package export

import (
	"fmt"
	"log"
	"sync"
	"time"
)

type CsvExporter struct {
	mFetcher DataFetcher
	file     FileAdapter
	count    int
	last     interface{}

	wg *sync.WaitGroup
}

func NewCsvExporter(fetcher DataFetcher, file FileAdapter) DataExporter {
	return &CsvExporter{
		mFetcher: fetcher,
		file:     file,
	}
}

func (ee *CsvExporter) Fetcher(fetcher DataFetcher) {
	ee.mFetcher = fetcher
}

func (ee *CsvExporter) File(file FileAdapter) {
	ee.file = file
}

func (ee *CsvExporter) WaitGroup(wg *sync.WaitGroup) {
	ee.wg = wg
}

func (ee *CsvExporter) Export(sql, pk string) error {
	begin := time.Now()
	data, err := ee.mFetcher.Fetch(sql)
	if err != nil {
		return fmt.Errorf("数据获取错误:%w", err)
	}
	log.Printf("数据获取耗时：%s \n", time.Now().Sub(begin).String())

	ee.count = len(data.Data)
	if ee.count > 0 {
		//异步导出数据到csv文件中
		go ee.exportToCsv(data)
		last := data.Data[ee.count-1]
		ee.last = last[ee.getPkIndex(data.Title, pk)]
	}
	return nil
}

func (ee *CsvExporter) exportToCsv(data *Data) {
	begin := time.Now()
	ee.file.Open()
	ee.file.WriteTitle(data.Title)

	for _, val := range data.Data {
		row := val
		ee.file.Write(row)
	}
	ee.file.Close()
	ee.wg.Done()
	end := time.Now()
	log.Printf("csv time:%s\n", end.Sub(begin).String())
}

func (ee *CsvExporter) Last() (int, interface{}) {
	return ee.count, ee.last
}

func (ee *CsvExporter) getPkIndex(titles []string, pk string) int {
	for i, title := range titles {
		if title == pk {
			return i
		}
	}
	return -1
}