using Microsoft.SqlServer.TransactSql.ScriptDom;
using SQLLinter.Core;

namespace SQLLinter.Infrastructure.Rules.Common;

public static class ColumnNumberCalculator
{
    public static int GetNodeColumnPosition(TSqlFragment node)
    {
        var line = string.Empty;
        var nodeStartLine = node.StartLine;
        var nodeLastLine = node.ScriptTokenStream[node.LastTokenIndex].Line;

        for (var tokenIndex = 0; tokenIndex <= node.LastTokenIndex; tokenIndex++)
        {
            var token = node.ScriptTokenStream[tokenIndex];
            if (token.Line >= nodeStartLine && token.Line <= nodeLastLine)
            {
                line += token.Text;
            }
        }

        var positionOfNodeOnLine = line.LastIndexOf(node.ScriptTokenStream[node.FirstTokenIndex].Text, StringComparison.Ordinal);
        var charactersBeforeNode = line.Substring(0, positionOfNodeOnLine);

        var offSet = 0;
        if (charactersBeforeNode.IndexOf(" ", StringComparison.Ordinal) != -1)
        {
            offSet = 1;
        }

        var tabCount = CountTabs(charactersBeforeNode);
        var totalTabLength = tabCount * Constants.TabWidth;

        var nodePosition = totalTabLength + (charactersBeforeNode.Length - tabCount) + offSet;
        return nodePosition;
    }

    /// <summary>
    /// Returns -1 if can't be found
    /// </summary>
    /// <param name="line"></param>
    /// <param name="column"></param>
    /// <returns></returns>
    public static int GetIndex(string line, int column)
    {
        var index = 0;
        while (index != column)
        {
            if (line.Length <= index)
            {
                return -1;
            }

            if (line[index] == '\t')
            {
                column -= (Constants.TabWidth - 1);
            }
            index++;
        }
        return column - 1;
    }

    private static int CountTabs(string charactersBeforeNode)
    {
        int tabCount = 0;
        foreach (var c in charactersBeforeNode)
        {
            if (c == '\t')
            {
                tabCount++;
            }
        }

        return tabCount;
    }

    // count all tabs on a line up to the last token index
    public static int CountTabsBeforeToken(int lastTokenLine, int lastTokenIndex, IEnumerable<TSqlParserToken> tokens)
    {
        var tabCount = 0;
        var sqlParserTokens = tokens as TSqlParserToken[] ?? tokens.ToArray();

        for (var tokenIndex = 0; tokenIndex < lastTokenIndex; tokenIndex++)
        {
            var token = sqlParserTokens[tokenIndex];
            if (token.Line != lastTokenLine || string.IsNullOrEmpty(token.Text))
            {
                continue;
            }

            tabCount += CountTabs(token.Text);
        }

        return tabCount;
    }

    public static int GetColumnNumberBeforeToken(int tabsOnLine, TSqlParserToken token)
    {
        return token.Column + ((tabsOnLine * Constants.TabWidth) - tabsOnLine);
    }

    public static int GetColumnNumberAfterToken(int tabsOnLine, TSqlParserToken token)
    {
        return token.Column + token.Text.Length + ((tabsOnLine * Constants.TabWidth) - tabsOnLine);
    }
}