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

namespace DrillTools
{
    /// <summary>
    /// ROU 成型参数替换：将参数文件中的 S/F/R/Z/H 参数追加到 .rou 文件的刀径定义行。
    /// </summary>
    internal static class RouParameterReplacer
    {
        private const int Gb2312CodePage = 936;
        private const double DiameterTolerance = 0.001;

        /// <summary>
        /// 匹配参数行：T00C<直径>S<参数...>
        /// 例：T00C1.800S55.0F5.0R25Z0H600
        /// </summary>
        private static readonly Regex ParamLinePattern = new(
            @"^T00C(?<diameter>\d+(?:\.\d+)?)(?<params>S.+?)\s*$",
            RegexOptions.Compiled | RegexOptions.IgnoreCase);

        /// <summary>
        /// 匹配 .rou 刀径定义行：T<刀号>C<直径>
        /// 例：T01C1.8
        /// </summary>
        private static readonly Regex ToolLinePattern = new(
            @"^T\d+C(?<diameter>\d+(?:\.\d+)?)",
            RegexOptions.Compiled | RegexOptions.IgnoreCase);

        /// <summary>
        /// 执行参数替换。
        /// </summary>
        /// <param name="rouFilePath">.rou 文件完整路径</param>
        /// <param name="paramFilePath">参数 .txt 文件完整路径</param>
        public static void ReplaceParameters(string rouFilePath, string paramFilePath)
        {
            // 1. 读取参数文件，构建直径→参数字符串映射
            var paramDict = LoadParameterDictionary(paramFilePath);

            if (paramDict.Count == 0)
                throw new InvalidOperationException("参数文件中未找到有效的参数行（格式：T00C<直径>S...）");

            // 2. 读取 .rou 文件
            string rouContent = CommandTypeFileReader.ReadAllText(rouFilePath);

            // 3. 执行替换
            string replacedContent = ReplaceParametersInContent(rouContent, paramDict);

            // 4. 备份原文件
            string backupFilePath = rouFilePath + ".bak";
            File.Copy(rouFilePath, backupFilePath, true);

            // 5. 写回文件
            using var writer = new StreamWriter(rouFilePath, false, Encoding.GetEncoding(Gb2312CodePage));
            writer.Write(replacedContent);
        }

        /// <summary>
        /// 从参数文件加载直径→参数字符串（从 S 开始到行尾）的映射。
        /// </summary>
        private static Dictionary<double, string> LoadParameterDictionary(string paramFilePath)
        {
            var dict = new Dictionary<double, string>();

            string content = CommandTypeFileReader.ReadAllText(paramFilePath);
            var lines = DrillTapeLineParser.SplitLines(content);

            foreach (var line in lines)
            {
                string trimmed = line.Text.Trim();
                var match = ParamLinePattern.Match(trimmed);
                if (!match.Success)
                    continue;

                if (!double.TryParse(match.Groups["diameter"].Value,
                        NumberStyles.Float, CultureInfo.InvariantCulture, out double diameter))
                    continue;

                string paramString = match.Groups["params"].Value;

                // 如果同一直径出现多次，后面的覆盖前面的
                dict[diameter] = paramString;
            }

            return dict;
        }

        /// <summary>
        /// 在 .rou 文件内容中，将 M48～% 区域内的刀径行末尾追加参数。
        /// </summary>
        private static string ReplaceParametersInContent(string rouContent, Dictionary<double, string> paramDict)
        {
            var lines = DrillTapeLineParser.SplitLines(rouContent);
            var builder = new StringBuilder(rouContent.Length + 1024);

            bool inHeader = false;

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

                // 检测 M48 头部开始
                if (!inHeader && trimmed == "M48")
                {
                    inHeader = true;
                    builder.Append(line.Text);
                    builder.Append(line.LineEnding);
                    continue;
                }

                // 检测 % 头部结束
                if (inHeader && trimmed == "%")
                {
                    inHeader = false;
                    builder.Append(line.Text);
                    builder.Append(line.LineEnding);
                    continue;
                }

                // 在头部区域内匹配刀径定义行
                if (inHeader)
                {
                    var match = ToolLinePattern.Match(trimmed);
                    if (match.Success &&
                        double.TryParse(match.Groups["diameter"].Value,
                            NumberStyles.Float, CultureInfo.InvariantCulture, out double diameter))
                    {
                        // 按直径数值匹配参数（允许浮点误差）
                        string? paramString = FindMatchingParameter(diameter, paramDict);
                        if (paramString != null)
                        {
                            // 保留原始行尾空白
                            string textWithoutTrailing = line.Text.TrimEnd();
                            int trailingLength = line.Text.Length - textWithoutTrailing.Length;
                            string trailing = trailingLength > 0 ? line.Text[^trailingLength..] : string.Empty;

                            builder.Append(textWithoutTrailing);
                            builder.Append(paramString);
                            builder.Append(trailing);
                            builder.Append(line.LineEnding);
                            continue;
                        }
                    }
                }

                // 其他行原样保留
                builder.Append(line.Text);
                builder.Append(line.LineEnding);
            }

            return builder.ToString();
        }

        /// <summary>
        /// 按直径查找匹配的参数字符串，允许 0.001 的浮点误差。
        /// 返回 null 表示未找到匹配。
        /// </summary>
        private static string? FindMatchingParameter(double diameter, Dictionary<double, string> paramDict)
        {
            // 精确匹配优先
            if (paramDict.TryGetValue(diameter, out string? paramString))
                return paramString;

            // 浮点容差匹配
            foreach (var kvp in paramDict)
            {
                if (Math.Abs(kvp.Key - diameter) < DiameterTolerance)
                    return kvp.Value;
            }

            return null;
        }
    }
}