import { isObj } from '../common/utils';

const getClassNames = (name: string) => ({
  enter: `van-${name}-enter van-${name}-enter-active enter-class enter-active-class`,
  'enter-to': `van-${name}-enter-to van-${name}-enter-active enter-to-class enter-active-class`,
  leave: `van-${name}-leave van-${name}-leave-active leave-class leave-active-class`,
  'leave-to': `van-${name}-leave-to van-${name}-leave-active leave-to-class leave-active-class`
});

const requestAnimationFrame = (cb: Function) => setTimeout(cb, 1000 / 60);

export const transition = function(showDefaultValue: boolean) {
  return Behavior({
    properties: {
      customStyle: String,
      show: {
        type: Boolean,
        value: showDefaultValue,
        observer: 'observeShow'
      },
      duration: {
        type: [Number, Object],
        value: 300,
        observer: 'observeDuration'
      },
      name: {
        type: String,
        value: 'fade',
        observer: 'updateClasses'
      }
    },

    data: {
      type: '',
      inited: false,
      display: false,
      classNames: getClassNames('fade')
    },

    attached() {
      if (this.data.show) {
        this.show();
      }
    },

    methods: {
      observeShow(value: boolean) {
        if (value) {
          this.show();
        } else {
          this.leave();
        }
      },

      updateClasses(name: string) {
        this.set({
          classNames: getClassNames(name)
        });
      },

      show() {
        const { classNames, duration } = this.data;

        this.set({
          inited: true,
          display: true,
          classes: classNames.enter,
          currentDuration: isObj(duration) ? duration.enter : duration
        }).then(() => {
          requestAnimationFrame(() => {
            this.set({
              classes: classNames['enter-to']
            });
          });
        });
      },

      leave() {
        const { classNames, duration } = this.data;

        this.set({
          classes: classNames.leave,
          currentDuration: isObj(duration) ? duration.leave : duration
        }).then(() => {
          requestAnimationFrame(() => {
            this.set({
              classes: classNames['leave-to']
            });
          });
        });
      },

      onTransitionEnd() {
        if (!this.data.show) {
          this.set({ display: false });
        }
      }
    }
  });
};