/*******************************************************************************
 * linkDoDeleteLinks
 * This function is the main loop through each object in the source module, 
 * looping through the links in the object and verifying the target OID is in 
 * the trace attribute.  If it is not in the trace attribute, then it calls 
 * the routine that actually deletes the link.
 * Function concludes by telling user if link deletion success, to save the 
 * appropriate module and if there were any link errors.
 * Function returns true if any links were deleted.
 */

bool linkDoDeleteLinks(Module src_mod, trg_mod, string trg_name, link_name,
                        attr_name, int link_dir) {
    Object  o, trg_obj
    string  values, value, msg, sTrgObj
    int     links_deleted = 0
    Link l
    bool bTraceAttrFound = false
    Module mTrg

    current = src_mod

    if (!exists attribute attr_name) {
        warningBox dxlStrformat(LS_("String_The_specified_attribute_s_does_not_exist",NLSTEMP_("The specified attribute '%s' does not exist")), attr_name)
        return false
    }

    for o in src_mod do {
        if ((link_dir == linkLinkSrcToTrg) || (link_dir == linkLinkBothWays)){
            //loop to check outgoing links
            for l in o->link_name do { //loop through outgoing links only through selected link module
               bTraceAttrFound = false
               mTrg = read(fullName(target l), false)
               if (null mTrg){
                  sError_Log = sError_Log "ERROR: Unable to open module " fullName(target l) " - skipping link from source module OID: " identifier o "\n"
                  continue
               }
               if (mTrg != trg_mod) { //check if right target module
                   continue //not right target module, so skip to next link
               }
               trg_obj = target l
               sTrgObj = trg_obj."Absolute Number" "" //get target OID
               values = probeAttr_(o, attr_name) //get all trace attribute OIDs
               while (!null values) { //loop through all values
                   value = linkNextValue(values) //get next value and adjust values        
                   if (!null value) {
                       if(value == sTrgObj) {
                          bTraceAttrFound = true //found OID in trace attr so set flag
                       }  //end if (value...
                   }  //end if !null value
               }  // end while (!null
               //done going through values, now check if should delete link
               if (bTraceAttrFound == false){
                   //Wasn't found, so try to delete the link
                   if(!canModify o) { //first check to see if can modify the object
                      //can't modify object, so put it in the error log
                      sError_Log = sError_Log "Unable to delete link from source OID:" identifier o " to target OID:" sTrgObj ".  Section not locked.\n"
                   }
                   else {
                      //can modify object so delete the link
                      if (DEBUG) print "Link not found in trace attribute, deleting link from source OID:" identifier o " to target OID:" sTrgObj "\n"
                      delete (l)
                      links_deleted++
                   }
               }
            } //end for l
        } //end of loop for outgoing links
        
        if ((link_dir == linkLinkTrgToSrc) || (link_dir == linkLinkBothWays)){
            //loop for all incoming links
            for l in o<-link_name do { //loop through incoming links only through selected link module
               bTraceAttrFound = false
               string smTrg = fullName(source l)
               if (DEBUG) print "smTrg=" smTrg "  trg_name=" trg_name "\n"
               if (smTrg != trg_name) { //check if right target module
                   continue //not right target module, so skip to next link
               }
               trg_obj = source l
               sTrgObj = trg_obj."Absolute Number" "" //get target OID
               values = probeAttr_(o, attr_name) //get all trace attribute OIDs
               while (!null values) { //loop through all values
                   value = linkNextValue(values) //get next value and adjust values        
                   if (!null value) {
                       if(value == sTrgObj) {
                          bTraceAttrFound = true //found OID in trace attr so set flag
                       }  //end if (value...
                   }  //end if !null value
               }  // end while (!null
               //done going through values, now check if should delete link
               if (bTraceAttrFound == false){
                   //Wasn't found, so delete the link
                   if(!canModify trg_obj) { //first check to see if can modify the object
                      //can't modify object, so put it in the error log
                      sError_Log = sError_Log "Unable to delete link from target OID:" sTrgObj " to source OID:" identifier o ".  Section not locked.\n"
                   }
                   else { 
                      if (DEBUG) print "Link not found in trace attribute, deleting link from target OID:" sTrgObj " to source OID:" identifier o "\n"
                      delete (l)
                      links_deleted++
                   }
               }
            }

        } //end of loop for incoming links
    }//end for o in...
        
    if (links_deleted == 0){
        return false
    }
    //links were made, flush to do link deletions and return success
    flushDeletions()
    refresh src_mod
    refresh trg_mod
    return true

} // linkDoDeleteLinks