//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
//     file="CodeLineHelper.cs"
//     Project: StgSharp
//     AuthorGroup: Nitload Space
//     Copyright (c) Nitload Space. All rights reserved.
//     
//     Permission is hereby granted, free of charge, to any person 
//     obtaining a copy of this software and associated documentation 
//     files (the “Software”), to deal in the Software without restriction, 
//     including without limitation the rights to use, copy, modify, merge,
//     publish, distribute, sublicense, and/or sell copies of the Software, 
//     and to permit persons to whom the Software is furnished to do so, 
//     subject to the following conditions:
//     
//     The above copyright notice and 
//     this permission notice shall be included in all copies 
//     or substantial portions of the Software.
//     
//     THE SOFTWARE IS PROVIDED “AS IS”, 
//     WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, 
//     INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
//     FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
//     IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
//     DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 
//     ARISING FROM, OUT OF OR IN CONNECTION WITH 
//     THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//     
//-----------------------------------------------------------------------
//-----------------------------------------------------------------------
using System;
using System.Collections.Generic;
using System.Text;

namespace StgSharp.Script
{
    public static class CodeLineHelper
    {

        public static string SliceAndTrim( this string line, int startIndex )
        {
            if( line == null ) {
                throw new ArgumentNullException( nameof( line ) );
            }

            if( startIndex < 0 || startIndex >= line.Length ) {
                throw new ArgumentOutOfRangeException( nameof( startIndex ) );
            }

            ReadOnlySpan<char> sourceSpan = line.AsSpan();
            ReadOnlySpan<char> subSpan = sourceSpan.Slice( startIndex );

            int start = 0;
            while( start < subSpan.Length && char.IsWhiteSpace(
                subSpan[ start ] ) ) {
                start++;
            }
            int end = subSpan.Length - 1;
            while( end >= start && char.IsWhiteSpace( subSpan[ end ] ) ) {
                end--;
            }
            if( start > end ) {
                return string.Empty;
            }
            int finalLength = end - start + 1;

            return new string( subSpan.Slice( start, finalLength ) );
        }

        public static string SliceAndTrim(
                                     this string line,
                                     int startIndex,
                                     int length )
        {
            if( line == null ) {
                throw new ArgumentNullException( nameof( line ) );
            }

            if( startIndex < 0 || startIndex >= line.Length ) {
                throw new ArgumentOutOfRangeException( nameof( startIndex ) );
            }

            if( length < 0 || startIndex + length > line.Length ) {
                throw new ArgumentOutOfRangeException( nameof( length ) );
            }

            ReadOnlySpan<char> sourceSpan = line.AsSpan();
            ReadOnlySpan<char> subSpan = sourceSpan.Slice( startIndex, length );

            int start = 0;
            while( start < subSpan.Length && char.IsWhiteSpace(
                subSpan[ start ] ) ) {
                start++;
            }
            int end = subSpan.Length - 1;
            while( end >= start && char.IsWhiteSpace( subSpan[ end ] ) ) {
                end--;
            }
            if( start > end ) {
                return string.Empty;
            }
            int finalLength = end - start + 1;

            return new string( subSpan.Slice( start, finalLength ) );
        }

    }
}