# $Id: xmlRecreatorVisitor.xotcl,v 1.5 2006/09/25 08:29:04 neumann Exp $

package provide xotcl::xml::recreatorVisitor 0.9
package require xotcl::xml::parser
package require XOTcl

namespace eval ::xotcl::xml::recreatorVisitor {
    namespace import ::xotcl::*

    ##############################################################################
    #
    # a visitor that recreates an XML representation from a
    # node tree
    #
    #############################################################################
    Class XMLRecreatorVisitor -superclass NodeTreeVisitor -parameter useCDATA

    #
    # determine nesting depth of an object if the aggregation tree
    #
    XMLRecreatorVisitor instproc nestingDepth {obj} {
	for {set d 0;set s [$obj info parent]} {$s ne "::"} {set s [$s info parent]} {
	    incr d
	}
	return $d
    }

    #
    # insert appropriate number of spaces for indentation -> return space string
    #
    XMLRecreatorVisitor instproc indent chars {
	set spaces "          "
	for {set l 9} {$l<$chars} {incr l $l} {append spaces $spaces}
	return [string range $spaces 1 $chars]
    }
    XMLRecreatorVisitor instproc insertIndent {obj} {
	my instvar nestingStart
	return [my indent [expr {([my nestingDepth $obj] - $nestingStart)*2} - 2]]
    }

    XMLRecreatorVisitor instproc attrIndent {objName fa} {
	upvar [self callinglevel] $fa firstAttr
	if {$firstAttr} {
	    set firstAttr 0
	    return  " "
	} else {
	    return "\n[my insertIndent $objName]    "
	}  
    }

    XMLRecreatorVisitor instproc getContent objName {
	return [$objName content]
    }
    XMLRecreatorVisitor instproc hasOnlyAttrs {obj} {
	if {[$obj exists pcdata]} {return 0}
	foreach c [$obj info children] {
	    if {[$c istype XMLNode]} {return 0}
	}
	return 1
    }

    #
    # hook to append line feed dependent on the object
    # default is to append one \n
    #
    XMLRecreatorVisitor instproc appendLineFeed obj {
	return "\n"
    }

    #
    # evaluate node objName
    #
    XMLRecreatorVisitor instproc visit objName {
	my instvar result
	set c [my getContent $objName]
	if {$c ne ""} {
	    $objName instvar attributes pcdata 
	    set ns [$objName resolveNS]
	    set firstAttr 1
	    set attrStr ""
	    if {[string first $objName $ns] != -1} {
		# append xmlns attributes, xmlns=... first
		if {[$ns exists nsArray(xmlns)]} {
		    append attrStr [my attrIndent $objName firstAttr]
		    append attrStr "xmlns = \"[$ns set nsArray(xmlns)]\""
		}
		foreach a [$ns array names nsArray] {
		    if {$a ne "xmlns"} {
			append attrStr [my attrIndent $objName firstAttr]
			append attrStr "xmlns:${a} = \"[$ns set nsArray($a)]\""
		    }
		}
	    }
	    foreach a [array names attributes] {
		append attrStr [my attrIndent $objName firstAttr]
		append attrStr "$a = \"$attributes($a)\""
	    }
	    append result "[my insertIndent $objName]<${c}$attrStr"

	    if {[my hasOnlyAttrs $objName]} { 
		append result "/>"
	    } else {
		append result ">"
	    }

	    if {[info exists pcdata] && [llength $pcdata]>1 && 
		[lindex $pcdata 0] eq ""} {
		append result " " [my pcdataString [lindex $pcdata 1]]
	    }
	    append result [my appendLineFeed $objName]
	}
	return $result
    }
    XMLRecreatorVisitor instproc pcdataString text {
	if {[my exists useCDATA] && [regexp < $text]} {
	    return "<!\[CDATA\[$text]]>"
	}
	return $text
    }

    #
    # evaluate end of a node
    # 
    XMLRecreatorVisitor instproc visitEnd objName {
	my instvar result
	set c [$objName content]
	if {$c ne ""} {
	    if {![my hasOnlyAttrs $objName]} {
		append result [my insertIndent $objName] </$c>\n
	    }
	}
	# a child is responsible for the "mixed content" data elements
	# that have a location after the child
	set p [$objName info parent]
	if {[$p istype XMLElement] && [$p mixedContent]} {
	    foreach {location data} [$p set pcdata] {
		if {$location == $objName} {
		    append result [my insertIndent $objName] \
			[my pcdataString $data] \n
		}
	    }
	}
    }


    #
    # public method to be called on top node -> returns XML text as result
    #
    XMLRecreatorVisitor instproc interpretNodeTree node {
	my instvar result
	set result ""
	my set nestingStart [my nestingDepth $node]
	$node accept [self]
	return $result
    }

    namespace export XMLRecreatorVisitor
}

namespace import ::xotcl::xml::recreatorVisitor::*