/*
 * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
 *
 * 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 cmd

import (
	"encoding/xml"
	"io"
	"net/http"

	"github.com/gorilla/mux"
	xhttp "github.com/minio/minio/cmd/http"
	"github.com/minio/minio/cmd/logger"
	bucketsse "github.com/minio/minio/pkg/bucket/encryption"
	"github.com/minio/minio/pkg/bucket/policy"
)

const (
	// Bucket Encryption configuration file name.
	bucketSSEConfig = "bucket-encryption.xml"
)

// PutBucketEncryptionHandler - Stores given bucket encryption configuration
// https://docs.aws.amazon.com/AmazonS3/latest/API/API_PutBucketEncryption.html
func (api objectAPIHandlers) PutBucketEncryptionHandler(w http.ResponseWriter, r *http.Request) {
	ctx := newContext(r, w, "PutBucketEncryption")

	defer logger.AuditLog(w, r, "PutBucketEncryption", mustGetClaimsFromToken(r))

	objAPI := api.ObjectAPI()
	if objAPI == nil {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrServerNotInitialized), r.URL, guessIsBrowserReq(r))
		return
	}

	vars := mux.Vars(r)
	bucket := vars["bucket"]

	// PutBucketEncyrption API requires Content-Md5
	if _, ok := r.Header[xhttp.ContentMD5]; !ok {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrMissingContentMD5), r.URL, guessIsBrowserReq(r))
		return
	}

	if s3Error := checkRequestAuthType(ctx, r, policy.PutBucketEncryptionAction, bucket, ""); s3Error != ErrNone {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Error), r.URL, guessIsBrowserReq(r))
		return
	}

	// Check if bucket exists.
	if _, err := objAPI.GetBucketInfo(ctx, bucket); err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL, guessIsBrowserReq(r))
		return
	}

	// Parse bucket encryption xml
	encConfig, err := validateBucketSSEConfig(io.LimitReader(r.Body, maxBucketSSEConfigSize))
	if err != nil {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrMalformedXML), r.URL, guessIsBrowserReq(r))
		return
	}

	// Return error if KMS is not initialized
	if GlobalKMS == nil {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrKMSNotConfigured), r.URL, guessIsBrowserReq(r))
		return
	}

	// Store the bucket encryption configuration in the object layer
	if err = objAPI.SetBucketSSEConfig(ctx, bucket, encConfig); err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL, guessIsBrowserReq(r))
		return
	}

	// Update the in-memory bucket encryption cache
	globalBucketSSEConfigSys.Set(bucket, *encConfig)

	// Update peer MinIO servers of the updated bucket encryption config
	globalNotificationSys.SetBucketSSEConfig(ctx, bucket, encConfig)

	writeSuccessResponseHeadersOnly(w)
}

// GetBucketEncryptionHandler - Returns bucket policy configuration
// https://docs.aws.amazon.com/AmazonS3/latest/API/API_GetBucketEncryption.html
func (api objectAPIHandlers) GetBucketEncryptionHandler(w http.ResponseWriter, r *http.Request) {
	ctx := newContext(r, w, "GetBucketEncryption")

	defer logger.AuditLog(w, r, "GetBucketEncryption", mustGetClaimsFromToken(r))

	objAPI := api.ObjectAPI()
	if objAPI == nil {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrServerNotInitialized), r.URL, guessIsBrowserReq(r))
		return
	}

	vars := mux.Vars(r)
	bucket := vars["bucket"]

	if s3Error := checkRequestAuthType(ctx, r, policy.GetBucketEncryptionAction, bucket, ""); s3Error != ErrNone {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Error), r.URL, guessIsBrowserReq(r))
		return
	}

	// Check if bucket exists
	var err error
	if _, err = objAPI.GetBucketInfo(ctx, bucket); err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL, guessIsBrowserReq(r))
		return
	}

	// Fetch bucket encryption configuration from object layer
	var encConfig *bucketsse.BucketSSEConfig
	if encConfig, err = objAPI.GetBucketSSEConfig(ctx, bucket); err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL, guessIsBrowserReq(r))
		return
	}

	var encConfigData []byte
	if encConfigData, err = xml.Marshal(encConfig); err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL, guessIsBrowserReq(r))
		return
	}

	// Write bucket encryption configuration to client
	writeSuccessResponseXML(w, encConfigData)
}

// DeleteBucketEncryptionHandler - Removes bucket encryption configuration
func (api objectAPIHandlers) DeleteBucketEncryptionHandler(w http.ResponseWriter, r *http.Request) {
	ctx := newContext(r, w, "DeleteBucketEncryption")

	defer logger.AuditLog(w, r, "DeleteBucketEncryption", mustGetClaimsFromToken(r))

	objAPI := api.ObjectAPI()
	if objAPI == nil {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrServerNotInitialized), r.URL, guessIsBrowserReq(r))
		return
	}

	vars := mux.Vars(r)
	bucket := vars["bucket"]

	if s3Error := checkRequestAuthType(ctx, r, policy.PutBucketEncryptionAction, bucket, ""); s3Error != ErrNone {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(s3Error), r.URL, guessIsBrowserReq(r))
		return
	}

	// Check if bucket exists
	var err error
	if _, err = objAPI.GetBucketInfo(ctx, bucket); err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL, guessIsBrowserReq(r))
		return
	}

	// Delete bucket encryption config from object layer
	if err = objAPI.DeleteBucketSSEConfig(ctx, bucket); err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL, guessIsBrowserReq(r))
		return
	}

	// Remove entry from the in-memory bucket encryption cache
	globalBucketSSEConfigSys.Remove(bucket)
	// Update peer MinIO servers of the updated bucket encryption config
	globalNotificationSys.RemoveBucketSSEConfig(ctx, bucket)

	writeSuccessNoContent(w)
}