// This procedure installs the new shelfButton if it does not exists

global proc QuadRemesher_shelf () {
	global string $gShelfTopLevel ;
	$verbose = false;
	
	if ($verbose) print "QuadRemesher_shelf execution...\n";
	
	$theButtonCommand = "import QuadRemesher\nqr = QuadRemesher.QuadRemesher()\n";
	
	// search if the shelfButton exists:
	// NB: shelfButton -query -exists "QuadRemesher" doesn't work because, the name of the shelfButtons are not saved by Maya in shelf.mel
	// so it works only after the install, but at next Maya start, it doesn't work....
	//$qrButtonExists = `shelfButton -query -exists "QuadRemesher"`;
	$qrButtonExists = false;
	string $shelves[] = `tabLayout -q -childArray $gShelfTopLevel`;
	for ( $shelf in $shelves ) {
		//if ($verbose) print ("  --- search in shelf: "+$shelf+"\n");
		string $shelfButtons[] = `shelfLayout -q -childArray $shelf`;
		for ( $button in $shelfButtons ) {
			//if ($verbose) print ("  button: "+$button+"\n");
			if (`shelfButton -q -exists $button`) {
				/*
				$buttonDocTag = `shelfButton -q -docTag $button`;
				if ($verbose) print ("  buttonDocTag = "+$buttonDocTag+"\n");
				if ($buttonDocTag == "QRBfd456sg45") {
					$qrButtonExists = true;
					break;
				}
				*/
				
				// NB: MMB drag icon in another shelf : the docTag is not copied -> need another way to identify it : the Command!
				$buttonCmd = `shelfButton -q -command $button`;
				//if ($verbose) print ("  buttonCmd = '"+$buttonCmd+"'\n");
				if ($theButtonCommand == $buttonCmd) {
					$qrButtonExists = true;
					break;
				}
			}
		}
		if ($qrButtonExists)
			break;
	}

	
	if ($verbose) print ("    QuadRemesher Button Exists (from Query 'QuadRemesher') = "+`shelfButton -query -exists "QuadRemesher"`+"\n");
	if ($verbose) print ("    QuadRemesher Button Exists (from Query 'QR') = "+`shelfButton -query -exists "QR"`+"\n");
	if ($verbose) print ("    QuadRemesher Button Exists (from docTag,cmd) = " + $qrButtonExists + "\n");
	
	if ( !$qrButtonExists	) {
		// new in 1.0.1 : always install in QuadRemesh shelf tab
		/*
		$theParentShelf = "Custom";
		$tabExists = `layout -ex $theParentShelf`;
		if ($tabExists==0) {
			if ($verbose) print "Custom shelf does not Exist...\n";
			addNewShelfTab "QuadRemesh";
			$theParentShelf = "QuadRemesh";
		} else {
			if ($verbose) print "Custom shelf exist => install in Custom!\n";
		}*/
		$theParentShelf = "QuadRemesh";
		int $shelfExists = `layout -q -ex $theParentShelf`;
		if ($shelfExists == 0)
			addNewShelfTab $theParentShelf;
		
		
		shelfButton
			-parent $theParentShelf
			-enable 1 -visible 1 -preventOverride 0
			-label "QR" 
			-annotation "QuadRemesher" 
			-image "QuadRemesher.png" 
			-style "iconOnly" 
			-noBackground 1
			-align "center" -marginWidth 1 -marginHeight 1
			-command $theButtonCommand
			-sourceType "python" 
			-commandRepeatable 1
			-docTag "QRBfd456sg45"
			"QuadRemesher";
			
		shelfTabLayout -edit -selectTab $theParentShelf $gShelfTopLevel ;
		
		// log info (not with verbose!)
		print ("Loading QuadRemesher (new shelfButton installed in '"+$theParentShelf+"' shelf)...\n");
		
	} else {
		if ($verbose) print "_shelf: Loading QuadRemesher...\n";
	}
}