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 → prefix="T01C", diameter="1.8"
        /// </summary>
        private static readonly Regex ToolLinePattern = new(
            @"^(?<prefix>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, out List<double> unmatchedDiameters)
        {
            // 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（同时收集未匹配直径）
            var unmatchedSet = new HashSet<double>();
            string replacedContent = ReplaceParametersInContent(rouContent, paramDict, unmatchedSet);

            // 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);

            // 6. 输出未匹配直径
            unmatchedDiameters = new List<double>(unmatchedSet);
        }

        /// <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;

                // 规范化到3位小数，消除浮点精度差异
                diameter = Math.Round(diameter, 3);

                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。
        /// 使用两遍扫描：第一遍按基准直径分组并从参数字典中分配可用键，第二遍执行替换。
        /// </summary>
        private static string ReplaceParametersInContent(string rouContent, Dictionary<double, string> paramDict, HashSet<double> unmatchedDiameters)
        {
            var lines = DrillTapeLineParser.SplitLines(rouContent);

            // === Pass 1: 收集头部区域所有刀径行，按基准直径分组，分配参数键 ===
            bool inHeader = false;
            var toolEntries = new List<(int Index, string Prefix, double Diameter)>();

            for (int i = 0; i < lines.Count; i++)
            {
                string trimmed = lines[i].Text.Trim();

                if (!inHeader && trimmed == "M48")
                {
                    inHeader = true;
                    continue;
                }

                if (inHeader && trimmed == "%")
                {
                    inHeader = false;
                    continue;
                }

                if (inHeader)
                {
                    var match = ToolLinePattern.Match(trimmed);
                    if (match.Success &&
                        double.TryParse(match.Groups["diameter"].Value,
                            NumberStyles.Float, CultureInfo.InvariantCulture, out double diameter))
                    {
                        diameter = Math.Round(diameter, 3);
                        string prefix = match.Groups["prefix"].Value;
                        toolEntries.Add((i, prefix, diameter));
                    }
                }
            }

            // 按基准直径分组，为每组分配显示直径和参数键
            // lineIndex -> (prefix, displayDiameter, assignedParamKey | null)
            var toolMap = new Dictionary<int, (string Prefix, double DisplayDiameter, double? ParamKey)>();

            foreach (var group in toolEntries.GroupBy(e => e.Diameter))
            {
                double baseDiam = group.Key;
                var occurrences = group.ToList();

                // 在 [baseDiam, baseDiam + 0.01) 范围内查找候选参数键
                var candidates = paramDict.Keys
                    .Where(k => k >= baseDiam && k < baseDiam + 0.01)
                    .OrderBy(k => k)
                    .ToList();

                // 如果没有候选键，尝试容差回退（仅对首个出现）
                if (candidates.Count == 0)
                {
                    foreach (var kvp in paramDict)
                    {
                        if (Math.Abs(kvp.Key - baseDiam) < DiameterTolerance)
                        {
                            candidates.Add(kvp.Key);
                            break;
                        }
                    }
                }

                // 分配：每个出现的显示直径为 baseDiam + j*0.001（3位小数补零）
                // 参数键从候选列表中按序取，超出则为 null（未匹配）
                for (int j = 0; j < occurrences.Count; j++)
                {
                    double displayDiameter = Math.Round(baseDiam + j * 0.001, 3);
                    double? assignedKey = j < candidates.Count ? candidates[j] : null;
                    toolMap[occurrences[j].Index] = (occurrences[j].Prefix, displayDiameter, assignedKey);
                }
            }

            // === Pass 2: 执行替换（修改直径文本 + 追加参数） ===
            var builder = new StringBuilder(rouContent.Length + 1024);

            for (int i = 0; i < lines.Count; i++)
            {
                if (toolMap.TryGetValue(i, out var toolInfo))
                {
                    if (toolInfo.ParamKey.HasValue)
                    {
                        string paramString = paramDict[toolInfo.ParamKey.Value];

                        // 重建行：prefix + 显示直径 + 参数
                        string displayDiam = toolInfo.DisplayDiameter.ToString("F3", CultureInfo.InvariantCulture);

                        // 保留行尾空白
                        string originalLine = lines[i].Text.TrimEnd();
                        int trailingLength = lines[i].Text.Length - originalLine.Length;
                        string trailing = trailingLength > 0 ? lines[i].Text[^trailingLength..] : string.Empty;

                        builder.Append(toolInfo.Prefix);
                        builder.Append(displayDiam);
                        builder.Append(paramString);
                        builder.Append(trailing);
                        builder.Append(lines[i].LineEnding);
                    }
                    else
                    {
                        // 未匹配：保留原始行，记录直径
                        unmatchedDiameters.Add(toolInfo.DisplayDiameter);
                        builder.Append(lines[i].Text);
                        builder.Append(lines[i].LineEnding);
                    }
                }
                else
                {
                    // 非刀径行原样保留
                    builder.Append(lines[i].Text);
                    builder.Append(lines[i].LineEnding);
                }
            }

            return builder.ToString();
        }
    }
}