_data["password"])
    for key, value in update_data.items():
        setattr(instance, key, value)
    await db.commit()
    await db.refresh(instance)
    return instance


@router.delete("/{instance_id}")
async def delete_instance(
    instance_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(require_role("admin", "dba")),
):
    result = await db.execute(select(Instance).where(Instance.id == instance_id))
    instance = result.scalar_one_or_none()
    if not instance:
        raise HTTPException(status_code=404, detail="数据源不存在")

    await AuditLogService.log(
        db, user_id=current_user.id, action="DELETE_INSTANCE",
        target_type="instance", target_id=instance.id,
        detail=f"删除数据源: {instance.name}",
    )
    await db.delete(instance)
    await db.commit()
    return {"message": "数据源已删除"}


@router.post("/{instance_id}/test", response_model=ConnectionTestResult)
async def test_connection(
    instance_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(require_role("admin", "dba")),
):
    result = await db.execute(select(Instance).where(Instance.id == instance_id))
    instance = result.scalar_one_or_none()
    if not instance:
        raise HTTPException(status_code=404, detail="数据源不存在")

    # Decrypt password for connection test
    instance.password = decrypt_password(instance.password)
    return await InstanceService.test_connection(instance)


@router.get("/{instance_id}/databases")
async def list_databases(
    instance_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    result = await db.execute(select(Instance).where(Instance.id == instance_id))
    instance = result.scalar_one_or_none()
    if not instance:
        raise HTTPException(status_code=404, detail="数据源不存在")

    return await InstanceService.list_databases(instance)


@router.get("/{instance_id}/databases/{database}/tables")
async def list_tables(
    instance_id: int,
    database: str,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    result = await db.execute(select(Instance).where(Instance.id == instance_id))
    instance = result.scalar_one_or_none()
    if not instance:
        raise HTTPException(status_code=404, detail="数据源不存在")

    return await InstanceService.list_tables(instance, database)