using System.Text.RegularExpressions;

namespace ConsoleApp2.Helpers;

public static partial class DumpDataHelper
{
    [GeneratedRegex(@"'.+\.dat'")]
    private static partial Regex MatchDatFile();
    [GeneratedRegex(@"\([^)]*\)")]
    private static partial Regex MatchBrackets();
    
    
    public static async Task<string[]> GetCsvHeadersFromSqlFileAsync(string filePath)
    {
        var txt = await File.ReadAllTextAsync(filePath);
        var match = MatchBrackets().Match(txt);

        return ParseHeader(match.ValueSpan);
    }

    private static string[] ParseHeader(ReadOnlySpan<char> headerStr)
    {
        headerStr = headerStr[1..^1];
        Span<Range> ranges = stackalloc Range[50];
        var count = headerStr.Split(ranges, ',');
        var arr = new string[count];

        for (var i = 0; i < count; i++)
        {
            arr[i] = headerStr[ranges[i]].Trim("@`").ToString(); // 消除列名的反引号，如果是变量则消除@
        }

        return arr;
    }
    
    
    public static string GetTableName(ReadOnlySpan<char> filePath)
    {
        filePath = filePath[(filePath.LastIndexOf('\\') + 1)..];
        var firstDotIdx = -1;
        var secondDotIdx = -1;
        var times = 0;
        for (var i = 0; i < filePath.Length; i++)
        {
            if (filePath[i] == '.')
            {
                ++times;
                if(times == 1)
                    firstDotIdx = i;
                if (times == 2)
                {
                    secondDotIdx = i;
                    break;
                }
            }
        }

        return filePath[(firstDotIdx+1)..secondDotIdx].ToString();
    }

    public static async Task<string[]> GetCsvFileNamesFromSqlFileAsync(string filePath)
    {
        var txt = await File.ReadAllTextAsync(filePath);
        var matches = MatchDatFile().Matches(txt);
        return matches.Select(match => match.ValueSpan[1..^1].ToString()).ToArray();
    }
    
    public static bool CheckHexField(string? str)
    {
        if (string.IsNullOrWhiteSpace(str))
            return false;
        
        if (str.StartsWith('\"'))
            return false;

        var isDigit = true;

        foreach (var c in str)
        {
            if (!char.IsAsciiHexDigit(c))
                return false;
            if (!char.IsNumber(c))
                isDigit = false;
        }

        if (isDigit)
            return false;

        return true;
    }
}