(: tools to analyse xml parse tree
@author Andy Bunce
:)
module namespace hnd="lsp/handlers";
import module namespace lspt = 'lsp-typedefs' at "lsp-typedefs.xqm";


declare record hnd:Result( 
    result as item()*,
    skipchildren? as xs:boolean:=false() 
);


declare function hnd:handle($el as element(*),$state)
{
  let $f:= function-lookup(xs:QName(name($el)=>trace("SSS")),2)
           otherwise fn($el,$state){hnd:Result($state,false())}
  return $f($el,$state)
};

declare function hnd:diags($parse as element(),$diags:=())
{
  let $_:=trace((name($parse),$diags),"diags")
  let $walk:= hnd:handle($parse,$diags)
 
  return if($walk?skipchildren)
        then $walk?result
        else fold-left($parse/*,$diags,
        fn($r,$this){
          hnd:diags($this,$r)
        })
};

declare function hnd:walk($parse as element(), 
                         $actions as map(*), 
                         $state as hnd:Result )
as hnd:Result{
  
  let $action:=$actions(name($parse))
  let $result:= if(exists($action))
                then $action($parse,$state)
                else hnd:Result($state)
 
  return if($result?skipchildren)
         then $result
         else fold-left(
                $parse/*,$state,
                fn($state,$this){hnd:walk($this, $actions, $state)}
                     )
};



declare function hnd:symbols($parse as element(),$syms as lspt:DocumentSymbol* :=() )
{
  let $actions:={
      "ContextValueDecl":  hnd:action#2,
      "VarDecl": hnd:VarDecl#2,
      "FunctionDecl": hnd:FunctionDecl#2,
      "ItemTypeDecl": hnd:action#2,
      "NamedRecordTypeDecl": hnd:action#2
  }
  let $state:= hnd:Result(())
  let $result:= hnd:walk($parse,$actions,$state)
  return $result?result
};

declare function hnd:action($parse  as element(),$state as hnd:Result  )
as hnd:Result{
  hnd:Result($state?result,true()) ,message(name($parse),"ACTION: ") 
};

declare function hnd:VarDecl($parse  as element(VarDecl),$state as hnd:Result  )
as hnd:Result{
  let $name:=$parse/VarNameAndType/EQName
  let $range:=lspt:Range(lspt:Position(0,0),lspt:Position(0,3))
  let $sym:=lspt:DocumentSymbol($name,$lspt:SymbolKindMap('Variable'),$range,$range,"TODO")
  return  ($state?result,$sym)=>hnd:Result(true())
};

declare function hnd:FunctionDecl($parse  as element(FunctionDecl),$state as hnd:Result  )
as hnd:Result{
  let $name:=$parse/UnreservedFunctionEQName
  let $range:=lspt:Range(lspt:Position(0,0),lspt:Position(0,3))
  let $sym:=lspt:DocumentSymbol($name,$lspt:SymbolKindMap('Method'),$range,$range,"TODO")
  return  ($state?result,$sym)=>hnd:Result(true())
};