using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;

namespace DrillTools
{
    /// <summary>
    /// 生成 CAM350 风格的钻孔使用报告。
    /// </summary>
    internal static class DrillUsageReportExporter
    {
        public static string GenerateReport(IReadOnlyList<ToolItem> tools, string layerName, DateTime exportTime)
        {
            if (tools == null)
                throw new ArgumentNullException(nameof(tools));

            var rows = tools.Select((tool, index) => CreateRow(tool, index + 1)).ToList();
            var report = new StringBuilder();

            AppendHeader(report, layerName, exportTime);
            AppendRows(report, rows);
            AppendTotals(report, rows);

            return report.ToString();
        }

        private static ReportRow CreateRow(ToolItem tool, int order)
        {
            // 当前导出顺序与 Tool Ref 相同；未来如有独立钻孔执行顺序可拆分维护。
            return new ReportRow(
                order,
                tool.ToolNumber,
                FormatDiameter(tool.Diameter),
                order,
                tool.RegularHoles,
                tool.SlotHoles,
                tool.TotalHoles);
        }

        private static void AppendHeader(StringBuilder report, string layerName, DateTime exportTime)
        {
            report.AppendLine("Project file name: ");
            report.AppendLine($"Date:              {FormatDate(exportTime)}");
            report.AppendLine($"Table:   DrillTable_1    Layer:   {layerName}");
            report.AppendLine("Drill Usage:");
            report.AppendLine("Table #  Tool Ref   Tool #           Size           Exp Ord  Plated Hits  Unplated Hits  Total Hits");
            report.AppendLine("=======  ========   ======           ====           =======  ===========  =============  ==========");
        }

        private static void AppendRows(StringBuilder report, IReadOnlyList<ReportRow> rows)
        {
            // Column widths and gaps match the header/separator layout exactly.
            // Separator sections: [0..6]=7 [9..16]=8 [20..25]=6 [37..40]=4 [52..58]=7 [61..71]=11 [74..86]=13 [89..98]=10
            // Gaps between sections:   2sp     3sp       11sp       11sp       2sp       2sp         2sp
            foreach (var row in rows)
            {
                report.AppendLine(string.Format(
                    CultureInfo.InvariantCulture,
                    "{0,-7}  {1,-8}   {2,-6}           {3,-4}           {4,-7}  {5,-11}  {6,-13}  {7,-10}",
                    1,
                    row.ToolRef,
                    row.ToolNumber,
                    row.Size,
                    row.ExportOrder,
                    row.PlatedHits,
                    row.UnplatedHits,
                    row.TotalHits));
            }
        }

        private static void AppendTotals(StringBuilder report, IReadOnlyList<ReportRow> rows)
        {
            report.AppendLine("===========================================================  ===========  =============  ==========");
            report.AppendLine(string.Format(
                CultureInfo.InvariantCulture,
                "{0,59}  {1,-11}  {2,-13}  {3,-10}",
                "Totals:",
                rows.Sum(row => row.PlatedHits),
                rows.Sum(row => row.UnplatedHits),
                rows.Sum(row => row.TotalHits)));
        }

        private static string FormatDate(DateTime value)
        {
            return $"{value:HH:mm:ss} {value.Year}年{value.Month}月{value.Day}日";
        }

        private static string FormatDiameter(double value)
        {
            return value.ToString("0.###", CultureInfo.InvariantCulture);
        }

        private sealed record ReportRow(
            int ToolRef,
            int ToolNumber,
            string Size,
            int ExportOrder,
            int PlatedHits,
            int UnplatedHits,
            int TotalHits);
    }
}