using Microsoft.Extensions.Logging;
using System.Collections.ObjectModel;
using System.Text.RegularExpressions;

namespace File_Folder_Helper.Helpers;

internal static partial class HelperVSCodePossibleExtension
{

    private record Method(string Name,
                          int ParameterCount,
                          int StartLine,
                          int EndLine,
                          int FirstUsedLine);

    [GeneratedRegex(@"(?<method>[A-Z]{1}[A-Za-z_0-9]*)\(")]
    private static partial Regex CSharpMethodName();

    [GeneratedRegex(@"\s[a-zA-Z_]*,")]
    private static partial Regex CSharpParameter();

    [GeneratedRegex(@"\b(public|private|internal|protected)\s\b(static)?\s?\b(partial)?\s?\b(async)?\s?[[\]<,>?a-zA-Z()\s]*\s[A-Z]{1}[a-zA-Z_]+\(.*\)")]
    private static partial Regex CSharpMethodLine();

    private static string? GetName(string line)
    {
        string? result;
        Match match = CSharpMethodName().Match(line);
        if (!match.Success)
            result = null;
        else
            result = match.Groups["method"].Value;
        return result;
    }

    private static int GetStartLine(string[] lines, int i)
    {
        int result = i;
        string line;
        for (int j = i - 1; j > -1; j--)
        {
            line = lines[j].Trim();
            if (!line.StartsWith('[') && !line.StartsWith("/// "))
                break;
            result--;
        }
        return result;
    }

    private static int GetParameterCount(string line, string search)
    {
        int result;
        string after = line.Split(search)[^1];
        if (after.StartsWith(')'))
            result = 0;
        else
        {
            string[] segments = CSharpParameter().Split(after);
            result = segments.Length;
        }
        return result;
    }

    private static int GetLineBlockCount(string line, bool isLinq)
    {
        int result = 0;
        bool ignore = false;
        for (int i = 0; i < line.Length; i++)
        {
            if (line[i] == '\'')
                i++;
            else if (!isLinq && !ignore && line[i] == '{')
                result++;
            else if (!isLinq && !ignore && line[i] == '}')
                result--;
            else if (isLinq && !ignore && line[i] == ';')
                result--;
            else if (i > 0 && line[i] == '"' && line[i - 1] != '\\')
                ignore = !ignore;
        }
        return result;
    }

    private static int? GetFirstUsedLine(string[] lines, int i, string search, string searchNot, string searchWrap, int parameterCount)
    {
        int? result = null;
        string[] segments;
        string[] afterSegments;
        string lastSegmentBeforeDot;
        for (int j = 0; j < lines.Length; j++)
        {
            if (j == i)
                continue;
            segments = lines[j].Split(search);
            if (segments.Length == 1)
            {
                segments = lines[j].Split(searchNot);
                if (segments.Length == 1)
                {
                    segments = lines[j].Split(searchWrap);
                    if (segments.Length == 1)
                        continue;
                }
            }
            lastSegmentBeforeDot = segments[^1].Split(").")[0];
            if (parameterCount == 0)
            {
                if (lastSegmentBeforeDot.Contains(','))
                    continue;
            }
            else
            {
                afterSegments = lastSegmentBeforeDot.Split(',');
                if (afterSegments.Length != parameterCount)
                    continue;
            }
            result = j;
            break;
        }
        return result;
    }

    private static ReadOnlyCollection<int> GetMethodLines(ReadOnlyCollection<Method> methods)
    {
        List<int> results = new();
        foreach (Method method in methods)
        {
            for (int i = method.StartLine; i < method.EndLine + 1; i++)
                results.Add(i);
        }
        return new(results);
    }

    private static ReadOnlyCollection<Method> GetMethods(string cSharpFile, ILogger<Worker> logger, string[] lines)
    {
        List<Method> results = new();
        int blocks;
        bool isLinq;
        int endLine;
        string line;
        string? name;
        int startLine;
        string search;
        string innerLine;
        string searchNot;
        string searchWrap;
        int parameterCount;
        int? firstUsedLine;
        string lineSegmentFirst;
        for (int i = 0; i < lines.Length; i++)
        {
            line = lines[i].Trim();
            if (string.IsNullOrEmpty(line))
                continue;
            if (line.Length < 5)
                continue;
            if (line.EndsWith(','))
                continue;
            if (!CSharpMethodLine().Match(line).Success)
                continue;
            name = GetName(line);
            search = $" {name}(";
            searchNot = $"!{name}(";
            searchWrap = $"({name}(";
            if (string.IsNullOrEmpty(name))
                continue;
            blocks = 0;
            startLine = GetStartLine(lines, i);
            parameterCount = GetParameterCount(line, search);
            isLinq = lines[i + 1].Trim() != "{";
            if (isLinq)
                blocks++;
            for (int j = i + 1; j < lines.Length; j++)
            {
                innerLine = lines[j].Trim();
                if (isLinq && string.IsNullOrEmpty(innerLine))
                {
                    if (line.EndsWith(';'))
                        blocks--;
                }
                blocks += GetLineBlockCount(innerLine, isLinq);
                if (blocks == 0)
                {
                    endLine = j;
                    if (lines.Length > j + 1 && string.IsNullOrEmpty(lines[j + 1].Trim()))
                        endLine++;
                    firstUsedLine = GetFirstUsedLine(lines, i, search, searchNot, searchWrap, parameterCount);
                    if (firstUsedLine is null)
                    {
                        lineSegmentFirst = line.Split(search)[0];
                        if (!lines[i - 1].Trim().StartsWith("[Obsolete"))
                        {
                            if (lineSegmentFirst.StartsWith("private"))
                                logger.LogWarning("<{cSharpFileName}> {name} with {parameterCount} parameter(s) <{line}>", Path.GetFileName(cSharpFile), name, parameterCount, lineSegmentFirst);
                            else
                                logger.LogInformation("<{cSharpFileName}> {name} with {parameterCount} parameter(s) <{line}>", Path.GetFileName(cSharpFile), name, parameterCount, lineSegmentFirst);
                        }
                        break;
                    }
                    if (j > lines.Length - 2)
                        throw new Exception();
                    results.Add(new(name, parameterCount, startLine, endLine, firstUsedLine.Value));
                    break;
                }
            }
        }
        return new(results.OrderBy(l => l.FirstUsedLine).ToArray());
    }

    private static bool WriteAllLines(string cSharpFile, string[] lines, ReadOnlyCollection<Method> methods)
    {
        bool result;
        List<string> results = new();
        ReadOnlyCollection<int> methodLines = GetMethodLines(methods);
        int minMethodLines = methodLines.Min();
        for (int i = 0; i < minMethodLines; i++)
            results.Add(lines[i]);
        foreach (Method method in methods)
        {
            for (int i = method.StartLine; i < method.EndLine + 1; i++)
                results.Add(lines[i]);
        }
        for (int i = minMethodLines; i < lines.Length; i++)
        {
            if (methodLines.Contains(i))
                continue;
            results.Add(lines[i]);
        }
        string text = File.ReadAllText(cSharpFile);
        string join = string.Join(Environment.NewLine, results);
        if (join == text)
            result = false;
        else
        {
            result = true;
            File.WriteAllText(cSharpFile, join);
        }
        return result;
    }

    private static bool SortFile(ILogger<Worker> logger, string cSharpFile, string[] lines)
    {
        bool result;
        ReadOnlyCollection<Method> methods = GetMethods(cSharpFile, logger, lines);
        if (methods.Count == 0)
            result = false;
        else
            result = WriteAllLines(cSharpFile, lines, methods);
        return result;
    }

    internal static void Sort(ILogger<Worker> logger, List<string> args)
    {
        bool result = false;
        bool check;
        string[] lines;
        long ticks = DateTime.Now.Ticks;
        logger.LogInformation("{ticks}", ticks);
        string[] cSharpFiles = Directory.GetFiles(args[0], "*.cs", SearchOption.TopDirectoryOnly);
        for (int i = 0; i < 10; i++)
        {
            foreach (string cSharpFile in cSharpFiles)
            {
                lines = File.ReadAllLines(cSharpFile);
                check = SortFile(logger, cSharpFile, lines);
                if (check && !result)
                    result = true;
            }
            if (!result)
                break;
        }
    }

}