package com.jclark.xsl.expr;

import com.jclark.xsl.om.*;

class IdFunction extends Function1 {
  ConvertibleExpr makeCallExpr(ConvertibleExpr e) throws ParseException {
    if (e instanceof NodeSetExpr) {
      final NodeSetExpr nse = (NodeSetExpr)e;
      return new ConvertibleNodeSetExpr() {
	public NodeIterator eval(Node node, ExprContext context) throws XSLException {
	  return id(node, nse.eval(node, context));
	}
      };
    }
    else if (e instanceof VariantExpr) {
      final VariantExpr ve = (VariantExpr)e;
      return new ConvertibleNodeSetExpr() {
	public NodeIterator eval(Node node, ExprContext context) throws XSLException {
	  Variant v = ve.eval(node, context);
	  if (v.isNodeSet())
	    return id(node, v.convertToNodeSet());
	  else
	    return id(node, v.convertToString());
	}
      };
    }
    else {
      final StringExpr se = e.makeStringExpr();
      return new ConvertibleNodeSetExpr() {
	public NodeIterator eval(Node node, ExprContext context) 
	  throws XSLException {
	  return id(node, se.eval(node, context));
	}
      };
    }
  }
  
  static private final NodeIterator id(Node node, NodeIterator iter) throws XSLException {
    return new UniqueNodeIterator(NodeListSorter.sort(new ValueIdIterator(node, iter),
						      new DocumentOrderComparator()));
  }

  static private final NodeIterator id(Node node, String str) throws XSLException {
    return new UniqueNodeIterator(NodeListSorter.sort(new ValueIdIterator.Iterator(node, str),
						      new DocumentOrderComparator()));
  }

}