// Copyright 2016 The Linux Foundation
//
// 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 (
	"embed"
	"net/http"

	v1 "github.com/opencontainers/image-spec/specs-go/v1"
)

// Media types for the OCI image formats
const (
	ValidatorMediaTypeDescriptor   Validator = v1.MediaTypeDescriptor
	ValidatorMediaTypeLayoutHeader Validator = v1.MediaTypeLayoutHeader
	ValidatorMediaTypeManifest     Validator = v1.MediaTypeImageManifest
	ValidatorMediaTypeImageIndex   Validator = v1.MediaTypeImageIndex
	ValidatorMediaTypeImageConfig  Validator = v1.MediaTypeImageConfig
	ValidatorMediaTypeImageLayer   Validator = v1.MediaTypeImageLayer
)

var (
	// specFS stores the embedded http.FileSystem having the OCI JSON schema files in root "/".
	//go:embed *.json
	specFS embed.FS

	// specsOrig maps OCI schema media types to schema files.
	specs = map[Validator]string{
		ValidatorMediaTypeDescriptor:   "content-descriptor.json",
		ValidatorMediaTypeLayoutHeader: "image-layout-schema.json",
		ValidatorMediaTypeManifest:     "image-manifest-schema.json",
		ValidatorMediaTypeImageIndex:   "image-index-schema.json",
		ValidatorMediaTypeImageConfig:  "config-schema.json",
	}

	// specURLs lists the various URLs a given spec may be known by.
	// This is generated from the "id" value in each spec and relative ref values they contain.
	specURLs = map[string][]string{
		"config-schema.json": {
			"https://opencontainers.org/schema/image/config",
		},
		"content-descriptor.json": {
			"https://opencontainers.org/schema/descriptor",
			"https://opencontainers.org/schema/image/content-descriptor.json",
		},
		"defs-descriptor.json": {
			"https://opencontainers.org/schema/image/descriptor/mediaType",
			"https://opencontainers.org/schema/defs-descriptor.json",
			"https://opencontainers.org/schema/image/defs-descriptor.json",
		},
		"defs.json": {
			"https://opencontainers.org/schema/defs.json",
			"https://opencontainers.org/schema/image/defs.json",
			"https://opencontainers.org/schema/image/descriptor/defs.json",
		},
		"image-index-schema.json": {
			"https://opencontainers.org/schema/image/index",
		},
		"image-layout-schema.json": {
			"https://opencontainers.org/schema/image/layout",
		},
		"image-manifest-schema.json": {
			"https://opencontainers.org/schema/image/manifest",
		},
	}
)

// FileSystem returns an in-memory filesystem including the schema files.
// The schema files are located at the root directory.
func FileSystem() http.FileSystem {
	return http.FS(specFS)
}