// 判断是否叶子节点
const isLeaf = (data, prop) => {
    return !(Array.isArray(data[prop]) && data[prop].length > 0)
}

// 创建 node 节点
export const renderNode = (h, data, context) => {
    const {props} = context
    const cls = ['org-tree-node']
    const childNodes = []
    const children = data[props.props.children]

    if (isLeaf(data, props.props.children)) {
        cls.push('is-leaf')
    }
    else if (props.collapsable && !data[props.props.expand]) {
        cls.push('collapsed')
    }

    childNodes.push(renderLabel(h, data, context))

    if (!props.collapsable || data[props.props.expand]) {
        childNodes.push(renderChildren(h, children, context))
    }

    return h('div', {
        domProps: {
            className: cls.join(' ')
        }
    }, childNodes)
}

// 创建展开折叠按钮
export const renderBtn = (h, data, context) => {
    const {props} = context
    const expandHandler = context.listeners['on-expand']

    let cls = ['org-tree-node-btn']

    if (data[props.props.expand]) {
        cls.push('expanded')
    }

    return h('span', {
        'class': 'org-tree-button-wrapper',
        on: {
            click: e => {
                e.stopPropagation()
                expandHandler && expandHandler(data)
            },
            mousedown: e => e.stopPropagation()
        }
    }, [
        props.buttonRender
            ? props.buttonRender(h, data)
            : h('span', {
                'class': cls.join(' ')
            })
    ])
}

// 创建 label 节点
export const renderLabel = (h, data, context) => {
    const {props} = context
    const label = data[props.props.label]
    const nodeRender = props.nodeRender
    const clickHandler = context.listeners['on-node-click']
    const mousedownHandler = e => {
        e.stopPropagation()
        if (context.listeners['on-node-mousedown']) {
            context.listeners['on-node-mousedown'](e, data)
        }
    }
    const mouseupHandler = context.listeners['on-node-mouseup']
    const touchstartHandler = context.listeners['on-node-touchstart']
    const touchleaveHandler = context.listeners['on-node-touchleave']

    const childNodes = []
    if (typeof nodeRender === 'function') {
        let vnode = nodeRender(h, data)
        vnode && childNodes.push(vnode)
    }
    else if (context.parent.$scopedSlots.default) {
        childNodes.push(context.parent.$scopedSlots.default(data))
    }
    else childNodes.push(label)

    if (props.collapsable && !isLeaf(data, props.props.children)) {
        childNodes.push(renderBtn(h, data, context))
    }

    const cls = ['org-tree-node-label-inner']
    let {labelWidth, labelClassName} = props
    if (typeof labelWidth === 'number') {
        labelWidth += 'px'
    }
    if (typeof labelClassName === 'function') {
        labelClassName = labelClassName(data)
    }
    labelClassName && cls.push(labelClassName)

    return h('div', {
        domProps: {
            className: 'org-tree-node-label'
        },
        on: {
            click: e => clickHandler && clickHandler(e, data),
            mousedown: mousedownHandler,
            mouseup: e => mouseupHandler && mouseupHandler(e, data),
            touchstart: e => touchstartHandler && touchstartHandler(e, data),
            touchleave: e => touchleaveHandler && touchleaveHandler(e, data)
        }
    }, [h('div', {
        domProps: {
            className: cls.join(' ')
        },
        style: {width: labelWidth}
    }, childNodes)])
}

// 创建 node 子节点
export const renderChildren = (h, list, context) => {
    if (Array.isArray(list) && list.length) {
        const children = list.map(item => {
            return renderNode(h, item, context)
        })

        return h('div', {
            domProps: {
                className: 'org-tree-node-children'
            }
        }, children)
    }
    return ''
}

export const render = (h, context) => {
    const {props} = context
    return renderNode(h, props.data, context)
}

export default render