class AutoScrollTable {
    loadingText = "正在加载..."

    constructor(el, columns, {
        width = null,
        headWidth = null,
        init = true,
        loadingSplash = true,
        caption = null,
    } = {},lineNum = 5) {
        this.lineNum = lineNum
        this.el = el
        this.columns = columns
        this.width = width
        this.headWidth = headWidth
        this.loadingSplash = loadingSplash
        this.caption = caption

        this.scrollInfo = null
        this.loaded = false
        this.initialized = false

        this.loadingText = "暂无数据"
        if (init) {
            this.init()
        }
    }

    init() {
        this.el.style.overflowY = "scroll"
        this.el.classList.add("hide-scrollbar")

        let html = ""
        html += `<table class="autoscroll-table">`

        if (this.caption) {
            html += `<caption class="autoscroll-table_caption">${this.caption}</caption>`
        }

        html += `<thead class="autoscroll-table_thead"><tr>`
        if (this.columns && this.columns.length > 0) {
            for (let item of this.columns) {
                html += `<th>${item}</th>`
            }
        }
        html += `</tr></thead>`

        html += `<tbody class="autoscroll-table_shadow"><tr><td>&nbsp;</td></tr></tbody>`
        // html += `<tbody class="autoscroll-table_shadow"><tr><td>&nbsp;</td></tr></tbody>`
        html += `<tbody class="autoscroll-table_tbody autoscroll-table_tbody1"></tbody>`
        html += `<tbody class="autoscroll-table_tbody autoscroll-table_tbody2"></tbody>`
        html += `</table>`
        html += `<div class="loading-splash">${this.loadingText}</div>`
        this.el.innerHTML = html

        const thead = this.el.querySelector(".autoscroll-table .autoscroll-table_thead");
        let tbody = this.el.querySelector(".autoscroll-table .autoscroll-table_tbody1");
        const shadow = this.el.querySelector(".autoscroll-table .autoscroll-table_shadow")

        thead.style.width = window.getComputedStyle(tbody).width
        thead.style.overflow = 'hidden'
        shadow.style.opacity = 0

        this.addFill()
        this.resize()

        if (this.loadingSplash) {
            this.loading()
        }

        this.el.addEventListener('scroll', ev => {
            if (this.el.scrollTop > 0) {
                thead.classList.add("thead-scroll-override")
            } else {
                thead.classList.remove("thead-scroll-override")
            }
        })

        this.initialized = true
        return this
    }

    addFill() {
        let tbody = this.el.querySelector(".autoscroll-table .autoscroll-table_tbody1");
        if (!tbody.children.length) {
            tbody.innerHTML += "<tr></tr>"
        }

        for (let item of this.columns) {
            tbody.children[0].innerHTML += '<td>&nbsp;</td>'
        }
    }

    loadData(data, fields = null, {
        append = false,
        autoScroll = false,
        scrollToEnd = false,
        includeHead = false,
    } = {}) {
        if (!fields) {
            fields = Object.keys(data[0])
        } else if (typeof fields === 'number') {
            let f = []
            for (let i = 0; i < fields; i++) {
                f.push(i)
            }

            fields = f
        }

        const tbody = this.el.querySelectorAll(".autoscroll-table .autoscroll-table_tbody")
        if (!this.loaded) {
            const loadingSplash = this.el.querySelector(".loading-splash")
            loadingSplash.style.display = "none"
            this.loaded = true
        }

        if (!append) {
            this.clear()
        }

        if (includeHead) {
            const rawRow = data.shift()
            let row = []
            for (let field of Object.values(fields)) {
                row.push(rawRow[field])
            }
            this.columns = row

            const thead = this.el.querySelector(".autoscroll-table .autoscroll-table_thead")

            let html = ""
            for (let item of Object.values(this.columns)) {
                html += `<th>${item}</th>`
            }

            thead.querySelector("tr").innerHTML = html
        }

        for (let item of Object.values(data)) {
            let html = `<tr>`
            for (let field of fields) {
                html += `<td>${item[field]}</td>`
            }
            html += '</tr>'
            tbody.forEach(value => value.innerHTML += html)
        }

        if (autoScroll) {
            this.startAutoScroll()
        } else {
            const l2 = this.el.querySelector(".autoscroll-table .autoscroll-table_tbody2")
            l2.style.display = 'none'

            if (scrollToEnd) {
                this.scrollToEnd()
            }
        }

        if (this.width) {
            tbody.forEach(value => {
                for (let i = 0; i < value.children.length; i++) {
                    const child = value.children[i]
                    for (let j = 0; j < child.children.length; j++) {
                        if (j < this.width.length && this.width[j]) {
                            child.children[j].style.width = this.width[j]
                        }
                    }
                }
            })
        }

        if (!data || data.length && data.length === 0) {
            this.addFill()
        }

        this.resize()
        setTimeout(() => this.resize(), 300)
        setTimeout(() => this.resize(), 500)
        setTimeout(() => this.resize(), 1000)
    }

    scrollToEnd() {
        const l1 = this.el.querySelector(".autoscroll-table .autoscroll-table_tbody1")
        this.el.scrollTop = l1.scrollHeight
    }

    clear() {
        const tbody = this.el.querySelectorAll(".autoscroll-table .autoscroll-table_tbody")
        for (let tb of tbody) {
            tb.innerHTML = ""
        }
    }

    startAutoScroll() {
        if (this.scrollInfo) {
            return
        }

        const l1 = this.el.querySelector(".autoscroll-table .autoscroll-table_tbody1")
        const l2 = this.el.querySelector(".autoscroll-table .autoscroll-table_tbody2")

        function scrollTimeout() {
            this.scrollInfo = setInterval(scrollUp, 50);
        }

        const scrollUp = () => {
            this.el.scrollTop = (this.el.scrollTop + 1) % (l1.offsetHeight * 1.004)
        }

        const startScroll = () => {
            if (l1.offsetHeight <= this.el.offsetHeight) {
                l2.style.display = 'none'
                return
            }

            l2.style.display = 'table-row-group'

            scrollTimeout.call(this);//数值越大，滚动速度越慢
            this.el.onmouseover = () => {
                this.stop()
            }
        }

        this.el.onmouseout = () => {
            scrollTimeout.call(this)
        }

        startScroll()
    }

    stop() {
        clearInterval(this.scrollInfo)
        this.scrollInfo = null
    }

    resize() {
        const parent = this.el.querySelector(".autoscroll-table").parentNode
        const thead = this.el.querySelector(".autoscroll-table .autoscroll-table_thead");
        const theadRow = thead.children[0]
        let tbody = this.el.querySelector(".autoscroll-table .autoscroll-table_tbody1");
        // let tbody2 = this.el.querySelector(".autoscroll-table .autoscroll-table_tbody2");
        const shadow = this.el.querySelector(".autoscroll-table .autoscroll-table_shadow")
        const caption = this.el.querySelector(".autoscroll-table .autoscroll-table_caption")

        const firstRow = tbody.children[0]

        if (firstRow && firstRow.children.length > 0) {
            for (let i = 0; i < theadRow.children.length; i++) {
                if (this.headWidth && this.headWidth.length > i) {
                    theadRow.children[i].style.width = this.headWidth[i]
                } else {
                    if (firstRow.children.length > i) {
                        theadRow.children[i].style.width = window.getComputedStyle(firstRow.children[i]).width
                    }
                }
            }
        }

        thead.style.width = window.getComputedStyle(tbody).width
        let tr = this.el.querySelectorAll(".autoscroll-table .autoscroll-table_tbody1 tr")
        tr.forEach(val => {
            val.style.lineHeight = `${(parseFloat(window.getComputedStyle(parent).height) - parseFloat(window.getComputedStyle(theadRow).height))/this.lineNum - 1.5}px`
        })

        shadow.style.display ='none'
        thead.style.top = '0'

        if (caption) {
            caption.style.width = thead.style.width
            const captionHeight = parseFloat(window.getComputedStyle(caption).height)

            thead.style.top = '0'
            shadow.style.height = `${parseFloat(shadow.style.height) + captionHeight}px`
        }
    }

    loading() {
        this.el.querySelector(".loading-splash").style.display = "block"
        this.loaded = false
    }
}