package file

import (
	"errors"
	"fmt"
	"os"
	"reflect"

	"github.com/xuri/excelize/v2"
)

// CreateEmptyFile 创建一个固定size大小的空文件
// 如果seek文件失败，则删除文件，并返回错误信息
func CreateEmptyFile(name string, size int64) (f *os.File, err error) {
	defer func() {
		if err != nil && f != nil {
			f.Close()
			os.Remove(name)
		}
	}()
	f, err = os.OpenFile(name, os.O_APPEND|os.O_CREATE|os.O_RDWR, 0666)
	if err != nil {
		return
	}
	if _, err = f.Seek(size-1, 0); err != nil {
		return
	}
	_, err = f.Write([]byte{0})
	return
}

func MakeDir(name string) error {
	if err := os.MkdirAll(name, 0755); err != nil {
		return errors.New("make dir wrong")
	}
	return nil
}

func WriteFile(data []byte, filename string) (err error) {
	defer func() {
		if err != nil {
			_ = os.Remove(filename)
		}
	}()
	pi := GetPathInfo(filename)
	if pi.Dir != "" {
		if err = os.MkdirAll(pi.Dir, 0755); err != nil {
			return
		}
	}
	f, err := os.OpenFile(filename, os.O_APPEND|os.O_CREATE|os.O_RDWR, 0666)
	if err != nil {
		return
	}
	_, err = f.Write(data)
	_ = f.Close()
	return
}

// WriteStruct2Xlsx 将struct切片写入Excel sheet
func WriteStruct2Xlsx(sheet string, records interface{}) *excelize.File {
	xlsx := excelize.NewFile()       // new file
	index, _ := xlsx.NewSheet(sheet) // new sheet
	xlsx.SetActiveSheet(index)       // set active (default) sheet
	t := reflect.TypeOf(records)
	if t.Kind() != reflect.Slice {
		panic("records must be slice")
	}
	s := reflect.ValueOf(records)
	for i := 0; i < s.Len(); i++ {
		elem := s.Index(i).Interface()
		elemType := reflect.TypeOf(elem)
		elemValue := reflect.ValueOf(elem)
		if elemType.Kind() == reflect.Ptr {
			elemType = elemType.Elem()
			elemValue = elemValue.Elem()
		}
		if elemType.Kind() != reflect.Struct {
			panic("record in slice must be a struct")
		}
		k := 0
		for j := 0; j < elemType.NumField(); j++ {
			field := elemType.Field(j)
			tag := field.Tag.Get("xlsx")
			if tag == "-" {
				continue
			}
			if tag == "" {
				tag = field.Name
			}
			column, _ := excelize.ColumnNumberToName(k + 1)
			k++
			name := tag
			// 设置表头
			if i == 0 {
				_ = xlsx.SetCellValue(sheet, fmt.Sprintf("%s%d", column, i+1), name)
			}
			// 设置内容
			_ = xlsx.SetCellValue(sheet, fmt.Sprintf("%s%d", column, i+2), elemValue.Field(j).Interface())
		}
	}
	return xlsx
}