/*
 * 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 madmin

import (
	"context"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"net/url"
	"strings"

	"github.com/minio/minio/pkg/auth"
)

// ServiceType represents service type
type ServiceType string

const (
	// ReplicationService specifies replication service
	ReplicationService ServiceType = "replication"
)

// IsValid returns true if ARN type represents replication
func (t ServiceType) IsValid() bool {
	return t == ReplicationService
}

// ARN is a struct to define arn.
type ARN struct {
	Type   ServiceType
	ID     string
	Region string
	Bucket string
}

// Empty returns true if arn struct is empty
func (a ARN) Empty() bool {
	return !a.Type.IsValid()
}
func (a ARN) String() string {
	return fmt.Sprintf("arn:minio:%s:%s:%s:%s", a.Type, a.Region, a.ID, a.Bucket)
}

// ParseARN return ARN struct from string in arn format.
func ParseARN(s string) (*ARN, error) {
	// ARN must be in the format of arn:minio:<Type>:<REGION>:<ID>:<remote-bucket>
	if !strings.HasPrefix(s, "arn:minio:") {
		return nil, fmt.Errorf("Invalid ARN %s", s)
	}

	tokens := strings.Split(s, ":")
	if len(tokens) != 6 {
		return nil, fmt.Errorf("Invalid ARN %s", s)
	}

	if tokens[4] == "" || tokens[5] == "" {
		return nil, fmt.Errorf("Invalid ARN %s", s)
	}

	return &ARN{
		Type:   ServiceType(tokens[2]),
		Region: tokens[3],
		ID:     tokens[4],
		Bucket: tokens[5],
	}, nil
}

// BucketTarget represents the target bucket and site association.
type BucketTarget struct {
	SourceBucket string            `json:"sourcebucket"`
	Endpoint     string            `json:"endpoint"`
	Credentials  *auth.Credentials `json:"credentials"`
	TargetBucket string            `json:"targetbucket"`
	Secure       bool              `json:"secure"`
	Path         string            `json:"path,omitempty"`
	API          string            `json:"api,omitempty"`
	Arn          string            `json:"arn,omitempty"`
	Type         ServiceType       `json:"type"`
	Region       string            `json:"omitempty"`
}

// Clone returns shallow clone of BucketTarget without secret key in credentials
func (t *BucketTarget) Clone() BucketTarget {
	return BucketTarget{
		SourceBucket: t.SourceBucket,
		Endpoint:     t.Endpoint,
		TargetBucket: t.TargetBucket,
		Credentials:  &auth.Credentials{AccessKey: t.Credentials.AccessKey},
		Secure:       t.Secure,
		Path:         t.Path,
		API:          t.Path,
		Arn:          t.Arn,
		Type:         t.Type,
		Region:       t.Region,
	}
}

// URL returns target url
func (t BucketTarget) URL() string {
	scheme := "http"
	if t.Secure {
		scheme = "https"
	}
	return fmt.Sprintf("%s://%s", scheme, t.Endpoint)
}

// Empty returns true if struct is empty.
func (t BucketTarget) Empty() bool {
	return t.String() == "" || t.Credentials == nil
}

func (t *BucketTarget) String() string {
	return fmt.Sprintf("%s %s", t.Endpoint, t.TargetBucket)
}

// BucketTargets represents a slice of bucket targets by type and endpoint
type BucketTargets struct {
	Targets []BucketTarget
}

// Empty returns true if struct is empty.
func (t BucketTargets) Empty() bool {
	if len(t.Targets) == 0 {
		return true
	}
	empty := true
	for _, t := range t.Targets {
		if !t.Empty() {
			return false
		}
	}
	return empty
}

// ListRemoteTargets - gets target(s) for this bucket
func (adm *AdminClient) ListRemoteTargets(ctx context.Context, bucket, arnType string) (targets []BucketTarget, err error) {
	queryValues := url.Values{}
	queryValues.Set("bucket", bucket)
	queryValues.Set("type", arnType)

	reqData := requestData{
		relPath:     adminAPIPrefix + "/list-remote-targets",
		queryValues: queryValues,
	}

	// Execute GET on /minio/admin/v3/list-remote-targets
	resp, err := adm.executeMethod(ctx, http.MethodGet, reqData)

	defer closeResponse(resp)
	if err != nil {
		return targets, err
	}

	if resp.StatusCode != http.StatusOK {
		return targets, httpRespToErrorResponse(resp)
	}

	b, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return targets, err
	}
	if err = json.Unmarshal(b, &targets); err != nil {
		return targets, err
	}
	return targets, nil
}

// SetRemoteTarget sets up a remote target for this bucket
func (adm *AdminClient) SetRemoteTarget(ctx context.Context, bucket string, target *BucketTarget) (string, error) {
	data, err := json.Marshal(target)
	if err != nil {
		return "", err
	}
	encData, err := EncryptData(adm.getSecretKey(), data)
	if err != nil {
		return "", err
	}
	queryValues := url.Values{}
	queryValues.Set("bucket", bucket)

	reqData := requestData{
		relPath:     adminAPIPrefix + "/set-remote-target",
		queryValues: queryValues,
		content:     encData,
	}

	// Execute PUT on /minio/admin/v3/set-remote-target to set a target for this bucket of specific arn type.
	resp, err := adm.executeMethod(ctx, http.MethodPut, reqData)

	defer closeResponse(resp)
	if err != nil {
		return "", err
	}

	if resp.StatusCode != http.StatusOK {
		return "", httpRespToErrorResponse(resp)
	}
	b, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return "", err
	}
	var arn string
	if err = json.Unmarshal(b, &arn); err != nil {
		return "", err
	}
	return arn, nil
}

// RemoveRemoteTarget removes a remote target associated with particular ARN for this bucket
func (adm *AdminClient) RemoveRemoteTarget(ctx context.Context, bucket, arn string) error {
	queryValues := url.Values{}
	queryValues.Set("bucket", bucket)
	queryValues.Set("arn", arn)

	reqData := requestData{
		relPath:     adminAPIPrefix + "/remove-remote-target",
		queryValues: queryValues,
	}

	// Execute PUT on /minio/admin/v3/remove-remote-target to remove a target for this bucket
	// with specific ARN
	resp, err := adm.executeMethod(ctx, http.MethodDelete, reqData)
	defer closeResponse(resp)
	if err != nil {
		return err
	}

	if resp.StatusCode != http.StatusNoContent {
		return httpRespToErrorResponse(resp)
	}
	return nil
}