/*
Copyright 2019 The Kubernetes Authors.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package schema

import (
	"github.com/go-openapi/spec"
)

// ToGoOpenAPI converts a structural schema to go-openapi schema. It is faithful and roundtrippable
// with the exception of `nullable:true` for empty type (`type:""`).
//
// WARNING: Do not use the returned schema to perform CRD validation until this restriction is solved.
//
// Nullable:true is mapped to `type:[<structural-type>,"null"]`
// if the structural type is non-empty, and nullable is dropped if the structural type is empty.
func (s *Structural) ToGoOpenAPI() *spec.Schema {
	if s == nil {
		return nil
	}

	ret := &spec.Schema{}

	if s.Items != nil {
		ret.Items = &spec.SchemaOrArray{Schema: s.Items.ToGoOpenAPI()}
	}
	if s.Properties != nil {
		ret.Properties = make(map[string]spec.Schema, len(s.Properties))
		for k, v := range s.Properties {
			ret.Properties[k] = *v.ToGoOpenAPI()
		}
	}
	s.Generic.toGoOpenAPI(ret)
	s.Extensions.toGoOpenAPI(ret)
	s.ValueValidation.toGoOpenAPI(ret)

	return ret
}

func (g *Generic) toGoOpenAPI(ret *spec.Schema) {
	if g == nil {
		return
	}

	if len(g.Type) != 0 {
		ret.Type = spec.StringOrArray{g.Type}
		if g.Nullable {
			// go-openapi does not support nullable, but multiple type values.
			// Only when type is already non-empty, adding null to the types is correct though.
			// If you add null as only type, you enforce null, in contrast to nullable being
			// ineffective if no type is provided in a schema.
			ret.Type = append(ret.Type, "null")
		}
	}
	if g.AdditionalProperties != nil {
		ret.AdditionalProperties = &spec.SchemaOrBool{
			Allows: g.AdditionalProperties.Bool,
			Schema: g.AdditionalProperties.Structural.ToGoOpenAPI(),
		}
	}
	ret.Description = g.Description
	ret.Title = g.Title
	ret.Default = g.Default.Object
}

func (x *Extensions) toGoOpenAPI(ret *spec.Schema) {
	if x == nil {
		return
	}

	if x.XPreserveUnknownFields {
		ret.VendorExtensible.AddExtension("x-kubernetes-preserve-unknown-fields", true)
	}
	if x.XEmbeddedResource {
		ret.VendorExtensible.AddExtension("x-kubernetes-embedded-resource", true)
	}
	if x.XIntOrString {
		ret.VendorExtensible.AddExtension("x-kubernetes-int-or-string", true)
	}
}

func (v *ValueValidation) toGoOpenAPI(ret *spec.Schema) {
	if v == nil {
		return
	}

	ret.Format = v.Format
	ret.Maximum = v.Maximum
	ret.ExclusiveMaximum = v.ExclusiveMaximum
	ret.Minimum = v.Minimum
	ret.ExclusiveMinimum = v.ExclusiveMinimum
	ret.MaxLength = v.MaxLength
	ret.MinLength = v.MinLength
	ret.Pattern = v.Pattern
	ret.MaxItems = v.MaxItems
	ret.MinItems = v.MinItems
	ret.UniqueItems = v.UniqueItems
	ret.MultipleOf = v.MultipleOf
	if v.Enum != nil {
		ret.Enum = make([]interface{}, 0, len(v.Enum))
		for i := range v.Enum {
			ret.Enum = append(ret.Enum, v.Enum[i].Object)
		}
	}
	ret.MaxProperties = v.MaxProperties
	ret.MinProperties = v.MinProperties
	ret.Required = v.Required
	for i := range v.AllOf {
		ret.AllOf = append(ret.AllOf, *v.AllOf[i].toGoOpenAPI())
	}
	for i := range v.AnyOf {
		ret.AnyOf = append(ret.AnyOf, *v.AnyOf[i].toGoOpenAPI())
	}
	for i := range v.OneOf {
		ret.OneOf = append(ret.OneOf, *v.OneOf[i].toGoOpenAPI())
	}
	ret.Not = v.Not.toGoOpenAPI()
}

func (vv *NestedValueValidation) toGoOpenAPI() *spec.Schema {
	if vv == nil {
		return nil
	}

	ret := &spec.Schema{}

	vv.ValueValidation.toGoOpenAPI(ret)
	if vv.Items != nil {
		ret.Items = &spec.SchemaOrArray{Schema: vv.Items.toGoOpenAPI()}
	}
	if vv.Properties != nil {
		ret.Properties = make(map[string]spec.Schema, len(vv.Properties))
		for k, v := range vv.Properties {
			ret.Properties[k] = *v.toGoOpenAPI()
		}
	}
	vv.ForbiddenGenerics.toGoOpenAPI(ret)   // normally empty. Exception: int-or-string
	vv.ForbiddenExtensions.toGoOpenAPI(ret) // shouldn't do anything

	return ret
}