// components/scroll-number/index.js
Component({
    externalClasses: ['container-class', 'item-class', 'dot-class'],
    properties: {
        value: {
            type: String,
            value: ''
        },
        /** 一次滚动耗时 单位ms */
        duration: {
            type: Number,
            value: 1600
        },
        /** 每个数字之间的延迟滚动 */
        delay: {
            type: Number,
            value: 200
        }
    },
    data: {
        valArr: [],
        aniArr: [], // 动画列表，和valArr对应
        numArr: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9], // 所有数字
        itemHeight: 0 // 数字项的高度
    },
    observers: {
        value: function (newVal) {
            // 监听value变化，格式化为valArr
            setTimeout(() => {
                let valArr = []
                if (newVal) {
                    valArr = newVal.split('').map(o => {
                        return {
                            val: o,
                            isNaN: isNaN(o)
                        }
                    })
                }
                this.setData({
                    valArr: valArr
                })
                this.getNumberHeight()
            }, 0);
        }
    },
    methods: {
        /** 计算数字高度 */
        getNumberHeight() {
            if (this.data.itemHeight > 0) {
                this.startScrollAni()
                return
            }
            const query = this.createSelectorQuery()
            query.select('.number-item').boundingClientRect()
            query.exec((res) => {
                this.setData({
                    itemHeight: res[0].height
                })
                this.startScrollAni()
            })
        },
        /** 开始滚动动画 */
        startScrollAni() {
            if (this.data.itemHeight <= 0) return
            const aniArr = []
            this.data.valArr.forEach((item, index) => {
                if (!item.isNaN) {
                    aniArr.push(`transition-delay: ${this.data.delay * index}ms; top: ${-this.data.itemHeight * (this.data.numArr[parseInt(item.val)] + 10)}px;`)
                } else {
                    aniArr.push(null)
                }
            })
            this.setData({
                aniArr: aniArr
            })
        }
    }
})