namespace WinFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnBrowseSource_Click(object sender, EventArgs e)
        {
            using (FolderBrowserDialog dialog = new FolderBrowserDialog())
            {
                dialog.Description = "选择Excel文件夹";
                if (dialog.ShowDialog() == DialogResult.OK)
                {
                    txtSourcePath.Text = dialog.SelectedPath;
                    txtOutputPath.Text = dialog.SelectedPath; // 默认输出到源文件夹
                    Log($"源文件夹: {dialog.SelectedPath}");
                }
            }
        }

        private void btnBrowseOutput_Click(object sender, EventArgs e)
        {
            using (FolderBrowserDialog dialog = new FolderBrowserDialog())
            {
                dialog.Description = "选择输出文件夹";
                if (dialog.ShowDialog() == DialogResult.OK)
                {
                    txtOutputPath.Text = dialog.SelectedPath;
                    Log($"输出文件夹: {dialog.SelectedPath}");
                }
            }
        }

        private void btnClear_Click(object sender, EventArgs e)
        {
            txtSourcePath.Clear();
            txtOutputPath.Clear();
            txtLog.Clear();
            progressBar.Value = 0;
        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void btnMerge_Click(object sender, EventArgs e)
        {
            // 前置校验
            if (string.IsNullOrEmpty(txtSourcePath.Text) || string.IsNullOrEmpty(txtOutputPath.Text))
            {
                MessageBox.Show("请选择源文件夹和输出文件夹", "错误", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            try
            {
                MergeExcel();
            }
            catch (Exception ex)
            {
                MessageBox.Show($"合并过程中发生错误: {ex.Message}", "错误", MessageBoxButtons.OK, MessageBoxIcon.Error);
                Log($"合并失败: {ex.Message}");
            }
        }

        private void MergeExcel()
        {
            var sourceDir = txtSourcePath.Text;
            var outputDir = txtOutputPath.Text;
            var outputFile = Path.Combine(outputDir, "合并结果.xlsx");

            if (!Directory.Exists(sourceDir))
            {
                MessageBox.Show("源文件夹不存在", "错误", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            // 查找xlsx文件（排除合并结果本身）
            var xlsxFiles = Directory.GetFiles(sourceDir, "*.xlsx")
                .Where(f => !Path.GetFileName(f).Equals("合并结果.xlsx", StringComparison.OrdinalIgnoreCase))
                .ToArray();

            if (xlsxFiles.Length == 0)
            {
                MessageBox.Show("未找到待合并的Excel文件", "错误", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            Log($"找到 {xlsxFiles.Length} 个文件，开始合并...");
            progressBar.Maximum = xlsxFiles.Length;
            progressBar.Value = 0;

            // 设置EPPlus许可证上下文
            OfficeOpenXml.ExcelPackage.LicenseContext = OfficeOpenXml.LicenseContext.NonCommercial;

            var allData = new List<System.Data.DataTable>();
            var headers = new List<string>();

            try
            {
                // 处理每个文件
                for (int idx = 0; idx < xlsxFiles.Length; idx++)
                {
                    var file = xlsxFiles[idx];
                    var fileName = Path.GetFileName(file);

                    Log($"处理: {fileName}");

                    try
                    {
                        using (var package = new OfficeOpenXml.ExcelPackage(new FileInfo(file)))
                        {
                            if (package.Workbook.Worksheets.Count == 0)
                            {
                                Log($"跳过空文件: {fileName}");
                                continue;
                            }

                            var worksheet = package.Workbook.Worksheets[0]; // 使用第一个工作表
                            var table = new System.Data.DataTable();

                            // 获取表头
                            if (headers.Count == 0)
                            {
                                var columnCount = worksheet.Dimension.End.Column;
                                for (int col = 1; col <= columnCount; col++)
                                {
                                    var header = worksheet.Cells[1, col].Text?.Trim() ?? $"Column{col}";
                                    headers.Add(header);
                                    table.Columns.Add(header);
                                }
                            }
                            else
                            {
                                // 创建相同结构的表
                                foreach (var header in headers)
                                {
                                    table.Columns.Add(header);
                                }
                            }

                            // 跳过表头行，从第二行开始读取数据
                            var rowCount = worksheet.Dimension.End.Row;
                            for (int row = 2; row <= rowCount; row++)
                            {
                                var dataRow = table.NewRow();
                                var isEmpty = true;

                                for (int col = 0; col < headers.Count; col++)
                                {
                                    var cellValue = worksheet.Cells[row, col + 1].Text;
                                    dataRow[col] = cellValue;
                                    if (!string.IsNullOrWhiteSpace(cellValue))
                                    {
                                        isEmpty = false;
                                    }
                                }

                                if (!isEmpty)
                                {
                                    table.Rows.Add(dataRow);
                                }
                            }

                            if (table.Rows.Count > 0)
                            {
                                allData.Add(table);
                                Log($"成功读取 {fileName}: {table.Rows.Count} 行数据");
                            }
                            else
                            {
                                Log($"跳过无数据文件: {fileName}");
                            }
                        }
                    }
                    catch (Exception ex)
                    {
                        Log($"处理失败: {fileName} - {ex.Message}");
                        continue;
                    }

                    progressBar.Value = idx + 1;
                    Application.DoEvents();
                }

                // 合并数据并保存
                if (allData.Count == 0)
                {
                    MessageBox.Show("无有效数据可合并", "错误", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    return;
                }

                // 创建合并后的Excel文件
                using (var outputPackage = new OfficeOpenXml.ExcelPackage())
                {
                    var outputSheet = outputPackage.Workbook.Worksheets.Add("合并结果");

                    // 写入表头
                    for (int col = 0; col < headers.Count; col++)
                    {
                        outputSheet.Cells[1, col + 1].Value = headers[col];
                    }

                    int currentRow = 2;
                    int totalRows = 0;

                    // 合并所有数据
                    foreach (var table in allData)
                    {
                        foreach (System.Data.DataRow row in table.Rows)
                        {
                            for (int col = 0; col < headers.Count; col++)
                            {
                                outputSheet.Cells[currentRow, col + 1].Value = row[col];
                            }
                            currentRow++;
                            totalRows++;
                        }
                    }

                    // 保存文件
                    outputPackage.SaveAs(new FileInfo(outputFile));

                    Log($"合并完成！文件路径: {outputFile}");
                    Log($"总行数: {totalRows} | 总列数: {headers.Count}");

                    MessageBox.Show($"合并成功！\n文件：{outputFile}\n行数：{totalRows}",
                        "完成", MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
            }
            catch (Exception ex)
            {
                Log($"保存失败: {ex.Message}");
                MessageBox.Show($"保存文件失败: {ex.Message}", "错误", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        private void Log(string msg)
        {
            txtLog.AppendText($"{msg}\r\n");
            txtLog.ScrollToCaret();
            Application.DoEvents();
        }
    }
}