{{/*
Copyright 2019-present Facebook Inc. All rights reserved.
This source code is licensed under the Apache 2.0 license found
in the LICENSE file in the root directory of this source tree.
*/}}

{{ define "dialect/gremlin/order/signature" -}}
	// OrderFunc applies an ordering on the graph traversal.
	type OrderFunc func(*dsl.Traversal)
{{- end }}

{{ define "dialect/gremlin/order/func" -}}
	{{- $order := $.Scope.Order -}}
	func(tr *dsl.Traversal) {
		for _, f := range fields {
			tr.By(f, dsl.{{ pascal $order }})
		}
	}
{{- end }}

{{/* custom signature for group-by function */}}
{{ define "dialect/gremlin/group/signature" -}}
	// It gets two labels as parameters. The first used in the `As` step for the predicate,
	// and the second is an optional name for the next predicates (or for later usage).
	type AggregateFunc func(string, string) (string, *dsl.Traversal)
{{- end }}

{{ define "dialect/gremlin/group/as" -}}
	func(start, _ string) (string, *dsl.Traversal) {
		return fn(start, end)
	}
{{- end }}

{{ define "dialect/gremlin/group/func" -}}
	{{- $fn := $.Scope.Func -}}
	{{- $withField := $.Scope.WithField -}}
	func(start, end string) (string, *dsl.Traversal) {
		if end == "" {
			end = Default{{ $fn }}Label
		}
		return end, __.As(start).{{ if $withField }}Unfold().Values(field).{{ $fn }}(){{ else }}{{ $fn }}(dsl.Local){{ end }}.As(end)
	}
{{- end }}

{{/* optional constants for group-by default values. */}}
{{ define "dialect/gremlin/group/const" -}}
	{{- $fn := $.Scope.Func }}
	{{- $name := $.Scope.Name }}
	{{- $pkg := base $.Config.Package }}
	// Default{{ $fn }}Label is the default label name for the {{ $fn }} aggregation function.
	// It should be used as the struct-tag for decoding, or a map key for interaction with the returned response.
	// In order to {{ quote $name }} 2 or more fields and avoid conflicting, use the `{{ $pkg }}.As({{ $pkg }}.{{ $fn }}(field), "custom_name")`
	// function with custom name in order to override it.
	const Default{{ $fn }}Label = {{ quote $name }}
{{- end }}