using System;
using System.Collections.Generic;
using System.Data;
using System.IO;
using System.Linq;
using ClosedXML.Excel;

namespace TfsExcelImporter
{
    /// <summary>一行待导入的工作项数据（列顺序与 Excel 模板一致）。</summary>
    public class WorkItemRow
    {
        public string Title { get; set; }
        public string State { get; set; }
        public string AssignedTo { get; set; }
        public string FinancialProject { get; set; }
        public string Completed { get; set; }
        public string LogDate { get; set; }
        public string CreatedDate { get; set; }
        public string ClosedDate { get; set; }
        public string PbiId { get; set; }
        public string Notes { get; set; }
    }

    /// <summary>
    /// Excel 读取与模板生成。
    /// 模板列: Title | State | Assigned To | FinancialProject | Completed | LogDate | Created Date | Closed Date | PBI Id | Notes
    /// </summary>
    public static class ExcelService
    {
        public static readonly string[] Headers =
        {
            "Title", "State", "Assigned To", "FinancialProject",
            "Completed", "LogDate", "Created Date", "Closed Date", "PBI Id", "Notes"
        };

        private static readonly string[] DateFormats =
        {
            "yyyy-MM-dd HH:mm:ss", "yyyy/MM/dd HH:mm:ss",
            "yyyy-MM-dd HH:mm", "yyyy/MM/dd HH:mm",
            "yyyy-MM-dd", "yyyy/MM/dd"
        };

        // --------------------------------------------------------- 生成模板

        public static void GenerateTemplate(string path)
        {
            using (var wb = new XLWorkbook())
            {
                var ws = wb.Worksheets.Add("工作项");

                for (int i = 0; i < Headers.Length; i++)
                {
                    var cell = ws.Cell(1, i + 1);
                    cell.Value = Headers[i];
                    cell.Style.Font.Bold = true;
                    cell.Style.Fill.BackgroundColor = XLColor.LightGray;
                }

                // 示例行（To Do / Done 各一，帮助理解格式）
                var sample1 = new WorkItemRow
                {
                    Title = "20261012 - 示例：货载报告解析并上传凭证受托报告相关内容",
                    State = "To Do",
                    AssignedTo = "李晓柯",
                    FinancialProject = "信托 - 上海信托",
                    Completed = "5",
                    LogDate = "2026-10-12",
                    CreatedDate = "2026-10-30 11:14:41",
                    ClosedDate = "",
                    Notes = "示例行，导入前请删除"
                };
                var sample2 = new WorkItemRow
                {
                    Title = "20261009 示例：受托报告bug修复",
                    State = "Done",
                    AssignedTo = "陈卫宇",
                    FinancialProject = "信托 - 上海信托",
                    Completed = "8",
                    LogDate = "2026-10-09",
                    CreatedDate = "2026-10-10 18:20:00",
                    ClosedDate = "2026-10-30 18:00:00",
                    Notes = "示例行，导入前请删除"
                };
                WriteRow(ws, 2, sample1);
                WriteRow(ws, 3, sample2);

                ws.Columns().AdjustToContents();
                ws.SheetView.FreezeRows(1);
                wb.SaveAs(path);
            }
        }

        private static void WriteRow(IXLWorksheet ws, int r, WorkItemRow row)
        {
            ws.Cell(r, 1).Value = row.Title ?? "";
            ws.Cell(r, 2).Value = row.State ?? "";
            ws.Cell(r, 3).Value = row.AssignedTo ?? "";
            ws.Cell(r, 4).Value = row.FinancialProject ?? "";
            ws.Cell(r, 5).Value = row.Completed ?? "";
            ws.Cell(r, 6).Value = row.LogDate ?? "";
            ws.Cell(r, 7).Value = row.CreatedDate ?? "";
            ws.Cell(r, 8).Value = row.ClosedDate ?? "";
            ws.Cell(r, 9).Value = row.PbiId ?? "";
            ws.Cell(r, 10).Value = row.Notes ?? "";
        }

        // --------------------------------------------------------- 读取数据

        /// <summary>读取 Excel（或同格式 CSV 由用户另存为 xlsx）数据行，跳过空标题行。</summary>
        public static List<WorkItemRow> ReadRows(string path)
        {
            var rows = new List<WorkItemRow>();
            using (var wb = new XLWorkbook(path))
            {
                var ws = wb.Worksheets.First();
                var range = ws.RangeUsed();
                if (range == null) return rows;

                // 按表头名定位列（顺序不限），找不到的列按 Headers 顺序兜底
                var headerMap = MapHeaders(ws, range);

                for (int r = range.FirstRow().RowNumber() + 1; r <= range.LastRow().RowNumber(); r++)
                {
                    var title = CellText(ws, r, headerMap, "Title");
                    if (string.IsNullOrWhiteSpace(title)) continue;
                    rows.Add(new WorkItemRow
                    {
                        Title = title.Trim(),
                        State = CellText(ws, r, headerMap, "State"),
                        AssignedTo = CellText(ws, r, headerMap, "Assigned To"),
                        FinancialProject = CellText(ws, r, headerMap, "FinancialProject"),
                        Completed = CellText(ws, r, headerMap, "Completed"),
                        LogDate = CellText(ws, r, headerMap, "LogDate"),
                        CreatedDate = CellText(ws, r, headerMap, "Created Date"),
                        ClosedDate = CellText(ws, r, headerMap, "Closed Date"),
                        PbiId = CellText(ws, r, headerMap, "PBI Id"),
                        Notes = CellText(ws, r, headerMap, "Notes")
                    });
                }
            }
            return rows;
        }

        private static Dictionary<string, int> MapHeaders(IXLWorksheet ws, IXLRange range)
        {
            var map = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase);
            var firstRow = range.FirstRow().RowNumber();
            int lastCol = range.LastColumn().ColumnNumber();
            for (int c = 1; c <= lastCol; c++)
            {
                var text = ws.Cell(firstRow, c).GetString().Trim();
                if (text.Length == 0) continue;
                // 归一化：去掉空格/下划线，兼容 "Assigned To" / "AssignedTo" / "Created Date" 等
                var key = text.Replace(" ", "").Replace("_", "");
                if (!map.ContainsKey(key)) map[key] = c;
            }
            // 兜底：模板标准列名
            foreach (var h in Headers)
            {
                var key = h.Replace(" ", "");
                if (!map.ContainsKey(key))
                {
                    int idx = Array.IndexOf(Headers, h) + 1;
                    if (idx <= lastCol) map[key] = idx;
                }
            }
            return map;
        }

        private static string CellText(IXLWorksheet ws, int row, Dictionary<string, int> map, string header)
        {
            int col;
            if (!map.TryGetValue(header.Replace(" ", ""), out col)) return "";
            var cell = ws.Cell(row, col);
            if (cell.IsEmpty()) return "";
            if (cell.DataType == XLDataType.DateTime)
                return cell.GetDateTime().ToString("yyyy-MM-dd HH:mm:ss");
            if (cell.DataType == XLDataType.Number)
            {
                double d;
                if (double.TryParse(cell.GetString(), out d))
                {
                    // 处理 Excel 日期序列号（如 46300.0）
                    if (d > 20000 && d < 80000 && Math.Abs(d - Math.Floor(d)) < 0.001)
                    {
                        try { return DateTime.FromOADate(d).ToString("yyyy-MM-dd HH:mm:ss"); }
                        catch { }
                    }
                    return d.ToString("0.####");
                }
            }
            return cell.GetString().Trim();
        }

        // --------------------------------------------------------- 时间转换

        /// <summary>把单元格文本转成 TFS 接受的 ISO 时间；空值返回 null；解析失败抛异常。</summary>
        public static string ToIsoDateTime(string value)
        {
            if (string.IsNullOrWhiteSpace(value)) return null;
            value = value.Trim();
            foreach (var fmt in DateFormats)
            {
                DateTime dt;
                if (DateTime.TryParseExact(value, fmt, System.Globalization.CultureInfo.InvariantCulture,
                        System.Globalization.DateTimeStyles.None, out dt))
                    return dt.ToString("yyyy-MM-ddTHH:mm:ss");
            }
            DateTime any;
            if (DateTime.TryParse(value, out any))
                return any.ToString("yyyy-MM-ddTHH:mm:ss");
            throw new FormatException("无法解析时间: " + value);
        }

        /// <summary>Completed 数值：整数去小数点，非法值返回 null。</summary>
        public static object ToNumber(string value)
        {
            if (string.IsNullOrWhiteSpace(value)) return null;
            double d;
            if (!double.TryParse(value.Trim(), out d))
                throw new FormatException("无法解析数值: " + value);
            return Math.Abs(d - Math.Floor(d)) < 0.0001 ? (object)(int)Math.Floor(d) : d;
        }
    }
}