using Microsoft.SqlServer.TransactSql.ScriptDom;
using System.Text.RegularExpressions;

namespace SQLLinter.Common.Helpers;

public static class FixHelpers
{
    public class FindViolatingNodeVisitor<T> : TSqlFragmentVisitor where T : TSqlFragment
    {
        private readonly Func<T, bool> Where;

        public List<T> Nodes = new List<T>();

        public FindViolatingNodeVisitor(Func<T, bool> where = null)
        {
            Where = where;
        }

        public override void Visit(TSqlFragment node)
        {
            if (node is T val && (Where == null || Where(val)))
            {
                Nodes.Add(val);
            }

            base.Visit(node);
        }
    }

    public static (TReturn, TFind) FindViolatingNode<TFind, TReturn>(List<string> fileLines, IRuleViolation ruleViolation, Func<TFind, TReturn> getFragment) where TFind : TSqlFragment where TReturn : TSqlFragment
    {
        TFind val = FindNodes<TFind>(fileLines).FirstOrDefault(delegate (TFind x)
        {
            TReturn val2 = getFragment(x);
            return val2?.StartLine == ruleViolation.Line && val2?.StartColumn == ruleViolation.Column;
        });
        return (getFragment(val), val);
    }

    public static List<T> FindNodes<T>(List<string> fileLines, Func<T, bool> where = null) where T : TSqlFragment
    {
        using StringReader input = new StringReader(string.Join("\n", fileLines));
        IList<ParseError> errors;
        TSqlFragment tSqlFragment = new TSql150Parser(initialQuotedIdentifiers: true, SqlEngineType.All).Parse(input, out errors);
        if (errors != null && errors.Any())
        {
            throw new Exception("Parsing failed. " + string.Join(". ", errors.Select((ParseError x) => x.Message)));
        }

        FindViolatingNodeVisitor<T> findViolatingNodeVisitor = new FindViolatingNodeVisitor<T>(where);
        tSqlFragment.Accept(findViolatingNodeVisitor);
        return findViolatingNodeVisitor.Nodes;
    }

    public static List<T> FindNodes<T>(TSqlFragment statement, Func<T, bool> where = null) where T : TSqlFragment
    {
        FindViolatingNodeVisitor<T> findViolatingNodeVisitor = new FindViolatingNodeVisitor<T>(where);
        statement.Accept(findViolatingNodeVisitor);
        return findViolatingNodeVisitor.Nodes;
    }

    public static T FindViolatingNode<T>(List<string> fileLines, IRuleViolation ruleViolation) where T : TSqlFragment
    {
        return FindViolatingNode(fileLines, ruleViolation, (T x) => x).Item1;
    }

    public static string GetIndent(List<string> fileLines, IRuleViolation ruleViolation)
    {
        return GetIndent(fileLines[ruleViolation.Line - 1]);
    }

    public static string GetIndent(List<string> fileLines, TSqlStatement statement)
    {
        return GetIndent(fileLines[statement.StartLine - 1]);
    }

    public static string GetString(TSqlFragment fragment)
    {
        return string.Join(string.Empty, from x in fragment.ScriptTokenStream.Where((TSqlParserToken x, int i) => i >= fragment.FirstTokenIndex && i <= fragment.LastTokenIndex)
                                         select x.Text);
    }

    private static string GetIndent(string ifLine)
    {
        Match match = new Regex("^\\s+").Match(ifLine);
        string result = string.Empty;
        if (match.Success)
        {
            result = match.Value;
        }

        return result;
    }
}