import { reactive, onBeforeUnmount, type Reactive } from 'vue'
import type { IObservable } from '@/core/state/IObservable.ts'

/**
 * Vue Hook: useObservable
 * 支持深层解构赋值，直接修改触发 ObservableImpl 通知 + Vue 响应式更新
 * @example
 * interface AppState {
 *   count: number
 *   user: { name: string; age: number }
 *   items: number[]
 * }
 *
 * // 创建 ObservableImpl
 * const obs = new ObservableImpl<AppState>({
 *   count: 0,
 *   user: { name: 'Alice', age: 20 },
 *   items: []
 * })
 *
 * export default defineComponent({
 *   setup() {
 *     // 深层解构 Hook
 *     const { count, user, items } = useObservable(obs)
 *
 *     const increment = () => {
 *       count += 1       // 触发 ObservableImpl 通知 + Vue 更新
 *     }
 *
 *     const changeAge = () => {
 *       user.age = 30    // 深层对象也能触发通知
 *     }
 *
 *     const addItem = () => {
 *       items.push(42)   // 数组方法拦截，触发通知
 *     }
 *
 *     return { count, user, items, increment, changeAge, addItem }
 *   }
 * })
 */
export function useObservable<T extends object>(observable: IObservable<T>): Reactive<T> {
  // 创建 Vue 响应式对象
  const state = reactive({} as T)

  /**
   * 将 ObservableImpl Proxy 映射到 Vue 响应式对象
   * 递归支持深层对象
   */
  function mapKeys(obj: any, proxy: any) {
    (Object.keys(proxy) as (keyof typeof proxy)[]).forEach(key => {
      const value = proxy[key]
      if (typeof value === 'object' && value !== null) {
        // 递归创建子对象 Proxy
        obj[key] = reactive({} as typeof value)
        mapKeys(obj[key], value)
      } else {
        // 基本类型通过 getter/setter 同步
        Object.defineProperty(obj, key, {
          enumerable: true,
          configurable: true,
          get() {
            return proxy[key]
          },
          set(val) {
            proxy[key] = val
          },
        })
      }
    })
  }

  // 获取 ObservableImpl 的 Proxy
  const refsProxy = observable.toRefsProxy()
  mapKeys(state, refsProxy)

  // 订阅 ObservableImpl，保持响应式同步
  const unsubscribe = observable.subscribe(() => {
    // 空实现即可，getter/setter 已同步
  })

  onBeforeUnmount(() => {
    unsubscribe()
  })

  return state
}