var d3 = require('d3')

export function readxml(xmldoc) {
    let forcast = xmldoc.childNodes[0]
    let data = forcast.children[1]

    // Time
    let times = data.getElementsByTagName('time-layout')[0]
    var startTimes = []
    for (let time of times.getElementsByTagName('start-valid-time')) {
        let date = new Date(time.textContent)
        startTimes.push(date)
    }
    var endTimes = []
    for (let time of times.getElementsByTagName('end-valid-time')) {
        let date = new Date(time.textContent)
        endTimes.push(date)
    }

    // Temperature
    var temperatures = []
    for (let temp_type of data.getElementsByTagName('temperature')) {
        if (temp_type.attributes.type.nodeValue === 'hourly') {
            for (let temp of temp_type.getElementsByTagName('value')) {
                let degC = (parseFloat(temp.textContent) - 32) * (5.0/9.0)
                temperatures.push(degC)
            }
        }
    }

    // Map
    let nElements = startTimes.length
    var forcastData = []
    for (var i = 0; i < nElements; i++) {
        let midtimeScale = d3.scaleTime()
            .domain([0, 1])
            .range([startTimes[i], endTimes[i]])
        let midpointTime = midtimeScale(0.5)
        forcastData.push({
            'date': midpointTime,
            'temp': temperatures[i]
        })
    }

    return {
        'startTimes': startTimes,
        'endTimes': endTimes,
        'temperature': forcastData
    }
}