library-ts/browser/math/MathX.ts

export class MathX
{
  static stringify( value:number, fractionDigits:number = 3, intDigits:number = 0, cutZeroFraction:boolean = true )
  {
    let fixed = value.toFixed( fractionDigits );

    let regex  = /(\+|\-)?(\d*)\.(\d*)/;
    let parsed = regex.exec( fixed );

    let sign     = parsed[ 1 ] || ""; 
    let ints     = parsed[ 2 ];
    let fraction = parsed[ 3 ];

    while ( intDigits > ints.length )
    {
      ints = "0" + ints;
    }

    if ( cutZeroFraction )
    {
      fraction = fraction.replace( /0+$/, "" );
    }

    if ( fraction.length === 0 )
    {
      return sign + ints;
    }

    return sign + ints + "." + fraction;

  }

  static log( value:number, base:number = Math.E )
  {
    return Math.log( value )/ Math.log( base );
  }

  static normalize( value:number, min:number, max:number )
  {
    return ( value - min ) / ( max - min );
  }

  static map( value:number, inputMin:number, inputMax:number, outputMin:number, outputMax:number )
  {
    let normalized = MathX.normalize( value, inputMin, inputMax );
    return MathX.lerp( outputMin, outputMax, normalized );
  }

  static mapClamped( value:number, inputMin:number, inputMax:number, outputMin:number, outputMax:number )
  {
    let normalized = MathX.normalize( value, inputMin, inputMax );
    normalized = MathX.clamp01( normalized );
    return MathX.lerp( outputMin, outputMax, normalized );
  }

  static maxAbs( ...values:number[] )
  {
    let maxValue = 0;
    let index = 0;

    for ( let i = 0; i < values.length; i++ )
    {
      let v = values[ i ];
      let abs = Math.abs( v );

      if ( Math.abs( v ) > maxValue )
      {
        maxValue = abs;
        index = i;
      }
    }

    return values[ index ];
  }


  static median( ...values:number[] )
  {
    let sorted = [].concat( values ).sort( ( a,b ) => a - b );

    console.log( sorted );
    return sorted[ Math.round( sorted.length/2 ) ];
  }

  static average( ...values:number[] )
  {
    let value = 0;

    values.forEach( v => value += v )

    return value / values.length;
  }

  static base( exponent:number, power:number )
  {
    return Math.pow( power, 1 / exponent );
  }

  static exponent( base:number, power:number )
  {
    return Math.log( power ) / Math.log( base );
  }
  

  static format( value:number, numZeros:number = 2 ):string
  {
    if ( numZeros <= 0 )
    {
      return Math.round( value ) + "";
    }

    numZeros = Math.round( numZeros );

    var sign = value < 0 ? "-" : "";
    value = Math.abs( value );

    var roundedBiggerValue = Math.round( value * Math.pow( 10, numZeros ) );  
    var stringValue = roundedBiggerValue + "";
    var minimumLength = numZeros + 1;
    
    while ( stringValue.length < minimumLength )
    {
      stringValue = "0" + stringValue;
    }


    var split = stringValue.length - numZeros;
    
    return sign + stringValue.substring( 0, split ) + "." + stringValue.substring( split );
  }

  static lerpAngle( a:number, b:number, amount:number )
  {
    let difference = MathX.angleDifference( a, b );
   

    let result = MathX.repeat( a + difference * amount, 360 );
    console.log( "lerping angle", a, b, "diff:", difference, "amount:", amount, ">>", result )
    return result;
  }

  static modulo( a:number, b:number )
  {
    return a - Math.floor( a / b ) * b;
  }

  static angleDifference( a:number, b:number )
  {
    a = MathX.repeat( a, 360 );
    b = MathX.repeat( b, 360 );

    let difference = b - a;   

    if ( difference < -180 )
    {
      difference = 360 + difference;
      return difference;
    }

    if ( difference > 180 )
    {
      difference = difference - 360;
      return difference;
    }

    return difference;
  }

  static align( baseWidth:number, elementWidth:number, alginmentNormalized:number )
  {
    return ( baseWidth - elementWidth ) * alginmentNormalized;
  }

  static clamp( value:number, min:number, max:number )
  {
    return value < min ? min : value > max ? max : value; 
  }

  static clamp01( value:number )
  {
    return value < 0 ? 0 : value > 1 ? 1 : value;
  }

  static repeat( value:number, range:number )
  {
    while ( value < 0 )
    {
      value += range;
    }

    while ( value >= range )
    {
      value -= range;
    }

    return value;
  }

  static repeatPolar( value:number, max:number )
  {
    while ( value > max )
    {
      value -= max * 2;
    }

    while ( value < -max )
    {
      value += max * 2;
    }

    return value;

  }

  static lerp( a:number, b:number, t:number )
  {
    t = MathX.clamp01( t );
    return a + t * ( b - a );
  }

  static lerpUnclamped( a:number, b:number, t:number )
  {
    return a + t * ( b - a );
  }

  static triangle( normalized:number )
  {
    normalized = normalized * 2;
    let invertedNormalized = 2 - normalized;

    return MathX.clamp01( Math.min( normalized, invertedNormalized ) );
  }

  static quantizeFloored( value:number, quantization:number )
  {
    return Math.floor( value / quantization ) * quantization;
  }

  static quantizeCeiled( value:number, quantization:number )
  {
    return Math.ceil( value / quantization ) * quantization;
  }

  static quantizeRounded( value:number, quantization:number )
  {
    return Math.round( value / quantization ) * quantization;
  }

  static inRange( value:number, lower:number, higher:number )
  {
    if ( value < lower )
    {
      return false;
    }

    if ( value > higher )
    {
      return false;
    }

    return true;
  }

  static advanceIndex<T>( array:T[], currentIndex:number, direction:number )
  {
    let nextIndex = currentIndex + direction;
    nextIndex = MathX.repeat( nextIndex, array.length );

    return nextIndex;
  }

  static nextIndex<T>(  array:T[], currentIndex:number )
  {
    return MathX.advanceIndex( array, currentIndex, 1 );
  }

  static previousIndex<T>(  array:T[], currentIndex:number )
  {
    return MathX.advanceIndex( array, currentIndex, -1 );
  }


}