from __future__ import annotations

from fastapi import APIRouter, Depends, Path
from sqlalchemy.ext.asyncio import AsyncSession

from app.dependencies import get_admin_user, get_db
from app.enums.resource_capacity import ResourceCapacityOperationEnum
from app.models.user import User
from app.schemas.resource_capacity import (
    AdminUserResourceCapacityOut,
    ResourceCapacityConfigOut,
    ResourceCapacityConfigUpdate,
)
from app.services.operation_log import log_operation
from app.services.resource_capacity_service import (
    build_global_resource_capacity_operation_detail,
    build_user_resource_capacity_operation_detail,
    delete_user_resource_capacity_config,
    get_admin_user_resource_capacity,
    get_global_resource_capacity_config,
    save_global_resource_capacity_config,
    save_user_resource_capacity_config,
)

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


@router.get(
    "/resource-capacity/global",
    response_model=ResourceCapacityConfigOut,
    summary="获取全局资源空间容量配置",
    description=(
        "获取管理后台全局生成资源空间容量管控配置。"
        "配置最终存储在 system_configs 表，key=resource_capacity_limit_config。"
        "enabled=false 表示全局容量管控关闭；enabled=true 表示按 limit_value + limit_unit 换算出的 limit_bytes 进行限制。"
        "单位枚举：MB=1048576字节，GB=1073741824字节，TB=1099511627776字节。"
    ),
)
async def get_global_resource_capacity(
    admin: User = Depends(get_admin_user),
    db: AsyncSession = Depends(get_db),
):
    _ = admin
    return await get_global_resource_capacity_config(db)


@router.put(
    "/resource-capacity/global",
    response_model=ResourceCapacityConfigOut,
    summary="保存全局资源空间容量配置",
    description=(
        "保存管理后台全局生成资源空间容量管控配置。"
        "enabled=true 时，limit_value 和 limit_unit 必填。"
        "limit_value 最小为1，不能为负数，最多支持3位小数。"
        "limit_unit 枚举明细：MB=1048576字节，GB=1073741824字节，TB=1099511627776字节。"
        "limit_bytes 不允许前端传入，由后端统一换算后保存。"
        "本接口会写入后台操作日志，action=更新全局资源容量配置，detail记录修改前后配置快照。"
    ),
)
async def update_global_resource_capacity(
    req: ResourceCapacityConfigUpdate,
    admin: User = Depends(get_admin_user),
    db: AsyncSession = Depends(get_db),
):
    before = await get_global_resource_capacity_config(db)
    result = await save_global_resource_capacity_config(db, req)
    await log_operation(
        db,
        admin.id,
        admin.username,
        ResourceCapacityOperationEnum.UPDATE_GLOBAL_CONFIG.value,
        "PUT",
        "/admin/resource-capacity/global",
        detail=build_global_resource_capacity_operation_detail(before, result),
    )
    await db.commit()
    return result


@router.get(
    "/users/{user_id}/resource-capacity",
    response_model=AdminUserResourceCapacityOut,
    summary="获取指定用户资源空间容量配置",
    description=(
        "获取指定用户的个人容量配置、全局容量配置以及最终生效容量数据。"
        "优先级：用户个人配置存在时优先使用；用户个人配置不存在时使用全局配置。"
        "注意：用户个人配置存在且 enabled=false，表示该用户个人明确关闭容量限制，不再回落到全局配置。"
    ),
)
async def get_user_resource_capacity(
    user_id: str = Path(..., description="用户ID，用于查询该用户个人容量配置和最终生效容量数据"),
    admin: User = Depends(get_admin_user),
    db: AsyncSession = Depends(get_db),
):
    _ = admin
    return await get_admin_user_resource_capacity(db, user_id)


@router.put(
    "/users/{user_id}/resource-capacity",
    response_model=AdminUserResourceCapacityOut,
    summary="保存指定用户个人资源空间容量配置",
    description=(
        "新增或更新指定用户个人资源空间容量配置。"
        "保存后该用户配置优先级高于全局配置。"
        "enabled=true 表示启用该用户个人容量限制；enabled=false 表示该用户个人明确关闭限制，不再回落到全局。"
        "limit_value 最小为1，不能为负数，最多3位小数。"
        "limit_unit 枚举明细：MB=1048576字节，GB=1073741824字节，TB=1099511627776字节。"
        "本接口会写入后台操作日志：首次创建 action=新增用户资源容量配置；已有配置更新 action=更新用户资源容量配置；detail记录修改前后配置快照。"
    ),
)
async def update_user_resource_capacity(
    req: ResourceCapacityConfigUpdate,
    user_id: str = Path(..., description="用户ID，用于新增或更新该用户个人容量配置"),
    admin: User = Depends(get_admin_user),
    db: AsyncSession = Depends(get_db),
):
    before = await get_admin_user_resource_capacity(db, user_id)
    result = await save_user_resource_capacity_config(db, user_id, req)
    is_create = not before.has_user_config
    await log_operation(
        db,
        admin.id,
        admin.username,
        (
            ResourceCapacityOperationEnum.CREATE_USER_CONFIG.value
            if is_create
            else ResourceCapacityOperationEnum.UPDATE_USER_CONFIG.value
        ),
        "PUT",
        f"/admin/users/{user_id}/resource-capacity",
        detail=build_user_resource_capacity_operation_detail(
            target_user_id=user_id,
            operation="create" if is_create else "update",
            before=before,
            after=result,
        ),
    )
    await db.commit()
    return result


@router.delete(
    "/users/{user_id}/resource-capacity",
    response_model=AdminUserResourceCapacityOut,
    summary="删除指定用户个人资源空间容量配置",
    description=(
        "删除指定用户个人容量配置。删除后该用户不再有个人覆盖配置，后续容量限制重新回落到全局配置。"
        "本接口会写入后台操作日志，action=删除用户资源容量配置，detail记录删除前个人配置、删除后最终生效配置。"
    ),
)
async def remove_user_resource_capacity(
    user_id: str = Path(..., description="用户ID，用于删除该用户个人容量配置并恢复走全局配置"),
    admin: User = Depends(get_admin_user),
    db: AsyncSession = Depends(get_db),
):
    before = await get_admin_user_resource_capacity(db, user_id)
    result = await delete_user_resource_capacity_config(db, user_id)
    await log_operation(
        db,
        admin.id,
        admin.username,
        ResourceCapacityOperationEnum.DELETE_USER_CONFIG.value,
        "DELETE",
        f"/admin/users/{user_id}/resource-capacity",
        detail=build_user_resource_capacity_operation_detail(
            target_user_id=user_id,
            operation="delete",
            before=before,
            after=result,
            remark="删除用户个人容量配置，用户恢复使用全局资源容量配置。",
        ),
    )
    await db.commit()
    return result