import {extend, warn} from '../_util'

const defaultOptions = {

currentLevel: 0,

maxLevel: 0,

values: [],

defaultIndex: [],

defaultValue: [],

}

function getDefaultIndex(data, defaultIndex, defaultValue) {

let activeIndex = 0

if (defaultIndex !== undefined) {

return defaultIndex

} else if (defaultValue !== undefined) {

data.some((item, index) => {

if (item.text === defaultValue || item.label === defaultValue || item.value === defaultValue) {

activeIndex = index

return true

}

})

}

return activeIndex

}

/**

* cascade column by set value of following columns

* @param {*} picker instance of picker-column

* @param {*} options { currentLevel, maxLevel, values }

* @param {*} fn

*/

export default function(picker, options = {}, fn) {

options = extend(defaultOptions, options)

/* istanbul ignore if */

if (!picker) {

warn('cascade: picker is undefined')

return

}

let values = options.values

/* istanbul ignore next */

for (let i = options.currentLevel + 1; i < options.maxLevel; i++) {

const columnValues = (!i ? values[i] : values.children) || []

picker.setColumnValues(i, columnValues)

let activeIndex = getDefaultIndex(columnValues, options.defaultIndex[i], options.defaultValue[i])

activeIndex >= columnValues.length && (activeIndex = 0)

values = columnValues[activeIndex] || []

}

fn && fn()

}