// ===========================================================================
// Copyright 2018 Autodesk, Inc. All rights reserved.
//
// Use of this software is subject to the terms of the Autodesk license
// agreement provided at the time of installation or download, or which
// otherwise accompanies this software in either electronic or hard copy form.
// ===========================================================================

//
//	Description :
//		A script to reparameterize the knot sequence of a selected NURBS Curve to 
//		the specified range [a,b].   
//
//	LIMITATIONS :
//		1. The NURBS curve should have NO history.
//		2. The "rescale" keeps no history.
//		3. a < b.
//
//  How to use:  select a curve (eg. curve1) and enter these commands to 
//  reparameterize the curve from 0 to 10:
//
//      reparameterizeNurbsCurve 0 10;  // performs the reparameterization
//		getAttr curve1.minValue;        // will return 0 
//		getAttr curve1.maxValue;        // will return 10
//      nurbsCurveKnots;                // will print knot vector of selected curve
//


proc float[] rescale( 
	float $knots[], 
	float $startParm, 
	float $endParm ) 
//
//	Description :
//		To rescale the knots to lie inbetween [0,1]
//
{
	float $scaledKnots[] ;
	
	int $n = size($knots) ;
	if( $n == 0 ) return $scaledKnots ;

	float $minKnot = $knots[0] ;
	float $maxKnot = $knots[0] ;
	int $i ;

	// get min, max knot.
	//
	for( $i = 1 ; $i < $n ; $i++ ) {
		$minKnot = `min $minKnot $knots[$i]` ;
		$maxKnot = `max $minKnot $knots[$i]` ;	
	}
	float $newMin = $startParm ;
	float $newMax = $endParm ;
	float $diff = $maxKnot - $minKnot ;
	float $scaleFactor = $endParm - $startParm ;
	float $scale = $scaleFactor / $diff ;
	for( $i = 0 ; $i < $n ; $i++ ) {
		float $v = ( $knots[$i] - $minKnot ) ; 
		$scaledKnots[$i] = $newMin + ($v * $scale) ; 
	}
	return $scaledKnots ;
}

proc string buildTemporaryCurve( float $knots[], int $deg, int $ns ) 
//
//	Description :
//		To build a temporary curve, multiple end Knots !
//
{
	int $n = size($knots) ;
	if( $n == 0 || $ns == 0  ) return " " ;


	// append degree.
	//
	string $args ;
	$args =  "curve" + " -d " + $deg ; 

	int $ncv = $deg + $ns ;
	int $i ;

	// append dummy x, y, z values.
	//
	for( $i = 0 ; $i < $ncv ; $i++ ) {	
		float $v = 0.0 ;
		$args = $args +  " -p " + $v ;
		$args = $args + " " + $v ;  
		$args = $args + " " + $v ;  
	}

	// append knots.
	//
	for( $i = 0 ; $i < $n ; $i++ ) {
		$args = $args + " -k " ;
		$args = $args + $knots[$i] ;
	}

	$args = $args + " ; " ;

	string $crvName ;

	$crvName = eval($args) ;
	return $crvName ;
}

proc int rebuildCurveToMatchKnots( string $crv, string $matchCrv )
//
//	Description :
//
{
	int $ok = 1 ; 
	string $nodes[] ;
	if( catch( $nodes = `rebuildCurve -ch false -rpo true -rt 2 -kr 1 -kcp 1 -kep 1 -kt 0 $crv $matchCrv` ) ) {
		warning (uiRes("m_reparameterizeNurbsCurve.kWarningRebuildToMatchKnotsFailed")) ;
		$ok = 0 ;
	}	
	return $ok ;
}

global proc int reparameterizeNurbsCurve(
	float $startParm,
	float $endParm ) 
//
//	Description :
//		To reparametrize the knot sequence of the nurbs curve
//		to be in the range [$startParm, $endParam].
//	NOTE : works on a NURBS curve of the selection list.
//
{

	// valid parameters ?
	//
	if( $startParm >= $endParm ) {
		error (uiRes("m_reparameterizeNurbsCurve.kErrorStartParamBiggerThanEnd")) ;
		return 0 ;
	}

	float $knotSeq[] ;

	// 0. Grab the select list.
	//
	string $selList[] ;
    $selList = `ls -sl` ;

	// 1. Run filter to select only the NURBS curves.
	//
	global int $gSelectNurbsCurvesBit ;
	string $crvList[] ;
	$crvList = `filterExpand -ex true -sm $gSelectNurbsCurvesBit $selList` ;	
	if( size($crvList) == 0 ) {
		warning (uiRes("m_reparameterizeNurbsCurve.kWarningNoCurveSelected")) ;
		return 1;
	}

	// 2. Work on the last item if more than one NURBS curve in list.
	//
	int $len = size($crvList) ;
	string $lastCrv = $crvList[$len-1] ;
	if( $len != 1 ) {
		string $w = `format -s $lastCrv (uiRes("m_reparameterizeNurbsCurve.kReturningKnotsForLastCurve"))`;
		warning $w ;
	}

	// 2.0 Check if curve has history.
	//
	string $hist[] = `listHistory -gl true -pdo true -lf true -f false $lastCrv` ;
	if( size($hist) > 0 ) {
		error (uiRes("m_reparameterizeNurbsCurve.kErrorCurveHasHistory")) ;
		return 1 ; 	
	}		

	// 2.1 Get the degree.
	//
	int $deg  ;
	string $inAttr = $lastCrv + ".degree" ;
	$deg = `getAttr $inAttr` ;

	int $nspans ;
	$inAttr = $lastCrv + ".spans" ;
	$nspans = `getAttr $inAttr` ;
	
	// 3. Extract the Knots.
	//
	select -r $lastCrv ;
	$knotSeq = nurbsCurveKnots() ;

	// 4. Scale the Knot Sequence to lie in between [0,1].
	//
	float $sKnots[] ;
	$sKnots = rescale( $knotSeq, $startParm, $endParm ) ;

	// 5. Build a temporary curve with the scaled Knots
	//
	int $okay = 1 ;
	string $tmpCurve ;
	$tmpCurve = buildTemporaryCurve( $sKnots, $deg, $nspans ) ;
	if( $tmpCurve == " " ) {
		$okay = 0 ;
	} 

	// 6. Rebuild curve inplace to match knots.
	//
	if( $okay == 1 )  {
		$okay = rebuildCurveToMatchKnots( $lastCrv, $tmpCurve ) ;
		delete $tmpCurve ;
	}

	// 7. select curve for which knots are returned.
	//
	select -r $lastCrv ;

	return $okay ;
}