using System.Reflection;
using OfficeOpenXml;

namespace Dlhis.ExcelHelper;

public static class ExcelExtensions
{
    public static async Task<byte[]> ToExcelBytesAsync<T>(this List<T> data)
    {
        ExcelPackage.LicenseContext = LicenseContext.NonCommercial;

        var type = typeof(T);
        var sheetName = type.GetCustomAttribute<ExcelAttribute>()?.Description ?? type.Name;
        var excelHeaderNames = type.GetProperties().Where(x => x.IsDefined(typeof(ExcelAttribute))).ToList();

        using var package = new ExcelPackage();
        ExcelWorksheet worksheet = package.Workbook.Worksheets.Add(sheetName);

        // 写入表头
        for (int i = 0; i < excelHeaderNames.Count; i++)
        {
            var cell = worksheet.Cells[1, i + 1];
            worksheet.Column(i + 1).BestFit = true;
            cell.Style.Font.Bold = true;
            cell.Value = excelHeaderNames[i].GetCustomAttribute<ExcelAttribute>()!.Description;
        }

        int row = 2;
        foreach (var item in data)
        {
            for (int col = 0; col < excelHeaderNames.Count; col++)
            {
                var column = excelHeaderNames[col];
                var value = column.GetValue(item);

                var cell = worksheet.Cells[row, col + 1];
                var format = column.GetCustomAttribute<ExcelAttribute>()!.Format;
                cell.Value = value;
                if (!string.IsNullOrEmpty(format))
                {
                    cell.Style.Numberformat.Format = format;
                }
            }

            row++;
        }

        worksheet.Cells.AutoFitColumns();
        return await package.GetAsByteArrayAsync();
    }
}