import { getImageMainColor } from '@/utils/tools';

const DEFAULT_COLOR = '#E6E6E8';
const pendingRequests = new Map<HTMLElement, Promise<string | void>>();

const imageMainColorDirective = {
  mounted(el: HTMLElement, binding: any) {
    updateColor(el, binding.value);
  },

  updated(el: HTMLElement, binding: any) {
    if (binding.value !== binding.oldValue) {
      updateColor(el, binding.value);
    }
  },

  beforeUnmount(el: HTMLElement) {
    pendingRequests.delete(el);
  }
};

function updateColor(el: HTMLElement, imageUrl: string) {
  if (!imageUrl) {
    el.style.backgroundColor = DEFAULT_COLOR;
    return;
  }

  // 创建新的请求
  const request = getImageMainColor(imageUrl)
    .then(color => {
      if (pendingRequests.get(el) === request) {
        el.style.backgroundColor = color;
        pendingRequests.delete(el);
      }
      return color;
    })
    .catch(error => {
      console.error('获取图片主色调失败:', error);
      el.style.backgroundColor = DEFAULT_COLOR;
      pendingRequests.delete(el);
    });

  pendingRequests.set(el, request);
}

// 获取图片主色调指令
export default {
  install(app: any) {
    app.directive('image-main-color', imageMainColorDirective);
  }
};