{{- /*
--------------------------------------------------------------------------------
Template file for use with tools/intrinsic-gen to generate the wgsl files in the
./gen/... subdirectories

See:
* tools/cmd/intrinsic-gen/gen for structures used by this template
* https://golang.org/pkg/text/template/ for documentation on the template syntax
--------------------------------------------------------------------------------
*/ -}}

{{- /* For each permutation of each overload of each function... */ -}}
{{- range .Sem.Functions -}}
{{-   range .Overloads  -}}
{{-     range Permute . -}}
{{- /*    Generate a ./gen/<function>/<permuataion-hash>.wgsl file using
          the Permutation macro defined below                             */ -}}
{{-       $file := printf "./gen/%v/%v.wgsl" .Function.Name .Hash -}}
{{-       $content := Eval "Permutation" . -}}
{{-       WriteFile $file $content -}}
{{-     end  }}
{{-   end  }}
{{- end  }}


{{- /* ------------------------------------------------------------------ */ -}}
{{-                          define "Permutation"                            -}}
{{- /* Emits the body of the intrinsic permuation .wgsl file              */ -}}
{{- /* ------------------------------------------------------------------ */ -}}
{{-   $function    := .Function.Name -}}
{{-   $permutation := printf "%v_%v" $function .Hash -}}
{{-   $args        := Map -}}

{{- /* Generate a storage buffer for runtime sized array parameters       */ -}}
{{-   if (Eval "HasStorageBufferArgs" .) -}}
[[block]]
struct SB {
{{-     range $i, $p := .Parameters  }}
{{-       $class := Eval "StorageClass" $p.Type -}}
{{-       if eq "STORAGE_BUFFER" $class }}
  arg_{{$i}}: {{template "Type" $p.Type}};
{{          $args.Put $i (printf "sb.arg_%v" $i) -}}
{{-       end -}}
{{-     end -}}
};
[[group(0), binding(0)]] var<storage, read> sb : SB;
{{    end -}}

{{- /* Generate module-scoped resource variables (textures, samplers, etc) */ -}}
{{-   range $i, $p := .Parameters  }}
{{-     $class := Eval "StorageClass" $p.Type -}}
{{-     if eq "RESOURCE" $class -}}
          [[group(1), binding({{$i}})]] var arg_{{$i}}: {{template "Type" $p.Type}};
{{        $args.Put $i (printf "arg_%v" $i) -}}
{{-     end -}}
{{-   end -}}

{{- /* Generate the function that calls the intrinsic */ -}}
fn {{$permutation}}() {
{{/* Build the parameters either as 'var' or inline values */ -}}
{{-   range $i, $p := .Parameters -}}
{{-     $class := Eval "StorageClass" $p.Type -}}
{{-     if eq "PRIVATE" $class  -}}
{{-       if eq "ptr" $p.Type.Target.Name -}}
{{- /*indent*/}}  var arg_{{$i}}: {{template "Type" index $p.Type.TemplateArguments 1}};
{{          $args.Put $i (printf "&arg_%v" $i) -}}
{{-       else -}}
{{-         $args.Put $i (Eval "ValueOf" $p.Type) -}}
{{-       end -}}
{{-     end -}}
{{-   end -}}

{{- /* Make the call to the intrinsic */ -}}
{{- /*indent*/}}  {{/*indent*/ -}}
{{-   if .ReturnType -}}
  var res: {{template "Type" .ReturnType}} = {{/* preserve space after = */ -}}
{{-   end -}}
  {{$function}}(
{{-   range $i, $p := .Parameters -}}
{{-     if $i -}}, {{end}}{{$args.Get $i -}}
{{-   end -}}
  );
}
{{/*new line*/ -}}

{{- if .CanBeUsedInStage.Vertex }}
[[stage(vertex)]]
fn vertex_main() -> [[builtin(position)]] vec4<f32> {
  {{$permutation}}();
  return vec4<f32>();
}
{{ end -}}

{{- if .CanBeUsedInStage.Fragment }}
[[stage(fragment)]]
fn fragment_main() {
  {{$permutation}}();
}
{{ end -}}

{{- if .CanBeUsedInStage.Compute }}
[[stage(compute)]]
fn compute_main() {
  {{$permutation}}();
}
{{ end -}}

{{- end -}}


{{- /* ------------------------------------------------------------------ */ -}}
{{-                       define "HasStorageBufferArgs"                      -}}
{{- /* Returns a non-empty string if the given overload has parameters    */ -}}
{{- /* that are in the STORAGE_BUFFER storage class                       */ -}}
{{- /* ------------------------------------------------------------------ */ -}}
{{-   range $i, $p := .Parameters  }}
{{-     $class := Eval "StorageClass" $p.Type -}}
{{-     if eq "STORAGE_BUFFER" $class -}}1
{{      end -}}
{{-   end -}}
{{- end -}}


{{- /* ------------------------------------------------------------------ */ -}}
{{-                           define "StorageClass"                          -}}
{{- /* Returns the storage classs STORAGE_BUFFER, RESOURCE, or PRIVATE    */ -}}
{{- /* for the given Fully Qualified Name                                 */ -}}
{{- /* ------------------------------------------------------------------ */ -}}
{{-   $name := .Target.Name -}}
{{-   if             eq $name "array"   -}}STORAGE_BUFFER
{{-   else if HasPrefix $name "texture" -}}RESOURCE
{{-   else if HasPrefix $name "sampler" -}}RESOURCE
{{-   else                              -}}PRIVATE
{{-   end -}}
{{- end -}}


{{- /* ------------------------------------------------------------------ */ -}}
{{-                              define "ValueOf"                            -}}
{{- /* Returns a value of the given Fully Qualified Name argument         */ -}}
{{- /* ------------------------------------------------------------------ */ -}}
{{-   if      eq .Target.Name "i32" -}}1
{{-   else if eq .Target.Name "u32" -}}1u
{{-   else if eq .Target.Name "f32" -}}1.0
{{-   else                          -}}{{template "Type" .}}()
{{-   end                           -}}
{{- end -}}


{{- /* ------------------------------------------------------------------ */ -}}
{{-                                define "Type"                             -}}
{{- /* Emits the WGSL for the Fully Qualified Name argument               */ -}}
{{- /* ------------------------------------------------------------------ */ -}}
{{-   if IsType .Target -}}
{{-     if      eq .Target.Name "vec" -}}vec{{index .TemplateArguments 0}}<{{template "Type" index .TemplateArguments 1}}>
{{-     else if eq .Target.Name "mat" -}}mat{{index .TemplateArguments 0}}x{{index .TemplateArguments 1}}<{{template "Type" index .TemplateArguments 2}}>
{{-     else                          -}}{{.Target.Name}}{{template "TemplateArguments" .TemplateArguments}}
{{-     end                           -}}
{{-   else if IsEnumEntry   .Target   -}}{{.Target.Name}}
{{-   else if IsEnumMatcher .Target   -}}{{(index .Target.Options 0).Name}}
{{-   else                            -}}<unhandled-fully-qualified-name-target={{- printf "%T" .Target -}}>
{{-   end                             -}}
{{- end -}}


{{- /* ------------------------------------------------------------------ */ -}}
{{-                          define "TemplateArguments"                      -}}
{{- /* Emits the WGSL for the template argument list                      */ -}}
{{- /* ------------------------------------------------------------------ */ -}}
{{-   if . -}}
<
{{-    range $i, $a := . -}}
{{-      if $i -}}, {{  end -}}
{{-      if IsInt $a -}}{{- . -}}
{{-      else        -}}{{- template "Type" $a -}}
{{-      end -}}
{{-    end -}}
>
{{-   end -}}
{{- end -}}