package services

import (
	"fmt"
	"os"

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

type ExcelService struct{}

func NewExcelService() *ExcelService {
	return &ExcelService{}
}

type ExcelInfo struct {
	Sheets     []string `json:"sheets"`
	SheetCount int      `json:"sheetCount"`
	FilePath   string   `json:"filePath"`
	Size       int64    `json:"size"`
}

type SheetData struct {
	Name    string     `json:"name"`
	Rows    int        `json:"rows"`
	Columns int        `json:"columns"`
	Data    [][]string `json:"data"`
}

func (s *ExcelService) GetExcelInfo(filePath string) (*ExcelInfo, error) {
	f, err := excelize.OpenFile(filePath)
	if err != nil {
		return nil, fmt.Errorf("打开Excel文件失败: %v", err)
	}
	defer f.Close()

	fileInfo, err := os.Stat(filePath)
	if err != nil {
		return nil, fmt.Errorf("获取文件信息失败: %v", err)
	}

	sheets := f.GetSheetList()

	return &ExcelInfo{
		Sheets:     sheets,
		SheetCount: len(sheets),
		FilePath:   filePath,
		Size:       fileInfo.Size(),
	}, nil
}

func (s *ExcelService) GetSheetData(filePath, sheetName string) (*SheetData, error) {
	f, err := excelize.OpenFile(filePath)
	if err != nil {
		return nil, fmt.Errorf("打开Excel文件失败: %v", err)
	}
	defer f.Close()

	if sheetName == "" {
		sheets := f.GetSheetList()
		if len(sheets) == 0 {
			return nil, fmt.Errorf("工作簿中没有工作表")
		}
		sheetName = sheets[0]
	}

	rows, err := f.GetRows(sheetName)
	if err != nil {
		return nil, fmt.Errorf("读取工作表失败: %v", err)
	}

	maxCols := 0
	for _, row := range rows {
		if len(row) > maxCols {
			maxCols = len(row)
		}
	}

	return &SheetData{
		Name:    sheetName,
		Rows:    len(rows),
		Columns: maxCols,
		Data:    rows,
	}, nil
}

func (s *ExcelService) ConvertToCSV(inputPath, outputPath string) error {
	if outputPath == "" {
		outputPath = ChangeExtension(inputPath, ".csv")
	}

	f, err := excelize.OpenFile(inputPath)
	if err != nil {
		return fmt.Errorf("打开Excel文件失败: %v", err)
	}
	defer f.Close()

	sheets := f.GetSheetList()
	if len(sheets) == 0 {
		return fmt.Errorf("工作簿中没有工作表")
	}

	rows, err := f.GetRows(sheets[0])
	if err != nil {
		return fmt.Errorf("读取工作表失败: %v", err)
	}

	outFile, err := os.Create(outputPath)
	if err != nil {
		return fmt.Errorf("创建输出文件失败: %v", err)
	}
	defer outFile.Close()

	for _, row := range rows {
		line := ""
		for i, cell := range row {
			if i > 0 {
				line += ","
			}
			if containsComma(cell) {
				line += "\"" + cell + "\""
			} else {
				line += cell
			}
		}
		_, err := outFile.WriteString(line + "\n")
		if err != nil {
			return fmt.Errorf("写入CSV失败: %v", err)
		}
	}

	return nil
}

func (s *ExcelService) ConvertToJSON(inputPath, outputPath string) error {
	if outputPath == "" {
		outputPath = ChangeExtension(inputPath, ".json")
	}

	f, err := excelize.OpenFile(inputPath)
	if err != nil {
		return fmt.Errorf("打开Excel文件失败: %v", err)
	}
	defer f.Close()

	sheets := f.GetSheetList()
	if len(sheets) == 0 {
		return fmt.Errorf("工作簿中没有工作表")
	}

	rows, err := f.GetRows(sheets[0])
	if err != nil {
		return fmt.Errorf("读取工作表失败: %v", err)
	}

	if len(rows) < 2 {
		return fmt.Errorf("工作表数据不足")
	}

	headers := rows[0]
	var jsonData []map[string]string

	for _, row := range rows[1:] {
		record := make(map[string]string)
		for i, header := range headers {
			if i < len(row) {
				record[header] = row[i]
			} else {
				record[header] = ""
			}
		}
		jsonData = append(jsonData, record)
	}

	outFile, err := os.Create(outputPath)
	if err != nil {
		return fmt.Errorf("创建输出文件失败: %v", err)
	}
	defer outFile.Close()

	_, err = outFile.WriteString("[\n")
	if err != nil {
		return err
	}

	for i, record := range jsonData {
		_, err = outFile.WriteString("  {\n")
		if err != nil {
			return err
		}

		j := 0
		for key, value := range record {
			_, err = outFile.WriteString(fmt.Sprintf("    \"%s\": \"%s\"", key, value))
			if err != nil {
				return err
			}
			if j < len(record)-1 {
				_, err = outFile.WriteString(",\n")
			} else {
				_, err = outFile.WriteString("\n")
			}
			if err != nil {
				return err
			}
			j++
		}

		_, err = outFile.WriteString("  }")
		if err != nil {
			return err
		}

		if i < len(jsonData)-1 {
			_, err = outFile.WriteString(",\n")
		} else {
			_, err = outFile.WriteString("\n")
		}
		if err != nil {
			return err
		}
	}

	_, err = outFile.WriteString("]")
	return err
}

func (s *ExcelService) CreateExcelFromData(outputPath string, data [][]string) error {
	f := excelize.NewFile()
	defer f.Close()

	sheetName := "Sheet1"
	index, err := f.NewSheet(sheetName)
	if err != nil {
		return fmt.Errorf("创建工作表失败: %v", err)
	}

	f.SetActiveSheet(index)

	for i, row := range data {
		for j, cell := range row {
			cellName, _ := excelize.CoordinatesToCellName(j+1, i+1)
			f.SetCellValue(sheetName, cellName, cell)
		}
	}

	if err := f.SaveAs(outputPath); err != nil {
		return fmt.Errorf("保存Excel文件失败: %v", err)
	}

	return nil
}

func containsComma(s string) bool {
	for _, c := range s {
		if c == ',' {
			return true
		}
	}
	return false
}