import { isRef, ref } from 'vue';
import { hyphenate, isObject, isString } from '@vue/shared';
import Loading from './loading';

// ts
import { LoadingInstance } from './createLoadingComponent';
import { LoadingOptions } from './types/loading';
import type { Directive, DirectiveBinding, UnwrapRef } from 'vue';

const INSTANCE_KEY = Symbol('IvueLoading');

export type LoadingBinding = boolean | UnwrapRef<LoadingOptions>;
export interface ElementLoading extends HTMLElement {
  INSTANCE_KEY: {
    instance: LoadingInstance;
    options: LoadingOptions;
  };
}

const createInstance = (
  el: ElementLoading,
  binding: DirectiveBinding<LoadingBinding>
) => {
  // 当前实例
  const vm = binding.instance;

  // 获取绑定的props
  const getBindingProp = <K extends keyof LoadingOptions>(
    key: K
  ): LoadingOptions[K] =>
    isObject(binding.value) ? binding.value[key] : undefined;

  const resolveExpression = (key: any) => {
    const data = (isString(key) && vm?.[key]) || key;
    if (data) return ref(data);
    else return data;
  };

  // 获取prop
  const getProp = <K extends keyof LoadingOptions>(name: K) =>
    resolveExpression(
      getBindingProp(name) || el.getAttribute(`ivue-loading-${hyphenate(name)}`)
    );

  // 开启全屏
  const fullscreen =
    getBindingProp('fullscreen') ?? binding.modifiers.fullscreen;

  // 设置参数
  const options: LoadingOptions = {
    // 显示在加载图标下方的加载文案
    text: getProp('text'),
    // 自定义加载图标类名
    iconClass: getProp('iconClass'),
    // 图标 slot
    iconText: getProp('iconText'),
    // 遮罩背景色
    background: getProp('background'),
    // Loading 的自定义类名
    customClass: getProp('customClass'),
    // 开启全屏
    fullscreen,
    // 需要覆盖的 DOM 节点
    target: getBindingProp('target') ?? (fullscreen ? undefined : el),
    // 使遮罩插入至 DOM 中的 body 上
    body: getBindingProp('body') ?? binding.modifiers.body,
    // 锁定屏幕的滚动
    lock: getBindingProp('lock') ?? binding.modifiers.lock,
  };

  // 重置实例
  el[INSTANCE_KEY] = {
    options,
    instance: Loading(options),
  };
};

// 更新选项
const updateOptions = (
  // 新的选项
  newOptions: UnwrapRef<LoadingOptions>,
  // 原始选项
  originalOptions: LoadingOptions
) => {
  for (const key of Object.keys(originalOptions)) {
    // 替换选项是否是 isRef
    if (isRef(originalOptions[key])) {
      originalOptions[key].value = newOptions[key];
    }
  }
};

const vLoading: Directive<ElementLoading, LoadingBinding> = {
  // mounted
  mounted(el, binding) {
    if (binding.value) {
      createInstance(el, binding);
    }
  },
  // 更新
  updated(el, binding) {
    const instance = el[INSTANCE_KEY];

    // 是否需要更新
    if (binding.oldValue !== binding.value) {
      // 初始化实例
      if (binding.value && !binding.oldValue) {
        createInstance(el, binding);
      }
      // 更新选项
      else if (binding.value && binding.oldValue) {
        if (isObject(binding.value)) {
          updateOptions(binding.value, instance.options);
        }
      }
      // 清除是实例
      else {
        instance?.instance.close();
      }
    }
  },
  // 销毁
  unmounted(el) {
    // 关闭实例
    el[INSTANCE_KEY]?.instance.close();
  },
};

export default vLoading;