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

namespace DrillTools.Integration
{
    /// <summary>
    /// Excellon 钻带涨缩引擎
    /// 对钻孔坐标进行 X/Y 方向独立缩放，保持槽孔长度不变
    /// </summary>
    internal static class ExcellonScaler
    {
        // 坐标模式：X 后跟可选符号的数字（可能含小数点），Y 同理
        private static readonly Regex CoordinatePattern = new(
            @"^X([+-]?\d+\.?\d*)Y([+-]?\d+\.?\d*)$",
            RegexOptions.Compiled);

        // G85 槽孔模式：X...Y...G85X...Y...
        private static readonly Regex SlotPattern = new(
            @"^(X[+-]?\d+\.?\d*Y[+-]?\d+\.?\d*)G85(X[+-]?\d+\.?\d*Y[+-]?\d+\.?\d*)$",
            RegexOptions.Compiled);

        // 解析 X 或 Y 坐标值的子模式
        private static readonly Regex XValuePattern = new(
            @"X([+-]?\d+\.?\d*)", RegexOptions.Compiled);
        private static readonly Regex YValuePattern = new(
            @"Y([+-]?\d+\.?\d*)", RegexOptions.Compiled);

        // 刀具定义行模式（在头部，如 T01C0.799H05000Z+0.000S060.00）
        private static readonly Regex ToolDefinitionPattern = new(
            @"^T\d+C", RegexOptions.Compiled | RegexOptions.IgnoreCase);

        /// <summary>
        /// 对钻带内容执行涨缩
        /// </summary>
        /// <param name="content">原始钻带内容</param>
        /// <param name="kx">X 方向缩放倍率</param>
        /// <param name="ky">Y 方向缩放倍率</param>
        /// <returns>缩放后的钻带内容</returns>
        public static string Scale(string content, double kx, double ky)
        {
            if (content == null)
                throw new ArgumentNullException(nameof(content));

            var lines = content.Split(new[] { "\r\n", "\r", "\n" }, StringSplitOptions.None);
            var result = new List<string>(lines.Length);

            foreach (var line in lines)
            {
                string trimmed = line.Trim();

                // 空行直接保留
                if (string.IsNullOrEmpty(trimmed))
                {
                    result.Add(line);
                    continue;
                }

                // 刀具定义行（TxxC...）：严格原样保留
                if (ToolDefinitionPattern.IsMatch(trimmed))
                {
                    result.Add(line);
                    continue;
                }

                // G85 槽孔行：缩放中心点，保持槽长不变
                var slotMatch = SlotPattern.Match(trimmed);
                if (slotMatch.Success)
                {
                    result.Add(ScaleSlotLine(trimmed, kx, ky));
                    continue;
                }

                // 普通坐标行：X...Y...
                var coordMatch = CoordinatePattern.Match(trimmed);
                if (coordMatch.Success)
                {
                    result.Add(ScaleCoordinateLine(trimmed, kx, ky));
                    continue;
                }

                // 其余行原样保留（M48, %, Txx, M30 等）
                result.Add(line);
            }

            return string.Join("\r\n", result);
        }

        /// <summary>
        /// 缩放普通坐标行
        /// </summary>
        private static string ScaleCoordinateLine(string line, double kx, double ky)
        {
            var xMatch = XValuePattern.Match(line);
            var yMatch = YValuePattern.Match(line);

            if (!xMatch.Success || !yMatch.Success)
                return line;

            double xOrig = double.Parse(xMatch.Groups[1].Value);
            double yOrig = double.Parse(yMatch.Groups[1].Value);

            long xNew = (long)Math.Round(xOrig * kx);
            long yNew = (long)Math.Round(yOrig * ky);

            return $"X{FormatCoordinateValue(xNew)}Y{FormatCoordinateValue(yNew)}";
        }

        /// <summary>
        /// 缩放 G85 槽孔行
        /// 缩放中心点，保持原始矢量恢复起止点（槽长不变）
        /// </summary>
        private static string ScaleSlotLine(string line, double kx, double ky)
        {
            var slotMatch = SlotPattern.Match(line);
            if (!slotMatch.Success)
                return line;

            // 解析起点坐标
            var startPart = slotMatch.Groups[1].Value;
            var xStartMatch = XValuePattern.Match(startPart);
            var yStartMatch = YValuePattern.Match(startPart);
            double xStart = double.Parse(xStartMatch.Groups[1].Value);
            double yStart = double.Parse(yStartMatch.Groups[1].Value);

            // 解析终点坐标
            var endPart = slotMatch.Groups[2].Value;
            var xEndMatch = XValuePattern.Match(endPart);
            var yEndMatch = YValuePattern.Match(endPart);
            double xEnd = double.Parse(xEndMatch.Groups[1].Value);
            double yEnd = double.Parse(yEndMatch.Groups[1].Value);

            // 计算中心点
            double cx = (xStart + xEnd) / 2.0;
            double cy = (yStart + yEnd) / 2.0;

            // 缩放中心点
            long cxNew = (long)Math.Round(cx * kx);
            long cyNew = (long)Math.Round(cy * ky);

            // 保持原始矢量（槽长不变）
            long dx = (long)Math.Round((xEnd - xStart) / 2.0);
            long dy = (long)Math.Round((yEnd - yStart) / 2.0);

            // 恢复起止点
            long newStartX = cxNew - dx;
            long newStartY = cyNew - dy;
            long newEndX = cxNew + dx;
            long newEndY = cyNew + dy;

            return
                $"X{FormatCoordinateValue(newStartX)}Y{FormatCoordinateValue(newStartY)}" +
                $"G85X{FormatCoordinateValue(newEndX)}Y{FormatCoordinateValue(newEndY)}";
        }

        /// <summary>
        /// 将坐标数值格式化为钻带使用的 6 位坐标文本，负数保留负号。
        /// </summary>
        private static string FormatCoordinateValue(long value)
        {
            if (value < 0)
                return "-" + Math.Abs(value).ToString("D6", CultureInfo.InvariantCulture);

            return value.ToString("D6", CultureInfo.InvariantCulture);
        }
    }
}