using System;
using System.Collections.Generic;
using System.Dynamic;
using System.IO;
using System.Linq;
using System.Text.RegularExpressions;
using CodingSeb.ExpressionEvaluator;

namespace CMSlib.ConsoleModule.Termios;

public class Constants : DynamicObject
{
    private readonly string[] _termiosPath;
    private readonly List<ExpressionEvaluator> _evaluators;

    public Constants(params string[] termiosPath)
    {
        _termiosPath = termiosPath;
        _evaluators = new List<ExpressionEvaluator>();

        ParseConstants();
    }

#nullable enable
    public override bool TryGetMember(GetMemberBinder binder, out object? result)
    {
        object? temp = null;

        if (_evaluators.Any(evaluator =>
            {
                try
                {
                    temp = evaluator.Evaluate(binder.Name);
                    return true;
                }
                catch
                {
                    return false;
                }
            }))
        {
            result = temp;
            return true;
        }

        result = temp;
        return false;
    }
#nullable disable

    private void ParseConstants()
    {
        var i = 0;
        foreach (var termiosPath in _termiosPath)
        {
            _evaluators.Add(new ExpressionEvaluator());
            var fileInfo = new FileInfo(termiosPath);

            using var file = fileInfo.OpenText();

            var fileString =
                Regex.Replace(file.ReadToEnd(),
                        @"\/\*(?s).*?\*\/|#ifndef.*?(\n|\r\n|\r)|#include.*?(\n|\r\n|\r)|#if.*?(\n|\r\n|\r)|#endif.*?(\n|\r\n|\r)",
                        string.Empty,
                        RegexOptions.Multiline)
                    .Replace("\t", " ");

            var stringReader = new StringReader(fileString);
            string line;
            while ((line = stringReader.ReadLine()) != null)
            {
                var splitLine = (from word in line.Split(" ")
                    where word != string.Empty
                    select word).ToArray();


                if (splitLine.Length != 0 && splitLine.Length > 2)
                {
                    switch (splitLine[0])
                    {
                        case "#if":
                        case "#error":
                            continue;
                        case "#define" when !splitLine[1].Contains("("):
                            _evaluators[i].Variables[splitLine[1]] =
                                new SubExpression(string.Join(' ', splitLine[2..]));
                            break;
                    }
                }
            }

            i++;
        }
    }
}