/*
 * Minimalist Object Storage, (C) 2015 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 donut

import (
	"encoding/json"
	"fmt"
	"path/filepath"

	"github.com/minio/minio/pkg/donut/disk"
	"github.com/minio/minio/pkg/iodine"
)

// Heal heal an existing donut
func (donut API) Heal() error {
	if err := donut.listDonutBuckets(); err != nil {
		return iodine.New(err, nil)
	}
	disks := make(map[int]disk.Disk)
	for _, node := range donut.nodes {
		nDisks, err := node.ListDisks()
		if err != nil {
			return iodine.New(err, nil)
		}
		for k, v := range nDisks {
			disks[k] = v
		}
	}

	missingDisks := make(map[int]disk.Disk)
	for order, disk := range disks {
		if !disk.IsUsable() {
			missingDisks[order] = disk
		}
	}

	bucketMetadata, err := donut.getDonutBucketMetadata()
	if err != nil {
		return iodine.New(err, nil)
	}

	for _, disk := range missingDisks {
		disk.MakeDir(donut.config.DonutName)
		bucketMetadataWriter, err := disk.CreateFile(filepath.Join(donut.config.DonutName, bucketMetadataConfig))
		if err != nil {
			return iodine.New(err, nil)
		}
		defer bucketMetadataWriter.Close()
		jenc := json.NewEncoder(bucketMetadataWriter)
		if err := jenc.Encode(bucketMetadata); err != nil {
			return iodine.New(err, nil)
		}
	}

	for order, disk := range missingDisks {
		for bucket := range bucketMetadata.Buckets {
			bucketSlice := fmt.Sprintf("%s$0$%d", bucket, order) // TODO handle node slices
			err := disk.MakeDir(filepath.Join(donut.config.DonutName, bucketSlice))
			if err != nil {
				return iodine.New(err, nil)
			}
		}
	}

	return nil
	// TODO heal data
}