# $Id: RDFCreator.xotcl,v 1.6 2006/09/27 08:12:40 neumann Exp $

package provide xotcl::rdf::tripleRecreator 0.9
package require XOTcl
package require xotcl::rdf::parser

namespace eval ::xotcl::rdf::tripleRecreator {
    namespace import ::xotcl::*

    Class RDFCreator -parameter {
	{rdfNS "http://www.w3.org/1999/02/22-rdf-syntax-ns#"}
	{openExprs ""}
    }

    Class OpenExpr -parameter {
	{type ""}
	{subject ""}
	{closing ""}
    } 

    RDFCreator instproc init args {
	next
    }

    RDFCreator instproc free {} {
	my instvar openExprs
	while {$openExprs ne ""} {
	    set o [lindex $openExprs 0]
	    set openExprs [lrange $openExprs 1 end]
	    $o destroy
	}
    }

    RDFCreator instproc sort {tl} {
	#
	# this assumes that the triples are created and named in node tree order, e.g. 
	# through autonames like triple0, triple1, ... (as in rdfTripleCreator)
	#
	# => bag types defs are before bag's _1, _2 -- etc.
	#
	# otherwise overload sorting method !
	#
	return [lsort $tl]
    }

    RDFCreator instproc createFromTriples {tripleList} {
	my instvar openExprs
	set heading "<?xml version=\"1.0\"?>\n<RDF
  xmlns:rdf=\"[my set rdfNS]\""
	set body ""
	XMLNamespace [self]::ns
	[self]::ns add rdf [set rdfNS [my rdfNS]]
	my free

	foreach t [my sort $tripleList] {
	    set p [$t predicate]
	    set o [$t object]
	    set s [$t subject]

	    
	    set opening ""
	    set closing ""
	    if {[regexp "(^.*://.*/(\[^/\]+)(/|\#))(\[^/\]+)\$" $p _ ns prefix __ name]} {
		
		if {[string match $rdfNS $ns]} {
		    if {"type" eq $name} {
			if {[regexp "${rdfNS}(RDFAlt|RDFBag|RDFSeq)" $o _ type]} {
			    set opening "\n<rdf:$type ID=\"$s\">"
			    set closing "\n</rdf:$type>"
			}
		    }
		}

		if {[set nsPrefix [[self]::ns searchFullName $ns]] == ""} {
		    [self]::ns add [set nsPrefix [my autoname $prefix]] $ns
		    append heading "\n  xmlns:${nsPrefix}=\"$ns\""
		}
		
		set oe [lindex [my set openExprs] 0]

		if {$oe eq "" || [$oe subject] != $s} {
		    if {$oe ne ""} {
			append body [$oe closing]
			[lindex [set openExprs] 0] destroy
			set openExprs [lrange $openExprs 1 end]
		    }
		    if {$opening eq ""} {
			append body "\n<rdf:Description about=\"$s\">"
			set closing "\n</rdf:Description>"
			set type "Description"
		    } else {
			append body $opening
		    }
		    set noe [my OpenExpr [my autoname oe]]
		    set openExprs [concat $noe $openExprs]
		    
		    $noe subject $s
		    $noe closing $closing
		    $noe type $type
		    set oe $noe
		}
		set tn ${nsPrefix}:$name

		switch -exact [$oe type] {
		    RDFDescription {
			#puts DESCRIPTION
			append body "\n<$tn> [$t object] </$tn>"
		    }
		    RDFAlt - RDFSeq {
			#puts ALT---$tn
			if {[regexp {rdf:_([0-9]*)} $tn _ __]} {
			    append body "\n<rdf:li resource=\"[$t object]\"/>"
			}
		    } 
		    RDFBag {
			if {[regexp {rdf:_([0-9]*)} $tn _ __]} {
			    append body "\n<$tn resource=\"[$t object]\"/>"
			}
		    }
		}
	    } else { 
		puts "Predicate '$p' not matched"
		# hier als xmlns behandeln ...
	    } 
	}
	append heading ">"
	set r $heading
	while {$openExprs ne ""} {
	    set oe [lindex $openExprs 0]
	    set openExprs [lrange $openExprs 1 end]
	    append body [$oe closing]
	    $oe destroy
	}
	append r $body
	append r "\n</RDF>"
	return $r
    }

    namespace export RDFCreator OpenExpr
}

namespace import ::xotcl::rdf::tripleRecreator::*