package export

import (
	"fmt"
	"reflect"
	"strconv"
	"strings"

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

type Exporter struct {
	File             string
	Path             string
	Sheets           []string
	Titles           []Title
	Data             interface{}
	xlsx             *excelize.File
	GlobalTitleStyle *excelize.Style
}

func NewExporter() *Exporter {
	return &Exporter{
		xlsx: excelize.NewFile(),
	}
}

func DefaultExporter() *Exporter {
	return &Exporter{
		xlsx:             excelize.NewFile(),
		GlobalTitleStyle: DefaultTitleStyle(),
		Sheets:           []string{"Sheet1"},
	}
}

func (e *Exporter) newSheet() error {
	for _, sheet := range e.Sheets {
		_, err := e.xlsx.NewSheet(sheet)
		if err != nil {
			return fmt.Errorf("init sheet error:%s", err)
		}
	}
	return nil
}

func (e *Exporter) Export(sheetIndex int) error {
	if len(e.Sheets) == 0 {
		return fmt.Errorf("excel file has no sheet")
	}
	err := e.newSheet()
	if err != nil {
		return err
	}
	if len(e.Titles) == 0 {
		return fmt.Errorf("excel title is null")
	}
	sheet := e.Sheets[sheetIndex]
	e.SetTitle(sheet)
	v := reflect.ValueOf(e.Data)
	if v.Kind() != reflect.Pointer {
		return fmt.Errorf("data must be pointer")
	}
	if v.Elem().Kind() != reflect.Slice {
		return fmt.Errorf("data must be slice")
	}
	for i := 0; i < v.Elem().Len(); i++ {
		value := v.Elem().Index(i)
		if value.Kind() != reflect.Struct {
			return fmt.Errorf("element must be struct")
		}
		e.dealElement(sheet, value, i)
	}
	return nil
}

func (e *Exporter) dealElement(sheet string, data reflect.Value, index int) error {
	for i := 0; i < data.NumField(); i++ {
		field := data.Field(i)
		switch field.Kind() {
		case reflect.Struct:
			e.dealElement(sheet, field, index)
		// 该逻辑有待验证
		case reflect.Slice:
			for j := 0; j < field.Len(); j++ {
				value := field.Index(j)
				if value.Kind() == reflect.Struct {
					e.dealElement(sheet, value, index)
				}
			}
		default:
			t := data.Type().Field(i)
			tag, ok := t.Tag.Lookup("export")
			if ok {
				tagMap := dealTag(tag)
				x, _ := strconv.Atoi(tagMap["x"])
				y, _ := strconv.Atoi(tagMap["y"])
				colSpan, _ := strconv.Atoi(tagMap["colspan"])
				rowSpan, _ := strconv.Atoi(tagMap["rowspan"])
				location := Location{
					X: x,
					Y: y + index,
				}
				cell := Cell{
					Location: location,
					Rowspan:  rowSpan,
					Colspan:  colSpan,
					Value:    field,
				}
				e.SetCell(sheet, cell)
			}
		}

	}
	return e.Save()
}

func dealTag(tag string) map[string]string {
	tag_list := strings.Split(tag, ",")
	tag_map := make(map[string]string)
	for _, tag := range tag_list {
		tag_kv := strings.Split(tag, ":")
		if len(tag_kv) != 2 {
			continue
		}
		tag_map[tag_kv[0]] = tag_kv[1]
	}
	return tag_map
}

func (e *Exporter) Save() error {
	return e.xlsx.SaveAs(fmt.Sprintf("%s/%s", e.Path, e.File))
}