let fs = require('fs');

let provinceNameArr = ["Barisal", "Chittagong", "Rajshahi", "Rangpur", "Dhaka", "Sylhet", "Mymensingh", "Khulna"];
let cityName = {
    Barisal:['Barguna','Patuakhali','Bhola','Barisal','Jhalokati','Pirojpur'],
    Chittagong:['Bandarban','Brahmanbaria','Chandpur','Chittagong','Khagrachhari','Lakshmipur','Noakhali','Rangamati','Comilla','Cox\'s Bazar','Feni'],
    Rajshahi:['Naogaon','Natore','Chapai Nawabganj','Pabna','Rajshahi','Sirajganj','Bogra','Joypurhat'],
    Rangpur:['Dinajpur','Gaibandha','Kurigram','Lalmonirhat','Nilphamari','Panchagarh','Rangpur','Thakurgaon'],
    Dhaka:[ 'Dhaka','Kishoreganj','Madaripur','Manikganj','Munshiganj','Narayanganj','Narsingdi','Rajbari','Shariatpur','Tangail','Faridpur','Gazipur','Gopalganj'],
    Sylhet:['Habiganj', 'Maulvibazar', 'Sunamganj', 'Sylhet'],
    Mymensingh:[ 'Mymensingh', 'Netrakona', 'Sherpur', 'Jamalpur'],
    Khulna:[ 'Bagerhat','Chuadanga','Jessore','Jhenaidah','Khulna','Kushtia','Magura','Meherpur','Narail','Satkhira']
};
function writeJson(paramsName){
    //现将json文件读出来
    fs.readFile('./'+paramsName+'.json',function(err,data){
        console.log('读取文件',paramsName)
        if(err){
            return console.error(err);
        }
        console.log('读取文件成功')
        let bangladesh = data.toString();//将二进制的数据转换为字符串
        bangladesh = JSON.parse(bangladesh);//将字符串转换为json对象

        let arr2 = [];
        console.log('开始计算')
        let arr3 = [];
        function fun(areaName){
            let params = {
                type: "FeatureCollection",
                totalFeatures: 544,
                features: [
                ]
            }
            for(let d of bangladesh.features){
                if(d.properties.Dist_name == areaName){
                    d.properties.name = d.properties.Upaz_name
                    params.features.push(d)
                    console.log(d.properties.name,d.geometry.coordinates[0][0].length)
                }
            }

            let str = JSON.stringify(params);//因为nodejs的写入文件只认识字符串或者二进制数，所以把json对象转换成字符串重新写入json文件中
            // console.log(str)
            try{
                //同步写入
                fs.writeFileSync('./area/'+areaName+'_3.json',str,"utf8");
                console.log("写入成功");    
            }catch(err){
                  console.log(err)
            }
            // fs.writeFile('./area/'+areaName+'_3.json',str,function(err){
            //     if(err){
            //         console.log(err);
            //     }
            //     console.log('----------计算完成-------------');
            // })
        }
        for(let key in cityName){
            for(let areaName of cityName[key]){
                fun(areaName)
            }
        }
       
    })
}
writeJson('map_bf')//执行一下;