// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package event

import (
	"encoding/json"
	"encoding/xml"
)

// Name - event type enum.
// Refer http://docs.aws.amazon.com/AmazonS3/latest/dev/NotificationHowTo.html#notification-how-to-event-types-and-destinations
// for most basic values we have since extend this and its not really much applicable other than a reference point.
// "s3:Replication:OperationCompletedReplication" is a MinIO extension.
type Name int

// Values of event Name
const (
	// Single event types (does not require expansion)

	ObjectAccessedGet Name = 1 + iota
	ObjectAccessedGetRetention
	ObjectAccessedGetLegalHold
	ObjectAccessedHead
	ObjectAccessedAttributes
	ObjectCreatedCompleteMultipartUpload
	ObjectCreatedCopy
	ObjectCreatedPost
	ObjectCreatedPut
	ObjectCreatedPutRetention
	ObjectCreatedPutLegalHold
	ObjectCreatedPutTagging
	ObjectCreatedDeleteTagging
	ObjectRemovedDelete
	ObjectRemovedDeleteMarkerCreated
	ObjectRemovedNoOP
	BucketCreated
	BucketRemoved
	ObjectReplicationFailed
	ObjectReplicationComplete
	ObjectReplicationMissedThreshold
	ObjectReplicationReplicatedAfterThreshold
	ObjectReplicationNotTracked
	ObjectRestorePost
	ObjectRestoreCompleted
	ObjectTransitionFailed
	ObjectTransitionComplete
	ObjectManyVersions
	PrefixManyFolders

	objectSingleTypesEnd
	// Start Compound types that require expansion:

	ObjectAccessedAll
	ObjectCreatedAll
	ObjectRemovedAll
	ObjectReplicationAll
	ObjectRestoreAll
	ObjectTransitionAll
	ObjectScannerAll
	Everything
)

// The number of single names should not exceed 64.
// This will break masking. Use bit 63 as extension.
var _ = uint64(1 << objectSingleTypesEnd)

// Expand - returns expanded values of abbreviated event type.
func (name Name) Expand() []Name {
	switch name {

	case ObjectAccessedAll:
		return []Name{
			ObjectAccessedGet, ObjectAccessedHead,
			ObjectAccessedGetRetention, ObjectAccessedGetLegalHold, ObjectAccessedAttributes,
		}
	case ObjectCreatedAll:
		return []Name{
			ObjectCreatedCompleteMultipartUpload, ObjectCreatedCopy,
			ObjectCreatedPost, ObjectCreatedPut,
			ObjectCreatedPutRetention, ObjectCreatedPutLegalHold,
			ObjectCreatedPutTagging, ObjectCreatedDeleteTagging,
		}
	case ObjectRemovedAll:
		return []Name{
			ObjectRemovedDelete,
			ObjectRemovedDeleteMarkerCreated,
			ObjectRemovedNoOP,
		}
	case ObjectReplicationAll:
		return []Name{
			ObjectReplicationFailed,
			ObjectReplicationComplete,
			ObjectReplicationNotTracked,
			ObjectReplicationMissedThreshold,
			ObjectReplicationReplicatedAfterThreshold,
		}
	case ObjectRestoreAll:
		return []Name{
			ObjectRestorePost,
			ObjectRestoreCompleted,
		}
	case ObjectTransitionAll:
		return []Name{
			ObjectTransitionFailed,
			ObjectTransitionComplete,
		}
	case ObjectScannerAll:
		return []Name{
			ObjectManyVersions,
			PrefixManyFolders,
		}
	case Everything:
		res := make([]Name, objectSingleTypesEnd-1)
		for i := range res {
			res[i] = Name(i + 1)
		}
		return res
	default:
		return []Name{name}
	}
}

// Mask returns the type as mask.
// Compound "All" types are expanded.
func (name Name) Mask() uint64 {
	if name < objectSingleTypesEnd {
		return 1 << (name - 1)
	}
	var mask uint64
	for _, n := range name.Expand() {
		mask |= 1 << (n - 1)
	}
	return mask
}

// String - returns string representation of event type.
func (name Name) String() string {
	switch name {
	case BucketCreated:
		return "s3:BucketCreated:*"
	case BucketRemoved:
		return "s3:BucketRemoved:*"
	case ObjectAccessedAll:
		return "s3:ObjectAccessed:*"
	case ObjectAccessedGet:
		return "s3:ObjectAccessed:Get"
	case ObjectAccessedGetRetention:
		return "s3:ObjectAccessed:GetRetention"
	case ObjectAccessedGetLegalHold:
		return "s3:ObjectAccessed:GetLegalHold"
	case ObjectAccessedHead:
		return "s3:ObjectAccessed:Head"
	case ObjectAccessedAttributes:
		return "s3:ObjectAccessed:Attributes"
	case ObjectCreatedAll:
		return "s3:ObjectCreated:*"
	case ObjectCreatedCompleteMultipartUpload:
		return "s3:ObjectCreated:CompleteMultipartUpload"
	case ObjectCreatedCopy:
		return "s3:ObjectCreated:Copy"
	case ObjectCreatedPost:
		return "s3:ObjectCreated:Post"
	case ObjectCreatedPut:
		return "s3:ObjectCreated:Put"
	case ObjectCreatedPutTagging:
		return "s3:ObjectCreated:PutTagging"
	case ObjectCreatedDeleteTagging:
		return "s3:ObjectCreated:DeleteTagging"
	case ObjectCreatedPutRetention:
		return "s3:ObjectCreated:PutRetention"
	case ObjectCreatedPutLegalHold:
		return "s3:ObjectCreated:PutLegalHold"
	case ObjectRemovedAll:
		return "s3:ObjectRemoved:*"
	case ObjectRemovedDelete:
		return "s3:ObjectRemoved:Delete"
	case ObjectRemovedDeleteMarkerCreated:
		return "s3:ObjectRemoved:DeleteMarkerCreated"
	case ObjectRemovedNoOP:
		return "s3:ObjectRemoved:NoOP"
	case ObjectReplicationAll:
		return "s3:Replication:*"
	case ObjectReplicationFailed:
		return "s3:Replication:OperationFailedReplication"
	case ObjectReplicationComplete:
		return "s3:Replication:OperationCompletedReplication"
	case ObjectReplicationNotTracked:
		return "s3:Replication:OperationNotTracked"
	case ObjectReplicationMissedThreshold:
		return "s3:Replication:OperationMissedThreshold"
	case ObjectReplicationReplicatedAfterThreshold:
		return "s3:Replication:OperationReplicatedAfterThreshold"
	case ObjectRestoreAll:
		return "s3:ObjectRestore:*"
	case ObjectRestorePost:
		return "s3:ObjectRestore:Post"
	case ObjectRestoreCompleted:
		return "s3:ObjectRestore:Completed"
	case ObjectTransitionAll:
		return "s3:ObjectTransition:*"
	case ObjectTransitionFailed:
		return "s3:ObjectTransition:Failed"
	case ObjectTransitionComplete:
		return "s3:ObjectTransition:Complete"
	case ObjectManyVersions:
		return "s3:Scanner:ManyVersions"
	case PrefixManyFolders:
		return "s3:Scanner:BigPrefix"
	}

	return ""
}

// MarshalXML - encodes to XML data.
func (name Name) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
	return e.EncodeElement(name.String(), start)
}

// UnmarshalXML - decodes XML data.
func (name *Name) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
	var s string
	if err := d.DecodeElement(&s, &start); err != nil {
		return err
	}

	eventName, err := ParseName(s)
	if err != nil {
		return err
	}

	*name = eventName
	return nil
}

// MarshalJSON - encodes to JSON data.
func (name Name) MarshalJSON() ([]byte, error) {
	return json.Marshal(name.String())
}

// UnmarshalJSON - decodes JSON data.
func (name *Name) UnmarshalJSON(data []byte) error {
	var s string
	if err := json.Unmarshal(data, &s); err != nil {
		return err
	}

	eventName, err := ParseName(s)
	if err != nil {
		return err
	}

	*name = eventName
	return nil
}

// ParseName - parses string to Name.
func ParseName(s string) (Name, error) {
	switch s {
	case "s3:BucketCreated:*":
		return BucketCreated, nil
	case "s3:BucketRemoved:*":
		return BucketRemoved, nil
	case "s3:ObjectAccessed:*":
		return ObjectAccessedAll, nil
	case "s3:ObjectAccessed:Get":
		return ObjectAccessedGet, nil
	case "s3:ObjectAccessed:GetRetention":
		return ObjectAccessedGetRetention, nil
	case "s3:ObjectAccessed:GetLegalHold":
		return ObjectAccessedGetLegalHold, nil
	case "s3:ObjectAccessed:Head":
		return ObjectAccessedHead, nil
	case "s3:ObjectAccessed:Attributes":
		return ObjectAccessedAttributes, nil
	case "s3:ObjectCreated:*":
		return ObjectCreatedAll, nil
	case "s3:ObjectCreated:CompleteMultipartUpload":
		return ObjectCreatedCompleteMultipartUpload, nil
	case "s3:ObjectCreated:Copy":
		return ObjectCreatedCopy, nil
	case "s3:ObjectCreated:Post":
		return ObjectCreatedPost, nil
	case "s3:ObjectCreated:Put":
		return ObjectCreatedPut, nil
	case "s3:ObjectCreated:PutRetention":
		return ObjectCreatedPutRetention, nil
	case "s3:ObjectCreated:PutLegalHold":
		return ObjectCreatedPutLegalHold, nil
	case "s3:ObjectCreated:PutTagging":
		return ObjectCreatedPutTagging, nil
	case "s3:ObjectCreated:DeleteTagging":
		return ObjectCreatedDeleteTagging, nil
	case "s3:ObjectRemoved:*":
		return ObjectRemovedAll, nil
	case "s3:ObjectRemoved:Delete":
		return ObjectRemovedDelete, nil
	case "s3:ObjectRemoved:DeleteMarkerCreated":
		return ObjectRemovedDeleteMarkerCreated, nil
	case "s3:ObjectRemoved:NoOP":
		return ObjectRemovedNoOP, nil
	case "s3:Replication:*":
		return ObjectReplicationAll, nil
	case "s3:Replication:OperationFailedReplication":
		return ObjectReplicationFailed, nil
	case "s3:Replication:OperationCompletedReplication":
		return ObjectReplicationComplete, nil
	case "s3:Replication:OperationMissedThreshold":
		return ObjectReplicationMissedThreshold, nil
	case "s3:Replication:OperationReplicatedAfterThreshold":
		return ObjectReplicationReplicatedAfterThreshold, nil
	case "s3:Replication:OperationNotTracked":
		return ObjectReplicationNotTracked, nil
	case "s3:ObjectRestore:*":
		return ObjectRestoreAll, nil
	case "s3:ObjectRestore:Post":
		return ObjectRestorePost, nil
	case "s3:ObjectRestore:Completed":
		return ObjectRestoreCompleted, nil
	case "s3:ObjectTransition:Failed":
		return ObjectTransitionFailed, nil
	case "s3:ObjectTransition:Complete":
		return ObjectTransitionComplete, nil
	case "s3:ObjectTransition:*":
		return ObjectTransitionAll, nil
	case "s3:Scanner:ManyVersions":
		return ObjectManyVersions, nil
	case "s3:Scanner:BigPrefix":
		return PrefixManyFolders, nil
	default:
		return 0, &ErrInvalidEventName{s}
	}
}