// Copyright 2019 The Kubernetes Authors.
// SPDX-License-Identifier: Apache-2.0

package settersutil

import (
	"fmt"
	"io/ioutil"

	"sigs.k8s.io/kustomize/kyaml/fieldmeta"
	"sigs.k8s.io/kustomize/kyaml/kio"
	"sigs.k8s.io/kustomize/kyaml/openapi"
	"sigs.k8s.io/kustomize/kyaml/setters2"
)

// SetterCreator creates or updates a setter in the OpenAPI definitions, and inserts references
// to the setter from matching resource fields.
type SetterCreator struct {
	// Name is the name of the setter to create or update.
	Name string

	SetBy string

	Description string

	Type string

	SchemaPath string

	// FieldName if set will add the OpenAPI reference to fields with this name or path
	// FieldName may be the full name of the field, full path to the field, or the path suffix.
	// e.g. all of the following would match spec.template.spec.containers.image --
	// [image, containers.image, spec.containers.image, template.spec.containers.image,
	//  spec.template.spec.containers.image]
	// Optional.  If unspecified match all field names.
	FieldName string

	// FieldValue if set will add the OpenAPI reference to fields if they have this value.
	// Optional.  If unspecified match all field values.
	FieldValue string

	// Required indicates that the setter must be set by package consumer before
	// live apply/preview. This field is added to the setter definition to record
	// the package publisher's intent to make the setter required to be set.
	Required bool
}

func (c SetterCreator) Create(openAPIPath, resourcesPath string) error {
	schema, err := schemaFromFile(c.SchemaPath)
	if err != nil {
		return err
	}

	// Update the resources with the setter reference
	inout := &kio.LocalPackageReadWriter{PackagePath: resourcesPath}
	a := &setters2.Add{
		FieldName:  c.FieldName,
		FieldValue: c.FieldValue,
		Ref:        fieldmeta.DefinitionsPrefix + fieldmeta.SetterDefinitionPrefix + c.Name,
		Type:       c.Type,
	}
	err = kio.Pipeline{
		Inputs:  []kio.Reader{inout},
		Filters: []kio.Filter{kio.FilterAll(a)},
		Outputs: []kio.Writer{inout},
	}.Execute()
	if a.Count == 0 {
		fmt.Printf("setter %s doesn't match any field in resources, but creating setter definition\n", c.Name)
	}
	if err != nil {
		return err
	}

	// Update the OpenAPI definitions to hace the setter
	sd := setters2.SetterDefinition{
		Name: c.Name, Value: c.FieldValue, SetBy: c.SetBy, Description: c.Description,
		Type: c.Type, Schema: schema, Required: c.Required,
	}
	if err := sd.AddToFile(openAPIPath); err != nil {
		return err
	}

	// Load the updated definitions
	if err := openapi.AddSchemaFromFile(openAPIPath); err != nil {
		return err
	}
	// if the setter is of array type write the derived list values back to
	// openAPI definitions
	if len(a.ListValues) > 0 {
		sd.ListValues = a.ListValues
		sd.Value = ""
		if err := sd.AddToFile(openAPIPath); err != nil {
			return err
		}
	}

	return nil
}

// schemaFromFile reads the contents from schemaPath and returns schema
func schemaFromFile(schemaPath string) (string, error) {
	if schemaPath == "" {
		return "", nil
	}
	sch, err := ioutil.ReadFile(schemaPath)
	if err != nil {
		return "", err
	}
	return string(sch), nil
}