library-ts/browser/text/replacing/TextSelectionRange.ts

export class TextSelectionRange
{
  start:number;
  length:number;

  get end():number
  {
    return this.start + this.length;
  }

  set end( value:number ) 
  {
    this.length = value - this.start;
  }

  get( source:string )
  {
    return source.substring( this.start, this.end );
  }

  replace( source:string, replacement:string )
  {
    let before = source.substring( 0, this.start );
    let after  = source.substring( this.end );  
    
    console.log( "start:", this.start, "end:", this.end)

    return [ before, replacement, after ].join( "" );
  }

  static fromWithLength( start:number, length:number )
  {
    let range = new TextSelectionRange();
    range.start = start;
    range.length = length;

    return range;
  }

  static fromToExclusive( start:number, end:number )
  {
    let range = new TextSelectionRange();

    range.start = start;
    range.end = end;

    return range;
  }

  static fromString( source:string )
  {
    let range = new TextSelectionRange();
    range.start = 0;
    range.length = source.length;

    return range;
  }

  static replaceRanges( source:string, ranges:TextSelectionRange[], replacements:string[] )
  {
    let fragments:string[] = [];
    let lastEnd = 0;

    

    for ( let i = 0; i < ranges.length; i++ )
    {
      let range       = ranges[ i ];
      let replacement = replacements[ i ];
      
      let beforeRange = source.substring( lastEnd, range.start );
      
      fragments.push( beforeRange );
      fragments.push( replacement );

      lastEnd = range.end;

      if ( i !== ( ranges.length - 1 ) )
      {
        continue;
      }

      let afterRange = source.substring( lastEnd, source.length );

      fragments.push( afterRange );
    }

    let replaced = fragments.join( "" );

    if ( replaced === undefined )
    {
      console.log( "Merging ranges failed:", ranges.length, fragments.length );
    }

    return replaced;


  }
}